Rapid and Rigorous IL-17A Production by a Distinct Subpopulation of Effector Memory T Lymphocytes Constitutes a Novel Mechanism of Toxic Shock Syndrome Immunopathology

Toxic shock syndrome (TSS) is caused by staphylococcal and streptococcal superantigens (SAgs) that provoke a swift hyperinflammatory response typified by a cytokine storm. The precipitous decline in the host's clinical status and the lack of targeted therapies for TSS emphasize the need to identify key players of the storm's initial wave. Using a humanized mouse model of TSS and human cells, we herein demonstrate that SAgs elicit in vitro and in vivo IL-17A responses within hours. SAg-triggered human IL-17A production was characterized by remarkably high mRNA stability for this cytokine. A distinct subpopulation of CD4+ effector memory T (TEM) cells that secrete IL-17A, but not IFN-γ, was responsible for early IL-17A production. We found mouse "TEM-17" cells to be enriched within the intestinal epithelium and among lamina propria lymphocytes. Furthermore, interfering with IL-17A receptor signaling in human PBMCs attenuated the expression of numerous inflammatory mediators implicated in the TSS-associated cytokine storm. IL-17A receptor blockade also abrogated the secondary effect of SAg-stimulated PBMCs on human dermal fibroblasts as judged by C/EBP δ expression. Finally, the early IL-17A response to SAgs was pathogenic because in vivo neutralization of IL-17A in humanized mice ameliorated hepatic and intestinal damage and reduced mortality. Together, our findings identify CD4+ TEM cells as a key effector of TSS and reveal a novel role for IL-17A in TSS immunopathogenesis. Our work thus elucidates a pathogenic, as opposed to protective, role for IL-17A during Gram-positive bacterial infections. Accordingly, the IL-17-IL-17R axis may provide an attractive target for the management of SAg-mediated illnesses.

Chronic expression of interferon-gamma leads to murine autoimmune cholangitis with a female predominance

In most autoimmune diseases the serologic hallmarks of disease precede clinical pathology by years. Therefore, the use of animal models in defining early disease events becomes critical. We took advantage of a "designer" mouse with dysregulation of interferon gamma (IFNγ) characterized by prolonged and chronic expression of IFNγ through deletion of the IFNγ 3'-untranslated region adenylate uridylate-rich element (ARE). The ARE-Del(-/-) mice develop primary biliary cholangitis (PBC) with a female predominance that mimics human PBC that is characterized by up-regulation of total bile acids, spontaneous production of anti-mitochondrial antibodies, and portal duct inflammation. Transfer of CD4 T cells from ARE-Del(-/-) to B6/Rag1(-/-) mice induced moderate portal inflammation and parenchymal inflammation, and RNA sequencing of liver gene expression revealed that up-regulated genes potentially define early stages of cholangitis. Interestingly, up-regulated genes specifically overlap with the gene expression signature of biliary epithelial cells in PBC, implying that IFNγ may play a pathogenic role in biliary epithelial cells in the initiation stage of PBC. Moreover, differentially expressed genes in female mice have stronger type 1 and type 2 IFN signaling and lymphocyte-mediated immune responses and thus may drive the female bias of the disease.

CONCLUSION

Changes in IFNγ expression are critical for the pathogenesis of PBC. (Hepatology 2016;64:1189-1201).

CD4 T Cell-Derived IFN-γ Plays a Minimal Role in Control of Pulmonary Mycobacterium tuberculosis Infection and Must Be Actively Repressed by PD-1 to Prevent Lethal Disease

IFN-γ–producing CD4 T cells are required for protection against Mycobacterium tuberculosis (Mtb) infection, but the extent to which IFN-γ contributes to overall CD4 T cell-mediated protection remains unclear. Furthermore, it is not known if increasing IFN-γ production by CD4 T cells is desirable in Mtb infection. Here we show that IFN-γ accounts for only ~30% of CD4 T cell-dependent cumulative bacterial control in the lungs over the first six weeks of infection, but >80% of control in the spleen. Moreover, increasing the IFN-γ–producing capacity of CD4 T cells by ~2 fold exacerbates lung infection and leads to the early death of the host, despite enhancing control in the spleen. In addition, we show that the inhibitory receptor PD-1 facilitates host resistance to Mtb by preventing the detrimental over-production of IFN-γ by CD4 T cells. Specifically, PD-1 suppressed the parenchymal accumulation of and pathogenic IFN-γ production by the CXCR3⁺KLRG1^-CX3CR1^- subset of lung-homing CD4 T cells that otherwise mediates control of Mtb infection. Therefore, the primary role for T cell-derived IFN-γ in Mtb infection is at extra-pulmonary sites, and the host-protective subset of CD4 T cells requires negative regulation of IFN-γ production by PD-1 to prevent lethal immune-mediated pathology.

The development of novel tuberculosis vaccines has been hindered by the poor understanding of the mechanisms of host-protection. It has been long-held that IFN-γ is the principle effector of CD4 T cell-mediated resistance to Mtb infection, but Mtb-specific CD4 T cells produce low amounts of IFN-γ in vivo, leading to the possibility that increasing IFN-γ production by Th1 cells might enhance control of Mtb infection. However, the precise contribution of IFN-γ to CD4 T cell-dependent protection and the outcome of increasing IFN-γ production by CD4 T cells have not been evaluated. Here we show that IFN-γ accounts for only ~30% of the cumulative CD4 T cell-mediated reduction in lung bacterial loads over the first 1.5 months of infection. Moreover, we find that increasing the per capita production of IFN-γ by CD4 T cells leads to the early death of the host. Lastly, we show that suppression of CD4 T cell-derived IFN-γ by the inhibitory receptor PD-1 is essential to prevent lethal disease. Therefore, poor control Mtb infection does not result from defective production of IFN-γ, and strategies to selectively boost it are unwarranted. Furthermore, identifying the primary mechanisms of CD4 T cell-dependent control of Mtb infection should be a priority.

Chronic Interferon-gamma expression triggers a female bias in the development of primary biliary cholangitis

An important issue in autoimmunity research has been the ability to identify the mechanisms that link genetic susceptibility to environmental influences. In most autoimmune diseases, including primary biliary cholangitis (PBC), the serologic hallmarks of disease precede clinical pathology by years, thus making early diagnosis and potential treatment difficult if not unlikely. Thus identifying animal models that present early events becomes essential to understanding disease initiation and progression. Although murine models of PBC have been identified, there are none that fully recapitulate the human disease. Herein we have utilized a novel mouse model exhibiting dysregulation of interferon-gamma (IFNg) expression, characterized by prolonged and chronic expression of IFNg as a result of the replacement of the IFNg 3′ UTR AU-rich element with random nucleotides (designated ARE-Del−/−). These C57 BL/6 ARE-Del−/− mice develop autoimmune cholangitis with a female predominance characterized by upregulation of total serum bile acids, portal duct inflammation, spontaneous production of AMA and increased skin pigmentation. RNA seq data has revealed that female ARE-Del−/− mice have >1000 genes deferentially expressed in hepatocytes compared to control mice, including genes that represent early responses in disease progression. Furthermore, the data indicates that the Type 1 IFN pathway is also involved, implying that Type II interferon interplays with Type I IFNs in the initiation of PBC. Thus persistent IFNg expression, along with Type I and Type II IFN pathway interactions, is critical for the pathogenesis of PBC and recapitulates the sex bias observed in patients.

Aging Converts Innate B1a Cells into Potent CD8+ T Cell Inducers

B cell dysregulation in aging is thought to mostly occur in conventional B2 cells without affecting innate B1 cells. Elderly humans and mice also accumulate 4-1BBL(+)MHC class-I(Hi)CD86(Hi)B cells of unknown origin. In this article, we report that these cells, termed 4BL cells, are activated murine and possibly human B1a cells. The activation is mediated by aging human monocytes and murine peritoneal macrophages. They induce expression and activation of 4-1BBL and IFN-γR1 on B1a cells to subsequently upregulate membrane TNF-α and CD86. As a result, activated B1a/4BL cells induce expression of granzyme B in CD8(+)T cells by targeting TNFR2 via membrane TNF-α and providing costimulation with CD86. Thus, for the first time, to our knowledge, these results indicate that aging affects the function of B1a cells. Upon aging, these cells lose their tumor-supporting activity and become inducers of potentially antitumor and autoimmune CD8(+)T cells.

Surface display of glycosylated Tyrosinase related protein-2 (TRP-2) tumour antigen on Lactococcus lactis

Background

The exploitation of the surface display system of food and commensal lactic acid bacteria (LAB) for bacterial, viral, or protozoan antigen delivery has received strong interest recently. The Generally Regarded as Safe (GRAS) status of the Lactococcus lactis coupled with a non-recombinant strategy of in-trans surface display, provide a safe platform for therapeutic drug and vaccine development. However, production of therapeutic proteins fused with cell-wall anchoring motifs is predominantly limited to prokaryotic expression systems. This presents a major disadvantage in the surface display system particularly when glycosylation has been recently identified to significantly enhance epitope presentation. In this study, the glycosylated murine Tyrosinase related protein-2 (TRP-2) with the ability to anchor onto the L. lactis cell wall was produced in suspension adapted Chinese Hamster Ovary (CHO-S) cells by expressing TRP-2 fused with cell wall anchoring LysM motif (cA) at the C-terminus.

Results

A total amount of 33 μg of partially purified TRP-2-cA from ~6.0 g in wet weight of CHO-S cells was purified by His-tag affinity chromatography. The purified TRP-2-cA protein was shown to be N-glycosylated and successfully anchored to the L. lactis cell wall.

Conclusions

Thus cell surface presentation of glycosylated mammalian antigens may now permit development of novel and inexpensive vaccine platforms.

Sera from patients with active systemic lupus erythematosus patients enhance the toll-like receptor 4 response in monocyte subsets

Background

Systemic Lupus Erythematosus (SLE) is an auto-immune disease whose complex pathogenesis remains unraveled. Here we aim to explore the inflammatory ability of SLE patients’ sera upon peripheral blood (PB) monocyte subsets and myeloid dendritic cells (mDCs) obtained from healthy donors.

Methods

In this study we included 11 SLE patients with active disease (ASLE), 11 with inactive disease (ISLE) and 10 healthy controls (HC). PB from healthy donors was stimulated with patients’ sera, toll-like receptor (TLR) 4 ligand – lipopolysaccharide or both. The intracellular production of TNF-α was evaluated in classical, non-classical monocytes and mDCs, using flow cytometry. TNF-α mRNA expression was assessed in all these purified cells, after sera treatment.

Results

We found that sera of SLE patients did not change spontaneous TNF-α production by monocytes or dendritic cells. However, upon stimulation of TLR4, the presence of sera from ASLE patients, but not ISLE, significantly increased the intracellular expression of TNF-α in classical and non-classical monocytes. This ability was related to titers anti-double stranded DNA antibodies in the serum. High levels of anti-TNF-α in the patients’ sera were associated with increased TNF-α expression by co-cultured mDCs. No relationship was found with the levels of a wide variety of other pro-inflammatory cytokines. A slight increase of TNF-α mRNA expression was observed in these purified cells when they were cultured only in the presence of SLE serum.

Conclusions

Our data suggest that SLE sera induce an abnormal in vitro TLR4 response in classical and non-classical monocytes, reflected by a higher TNF-α intracellular expression. These effects may be operative in the pathogenesis of SLE.

NOS Inhibition Modulates Immune Polarization and Improves Radiation-Induced Tumor Growth Delay

Nitric oxide synthases (NOS) are important mediators of progrowth signaling in tumor cells, as they regulate angiogenesis, immune response, and immune-mediated wound healing. Ionizing radiation (IR) is also an immune modulator and inducer of wound response. We hypothesized that radiation therapeutic efficacy could be improved by targeting NOS following tumor irradiation. Herein, we show enhanced radiation-induced (10 Gy) tumor growth delay in a syngeneic model (C3H) but not immunosuppressed (Nu/Nu) squamous cell carcinoma tumor-bearing mice treated post-IR with the constitutive NOS inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME). These results suggest a requirement of T cells for improved radiation tumor response. In support of this observation, tumor irradiation induced a rapid increase in the immunosuppressive Th2 cytokine IL10, which was abated by post-IR administration of L-NAME. In vivo suppression of IL10 using an antisense IL10 morpholino also extended the tumor growth delay induced by radiation in a manner similar to L-NAME. Further examination of this mechanism in cultured Jurkat T cells revealed L-NAME suppression of IR-induced IL10 expression, which reaccumulated in the presence of exogenous NO donor. In addition to L-NAME, the guanylyl cyclase inhibitors ODQ and thrombospondin-1 also abated IR-induced IL10 expression in Jurkat T cells and ANA-1 macrophages, which further suggests that the immunosuppressive effects involve eNOS. Moreover, cytotoxic Th1 cytokines, including IL2, IL12p40, and IFNγ, as well as activated CD8(+) T cells were elevated in tumors receiving post-IR L-NAME. Together, these results suggest that post-IR NOS inhibition improves radiation tumor response via Th1 immune polarization within the tumor microenvironment.

Impact of dietary components on NK and Treg cell function for cancer prevention

An important characteristic of cancer is that the disease can overcome the surveillance of the immune system. A possible explanation for this resistance arises from the ability of tumor cells to block the tumoricidal activity of host immune cells such as natural killer (NK) cells by inducing the localized accumulation of regulatory T (Treg) cells. Evidence exists that components in commonly consumed foods including vitamins A, D, and E, water-soluble constituents of mushrooms, polyphenolics in fruits and vegetables, and n-3 fatty acids in fish oil can modulate NK cell activities, Treg cell properties, and the interactions between those two cell types. Thus, it is extremely important for cancer prevention to understand the involvement of dietary components with the early stage dynamics of interactions among these immune cells. This review addresses the potential significance of diet in supporting the function of NK cells, Treg cells, and the balance between those two cell types, which ultimately results in decreased cancer risk.

Does the microbiota play a role in the pathogenesis of autoimmune diseases?

The microbiota of the human metaorganism is not a mere bystander. These microbes have coevolved with us and are pivotal to normal development and homoeostasis. Dysbiosis of the GI microbiota is associated with many disease susceptibilities, including obesity, malignancy, liver disease and GI pathology such as IBD. It is clear that there is direct and indirect crosstalk between this microbial community and host immune response. However, the precise mechanism of this microbial influence in disease pathogenesis remains elusive and is now a major research focus. There is emerging literature on the role of the microbiota in the pathogenesis of autoimmune disease, with clear and increasing evidence that changes in the microbiota are associated with some of these diseases. Examples include type 1 diabetes, coeliac disease and rheumatoid arthritis, and these contribute significantly to global morbidity and mortality. Understanding the role of the microbiota in autoimmune diseases may offer novel insight into factors that initiate and drive disease progression, stratify patient risk for complications and ultimately deliver new therapeutic strategies. This review summarises the current status on the role of the microbiota in autoimmune diseases.

Interferons: Success in anti-viral immunotherapy

The interferons (IFNs) are glycoproteins with strong antiviral activities that represent one of the first lines of host defense against invading pathogens. These proteins are classified into three groups, Type I, II and III IFNs, based on the structure of their receptors on the cell surface. Due to their ability to modulate immune responses, they have become attractive therapeutic options to control chronic virus infections. In combination with other drugs, Type I IFNs are considered as "standard of care" in suppressing Hepatitis C (HCV) and Hepatitis B (HBV) infections, while Type III IFN has generated encouraging results as a treatment for HCV infection in phase III clinical trials. However, though effective, using IFNs as a treatment is not without the need for caution. IFNs are such powerful cytokines that affect a wide array of cell types; as a result, patients usually experience unpleasant symptoms, with a percentage of patients suffering system wide effects. Thus, constant monitoring is required for patients treated with IFN in order to reach the treatment goals of suppressing virus infection and maintaining quality of life.

Impaired HCV clearance in HIV/HCV coinfected subjects treated with PegIFN and RBV due to interference of IFN signaling by IFNαR2a

Enhanced endogenous interferon (IFN) stimulated gene (ISG) signature has been associated with nonresponsiveness to hepatitis C treatment using pegylated-IFNα (pegIFNα) and ribavirin (RBV) in human immunodeficiency virus/hepatitis C virus (HIV/HCV) coinfected patients. Using a proteomic approach, we identified high levels of IFNα receptor 2a (IFNαR2a) in the serum of null responders to pegIFNα/RBV. IFNαR2a inhibited antiviral activity of all formulations of IFNα in JFH/Huh7.5 cells. Furthermore, serum from null responders, but not from those who achieved sustained virologic response, suppressed IFN-signaling and ISG expression in IFNα-stimulated PBMCs of healthy donors in an IFNαR2a specific fashion. An IFNαR2a transgenic mice model (C57BL/6) was generated that had significantly higher levels of IFNαR2a in the serum than the controls (P=0.001). Total ISG expression in the lymph nodes was significantly higher compared to wild-type mice (P value=0.0016). In addition, IFITM1 and SP110 had significantly increased expression in the liver, IFITM1 and ISG15 in the lymph node, and ISG15 and PLSCR1 in the spleen (P value<0.05). The underlying mechanism of resistance to hepatitis C treatment may involve transsignaling of the JAK/STAT pathway by the sIFNαR2a-IFNα/β complex and result in the enhanced ISG signature observed in null responders. In this regard, the transgenic mice model simulated nonresponders to IFNα therapy and provides valuable insights into the role of sIFNαR2a-IFNα interactions in vivo.

Caffeine can decrease subjective energy depending on the vehicle with which it is consumed and when it is measured

RATIONALE

Energy drinks contain glucose and caffeine, although in the longer term both adversely influence blood glucose homeostasis, with the unconsidered potential to have adverse consequences for cognition and mood.

OBJECTIVE

The objective of this study was to consider the influence on interstitial glucose levels, mood and cognition of drinks differing in their caffeine content and glycaemic load.

METHODS

Ninety minutes after a standard breakfast, a yoghurt-, glucose- or water-based drink, with or without 80 mg of caffeine, was consumed.

RESULTS

The consumption of caffeine negatively influenced glucose homeostasis: that is, irrespective of the vehicle, caffeine consumption resulted in elevated levels of blood glucose throughout the study. Thirty minutes after consuming caffeine and water, rather than water alone, greater subjective energy was reported. However, after 90 and 150 min, caffeine administered in water increased tiredness, hostility and confusion. In contrast, combining caffeine with a yoghurt-based drink increased energy, agreeableness and clearheadedness later in the morning. There were no effects of caffeine on ratings of mood when it was taken with glucose. Caffeine, irrespective of vehicle, resulted in better memory, quicker reaction times in the choice reaction time test and the working memory task, and better and quicker responses with the vigilance task.

CONCLUSION

Further research should consider how caffeine interacts with macronutrients and the timescale over which such effects occur.

The pivotal role of IKKα in the development of spontaneous lung squamous cell carcinomas

Here, we report that kinase-dead IKKα knockin mice develop spontaneous lung squamous cell carcinomas (SCCs) associated with IKKα downregulation and marked pulmonary inflammation. IKKα reduction upregulated the expression of p63, Trim29, and keratin 5 (K5), which serve as diagnostic markers for human lung SCCs. IKKα(low)K5(+)p63(hi) cell expansion and SCC formation were accompanied by inflammation-associated deregulation of oncogenes, tumor suppressors, and stem cell regulators. Reintroducing transgenic K5.IKKα, depleting macrophages, and reconstituting irradiated mutant animals with wild-type bone marrow (BM) prevented SCC development, suggesting that BM-derived IKKα mutant macrophages promote the transition of IKKα(low)K5(+)p63(hi) cells to tumor cells. This mouse model resembles human lung SCCs, sheds light on the mechanisms underlying lung malignancy development, and identifies targets for therapy of lung SCCs.

Molecular pathways: toll-like receptors in the tumor microenvironment--poor prognosis or new therapeutic opportunity

Numerous reports have described Toll-like receptor (TLR) expression in the tumor microenvironment as it relates to cancer progression, as well as their involvement in inflammation. While TLRs mediate immune surveillance, clinical studies have associated TLR expression in the tumor with poor patient survival, indicating that TLR expression may affect cancer treatment and survival. This review will examine mechanisms in which TLR activation upregulates protumorigenic pathways, including the induction of inducible nitric oxide synthase (iNOS2) and COX2, which in turn increase TLR expression and promote a feed-forward loop leading to tumor progression and the development of more aggressive tumor phenotypes. These propagating loops involve cancer cell, stroma, and/or immune cell TLR expression. Because of abundant TLR expression in many human tumors, several TLR agonists are now in clinical and preclinical trials and some have shown enhanced efficacy when used as adjuvant with radiation, chemotherapy, or cancer vaccines. These findings suggest that TLR expression influences cancer biology and therapeutic response, which may involve specific interactions within the tumor microenvironment, including mediators of inflammation such as nitric oxide and the arachidonic acid signaling pathways.

Interferon-β therapy prolongs survival in rhesus macaque models of Ebola and Marburg hemorrhagic fever

There is a clear need for novel, effective therapeutic approaches to hemorrhagic fever due to filoviruses. Ebola virus hemorrhagic fever is associated with robust interferon (IFN)-α production, with plasma concentrations of IFN-α that greatly (60- to 100-fold) exceed those seen in other viral infections, but little IFN-β production. While all of the type I IFNs signal through the same receptor complex, both quantitative and qualitative differences in biological activity are observed after stimulation of the receptor complex with different type I IFNs. Taken together, this suggested potential for IFN-β therapy in filovirus infection. Here we show that early postexposure treatment with IFN-β significantly increased survival time of rhesus macaques infected with a lethal dose of Ebola virus, although it failed to alter mortality. Early treatment with IFN-β also significantly increased survival time after Marburg virus infection. IFN-β may have promise as an adjunctive postexposure therapy in filovirus infection.

Progression of chronic liver inflammation and fibrosis driven by activation of c-JUN signaling in Sirt6 mutant mice

The human body has a remarkable ability to regulate inflammation, a biophysical response triggered by virus infection and tissue damage. Sirt6 is critical for metabolism and lifespan; however, its role in inflammation is unknown. Here we show that Sirt6-null (Sirt6(-/-)) mice developed chronic liver inflammation starting at ∼2 months of age, and all animals were affected by 7-8 months of age. Deletion of Sirt6 in T cells or myeloid-derived cells was sufficient to induce liver inflammation and fibrosis, albeit to a lesser degree than that in the global Sirt6(-/-) mice, suggesting that Sirt6 deficiency in the immune cells is the cause. Consistently, macrophages derived from the bone marrow of Sirt6(-/-) mice showed increased MCP-1, IL-6, and TNFα expression levels and were hypersensitive to LPS stimulation. Mechanistically, SIRT6 interacts with c-JUN and deacetylates histone H3 lysine 9 (H3K9) at the promoter of proinflammatory genes whose expression involves the c-JUN signaling pathway. Sirt6-deficient macrophages displayed hyperacetylation of H3K9 and increased occupancy of c-JUN in the promoter of these genes, leading to their elevated expression. These data suggest that Sirt6 plays an anti-inflammatory role in mice by inhibiting c-JUN-dependent expression of proinflammatory genes.

Interleukin-18 in pulmonary inflammatory diseases

The proinflammatory cytokine interleukin (IL)-18 was originally discovered as an interferon-γ-inducing factor in 1995. IL-18 is known to play an important role in Th1/Tc1 polarization and promoting the production of Th2 cytokines (e.g., IL-4, IL-5, IL-9, and IL-13) by T cells, NK cells, basophils, and mast cells. IL-18 can act as a cofactor for Th2 cell development and IgE production, and also plays an important role in the differentiation of Th17 cells. IL-18 is a key player in the pathogenesis of inflammatory diseases such as atopic dermatitis, rheumatoid arthritis, adult-onset Still's disease, Sjögren's syndrome, and inflammatory bowel diseases. Furthermore, many lines of evidence suggest that IL-18 plays a key role in the pathogenesis of pulmonary inflammatory diseases, including bronchial asthma and chronic obstructive pulmonary disease. Here, we review the pathological roles of IL-18 in pulmonary inflammatory diseases.

MCP-1/CCR2 interactions direct migration of peripheral B and T lymphocytes to the thymus during acute infectious/inflammatory processes

Mature lymphocyte immigration into the thymus has been documented in mouse, rat, and pig models, and highly increases when cells acquire an activated phenotype. Entrance of peripheral B and T cells into the thymus has been described in healthy and pathological situations. However, it has not been proposed that leukocyte recirculation to the thymus could be a common feature occurring during the early phase of a Th1 inflammatory/infectious process when a large number of peripheral cells acquire an activated phenotype and the cellularity of the thymus is seriously compromised. The data we present here demonstrate that in well-established Th1 models triggered by different types of immunogens, for example, LPS treatment (a bacterial product), Candida albicans infection (a fungus), and after Trypanosoma cruzi infection (a parasite), a large number of mature peripheral B and T cells enter the thymus. This effect is dependent on, but not exclusive of, the available space in the thymus. Our data also demonstrate that MCP-1/CCR2 (where MCP-1 is monocyte chemoattractant protein-1) interaction is responsible for the infiltration of peripheral cells to the thymus in these Th1-inflammatory/infectious situations. Finally, systemic expression of IL-12 and IL-18 produced during the inflammatory process is ultimately responsible for these migratory events.

Abstract 2560: IKKα inactivation predisposes to spontaneous lung squamous cell carcinomas

Lung cancer is the leading cause of cancer deaths worldwide. To advance the understanding of this disease, various genetically engineered and chemical induced mouse models have been established. However, most animal models resemble human lung adenocarcinoma, and spontaneous lung squamous cell carcinomas (SCCs) mouse models are very rare. Here, we generated Ikkα-KA/KA knock-in mice (KA/KA) in which an ATP binding site of IKKα, Lys 44 was replaced by alanine. The knock-in mice develop severe skin lesions and begin to die after 6 months. We found lung SCCs in some of the mice. To study lung SCC development, we decided to stabilize the skin condition by reintroducing transgenic IKKα by crossing KA/KA with Lori.IKKα transgenic mice to generate KA/KA/Lori.IKKα (KA/KAL) mice. Almost all the KA/KAL (100%) mice at 4 to 6 months of age developed spontaneous lethal lung SCCs. The endogenous IKKα protein level generally markedly declined in an age dependent manner in these IKKα mutant mice. Progenitor cell related markers Sox2, OCT3/4 and Nanog were only increased in the lung SCC tissue but not in the tumor adjacent tissues, implying the involvement of cancer stem cells in lung SCC. Furthermore, we detected substantial increases in Ras and CyclinD1 levels and EGFR, ERK and p38 activities in lung SCCs. On the other hand, we detected reduction in tumor suppressor gene Rb and IαBβ accompanying with reduced IKKα levels in KA/KAL lungs as well as in lung SCCs. Importantly, we observed a similar alteration pattern in mouse and human lung SCCs. Finally, reintroducing IKKα into lung epithelial cells prevented lung SCC development in mice. Collectively, our study supports the tumor suppressing role of IKKα in lung tumorigenesis. This novel lung SCC mouse model may facilitate investigations in pathogenesis, diagnosis, and treatment of human lung SCC disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2560. doi:1538-7445.AM2012-2560

The successful use of cardiopulmonary support for a transected bronchus

A 20-year-old male was involved in a motor vehicle accident and computed tomography revealed a completely transected right mainstem bronchus. An Emergency Department (ED) right anterior thoracotomy was necessary soon after arrival at our institution secondary to acute desaturation that was unresponsive to ventilator and chest tube management. This allowed direct intubation and ventilation of the right middle and lower lobes directly through the thoracotomy incision, which stabilized the patient for transport to the operating room. Once there, percutaneous cardiopulmonary support (CPS) was initiated to allow primary surgical repair of the transected bronchus. Post surgery, the patient was transported to the surgical intensive care unit on CPS which he required for an additional two days. The patient eventually did well and was discharged home. To our knowledge this is the first successful reported case of using the Avalon Elite dual lumen veno-venous cannula for CPS in a patient with complete right main-stem bronchus transection and bilateral pulmonary contusions.

In vivo consequences of liver-specific interleukin-22 expression in mice: Implications for human liver disease progression

Interleukin-22 (IL-22), which acts as either a proinflammatory or anti-inflammatory cytokine in various disease models, is markedly up-regulated in chronic liver diseases, including hepatitis B and C. In this report, we demonstrate a strong correlation between IL-22 expression in the liver with active, inflammatory human liver disease. To clarify the role of IL-22 up-regulation in the pathogenesis of liver diseases, liver-specific IL-22 transgenic (IL-22TG) mice, under the control of albumin promoter, were developed. Despite elevated IL-22 serum levels ranging from 4,000 to 7,000 pg/mL, IL-22TG mice developed normally without obvious adverse phenotypes or evidence of chronic inflammation (except for slightly thicker epidermis and minor inflammation of the skin) compared with wild-type mice. Interestingly, IL-22TG mice were completely resistant to concanavalin A-induced T cell hepatitis with minimal effect on liver inflammation and had accelerated liver regeneration after partial hepatectomy. Although they did not spontaneously develop liver tumors, IL-22TG mice were more susceptible to diethylnitrosamine-induced liver cancer. Microarray analyses revealed that a variety of antioxidant, mitogenic, acute phase genes were up-regulated in the livers of IL-22TG mice compared with those from wild-type mice.

CONCLUSION

These findings indicate that localized production of IL-22 in the liver promotes hepatocyte survival and proliferation but primes the liver to be more susceptible to tumor development without significantly affecting liver inflammation.

Gut microbiota and probiotics in colon tumorigenesis

The human gastrointestinal tract harbors a complex and abundant microbial community reaching as high as 10(13)-10(14) microorganisms in the colon. This endogenous microbiota forms a symbiotic relationship with their eukaryotic host and this close partnership helps maintain homeostasis by performing essential and non-redundant tasks (e.g. nutrition/energy and, immune system balance, pathogen exclusion). Although this relationship is essential and beneficial to the host, various events (e.g. infection, diet, stress, inflammation) may impact microbial composition, leading to the formation of a dysbiotic microbiota, further impacting on health and disease states. For example, Crohn's disease and ulcerative colitis, collectively termed inflammatory bowel diseases (IBD), have been associated with the establishment of a dysbiotic microbiota. In addition, extra-intestinal disorders such as obesity and metabolic syndrome are also associated with the development of a dysbiotic microbiota. Consequently, there is an increasing interest in harnessing the power of the microbiome and modulating its composition as a means to alleviate intestinal pathologies/disorders and maintain health status. In this review, we will discuss the emerging relationship between the microbiota and development of colorectal cancer as well as present evidence that microbial manipulation (probiotic, prebiotic) impacts disease development.

Cutting edge: Ku70 is a novel cytosolic DNA sensor that induces type III rather than type I IFN

Cytosolic foreign DNA is detected by pattern recognition receptors and mainly induces type I IFN production. We found that transfection of different types of DNA into various untreated cells induces type III IFN (IFN-λ1) rather than type I IFN, indicating the presence of uncharacterized DNA sensor(s). A pull-down assay using cytosolic proteins identified that Ku70 and Ku80 are the DNA-binding proteins. The knockdown studies and the reporter assay revealed that Ku70 is a novel DNA sensor inducing the IFN-lambda1 activation. The functional analysis of IFNL1 promoter revealed that positive-regulatory domain I and IFN-stimulated response element sites are predominantly involved in the DNA-mediated IFNL1 activation. A pull-down assay using nuclear proteins demonstrated that the IFN-λ1 induction is associated with the activation of IFN regulatory factor-1 and -7. Thus, to our knowledge, we show for the first time that Ku70 mediates type III IFN induction by DNA.

Localized delivery of interferon-β by Lactobacillus exacerbates experimental colitis

Background

There have been conflicting reports of the role of Type I interferons (IFN) in inflammatory bowel disease (IBD). Clinical trials have shown potent efficacy of systemic interferon-beta (IFN-β) in inducing remission of ulcerative colitis. Likewise, IFNAR1^−/− mice display an increased sensitivity to dextran sulfate sodium (DSS)-induced colitis, suggesting Type I IFN play a protective role during inflammation of the gut. Curiously, however, there have also been reports detailing the spontaneous development of IBD in patients receiving systemic IFN-β therapy for multiple sclerosis or hepatitis.

Methodology/Principal Findings

To investigate the effects of local administration of IFN-β on a murine model of colitis, we developed a transgenic Lactobacillus acidophilus strain that constitutively expresses IFN-β (La-IFN-β). While pretreatment of mice with control Lactobacillus (La-EV) provided slight protective benefits, La-IFN-β increased sensitivity to DSS. Analysis showed colitic mice pretreated with La-IFN-β had increased production of TNF-α, IFN-γ, IL-17A and IL-13 by intestinal tissues and decreased regulatory T cells (Tregs) in their small intestine. Examination of CD103⁺ dendritic cells (DCs) in the Peyer's patches revealed that IFNAR1 expression was dramatically reduced by La-IFN-β. Similarly, bone marrow-derived DCs matured with La-IFN-β experienced a 3-fold reduction of IFNAR1 and were impaired in their ability to induce Tregs.

Conclusions/Significance

Our IFNAR1 expression data identifies a correlation between the loss/downregulation of IFNAR1 on DCs and exacerbation of colitis. Our data show that Lactobacillus secreting IFN-β has an immunological effect that in our model results in the exacerbation of colitis. This study underscores that the selection of therapeutics delivered by a bacterial vehicle must take into consideration the simultaneous effects of the vehicle itself.

A novel role for IL-22R1 as a driver of inflammation

The interleukin (IL)-22R1 chain of the heterodimeric IL-22 receptor is not expressed on normal leukocytes, but this receptor is expressed on T cells from anaplastic lymphoma kinase-positive (ALK(+)) anaplastic large cell lymphoma (ALCL) patients. To investigate the consequences of aberrant expression of this receptor on lymphocytes, we generated transgenic mice that express IL-22R1 on lymphocytes. The health of these animals progressively deteriorated at 8 to 12 weeks of age, as they displayed respiratory distress, rough coat and sluggish movement, and subsequent lethality due to multiorgan inflammation. The IL-22R1 transgenic animals developed neutrophilia that correlated with increased levels of circulating IL-17 and granulocyte colony-stimulating factor. In addition, these mice had increased serum IL-22 levels, suggesting that T cells expressing IL-22R1 generate IL-22 in a positive autoregulatory loop. As a result of the mouse model findings, we analyzed circulating cytokine levels in ALK(+)ALCL patients and detected elevated levels of IL-22, IL-17, and IL-8 in untreated patient samples. Importantly, IL-22 and IL-17 were undetectable in all patients who were in complete remission after chemotherapy. This study documents a previously unknown role of IL-22R1 in inflammation and identifies the involvement of IL-22R1/IL-22 in ALK(+)ALCL.

Probiotics: from bench to market

"Probiotics: From Bench to Market" was a one-day conference convened by the New York Academy of Sciences on June 11, 2010, with the goal of stimulating discussion of the physiological effects of probiotics on the gastrointestinal, nervous, and immune systems. The program included speakers from academia, industry, and government to give conference participants a full understanding of the state of the field of probiotics. The overall goal of the program was to increase communication and collaboration among these groups to advance probiotic research and probiotic contributions to public health. The conference was divided into three sessions and included both oral and visual presentations as well as panel discussions.

Interleukin-26: an IL-10-related cytokine produced by Th17 cells

IL-26 is classified as a member of the IL-10 cytokine family because it has limited sequence homology to IL-10 and the IL-10-related cytokines. The human IL-26 gene, IL26, is located on chromosome 12q15 between the genes for two other important class-2 cytokines, IFNG (IFN-γ) and IL22 (IL-22). IL-26 is often co-expressed with IL-22 by activated T cells, especially Th17 cells. It signals through a heterodimeric receptor complex composed of the IL-20R1 and IL-10R2 chains. IL-26 receptors are primarily expressed on non-hematopoietic cell types, particularly epithelial cells. Signaling through IL-26 receptor complexes results in the activation of STAT1 and STAT3 with subsequent induction of IL-26-responsive genes. The biological functions of IL-26 have only begun to be defined.

Clinical Use of Interferon-gamma

Interferon gamma (IFN-gamma), a pleotropic cytokine, has been shown to be important to the function of virtually all immune cells and both innate and adaptive immune responses. In 1986, early clinical trials of this cytokine began to evaluate its therapeutic potential. The initial studies focused on the tolerability and pharmacology of IFN-gamma and systematically determined its antitumor and anti-infection activities. In the 20-plus years since those first trials, IFN-gamma has been used in a wide variety of clinical indications, which are reviewed in this article.

An overview of cytokines and cytokine antagonists as therapeutic agents

Cytokine-based therapies have the potential to provide novel treatments for cancer, autoimmune diseases, and many types of infectious disease. However, to date, the full clinical potential of cytokines as drugs has been limited by a number of factors. To discuss these limitations and explore ways to overcome them, the FDA partnered with the New York Academy of Sciences in March 2009 to host a two-day forum to discuss more effective ways to harness the clinical potential of cytokines and cytokine antagonists as therapeutic agents. The first day was focused primarily on the use of recombinant cytokines as therapeutic agents for treatment of human diseases. The second day focused largely on the use of cytokine antagonists as therapeutic agents for treatment of human diseases. This issue of the Annals includes more than a dozen papers that summarize much of the information that was presented during this very informative two-day conference.

Lentiviral gene transduction in human and mouse NK cell lines

Natural killer (NK) cells play a vital role in the control of cancer and microbial infections. A major hinderance in studying NK cells is the resistance of these cells to gene transfer. Considering over-expression and gene knockdown studies are crucial tools to study the biology of cells, technologies suitable for transferring genes into NK cells are invaluable. Among various technologies available for gene transfer, lentiviral-mediated transduction has been successful in introducing genes into NK cells. We have standardized methods of lentiviral infection in human and mouse NK cell lines. We obtain transduction efficiencies of 15% in the NK-92 cell line and 30-40% in LNK, YT, and DERL7 cell lines. This method allows efficient and stable introduction of genes and shRNAs into NK cell lines.

Role of proinflammatory cytokines IL-18 and IL-1beta in bleomycin-induced lung injury in humans and mice

Administration of several chemotherapeutic drugs, such as bleomycin, busulfan, and gefitinib, often induces lethal lung injury. However, the precise mechanisms responsible for this drug-induced lung injury are still unclear. In the present study, we examined the role of the proinflammatory cytokines IL-18 and IL-1beta in the mechanism of bleomycin-induced lung injury. We performed immunohistochemical analysis of IL-18 and IL-18 receptor (R) alpha chain expression in the lungs of five patients with bleomycin-induced lethal lung injury. Enhanced expression of both IL-18 and IL-18Ralpha was observed in the lungs of all five patients with bleomycin-induced lung injury. To support the data obtained from patient samples, the levels of IL-1beta and IL-18 mRNA and protein, pulmonary inflammation, and lung fibrosis were examined in mouse models of bleomycin-induced lung injury. Intravenous administration of bleomycin induced the expression of IL-1beta and IL-18 in the serum and lungs of wild-type C57BL/6 mice. IL-18-producing F4/80(+) neutrophils, but not CD3(+) T cells, were greatly increased in the lungs of treated mice. Moreover, bleomycin-induced lung injury was significantly attenuated in caspase-1(-/-), IL-18(-/-), and IL-18Ralpha(-/-) mice in comparison with control mice. Thus, our results provide evidence for an important role of IL-1beta and IL-18 in chemotherapy-induced lung injury.

Coexpression of IL-18 strongly attenuates IL-12-induced systemic toxicity through a rapid induction of IL-10 without affecting its antitumor capacity

IL-12 is an excellent candidate for the treatment of cancer due to its ability to drive strong antitumor responses. Recombinant IL-12 protein is currently used in cancer patients; however, systemic expression of rIL-12 presents disadvantages including cost and dose limitation due to its toxicity. In this study, we used hydrodynamic shear of cDNA as a tool to achieve systemic expression of IL-12. We found that sustained but toxic levels of serum IL-12 could be generated in 6- to 7-wk-old B6 mice after a single injection of the cDNA. Unexpectedly, we observed that when IL-12 cDNA is coinjected with IL-18 cDNA, IL-12 antitumor activity was maintained, but there was a significant attenuation of IL-12 toxicity, as evidenced by a greater survival index and a diminution of liver enzymes (ALT and AST). Interestingly, after IL-12 plus IL-18 cDNA administration, more rapid and higher IL-10 levels were observed than after IL-12 cDNA treatment alone. To understand the mechanism of protection, we coinjected IL-12 plus IL-10 cDNAs and observed an increase in survival that correlated with diminished serum levels of the inflammatory cytokines TNF-alpha and IFN-gamma. Confirming the protective role of early IL-10 expression, we observed a significant decrease in survival in IL-10 knockout mice or IL-10R-blocked B6 mice after IL-12 plus IL-18 treatment. Thus, our data demonstrate that the high and early IL-10 expression induced after IL-12 plus IL-18 cDNA treatment is critical to rapidly attenuate IL-12 toxicity without affecting its antitumor capacity. These data could highly contribute to the design of more efficient/less toxic protocols for the treatment of cancer.

Interleukin-15 enhances proteasomal degradation of bid in normal lymphocytes: implications for large granular lymphocyte leukemias

Large granular lymphocyte (LGL) leukemia is a clonal proliferative disease of T and natural killer (NK) cells. Interleukin (IL)-15 is important for the development and progression of LGL leukemia and is a survival factor for normal NK and T memory cells. IL-15 alters expression of Bcl-2 family members, Bcl-2, Bcl-XL, Bim, Noxa, and Mcl-1; however, effects on Bid have not been shown. Using an adoptive transfer model, we show that NK cells from Bid-deficient mice survive longer than cells from wild-type control mice when transferred into IL-15-null mice. In normal human NK cells, IL-15 significantly reduces Bid accumulation. Decreases in Bid are not due to alterations in RNA accumulation but result from increased proteasomal degradation. IL-15 up-regulates the E3 ligase HDM2 and we find that HDM2 directly interacts with Bid. HDM2 suppression by short hairpin RNA increases Bid accumulation lending further support for HDM2 involvement in Bid degradation. In primary leukemic LGLs, Bid levels are low but are reversed with bortezomib treatment with subsequent increases in LGL apoptosis. Overall, these data provide a novel molecular mechanism for IL-15 control of Bid that potentially links this cytokine to leukemogenesis through targeted proteasome degradation of Bid and offers the possibility that proteasome inhibitors may aid in the treatment of LGL leukemia.

Role of micro-RNA and AU-rich elements in post-transcriptional regulation of interferon gamma (38.1)

Interferon gamma (IFN-g) is an important immunomodulatory cytokine that plays a significant role in innate and adaptive immune responses of the host. The tightly-regulated expression of this pleiotropic cytokine provides robust host protection from various infections and tumors while limiting the pathological damage to the host from the inflammatory response. Similar to many inflammatory cytokines, the IFN-g 3'UTR harbors AU-rich element (ARE), that is subjected to ARE-mediated decay (AMD). The destabilization of the mRNA by AMD results in a rapid decrease in IFN-g levels. MicroRNAs (miRNAs) are another class of RNA which have regulatory potential to impact post-transcriptional regulation of gene expression. Our study has identified a miRNA-29 binding site (BS) located at the 3' end of the 3'UTR of IFN-g. Several 3' IFN-g-UTR-mutant reporter constructs have been generated by mutating the ARE and miRNA-BS, revealing competing effects between the ARE and miRNA affecting the stability of the message. Although ARE and miRNA-BS individually inhibit translation of IFN-g, mutations of both the ARE and miRNA-BS does not result in any synergistic effect. From these results, we propose that the AMD and RISC pathways competitively interact in the post-transcriptional control of IFN-g gene expression.

Structural conservation of interferon gamma among vertebrates

Interferon gamma (IFN-gamma), being the hallmark of the T-cell T(H)1 response, has been extensively studied with respect to its expression and regulation of immune function. This gene has been extensively characterized in many mammalian species, making it one of the most widely cloned immunoregulatory genes. Recently, the gene has been identified in avian and piscine species and we have identified the gene in the frog genome. Based on these identified DNA sequences, we have constructed an evolutionary history of IFN-gamma that shows this molecule can be traced back more than 450 million years ago. Our analysis shows that type II interferon (IFN-gamma) function evolved before the tetrapod-fish split, a finding that contrasts earlier studies showing its origins in tetrapods. The IFN-gamma gene has undergone a further duplication event in teleosts after the tetrapod-fish split suggesting a specific-evolutionary adaptation in fish. The analyses of IFN-gamma, IL-22 and IL-26 genomic region in mammals, chicken, frog and fish reveal an evolutionary conservation of the loci and several regulatory elements controlling IFN-gamma gene transcription. Furthermore, across the vertebrata, the first intron of IFN-gamma gene contains a polymorphic microsatellite that has been closely correlated with disease susceptibility. Comparative-modeling of IFN-gamma structure revealed differences among the representative species but with an overall conservation of the fold, dimer interface and some interactions with the receptor. The structural and functional conservation of IFN-gamma suggests the presence of an innate, natural killer (NK) like response or even an adaptive T(H)1 immune response in lower vertebrates.

Cytokine multiplex analysis

The ability to monitor gene expression in experimental and clinical samples is an essential element of modern molecular biology and cell biology research. However with the advent of a systems biology approach toward understanding cell and cancer biology, analysis of expression of a single gene is no longer desirable. Today, multiplex analysis, where the expression of 8-100 genes can be monitored in one sample, has become a routine aspect of gene expression analysis. In this chapter the various assays systems commercially available for multiplex analysis of both RNA and protein will be discussed.

Triptolide Attenuates Endotoxin- and Staphylococcal Exotoxin-Induced T-Cell Proliferation and Production of Cytokines and Chemokines

Proinflammatory cytokines mediate the toxic effects of superantigenic staphylococcal exotoxins (SE) and bacterial lipopolysaccharide (LPS). Triptolide, an oxygenated diterpene derived from a traditional Chinese medicinal herb, Tripterygium wilfordii, inhibited SE-stimulated T-cell proliferation (by 98%) and expression of interleukin 1beta, interleukin 6, tumor necrosis factor, gamma interferon, monocyte chemotactic protein 1, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta by human peripheral blood mononuclear cells (PBMC). It also blocked the production of these cytokines and chemokines by LPS-stimulated PBMC in a dose-dependent manner. These results suggest that triptolide has potent immunosuppressive effects even counteracting the effects of superantigens and LPS. It also may be therapeutically useful for mitigating the pathogenic effects of these microbial products by downregulating the signaling pathways activated by both bacterial exotoxins and endotoxins.

Conformationally constrained analogues of diacylglycerol. 29. Cells sort diacylglycerol-lactone chemical zip codes to produce diverse and selective biological activities

Diacylglycerol-lactone (DAG-lactone) libraries generated by a solid-phase approach using IRORI technology produced a variety of unique biological activities. Subtle differences in chemical diversity in two areas of the molecule, the combination of which generates what we have termed "chemical zip codes", are able to transform a relatively small chemical space into a larger universe of biological activities, as membrane-containing organelles within the cell appear to be able to decode these "chemical zip codes". It is postulated that after binding to protein kinase C (PKC) isozymes or other nonkinase target proteins that contain diacylglycerol responsive, membrane interacting domains (C1 domains), the resulting complexes are directed to diverse intracellular sites where different sets of substrates are accessed. Multiple cellular bioassays show that DAG-lactones, which bind in vitro to PKCalpha to varying degrees, expand their biological repertoire into a larger domain, eliciting distinct cellular responses.