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Abstract: Regulatory T cells play essential roles in inducing self-tolerance by suppressing immune responses against self such as autoantigens or non-self-antigens such as tumor and pathogenic antigens. Despite the importance of CD4+ regulatory T cells in many immune-related diseases, their antigen specificity and suppressive mechanisms remain elusive. This review discusses the natural ligands and their potential roles of tumor-specific CD4+ regulatory T cells in cancer therapy. [Copyright &y& Elsevier]

Azo dyes are widely used in dye manufacturing, paper printing, textile industries, and as tattoo pigmentation. Since intestinal and skin bacteria can metabolize certain azo dyes to carcinogenic compounds, many researchers have studied the azoreductases of these bacteria. In this study, we used a microarray method to identify the intestinal bacterial species from cultured fecal samples in Brain Heart Infusion (BHI) broth with or without azo dyes that may be involved in azo dye reduction. The microarray was designed to identify 40 bacterial species that are reported in the literature to be predominant in human feces. Results from this study showed 26–30 species are present in the cultured fecal samples. The representative bacteria were then examined for the azo dye reduction activity. [Copyright &y& Elsevier]

In the last few years, a great deal of efforts have been directed towards understanding the molecular basis of T cell-mediated anti-tumor immunity and elucidating the molecular nature of tumor antigens recognized by T cells. Identification of a number of major histocompatibility complex (MHC) class I-restricted melanoma antigens has led to clinical trials aimed at developing effective cancer vaccines. These studies showed some evidence of therapeutic effect on the treatment of cancer, but the exclusive use of CD8+ T cells may not be effective in eradicating tumor. This rekindles interest in the role of CD4+ T cells in antitumor immunity, which play a central role in orchestrating the host immune response against cancer. Thus, we have attempted to identify MHC class II-restricted tumor antigens recognized by tumor-specific CD4+ T cells. The identification of tumor rejection antigens provides new opportunities for the development of therapeutic strategies against cancer. This review will summarize the current status of MHC class I and class II-restricted human tumor antigens, and their potential application to cancer treatment. [Copyright &y& Elsevier]

Vaccination with dendritic cells (DCs) pulsed with antigenic peptides derived from various tumor antigens has great, but as yet significantly unrealized, potential in cancer treatment. Here, we describe a strategy for prolonged presentation of an MHC class I-restricted self-peptide on DCs through linkage of it to a cell penetrating peptide (CPP). DCs loaded with a peptide derived from tyrosinase-related protein 2 (TRP2) covalently linked to a CPP1 sequence retained full capacity to stimulate T cells for at least 24 h, completely protected immunized mice from subsequent tumor challenge, and significantly inhibited lung metastases in a 3-day tumor model. DCs pulsed with TRP2 alone failed to provide any of these protections. In addition, we demonstrate that both CD4+ and CD8+ T cells were required for potent antitumor immunity. This CPPbased approach may be generally applicable to enhance the efficacy of DC-based peptide vaccines against cancer and other diseases. [ABSTRACT FROM AUTHOR]

Presents an approach that allows the screening of an invariant chain-complementary DNA fusion library in a genetically engineered cell line expressing the essential components of the major histocompatibility complex (MHC). Efforts to identify tumor-specific antigens recognized by CD4+T cells; Identification of a mutated form of human CDC27 protein; Development of strategies for the treatment of patients with cancer, autoimmune diseases, or infectious diseases.

Presents information on the mrsC gene of Escherichia coli which is required for mRNA turnover and cell growth. Information on cloned mrsC genes; Details on a study of the gene; Results of the study.

Over the past decade, immunotherapy has emerged as one of the most promising approaches to cancer treatment. The use of immune checkpoint inhibitors has resulted in impressive and durable clinical responses in the treatment of various cancers. Additionally, immunotherapy utilizing chimeric antigen receptor (CAR)-engineered T cells has produced robust responses in blood cancers, and T cell receptor (TCR)-engineered T cells are showing promising results in the treatment of solid cancers. Despite these noteworthy advancements in cancer immunotherapy, numerous challenges remain. Some patient populations are unresponsive to immune checkpoint inhibitor therapy, and CAR T cell therapy has yet to show efficacy against solid cancers. In this review, we first discuss the significant role that T cells play in the body's defense against cancer. We then delve into the mechanisms behind the current challenges facing immunotherapy, starting with T cell exhaustion due to immune checkpoint upregulation and changes in the transcriptional and epigenetic landscapes of dysfunctional T cells. We then discuss cancer-cell-intrinsic characteristics, including molecular alterations in cancer cells and the immunosuppressive nature of the tumor microenvironment (TME), which collectively facilitate tumor cell proliferation, survival, metastasis, and immune evasion. Finally, we examine recent advancements in cancer immunotherapy, with a specific emphasis on T-cell-based treatments. [ABSTRACT FROM AUTHOR]

Cyclic GMP‐AMP synthase (cGAS) and stimulator of interferon genes (STING) play critical roles in the innate immunity against infectious diseases and are required to link pathogen DNA sensing to immune responses. However, the mechanisms by which cGAS‐STING‐induced cytokines suppress the adaptive immune response against malaria infections remain poorly understood. Here, cGAS‐STING signaling is identified to play a detrimental role in regulating anti‐malaria immunity. cGAS or STING deficiency in mice markedly prolongs mouse survival during lethal malaria Plasmodium yoelii nigeriensis N67C infections by reducing late interleukin (IL)‐6 production. Mechanistically, cGAS/STING recruits myeloid differentiation factor 88 (MyD88) and specifically induces the p38‐dependent signaling pathway for late IL‐6 production, which, in turn, expands CD11b+Ly6Chi proinflammatory monocytes to inhibit immunity. Moreover, the blockage or ablation of the cGAS‐STING‐MyD88‐p38‐IL‐6 signaling axis or the depletion of CD11b+Ly6Chi proinflammatory monocytes provides mice a significant survival benefit during N67C and other lethal malaria‐strain infections. Taken together, these findings identify a previously unrecognized detrimental role of cGAS‐STING‐MyD88‐p38 axis in infectious diseases through triggering the late IL‐6 production and proinflammatory monocyte expansion and provide insight into how targeting the DNA sensing pathway, dysregulated cytokines, and proinflammatory monocytes enhances immunity against infection. [ABSTRACT FROM AUTHOR]

Cyclic GMP‐AMP synthase (cGAS) and stimulator of interferon genes (STING) play critical roles in the innate immunity against infectious diseases and are required to link pathogen DNA sensing to immune responses. However, the mechanisms by which cGAS‐STING‐induced cytokines suppress the adaptive immune response against malaria infections remain poorly understood. Here, cGAS‐STING signaling is identified to play a detrimental role in regulating anti‐malaria immunity. cGAS or STING deficiency in mice markedly prolongs mouse survival during lethal malaria Plasmodium yoelii nigeriensis N67C infections by reducing late interleukin (IL)‐6 production. Mechanistically, cGAS/STING recruits myeloid differentiation factor 88 (MyD88) and specifically induces the p38‐dependent signaling pathway for late IL‐6 production, which, in turn, expands CD11b+Ly6Chi proinflammatory monocytes to inhibit immunity. Moreover, the blockage or ablation of the cGAS‐STING‐MyD88‐p38‐IL‐6 signaling axis or the depletion of CD11b+Ly6Chi proinflammatory monocytes provides mice a significant survival benefit during N67C and other lethal malaria‐strain infections. Taken together, these findings identify a previously unrecognized detrimental role of cGAS‐STING‐MyD88‐p38 axis in infectious diseases through triggering the late IL‐6 production and proinflammatory monocyte expansion and provide insight into how targeting the DNA sensing pathway, dysregulated cytokines, and proinflammatory monocytes enhances immunity against infection. [ABSTRACT FROM AUTHOR]

(C) The interaction between Jmjd3 and Brg1 was determined by CoIP analysis of 293T cells expressing HA-tagged Jmjd3 and FLAG-tagged Brg1. (D) Cell-based luciferase assay was used to evaluate SP-B promoter activity in 293T cells cotransfected with Nkx2.1, Jmjd3, Brg1, and mouse SP-B promoter-linked episomal luciferase vector. (B) A cell-based luciferase assay was used to evaluate SP-B promoter activity in 293T cells cotransfected with Nkx2.1, Jmjd3, and mouse SP-B promoter-linked episomal luciferase vector (containing Nkx2.1 binding sites). [Extracted from the article]

Introduction: Visualization of tumor angiogenesis using radionuclide targeting provides important diagnostic information. In previous study, we proved that an arginine-arginine-leucine (RRL) peptide should be a tumor endothelial cell specific binding sequence. The overall aim of this study was to evaluate whether 99mTc-radiolabeled RRL could be noninvasively used for imaging of malignant tumors in vivo, and act as a new molecular probe targeting tumor angiogenesis. Methods: The RRL peptide was designed and radiosynthesized with 99mTc by a one-step method. The radiolabeling efficiency and radiochemical purity were then characterized in vitro. 99mTc-RRL was injected intravenously in HepG2 xenograft-bearing BALB/c nude mice. Biodistribution and in vivo imaging were performed periodically. The relationship between tumor size and %ID uptake of 99mTc-RRL was also explored. Results: The labeling efficiencies of 99mTc-RRL reached 76.9%±4.5% (n = 6) within 30–60 min at room temperature, and the radiochemical purity exceeded 96% after purification. In vitro stability experiment revealed the radiolabeled peptide was stable. Biodistribution data showed that 99mTc-RRL rapidly cleared from the blood and predominantly accumulated in the kidneys and tumor. The specific uptake of 99mTc-RRL in tumor was significantly higher than that of unlabeled RRL blocking and free pertechnetate control test after injection (p<0.05). The ratio of the tumor-to-muscle exceeded 6.5, tumor-to-liver reached 1.98 and tumor-to-blood reached 1.95. In planar gamma imaging study, the tumors were imaged clearly at 2–6 h after injection of 99mTc-RRL, whereas the tumor was not imaged clearly in blocking group. The tumor-to-muscle ratio of images with 99mTc-RRL was comparable with that of 18F-FDG PET images. Immunohistochemical analysis verified the excessive vasculature of tumor. There was a linear relationship between the tumor size and uptake of 99mTc-RRL with R2 = 0.821. Conclusion: 99mTc-RRL can be used as a potential candidate for visualization of tumor angiogenesis in malignant carcinomas. [ABSTRACT FROM AUTHOR]

CD4+ T cells play important roles in orchestrating host immune responses against cancer and infectious diseases. Although EBV-encoded nuclear antigen 1-specific (EBNA1-specific) CD4+ T cells have been implicated in controlling the growth of EBV-associated tumors such as Burkitt lymphoma (BL) in vitro, direct evidence for their in vivo function remains elusive due to the lack of an appropriate experimental BL model. Here, we describe the development of a mouse EBNA1-expressing BL tumor model and the identification of 2 novel MHC H-2I-A(b)-restricted T cell epitopes derived from EBNA1. Using our murine BL tumor model and the relevant peptides, we show that vaccination of mice with EBNA1 peptide-loaded DCs can elicit CD4+ T cell responses. These EBNA1-specific CD4+ T cells recognized peptide-pulsed targets as well as EBNA1-expressing tumor cells and were necessary and sufficient for suppressing tumor growth in vivo. By contrast, EBNA1 peptide-reactive CD8+ T cells failed to recognize tumor cells and did not contribute to protective immunity. These studies represent what we believe to be the first demonstration that EBNA1-specific CD4+ T cells can suppress tumor growth in vivo, which suggests that CD4+ T cells play an important role in generating protective immunity against EBV-associated cancer. [ABSTRACT FROM AUTHOR]

'Naked' nucleic acid vaccines are potentially useful candidates for the treatment of patients with cancer, but their clinical efficacy has yet to be demonstrated. We sought to enhance the immunogenicity of a nucleic acid vaccine by making it 'self-replicating'. We accomplished this by using a gene encoding an RNA replicase polyprotein derived from the Semliki forest virus, in combination with a model antigen. A single intramuscular injection of a selfreplicating RNA immunogen elicited antigen-specific antibody and CD8[sup +] T-cell responses at doses as low as 0.1 µg. Pre-immunization with a self-replicating RNA vector protected mice from tumor challenge, and therapeutic immunization prolonged the survival of mice with established tumors. The self-replicating RNA vectors did not mediate the production of substantially more model antigen than a conventional DNA vaccine did in vitro. However, the enhanced efficacy in vivo correlated with a caspase-dependent apoptotic death in transfected cells. This death facilitated the uptake of apoptotic cells by dendritic cells, providing a potential mechanism for enhanced immunogenicity. Naked, non-infectious, self-replicating RNA may be an excellent candidate for the development of new cancer vaccines. [ABSTRACT FROM AUTHOR]

Presents information on a gene identified in Escherichia coli that is required for both the normal decay of mRNA and RNA synthesis. Identification of the gene; Information on the gene; Details on a study of the gene at various temperatures; Results of the study.

Beclin 2 plays a critical role in metabolic regulation and obesity, but its functions in innate immune signaling and cancer development remain largely unknown. Here, we identified Beclin 2 as a critical negative regulator of inflammation and lymphoma development. Mice with homozygous ablation of BCL2-interacting protein 2 (Becn2) developed splenomegaly and lymphadenopathy and markedly increased ERK1/2 and NF-κB signaling for proinflammatory cytokine production. Beclin 2 targeted the key signaling kinases MEKK3 and TAK1 for degradation through an ATG9A-dependent, but ATG16L/Beclin 1/LC3-independent, autophagic pathway. Mechanistically, Beclin 2 recruited MEKK3 or TAK1 through ATG9A to form a complex (Beclin 2-ATG9A-MEKK3) on ATG9A+ vesicles upon ULK1 activation. Beclin 2 further interacted with STX5 and STX6 to promote the fusion of MEKK3- or TAK1-associated ATG9A+ vesicles to phagophores for subsequent degradation. Importantly, Becn2-deficient mice had a markedly increased incidence of lymphoma development, with persistent STAT3 activation. Myeloid-specific ablation of MEKK3 (Map3k3) completely rescued the phenotypes (splenomegaly, higher amounts of proinflammatory cytokines, and cancer incidence) of Becn2-deficient mice. Hence, our findings have identified an important role of Beclin 2 in the negative regulation of innate immune signaling and tumor development through an ATG9A-dependent, but ATG16L/Beclin 1/LC3-independent, autophagic pathway, thus providing a potential target for the treatment of inflammatory diseases and cancer. [ABSTRACT FROM AUTHOR]

Melanoma differentiation-associated gene-5 (MDA5) recognizes distinct subsets of viruses including Encephalomyocarditis virus (EMCV) of picornavirus family, but the molecular mechanisms underlying the specificity of the viral recognition of MDA5 in immune cells remain obscure. DHX29 is a RNA helicase required for the translation of 5’ structured mRNA of host and many picornaviruses (such as EMCV). We identify that DXH29 as a key RNA co-sensor, plays a significant role for specific recognition and triggering anti-EMCV immunity. We have observed that DHX29 regulates MDA5-, but not RIG-I-, mediated type I interferon signaling by preferentially interacting with structured RNAs and specifically with MDA5 for enhancing MDA5-dsRNA binding affinity. Overall, our results identify a critical role for DHX29 in innate immune response and provide molecular insights into the mechanisms by which DHX29 recognizes 5’ structured EMCV RNA and interacts with MDA5 for potent type I interferon signaling and antiviral immunity. [ABSTRACT FROM AUTHOR]

Abstract: The RIG‐I‐like receptors (RLRs) are critical for protection against RNA virus infection, and their activities must be stringently controlled to maintain immune homeostasis. Here, we report that leucine‐rich repeat containing protein 25 (LRRC25) is a key negative regulator of RLR‐mediated type I interferon (IFN) signaling. Upon RNA virus infection, LRRC25 specifically binds to ISG15‐associated RIG‐I to promote interaction between RIG‐I and the autophagic cargo receptor p62 and to mediate RIG‐I degradation via selective autophagy. Depletion of either LRRC25 or ISG15 abrogates RIG‐I‐p62 interaction as well as the autophagic degradation of RIG‐I. Collectively, our findings identify a previously unrecognized role of LRRC25 in type I IFN signaling activation by which LRRC25 acts as a secondary receptor to assist RIG‐I delivery to autophagosomes for degradation in a p62‐dependent manner. [ABSTRACT FROM AUTHOR]

Summary Type I interferon (IFN) is critical for controlling pathogen infection; however, its regulatory mechanisms in plasmacytoid cells (pDCs) still remain unclear. Here, we have shown that nucleic acid sensors cGAS-, STING-, MDA5-, MAVS-, or transcription factor IRF3-deficient mice produced high amounts of type I IFN-α and IFN-β (IFN-α/β) in the serum and were resistant to lethal plasmodium yoelii YM infection. Robust IFN-α/β production was abolished when gene encoding nucleic acid sensor TLR7, signaling adaptor MyD88, or transcription factor IRF7 was ablated or pDCs were depleted. Further, we identified SOCS1 as a key negative regulator to inhibit MyD88-dependent type I IFN signaling in pDCs. Finally, we have demonstrated that pDCs, cDCs, and macrophages were required for generating IFN-α/β-induced subsequent protective immunity. Thus, our findings have identified a critical regulatory mechanism of type I IFN signaling in pDCs and stage-specific function of immune cells in generating potent immunity against lethal YM infection. [ABSTRACT FROM AUTHOR]

Summary TBK1 is a component of the type I interferon (IFN) signaling pathway, yet the mechanisms controlling its activity and degradation remain poorly understood. Here we report that USP38 negatively regulates type I IFN signaling by targeting the active form of TBK1 for degradation in vitro and in vivo. USP38 specifically cleaves K33-linked poly-ubiquitin chains from TBK1 at Lys670, and it allows for subsequent K48-linked ubiquitination at the same position mediated by DTX4 and TRIP. Knockdown or knockout of USP38 increases K33-linked ubiquitination, but it abrogates K48-linked ubiquitination and degradation of TBK1, thus enhancing type I IFN signaling. Our findings identify an essential role for USP38 in negatively regulating type I IFN signaling, and they provide insights into the mechanisms by which USP38 regulates TBK1 ubiquitination through the NLRP4 signalosome. [ABSTRACT FROM AUTHOR]

Summary Cyclic GMP-AMP synthase (cGAS) is an essential DNA virus sensor that triggers type I interferon (IFN) signaling by producing cGAMP to initiate antiviral immunity. However, post-translational regulation of cGAS remains largely unknown. We report that K48-linked ubiquitination of cGAS is a recognition signal for p62-depdendent selective autophagic degradation. The induction of TRIM14 by type I IFN accelerates cGAS stabilization by recruiting USP14 to cleave the ubiquitin chains of cGAS at lysine (K) 414. Knockout of TRIM14 impairs herpes simplex virus type 1 (HSV-1)-triggered antiviral responses in a cGAS-dependent manner. Due to impaired type I IFN production, Trim14 − /− mice are highly susceptible to lethal HSV-1 infection. Taken together, our findings reveal a positive feedback loop of cGAS signaling generated by TRIM14-USP14 and provide insights into the crosstalk between autophagy and type I IFN signaling in innate immunity. [ABSTRACT FROM AUTHOR]

Arsenic, a common highly-toxic pollutant, is mainly associated with the hydrous ferric oxides in soils and minerals. A possible mechanism for arsenic mobilization is the reductive dissolution of iron (hydr) oxides. In this paper, the possibilities of iron-reducing bacteria Shewanella oneidensis MR-1 and Shewanella sp. strain MR-4 in mobilization, oxidization and methylation of arsenic were investigated. Under laboratory conditions, the dynamics of As- and Fe-release from arsenopyrite and scorodite under microbial activities, the transformation of arsenic release from iron minerals and the environment factors affecting the arsenic release and transformation during reactions were examined. The aqueous concentrations of different forms of As were determined by a liquid chromatography–atomic fluorescence spectrometry (LC–AFS) and the new surface morphology of iron minerals was also measured and characterized using scanning electron microscopy (SEM) and X-ray diffractometry (XRD). Results indicated that As could be dissolved from arsenopyrite or scorodite and oxidized or even methylated quickly in the presence of Shewanella strains. The transformation of arsenic forms were affected by the culture temperatures, pH of environment medium, and spiked Fe(III) content in the solutions. Moreover, solid-phase analysis revealed that the morphology and mineralogy in the solid-phase products were changed, such as many wrinkle-shaped gullies were formed on surfaces of iron minerals. The amount of secondary precipitates also increased with time. The As mobility could be enhanced by the activity of dissimilatory iron-reducing bacteria in the environment. This study provides insights into in situ remediation of As pollution. [ABSTRACT FROM AUTHOR]

Autophagy, mediated by a number of autophagy-related ( ATG) proteins, plays an important role in the bulk degradation of cellular constituents. Beclin-1 (also known as Atg6 in yeast) is a core protein essential for autophagic initiation and other biological processes. The activity of Beclin-1 is tightly regulated by multiple post-translational modifications, including ubiquitination, yet the molecular mechanism underpinning its reversible deubiquitination remains poorly defined. Here, we identified ubiquitin-specific protease 19 ( USP19) as a positive regulator of autophagy, but a negative regulator of type I interferon ( IFN) signaling. USP19 stabilizes Beclin-1 by removing the K11-linked ubiquitin chains of Beclin-1 at lysine 437. Moreover, we found that USP19 negatively regulates type I IFN signaling pathway, by blocking RIG-I- MAVS interaction in a Beclin-1-dependent manner. Depletion of either USP19 or Beclin-1 inhibits autophagic flux and promotes type I IFN signaling as well as cellular antiviral immunity. Our findings reveal novel dual functions of the USP19-Beclin-1 axis by balancing autophagy and the production of type I IFNs. [ABSTRACT FROM AUTHOR]

Immunotherapy has emerged as a promising strategy for the treatment of metastatic melanoma. Clinical studies have demonstrated the feasibility of cancer immunotherapy using tumor antigens recognized by CD8+ T cells. However, the overall immune responses induced by these antigens are too weak and transient to induce tumor regression in the majority of patients who received immunization. A growing body of evidence suggests that CD4+ T helper (Th) cells play an important role in antitumor immunity. Therefore, the identification of MHC class II-restricted tumor antigens capable of stimulating CD4+ T cells may provide opportunities for developing effective cancer vaccines. To this end, we describe the identification of developmentally regulated GTP-binding protein 1 (DRG-1) as a melanoma-associated antigen recognized by HLA-DR11-restricted CD4+ Th1 cells. Epitope mapping analysis showed that the DRG1248-268 epitope of DRG-1 was required for T cell recognition. Reverse transcription-polymerase chain reaction revealed that DRG-1 was highly expressed in melanoma cell lines but not in normal tissues. DRG-1 knockdown by lentiviral-based shRNA suppressed melanoma cell proliferation and soft agar colony formation. Taken together, these data suggest that DRG-1 plays an important role in melanoma cell growth and transformation, indicating that DRG1 may represent a novel target for CD4+ T cell-mediated immunotherapy in melanoma. [ABSTRACT FROM AUTHOR]

(B) Agarose gel electrophoresis (1.2%) exhibited a single and specific polymerase chain reaction product of each reference gene. Oncol Lett 14: 6001-6011, 2017; DOI: 10.3892/ol.2017.7002 Following the publication of the above article, the authors have realized that they inadvertently included the same data for the HSP90AB1 and ATP5B experiments shown in Fig. [Extracted from the article]

Histone demethylases have emerged as important players in developmental processes. Jumonji domain containing-3 (Jmjd3) has been identified as a key histone demethylase that plays a critical role in the regulation of gene expression; however, the in vivo function of Jmjd3 in embryonic development remains largely unknown. To this end, we generated Jmjd3 global and conditional knockout mice. Global deletion of Jmjd3 induces perinatal lethality associated with defective lung development. Tissue and stage-specific deletion revealed that Jmjd3 is dispensable in the later stage of embryonic lung development. Jmjd3 ablation downregulates the expression of genes critical for lung development and function, including AQP-5 and SP-B. Jmjd3-mediated alterations in gene expression are associated with locus-specific changes in the methylation status of H3K27 and H3K4. Furthermore, Jmjd3 is recruited to the SP-B promoter through interactions with the transcription factor Nkx2.1 and the epigenetic protein Brg1. Taken together, these findings demonstrate that Jmjd3 plays a stage-dependent and locus-specific role in the mouse lung development. Our study provides molecular insights into the mechanisms by which Jmjd3 regulates target gene expression in the embryonic stages of lung development. [ABSTRACT FROM AUTHOR]

Objective: The α7 nicotinic acetylcholine receptors (nAChRs) play a vital role in the pathophysiology of neuropsychiatric diseases such as Alzheimer’s disease and depression. However, there is currently no suitable positron emission tomography (PET) or Single-Photon Emission Computed Tomography (SPECT) radioligands for imaging α7 nAChRs in brain. Here our aim is to radiosynthesize a novel SPECT radioligand 131I-CHIBA-1001 for whole body biodistribution study and in vivo imaging of α7 nAChRs in brain. Method: 131I-CHIBA-1001 was radiosynthesized by chloramine-T method. Different conditions of reaction time and temperature were tested to get a better radiolabeling yield. Radiolabeling yield and radiochemical purities of 131I-CHIBA-1001 were analyzed by thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) system. Whole body biodistribution study was performed at different time points post injection of 131I-CHIBA-1001 in KM mice. Monkey subject was used for in vivo SPECT imaging in brain. Result: The radiolabeling yield of 131I-CHIBA-1001 reached 96% within 1.5∼2.0 h at 90∼95°C. The radiochemical purity reached more than 99% after HPLC purification. 131I-CHIBA-1001 was highly stable in saline and fresh human serum in room temperature and 37°C separately. The biodistribution data of brain at 15, 30, and 60 min were 11.05±1.04%ID/g, 8.8±0.04%ID/g and 6.28±1.13%ID/g, respectively. In experimental SPECT imaging, the distribution of radioactivity in the brain regions was paralleled with the distribution of α7 nAChRs in the monkey brain. Moreover, in the blocking SPECT imaging study, the selective α7 nAChR agonist SSR180711 blocked the radioactive uptake in the brain successfully. Conclusion: The CHIBA-1001 can be successfully radiolabeled with 131I using the chloramine-T method. 131I-CHIBA-1001 can successfully accumulate in the monkey brain and image the α7 acetylcholine receptors. 131I-CHIBA-1001 can be a candidate for imagingα7 acetylcholine receptors, which will be of great value for the diagnosis and treatment of mental diseases. [ABSTRACT FROM AUTHOR]

Summary: Although somatic cell reprogramming to generate inducible pluripotent stem cells (iPSCs) is associated with profound epigenetic changes, the roles and mechanisms of epigenetic factors in this process remain poorly understood. Here, we identify Jmjd3 as a potent negative regulator of reprogramming. Jmjd3-deficient MEFs produced significantly more iPSC colonies than did wild-type cells, whereas ectopic expression of Jmjd3 markedly inhibited reprogramming. We show that the inhibitory effects of Jmjd3 are produced through both histone demethylase-dependent and -independent pathways. The latter pathway involves Jmjd3 targeting of PHF20 for ubiquitination and degradation via recruitment of an E3 ligase, Trim26. Importantly, PHF20-deficient MEFs could not be converted to fully reprogrammed iPSCs, even with knockdown of Jmjd3, Ink4a, or p21, indicating that PHF20 is required for reprogramming. Our findings demonstrate, to the best of our knowledge, a previously unrecognized role of Jmjd3 in cellular reprogramming and provide molecular insight into the mechanisms by which the Jmjd3-PHF20 axis controls this process. [Copyright &y& Elsevier]

Background: A large number of human tumor-associated antigens that are recognized by CD8+ T cells in a human leukocyte antigen class I (HLA-I)-restricted fashion have been identified. Special AT-rich sequence binding protein 1 (SATB1) is highly expressed in many types of human cancers as part of their neoplastic phenotype, and up-regulation of SATB1 expression is essential for tumor survival and metastasis, thus this protein may serve as a rational target for cancer vaccines. Methodology/Principal Findings: Twelve SATB1-derived peptides were predicted by an immuno-informatics approach based on the HLA-A*02 binding motif. These peptides were examined for their ability to induce peptide-specific T cell responses in peripheral blood mononuclear cells (PBMCs) obtained from HLA-A*02+ healthy donors and/or HLA-A*02+ cancer patients. The recognition of HLA-A*02+ SATB1-expressing cancer cells was also tested. Among the twelve SATB1-derived peptides, SATB1565–574 frequently induced peptide-specific T cell responses in PBMCs from both healthy donors and cancer patients. Importantly, SATB1565–574-specific T cells recognized and killed HLA-A*02+ SATB1+ cancer cells in an HLA-I-restricted manner. Conclusions/Significance: We have identified a novel HLA-A*02-restricted SATB1-derived peptide epitope recognized by CD8+ T cells, which, in turn, recognizes and kills HLA-A*02+ SATB1+ tumor cells. The SATB1-derived epitope identified may be used as a diagnostic marker as well as an immune target for development of cancer vaccines. [ABSTRACT FROM AUTHOR]

Background: Prostate cancer is the most common cancer among elderly men in the US, and immunotherapy has been shown to be a promising strategy to treat patients with metastatic castration-resistant prostate cancer. Efforts to identify novel prostate specific tumor antigens will facilitate the development of effective cancer vaccines against prostate cancer. Prostate-specific G-protein coupled receptor (PSGR) is a novel antigen that has been shown to be specifically over-expressed in human prostate cancer tissues. In this study, we describe the identification of PSGR-derived peptide epitopes recognized by CD8+ T cells in an HLA-A2 dependent manner. Methodology/Principal Findings: Twenty-one PSGR-derived peptides were predicted by an immuno-informatics approach based on the HLA-A2+ binding motif. These peptides were examined for their ability to induce peptide-specific T cell responses in peripheral blood mononuclear cells (PBMCs) obtained from either HLA-A2+ healthy donors or HLA- A2+ prostate cancer patients. The recognition of HLA-A2 positive and PSGR expressing LNCaP cells was also tested. Among the 21 PSGR-derived peptides, three peptides, PSGR3, PSGR4 and PSGR14 frequently induced peptide-specific T cell responses in PBMCs from both healthy donors and prostate cancer patients. Importantly, these peptide-specific T cells recognized and killed LNCaP prostate cancer cells in an HLA class I-restricted manner. Conclusions/Significance: We have identified three novel HLA-A2-restricted PSGR-derived peptides recognized by CD8+ T cells, which, in turn, recognize HLA-A2+ and PSGR+ tumor cells. The PSGR-derived peptides identified may be used as diagnostic markers as well as immune targets for development of anticancer vaccines. [ABSTRACT FROM AUTHOR]

Summary: Stringent control of NF-κB and mitogen-activated protein kinase (MAPK) signaling is critical during innate immune responses. TGF-β activated kinase-1 (TAK1) is essential for NF-κB activation in T and B cells but has precisely the opposite activity in myeloid cells. Specific deletion of TAK1 (Map3k7 ΔM/ΔM) led to development of splenomegaly and lymphomegaly associated with neutrophilia. Compared with wild-type cells, TAK1-deficient neutrophils enhanced the phosphorylation of the kinases IKK, p38, and JNK and the production of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), and reactive oxygen species (ROS) after lipopolysaccharide (LPS) stimulation. Map3k7 ΔM/ΔM mice were significantly more susceptible to LPS-induced septic shock and produced higher amounts of IL-1β, IL-6, and TNF-α in plasma than do wild-type mice. Specific ablation of p38 rescued the phenotype and functional properties of Map3k7 ΔM/ΔM mice. Our findings identify a previously unrecognized role of TAK1 as a negative regulator of p38 and IKK activation in a cell type-specific manner. [ABSTRACT FROM AUTHOR]

Summary: Tight regulation of NF-κB signaling is essential for innate and adaptive immune responses, yet the molecular mechanisms responsible for its negative regulation are not completely understood. Here, we report that NLRX1, a NOD-like receptor family member, negatively regulates Toll-like receptor-mediated NF-κB activation. NLRX1 interacts with TRAF6 or IκB kinase (IKK) in an activation signal-dependent fashion. Upon LPS stimulation, NLRX1 is rapidly ubiquitinated, disassociates from TRAF6, and then binds to the IKK complex, resulting in inhibition of IKKα and IKKβ phosphorylation and NF-κB activation. Knockdown of NLRX1 in various cell types markedly enhances IKK phosphorylation and the production of NF-κB-responsive cytokines after LPS stimulation. We further provide in vivo evidence that NLRX1 knockdown in mice markedly enhances susceptibility to LPS-induced septic shock and plasma IL-6 level. Our study identifies a previously unrecognized role for NLRX1 in the negative regulation of TLR-induced NF-κB activation by dynamically interacting with TRAF6 and the IKK complex. [ABSTRACT FROM AUTHOR]

Summary: Stringent control of the NF-κB and type I interferon signaling pathways is critical to effective host immune responses, yet the molecular mechanisms that negatively regulate these pathways are poorly understood. Here, we show that NLRC5, a member of the highly conserved NOD-like protein family, can inhibit the IKK complex and RIG-I/MDA5 function. NLRC5 inhibited NF-κB-dependent responses by interacting with IKKα and IKKβ and blocking their phosphorylation. It also interacted with RIG-I and MDA5, but not with MAVS, to inhibit RLR-mediated type I interferon responses. Consistent with these observations, NLRC5-specific siRNA knockdown not only enhanced the activation of NF-κB and its responsive genes, TNF-α and IL-6, but also promoted type I interferon signaling and antiviral immunity. Our findings identify NLRC5 as a negative regulator that blocks two central components of the NF-κB and type I interferon signaling pathways and suggest an important role for NLRC5 in homeostatic control of innate immunity. [ABSTRACT FROM AUTHOR]

Summary: γδ T cells are important contributors to innate immunity against cancer, but their regulatory role in controlling immune responses remains largely unknown. Here we report that a dominant γδ1 T cell population among lymphocytes infiltrating breast tumors possessed a potent ability to suppress naive and effector T cell responses and to block the maturation and function of dendritic cells. Adoptive cotransfer experiments demonstrated their in vivo suppressive activity. However, their immunosuppressive activity could be reversed by human Toll-like receptor (TLR) 8 ligands both in vitro and in vivo. siRNA-mediated knockdown experiments revealed that MyD88, TRAF6, IKKα IKKβ, and p38α molecules in γδ1 cells were required for these cells to respond to TLR8 ligands, whereas TAK1, JNK, and ERK molecules did not appear to be involved in functional regulation. These results provide new insights into the regulatory mechanisms of tumor-specific γδ T cells and identify a unique TLR8 signaling pathway linking to their functional regulation. [Copyright &y& Elsevier]

CD4[sup +] regulatory T (Treg) cells have a profound ability to suppress host immune responses, yet little is understood about how these cells are regulated. We describe a mechanism linking Toll-like receptor (TLR) 8 signaling to the control of Treg cell function, in which synthetic and natural ligands for human TLR8 can reverse Treg cell function. This effect was independent of dendritic cells but required functional TLR8-MyD88-IRAK4 signaling in Treg cells. Adoptive transfer of TLR8 ligand-stimulated Treg cells into tumor-bearing mice enhanced antitumor immunity. These results suggest that TLR8 signaling could play a critical role in controlling immune responses to cancer and other diseases. [ABSTRACT FROM AUTHOR]

Regulatory T cells play an important role in the maintenance of immunological self-tolerance by suppressing immune responses against autoimmune diseases and cancer. Little is known, however, about the nature of the physiological target antigens for CD4+ regulatory T (Treg) cells. Here we report the identification of the LAGE1 protein as a ligand for tumor-specific CD4+ Treg cell clones generated from the tumor-infiltrating lymphocytes (TILs) of cancer patients. Phenotypic and functional analyses demonstrated that they were antigen-specific CD4+ Treg cells expressing CD25 and GITR molecules and possessing suppressive activity on the proliferative response of naive CD4+ T cells to anti-CD3 antibody stimulation. Ligand-specific activation and cell-cell contact were required for TIL102 Treg cells to exert suppressive activity on CD4+ effector cells. These findings suggest that the presence of tumor-specific CD4+ Treg cells at tumor sites may have a profound effect on the inhibition of T cell responses against cancer. [Copyright &y& Elsevier]

Dendritic cell-based (DC-based) immunotherapy represents a promising approach to the prevention and treatment of many diseases, including cancer, but current strategies have met with only limited success in clinical and preclinical studies. Previous studies have demonstrated that a TAT peptide derived from the HIV TAT protein has the ability to transduce peptides or proteins into various cells. Here, we describe the use of TAT-mediated delivery of T cell peptides into DCs to prolong antigen presentation and enhance T cell responses. While immunization of mice with DCs pulsed with an antigenic peptide derived from the human TRP2 protein generated partial protective immunity against B16 tumor, immunization with DCs loaded with a TAT-TRP2 peptide resulted in complete protective immunity, as well as significant inhibition of lung metastases in a 3-day tumor model. Although both DC/TRP2 and DC/TAT-TRP2 immunization increased the number of TRP2-specific CD8(+) T cells detected by K(b)/TRP2 tetramers, T cell activity elicited by DC/TAT-TRP2 was three- to tenfold higher than that induced by DC/TRP2. Furthermore, both CD4(+) and CD8(+) T cells were required for antitumor immunity demonstrated by experiments with antibody depletion of subsets of T cells, as well as with various knockout mice. These results suggest that a TAT-mediated antigen delivery system may have important clinical applications for cancer therapy. [ABSTRACT FROM AUTHOR]

Development of central nervous system (CNS) is regulated by both intrinsic and peripheral signals. Previous studies have suggested that environmental factors affect neurological activities under both physiological and pathological conditions. Although there is anatomical separation, emerging evidence has indicated the existence of bidirectional interaction between gut microbiota, i.e., (diverse microorganisms colonizing human intestine), and brain. The cross-talk between gut microbiota and brain may have crucial impact during basic neurogenerative processes, in neurodegenerative disorders and tumors of CNS. In this review, we discuss the biological interplay between gut-brain axis, and further explore how this communication may be dysregulated in neurological diseases. Further, we highlight new insights in modification of gut microbiota composition, which may emerge as a promising therapeutic approach to treat CNS disorders. [ABSTRACT FROM AUTHOR]

Summary Mitochondrial antiviral signaling platform protein (MAVS) acts as a central hub for RIG-I receptor proximal signal propagation. However, key components in the assembly of the MAVS mitochondrial platform that promote RIG-I mitochondrial localization and optimal activation are still largely undefined. Employing pooled RNAi and yeast two-hybrid screenings, we report that the mitochondrial adaptor protein tripartite motif (TRIM)14 provides a docking platform for the assembly of the mitochondrial signaling complex required for maximal activation of RIG-I-mediated signaling, consisting of WHIP and protein phosphatase PPP6C. Following viral infection, the ubiquitin-binding domain in WHIP bridges RIG-I with MAVS by binding to polyUb chains of RIG-I at lysine 164. The ATPase domain in WHIP contributes to stabilization of the RIG-I-dsRNA interaction. Moreover, phosphatase PPP6C is responsible for RIG-I dephosphorylation. Together, our findings define the WHIP-TRIM14-PPP6C mitochondrial signalosome required for RIG-I-mediated innate antiviral immunity. [ABSTRACT FROM AUTHOR]

Nuclear factor κB (NF-κB) is a key transcription factor in inflammatory immune responses and cell survival. Multiple types of ubiquitination play critical roles in the activation of NF-κB signaling, yet the molecular mechanisms responsible for their reversible deubiquitination are still poorly understood. In this study, we identified a member of the deubiquitinases family, ubiquitin-specific protease 18 (USP18), as a novel negative regulator in Toll-like receptor (TLR)-mediated NF-κB activation in human macrophages. USP18 is an interferon inducible gene, which is also upregulated by various TLR ligands in human monocytes and macrophages. Knockdown of USP18 enhanced the phosphorylation of IKK, the degradation of IκB, and augmented the expression of pro-inflammatory cytokines. Furthermore, USP18 interacted with TAK1-TAB1 complex and IKKα/β-NEMO complex, respectively. USP18 cleaved the K63-linked polyubiquitin chains attached to TAK1 in a protease-dependent manner. Moreover, USP18 targeted the IKK complex through the regulatory subunit NEMO of IKK, and specifically inhibited K63-linked ubiquitination of NEMO. Mutation analysis revealed direct binding of USP18 to the UBAN motif of NEMO. Our study has identified a previously unrecognized role for USP18 in the negative regulation of NF-κB activation by inhibiting K63-linked ubiquitination of TAK1 and NEMO through distinct mechanisms. [ABSTRACT FROM AUTHOR]