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Sample records for mhc ii-positive apcs

  1. CD4+ T cell-mediated rejection of MHC class II-positive tumor cells is dependent on antigen secretion and indirect presentation on host APCs.

    Science.gov (United States)

    Haabeth, Ole Audun Werner; Fauskanger, Marte; Manzke, Melanie; Lundin, Katrin U; Corthay, Alexandre; Bogen, Bjarne; Tveita, Anders Aune

    2018-05-11

    Tumor-specific CD4+ T cells have been shown to mediate efficient anti-tumor immune responses against cancer. Such responses can occur through direct binding to MHC class II (MHC II)-expressing tumor cells or indirectly via activation of professional antigen-presenting cells (APC) that take up and present the tumor antigen. We have previously shown that CD4+ T cells reactive against an epitope within the Ig light chain variable region of a murine B cell lymphoma can reject established tumors. Given the presence of MHC II molecules at the surface of lymphoma cells, we investigated whether MHC II-restricted antigen presentation on tumor cells alone was required for rejection. Variants of the A20 B lymphoma cell line that either secreted or intracellularly retained different versions of the tumor-specific antigen revealed that antigen secretion by the MHC II-expressing tumor cells was essential both for the priming and effector phase of CD4+ T cell-driven anti-tumor immune responses. Consistent with this, genetic ablation of MHC II in tumor cells, both in the case of B lymphoma and B16 melanoma, did not preclude rejection of tumors by tumor antigen-specific CD4+ T cells in vivo. These findings demonstrate that MHC class II expression on tumor cells themselves is not required for CD4+ T cell-mediated rejection, and that indirect display on host APC is sufficient for effective tumor elimination. These results support the importance of tumor-infiltrating APC as mediators of tumor cell killing by CD4+ T cells. Copyright ©2018, American Association for Cancer Research.

  2. Distribution of CD163-positive cell and MHC class II-positive cell in the normal equine uveal tract.

    Science.gov (United States)

    Sano, Yuto; Matsuda, Kazuya; Okamoto, Minoru; Takehana, Kazushige; Hirayama, Kazuko; Taniyama, Hiroyuki

    2016-02-01

    Antigen-presenting cells (APCs) in the uveal tract participate in ocular immunity including immune homeostasis and the pathogenesis of uveitis. In horses, although uveitis is the most common ocular disorder, little is known about ocular immunity, such as the distribution of APCs. In this study, we investigated the distribution of CD163-positive and MHC II-positive cells in the normal equine uveal tract using an immunofluorescence technique. Eleven eyes from 10 Thoroughbred horses aged 1 to 24 years old were used. Indirect immunofluorescence was performed using the primary antibodies CD163, MHC class II (MHC II) and CD20. To demonstrate the site of their greatest distribution, positive cells were manually counted in 3 different parts of the uveal tract (ciliary body, iris and choroid), and their average number was assessed by statistical analysis. The distribution of pleomorphic CD163- and MHC II-expressed cells was detected throughout the equine uveal tract, but no CD20-expressed cells were detected. The statistical analysis demonstrated the distribution of CD163- and MHC II-positive cells focusing on the ciliary body. These results demonstrated that the ciliary body is the largest site of their distribution in the normal equine uveal tract, and the ciliary body is considered to play important roles in uveal and/or ocular immune homeostasis. The data provided in this study will help further understanding of equine ocular immunity in the normal state and might be beneficial for understanding of mechanisms of ocular disorders, such as equine uveitis.

  3. Donor T cells primed on leukemia lysate-pulsed recipient APCs mediate strong graft-versus-leukemia effects across MHC barriers in full chimeras

    OpenAIRE

    Ghosh, Arnab; Koestner, Wolfgang; Hapke, Martin; Schlaphoff, Verena; Länger, Florian; Baumann, Rolf; Koenecke, Christian; Cornberg, Markus; Welte, Karl; Blazar, Bruce R.; Sauer, Martin G.

    2009-01-01

    Antigen-presenting cells (APCs) of host origin drive graft-versus-leukemia (GVL) effects but can also trigger life-threatening graft-versus-host disease (GVHD) after hematopoietic cell transplantation (HCT) across major histocompatibility complex (MHC) barriers. We show that in vitro priming of donor lymphocytes can circumvent the need of recipient-derived APCs in vivo for mediating robust GVL effects and significantly diminishes the risk of severe GVHD. In vitro, generated and expanded T cel...

  4. Donor T cells primed on leukemia lysate-pulsed recipient APCs mediate strong graft-versus-leukemia effects across MHC barriers in full chimeras.

    Science.gov (United States)

    Ghosh, Arnab; Koestner, Wolfgang; Hapke, Martin; Schlaphoff, Verena; Länger, Florian; Baumann, Rolf; Koenecke, Christian; Cornberg, Markus; Welte, Karl; Blazar, Bruce R; Sauer, Martin G

    2009-04-30

    Antigen-presenting cells (APCs) of host origin drive graft-versus-leukemia (GVL) effects but can also trigger life-threatening graft-versus-host disease (GVHD) after hematopoietic cell transplantation (HCT) across major histocompatibility complex (MHC) barriers. We show that in vitro priming of donor lymphocytes can circumvent the need of recipient-derived APCs in vivo for mediating robust GVL effects and significantly diminishes the risk of severe GVHD. In vitro, generated and expanded T cells (ETCs) mediate anti-leukemia effects only when primed on recipient-derived APCs. Loading of APCs in vitro with leukemia cell lysate, chimerism status of the recipient, and timing of adoptive transfer after HCT are important factors determining the outcome. Delayed transfer of ETCs resulted in strong GVL effects in leukemia-bearing full chimera (FC) and mixed chimera (MC) recipients, which were comparable with the GVL/GVHD rates observed after the transfer of naive donor lymphocyte infusion (DLI). Upon early transfer, GVL effects were more pronounced with ETCs but at the expense of significant GVHD. The degree of GVHD was most severe in MCs after transfer of ETCs that had been in vitro primed either on nonpulsed recipient-derived APCs or with donor-derived APCs.

  5. The systems biology of MHC class II antigen presentation

    NARCIS (Netherlands)

    Paul, Petra

    2012-01-01

    Major histocompatibility class II molecules (MHC class II) are one of the key regulators of adaptive immunity because of their specific expression by professional antigen presenting cells (APC). They present peptides derived from endocytosed material to T helper lymphocytes. Consequently, MHC class

  6. MHC protocols

    National Research Council Canada - National Science Library

    Powis, Stephen H; Vaughan, Robert W

    2003-01-01

    ... because it contains genes encoding components of the complement pathway. The entire human MHC has recently been sequenced (1) and each subregion is now known to contain many other genes, a number of which have immunological functions. The study of polymorphism within the MHC is well established, because the region contains the highly polymorphic HLA genes. HLA polym...

  7. MHC class II expression in lung cancer.

    Science.gov (United States)

    He, Yayi; Rozeboom, Leslie; Rivard, Christopher J; Ellison, Kim; Dziadziuszko, Rafal; Yu, Hui; Zhou, Caicun; Hirsch, Fred R

    2017-10-01

    Immunotherapy is an exciting development in lung cancer research. In this study we described major histocompatibility complex (MHC) Class II protein expression in lung cancer cell lines and patient tissues. We studied MHC Class II (DP, DQ, DR) (CR3/43, Abcam) protein expression in 55 non-small cell lung cancer (NSCLC) cell lines, 42 small cell lung cancer (SCLC) cell lines and 278 lung cancer patient tissues by immunohistochemistry (IHC). Seven (12.7%) NSCLC cell lines were positive for MHC Class II. No SCLC cell lines were found to be MHC Class II positive. We assessed 139 lung cancer samples available in the Hirsch Lab for MHC Class II. There was no positive MHC Class II staining on SCLC tumor cells. MHC Class II expression on TILs in SCLC was significantly lower than that on TILs in NSCLC (P<0.001). MHC Class II was also assessed in an additional 139 NSCLC tumor tissues from Medical University of Gdansk, Poland. Patients with positive staining of MHC Class II on TILs had longer regression-free survival (RFS) and overall survival (OS) than those whose TILs were MHC Class II negative (2.980 years, 95% CI 1.628-4.332 vs. 1.050 years, 95% CI 0.556-1.554, P=0.028) (3.230 years, 95% CI 2.617-3.843 vs. 1.390 years, 95% CI 0.629-2.151, P=0.014). MHC Class II was expressed both in NSCLC cell lines and tissues. However, MHC Class II was not detected in SCLC cell lines or tissue tumor cells. MHC Class II expression was lower on SCLC TILs than on NSCLC TILs. Loss of expression of MHC Class II on SCLC tumor cells and reduced expression on SCLC TILs may be a means of escaping anti-cancer immunity. Higher MHC Class II expression on TILs was correlated with better prognosis in patients with NSCLC. Copyright © 2017. Published by Elsevier B.V.

  8. Schwann cells promote post-traumatic nerve inflammation and neuropathic pain through MHC class II.

    Science.gov (United States)

    Hartlehnert, Maike; Derksen, Angelika; Hagenacker, Tim; Kindermann, David; Schäfers, Maria; Pawlak, Mathias; Kieseier, Bernd C; Meyer Zu Horste, Gerd

    2017-10-02

    The activation of T helper cells requires antigens to be exposed on the surface of antigen presenting cells (APCs) via MHC class II (MHC-II) molecules. Expression of MHC-II is generally limited to professional APCs, but other cell types can express MHC-II under inflammatory conditions. However, the importance of these conditional APCs is unknown. We and others have previously shown that Schwann cells are potentially conditional APCs, but the functional relevance of MHC-II expression by Schwann cells has not been studied in vivo. Here, we conditionally deleted the MHC-II β-chain from myelinating Schwann cells in mice and investigated how this influenced post-traumatic intraneural inflammation and neuropathic pain using the chronic constriction injury (CCI) model. We demonstrate that deletion of MHC-II in myelinating Schwann cells reduces thermal hyperalgesia and, to a lesser extent, also diminishes mechanical allodynia in CCI in female mice. This was accompanied by a reduction of intraneural CD4+ T cells and greater preservation of preferentially large-caliber axons. Activation of T helper cells by MHC-II on Schwann cells thus promotes post-traumatic axonal loss and neuropathic pain. Hence, we provide experimental evidence that Schwann cells gain antigen-presenting function in vivo and modulate local immune responses and diseases in the peripheral nerves.

  9. How Do CD4+ T Cells Detect and Eliminate Tumor Cells That Either Lack or Express MHC Class II Molecules?

    Science.gov (United States)

    Haabeth, Ole Audun Werner; Tveita, Anders Aune; Fauskanger, Marte; Schjesvold, Fredrik; Lorvik, Kristina Berg; Hofgaard, Peter O.; Omholt, Hilde; Munthe, Ludvig A.; Dembic, Zlatko; Corthay, Alexandre; Bogen, Bjarne

    2014-01-01

    CD4+ T cells contribute to tumor eradication, even in the absence of CD8+ T cells. Cytotoxic CD4+ T cells can directly kill MHC class II positive tumor cells. More surprisingly, CD4+ T cells can indirectly eliminate tumor cells that lack MHC class II expression. Here, we review the mechanisms of direct and indirect CD4+ T cell-mediated elimination of tumor cells. An emphasis is put on T cell receptor (TCR) transgenic models, where anti-tumor responses of naïve CD4+ T cells of defined specificity can be tracked. Some generalizations can tentatively be made. For both MHCIIPOS and MHCIINEG tumors, presentation of tumor-specific antigen by host antigen-presenting cells (APCs) appears to be required for CD4+ T cell priming. This has been extensively studied in a myeloma model (MOPC315), where host APCs in tumor-draining lymph nodes are primed with secreted tumor antigen. Upon antigen recognition, naïve CD4+ T cells differentiate into Th1 cells and migrate to the tumor. At the tumor site, the mechanisms for elimination of MHCIIPOS and MHCIINEG tumor cells differ. In a TCR-transgenic B16 melanoma model, MHCIIPOS melanoma cells are directly killed by cytotoxic CD4+ T cells in a perforin/granzyme B-dependent manner. By contrast, MHCIINEG myeloma cells are killed by IFN-γ stimulated M1-like macrophages. In summary, while the priming phase of CD4+ T cells appears similar for MHCIIPOS and MHCIINEG tumors, the killing mechanisms are different. Unresolved issues and directions for future research are addressed. PMID:24782871

  10. How do CD4+ T cells detect and eliminate tumor cells that either lack or express MHC class II molecules?

    Directory of Open Access Journals (Sweden)

    Ole Audun Werner Haabeth

    2014-04-01

    Full Text Available CD4+ T cells contribute to tumor eradication, even in the absence of CD8+ T cells. Cytotoxic CD4+ T cells can directly kill MHC class II positive tumor cells. More surprisingly, CD4+ T cells can indirectly eliminate tumor cells that lack MHC class II expression. Here, we review the mechanisms of direct and indirect CD4+ T cell-mediated elimination of tumor cells. An emphasis is put on T cell receptor (TCR transgenic models, where anti-tumor responses of naïve CD4+ T cells of defined specificity can be tracked. Some generalizations can tentatively be made. For both MHCIIPOS and MHCIINEG tumors, presentation of tumor specific antigen by host antigen presenting cells (APCs appears to be required for CD4+ T cell priming. This has been extensively studied in a myeloma model (MOPC315, where host APCs in tumor-draining lymph nodes are primed with secreted tumor antigen. Upon antigen recognition, naïve CD4+ T cells differentiate into Th1 cells and migrate to the tumor. At the tumor site, the mechanisms for elimination of MHCIIPOS and MHCIINEG tumor cells differ. In a TCR transgenic B16 melanoma model, MHCIIPOS melanoma cells are directly killed by cytotoxic CD4+ T cells in a perforin/granzyme B-dependent manner. By contrast, MHCIINEG myeloma cells are killed by IFN-g stimulated M1-like macrophages. In summary, while the priming phase of CD4+ T cells appears similar for MHCIIPOS and MHCIINEG tumors, the killing mechanisms are different. Unresolved issues and directions for future research are addressed.

  11. MHC motif viewer

    DEFF Research Database (Denmark)

    Rapin, Nicolas Philippe Jean-Pierre; Hoof, Ilka; Lund, Ole

    2008-01-01

    . Algorithms that predict which peptides MHC molecules bind have recently been developed and cover many different alleles, but the utility of these algorithms is hampered by the lack of tools for browsing and comparing the specificity of these molecules. We have, therefore, developed a web server, MHC motif....... A special viewing feature, MHC fight, allows for display of the specificity of two different MHC molecules side by side. We show how the web server can be used to discover and display surprising similarities as well as differences between MHC molecules within and between different species. The MHC motif...

  12. Dimeric MHC-peptides inserted into an immunoglobulin scaffold as new immunotherapeutic agents

    Science.gov (United States)

    Goldberg, Burt; Bona, Constantin

    2011-01-01

    Abstract The interactions of the T cell receptor (TCR) with cognate MHC-peptide and co-stimulatory molecules expressed at surface of antigen presenting cells (APC) leads to activation or tolerance of T cells. The development of molecular biological tools allowed for the preparation of soluble MHC-peptide molecules as surrogate for the APC. A decade ago a monomeric class II MHC molecule in which the peptide was covalently linked to β-chain of class II molecule was generated. This type of molecule had a low-binding affinity and did not cause the multimerization of TCR. The requirement of multimerization of TCR led to development of a new class of reagents, chimeric peptides covalently linked to MHC that was dimerized via Fc fragment of an immunoglobulin and linked to 3′ end of the β-chain of MHC class II molecule. These soluble dimerized MHC-peptide chimeric molecules display high affinity for the TCR and caused multimerization of TCR without processing by an APC. Because dimeric molecules are devoid of co-stimulatory molecules interacting with CD28, a second signal, they induce anergy rather the activation of T cells. In this review, we compare the human and murine dimerized MHC class II-peptides and their effect on CD4+ T cells, particularly the generation of T regulatory cells, which make these chimeric molecules an appealing approach for the treatment of autoimmune diseases. PMID:21435177

  13. Subepithelial myofibroblasts are novel nonprofessional APCs in the human colonic mucosa.

    Science.gov (United States)

    Saada, Jamal I; Pinchuk, Irina V; Barrera, Carlos A; Adegboyega, Patrick A; Suarez, Giovanni; Mifflin, Randy C; Di Mari, John F; Reyes, Victor E; Powell, Don W

    2006-11-01

    The human gastrointestinal mucosa is exposed to a diverse normal microflora and dietary Ags and is a common site of entry for pathogens. The mucosal immune system must respond to these diverse signals with either the initiation of immunity or tolerance. APCs are important accessory cells that modulate T cell responses which initiate and maintain adaptive immunity. The ability of APCs to communicate with CD4+ T cells is largely dependent on the expression of class II MHC molecules by the APCs. Using immunohistochemistry, confocal microscopy, and flow cytometry, we demonstrate that alpha-smooth muscle actin(+), CD90+ subepithelial myofibroblasts (stromal cells) constitutively express class II MHC molecules in normal colonic mucosa and that they are distinct from professional APCs such as macrophages and dendritic cells. Primary isolates of human colonic myofibroblasts (CMFs) cultured in vitro were able to stimulate allogeneic CD4+ T cell proliferation. This process was dependent on class II MHC and CD80/86 costimulatory molecule expression by the myofibroblasts. We also demonstrate that CMFs, engineered to express a specific DR4 allele, can process and present human serum albumin to a human serum albumin-specific and DR4 allele-restricted T cell hybridoma. These studies characterize a novel cell phenotype which, due to its strategic location and class II MHC expression, may be involved in capture of Ags that cross the epithelial barrier and present them to lamina propria CD4+ T cells. Thus, human CMFs may be important in regulating local immunity in the colon.

  14. Germline APC mutations in hepatoblastoma.

    Science.gov (United States)

    Yang, Adeline; Sisson, Rebecca; Gupta, Anita; Tiao, Greg; Geller, James I

    2018-04-01

    Conflicting reports on the frequency of germline adenomatous polyposis coli (APC) gene mutations in patients with hepatoblastoma (HB) have called into question the clinical value of APC mutation testing on apparently sporadic HB. An Institutional Review Board approved retrospective review of clinical data collected from patients with HB who received APC testing at our institution was conducted. All HB patients seen at Cincinnati Children's Hospital Medical Center were eligible for testing. Potential genotype/phenotype correlations were assessed. As of July 2015, 29 patients with HB had received constitutional APC testing. Four (14%) were found to have APC pathogenic truncations of the APC protein and in addition two (7%) had APC missense variants of unknown clinical significance. Two patients (7%) had family histories indicative of familial adenomatous polyposis (FAP). Response to chemotherapy tracked differently in APC pathogenic cases, with a slower imaging response despite an equivalent or slightly faster α-fetoprotein (AFP) response. The prevalence of pathogenic APC variants in apparently sporadic HB may be higher than previously detected. Differences in time to imaging response, despite similar AFP response, may impact surgical planning. All patients with HB warrant germline APC mutation testing for underlying FAP. © 2017 Wiley Periodicals, Inc.

  15. Immunopurification of adenomatous polyposis coli (APC) proteins

    Science.gov (United States)

    2013-01-01

    Background The adenomatous polyposis coli (APC) tumour suppressor gene encodes a 2843 residue (310 kDa) protein. APC is a multifunctional protein involved in the regulation of β-catenin/Wnt signalling, cytoskeletal dynamics and cell adhesion. APC mutations occur in most colorectal cancers and typically result in truncation of the C-terminal half of the protein. Results In order to investigate the biophysical properties of APC, we have generated a set of monoclonal antibodies which enable purification of recombinant forms of APC. Here we describe the characterisation of these anti-APC monoclonal antibodies (APC-NT) that specifically recognise endogenous APC both in solution and in fixed cells. Full-length APC(1–2843) and cancer-associated, truncated APC proteins, APC(1–1638) and APC(1–1311) were produced in Sf9 insect cells. Conclusions Recombinant APC proteins were purified using a two-step affinity approach using our APC-NT antibodies. The purification of APC proteins provides the basis for detailed structure/function analyses of full-length, cancer-truncated and endogenous forms of the protein. PMID:24156781

  16. One-pot, mix-and-read peptide-MHC tetramers

    DEFF Research Database (Denmark)

    Leisner, Christian Valdemar Vinge; Loeth, Nina; Lamberth, Kasper

    2008-01-01

    BACKGROUND: Cytotoxic T Lymphocytes (CTL) recognize complexes of peptide ligands and Major Histocompatibility Complex (MHC) class I molecules presented at the surface of Antigen Presenting Cells (APC). Detection and isolation of CTL's are of importance for research on CTL immunity, and development...... molecules can be refolded in vitro, tetramerized with streptavidin, and used for specific T cell staining-all in a one-pot reaction without any intervening purification steps. CONCLUSIONS/SIGNIFICANCE: We have developed an efficient "one-pot, mix-and-read" strategy for peptide-MHC tetramer generation...

  17. MHC and Evolution in Teleosts

    OpenAIRE

    Grimholt, Unni

    2016-01-01

    Major histocompatibility complex (MHC) molecules are key players in initiating immune responses towards invading pathogens. Both MHC class I and class II genes are present in teleosts, and, using phylogenetic clustering, sequences from both classes have been classified into various lineages. The polymorphic and classical MHC class I and class II gene sequences belong to the U and A lineages, respectively. The remaining class I and class II lineages contain nonclassical gene sequences that, de...

  18. Antigen processing of glycoconjugate vaccines; the polysaccharide portion of the pneumococcal CRM(197) conjugate vaccine co-localizes with MHC II on the antigen processing cell surface.

    Science.gov (United States)

    Lai, Zengzu; Schreiber, John R

    2009-05-21

    Pneumococcal (Pn) polysaccharides (PS) are T-independent (TI) antigens and do not induce immunological memory or antibodies in infants. Conjugation of PnPS to the carrier protein CRM(197) induces PS-specific antibody in infants, and memory similar to T-dependent (Td) antigens. Conjugates have improved immunogenicity via antigen processing and presentation of carrier protein with MHC II and recruitment of T cell help, but the fate of the PS attached to the carrier is unknown. To determine the location of the PS component of PnPS-CRM(197) in the APC, we separately labeled PS and protein and tracked their location. The PS of types 14-CRM(197) and 19F-CRM(197) was specifically labeled by Alexa Fluor 594 hydrazide (red). The CRM(197) was separately labeled red in a reaction that did not label PS. Labeled antigens were incubated with APC which were fixed, permeabilized and incubated with anti-MHC II antibody labeled green by Alexa Fluor 488, followed by confocal microscopy. Labeled CRM(197) was presented on APC surface and co-localized with MHC II (yellow). Labeled unconjugated 14 or 19F PS did not go to the APC surface, but PS labeled 14-CRM(197) and 19F-CRM(197) was internalized and co-localized with MHC II. Monoclonal antibody to type 14 PS bound to intracellular type 14 PS and PS-CRM(197). Brefeldin A and chloroquine blocked both CRM(197) and PS labeled 14-CRM(197) and 19F-CRM(197) from co-localizing with MHC II. These data suggest that the PS component of the CRM(197) glycoconjugate enters the endosome, travels with CRM(197) peptides to the APC surface and co-localizes with MHC II.

  19. Development of two distinct dendritic-like APCs in the context of splenic stroma

    Directory of Open Access Journals (Sweden)

    Pravin ePeriasamy

    2013-03-01

    Full Text Available Murine splenic stroma has been found to provide an in vitro niche for hematopoiesis of dendritic-like APCs (APC. Two distinct cell types have been characterised. The novel ‘L-DC’ subset, has cross presenting capacity leading to activation of CD8+ T cells, but do not activate CD4+ T cells consistent with their CD11cloCD11bhiMHC-II- phenotype. For L-DC, an equivalent tissue-specific APC has been found only in spleen. A second population of CD11chiCD11bloMHC-II+ cells resembling conventional dendritic cells (cDC can activate both CD4 and CD8 T cells. Production of L-DC but not cDC-like cells is now shown to be dependent on contact between the L-DC progenitor and stroma such that the presence of a Transwell membrane can prevent L-DC development. Since L-DC can be produced continuously in vitro in stromal co-cultures overlaid with bone marrow (BM progenitors, it was hypothesised that L-DC progenitors are self-renewing. The L-DC progenitor is shown here to be defined by the Flt3-c-kit+Lin-Sca-1+ (F-KLS subset of adult BM which contains primitive HSC. Since the less primitive F+KLS HSC subset also contains L-DC progenitors, Flt3 does not appear to be a defining marker for this progenitor. Precursors of the cDC-like subset are found only within the F+KLS subset and seed production of a transient population of APC. All data identify differentiation of L-DC from HSC, and of cDC-like cells from DC precursors, which occurs independently of inflammatory signals and is dependent on a splenic stromal microenvironment.

  20. Different Phenotypic Consequences of Simultaneous Versus Stepwise Apc Loss

    OpenAIRE

    Fischer, Jared M; Miller, Ashleigh J; Shibata, Darryl; Liskay, R Michael

    2011-01-01

    APC is considered a gatekeeper for colorectal cancer (CRC). Cells with heterozygous APC mutations have altered expression profiles suggesting that the first APC hit may help set the stage for subsequent transformation. Therefore, we measured transformation efficiency following what we have designated as “simultaneous” versus “stepwise” Apc loss. We combined a conditional Apc allele (ApcCKO ) with a Cre reporter gene and an out-of-frame Cre allele (Pms2cre ) that stochastically becomes functio...

  1. Increase in a distinct pulmonary macrophage subset possessing an antigen-presenting cell phenotype and in vitro APC activity following silica exposure

    International Nuclear Information System (INIS)

    Migliaccio, Christopher T.; Hamilton, Raymond F.; Holian, Andrij

    2005-01-01

    Silica inhalation results in chronic lung inflammation and fibrosis. While the role of the alveolar macrophage (AM) is considered key to the effects of silica on lung pathology, the etiology is not completely understood. Evidence suggests an increase in antigen presenting cell (APC) activity as a contributing factor to this process, as well as potential roles for both AM and interstitial macrophages (IM) in silicosis. In order to study the effects of crystalline silica on the APC activity of pulmonary macrophages, mice were exposed intranasally and changes in pulmonary macrophage populations were assessed using flow cytometry. Following intranasal instillation of silica, a significant increase in the APC activity of AM was observed, as well as a significant increase in a subset of IM expressing classic APC markers (MHC class II, CD11c). In addition, an in vitro system using bone marrow-derived macrophages (BMDM) was generated to assess the effects of silica on the APC activity of macrophages in vitro. Data using BMDM in the in vitro APC assay demonstrated a significant increase in APC activity following silica exposure, but not following exposure to saline or a control particle (TiO 2 ). Using a combination of in vivo and in vitro experiments, the current study describes a significant increase in an interstitial macrophage subset with an APC phenotype, as well as an increase in the APC activity of both AM and BMDM, as a direct result of exposure to crystalline silica. These studies suggest a specific mechanism, macrophage subset activation, by which crystalline silica exposure results in chronic pulmonary inflammation and, eventually, fibrosis

  2. MHC class II molecules regulate growth in human T cells

    DEFF Research Database (Denmark)

    Nielsen, M; Odum, Niels; Bendtzen, K

    1994-01-01

    MHC-class-II-positive T cells are found in tissues involved in autoimmune disorders. Stimulation of class II molecules by monoclonal antibodies (mAbs) or bacterial superantigens induces protein tyrosine phosphorylation through activation of protein tyrosine kinases in T cells, and class II signals...... lines tested. Only one of three CD4+, CD45RAhigh, ROhigh T cells responded to class II costimulation. There was no correlation between T cell responsiveness to class II and the cytokine production profile of the T cell in question. Thus, T cell lines producing interferon (IFN)-gamma but not IL-4 (TH1...... modulate several T cell responses. Here, we studied further the role of class II molecules in the regulation of T cell growth. Costimulation of class II molecules by immobilized HLA-DR mAb significantly enhanced interleukin (IL)-2-supported T cell growth of the majority of CD4+, CD45RAlow, ROhigh T cell...

  3. APC implementation in Chandra Asri - ethylene plant

    Science.gov (United States)

    Sidiq, Mochamad; Mustofa, Ali

    2017-05-01

    Nowadays, the modern process plants are continuously improved for maximizing production, Optimization of the energy and raw material and reducing the risk. Due to many disturbances appearance between the process units, hence, the failure of one unit might have a bad effect on the overall productivity. Ethylene Plant have significant opportunities for using Advanced Process Control (APC) technologies to improve operation stability, push closer to quality or equipment limit, and improve the capability of process units to handle disturbances. APC implementation had considered a best answer for solving multivariable control problem. PT. Chandra Asri Petrochemical, Tbk (CAP) operates a large naphtha cracker complex at Cilegon, Indonesia. To optimize the plant operation and to enhance the benefit, Chandra Asri has been decided to implement Advance Process Control (APC) for ethylene plant. The APC implementation technology scopes at CAP are as follows: 1. Hot Section : Furnaces, Quench Tower 2. Cold Section : Demethanizer, Deethanizer, Acetylene Converter, Ethylene Fractionator, Depropanizer, Propylene Fractionator, Debutanizer

  4. Antigen presentation and MHC class II expression by human esophageal epithelial cells: role in eosinophilic esophagitis.

    Science.gov (United States)

    Mulder, Daniel J; Pooni, Aman; Mak, Nanette; Hurlbut, David J; Basta, Sameh; Justinich, Christopher J

    2011-02-01

    Professional antigen-presenting cells (APCs) play a crucial role in initiating immune responses. Under pathological conditions, epithelial cells at mucosal surfaces act as nonprofessional APCs, thereby regulating immune responses at the site of exposure. Epithelial cells in the esophagus may contribute to the pathogenesis of eosinophilic esophagitis (EoE) by presenting antigens on the major histocompatibility complex (MHC) class II. Our goal was to demonstrate the ability of esophageal epithelial cells to process and present antigens on the MHC class II system and to investigate the contribution of epithelial cell antigen presentation to EoE. Immunohistochemistry detected HLA-DR, CD80, and CD86 expression and enzyme-linked immunosorbent assay detected interferon-γ (IFNγ) in esophageal biopsies. Antigen presentation was studied using the human esophageal epithelial cell line HET-1A by reverse transcriptase-PCR, flow cytometry, and confocal microscopy. T helper cell lymphocyte proliferation was assessed by flow cytometry and IL-2 secretion. IFNγ and MHC class II were increased in mucosa of patients with EoE. IFNγ increased mRNA of HLA-DP, HLA-DQ, HLA-DR, and CIITA in HET-1A cells. HET-1A engulfed cell debris and processed ovalbumin. HET-1A cells expressed HLA-DR after IFNγ treatment. HET-1A stimulated T helper cell activation. In this study, we demonstrated the ability of esophageal epithelial cells to act as nonprofessional APCs in the presence of IFNγ. Esophageal epithelial cell antigen presentation may contribute to the pathophysiology of eosinophilic esophagitis. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  5. Patterns of MHC-G-Like and MHC-B Diversification in New World Monkeys.

    Directory of Open Access Journals (Sweden)

    Juan S Lugo

    Full Text Available The MHC class I (MHC-I region in New World monkeys (Platyrrhini has remained relatively understudied. To evaluate the diversification patterns and transcription behavior of MHC-I in Platyrrhini, we first analyzed public genomic sequences from the MHC-G-like subregion in Saimiri boliviensis, Ateles geoffroyi and Callicebus moloch, and from the MHC-B subregion in Saimiri boliviensis. While S. boliviensis showed multiple copies of both MHC-G-like (10 and -B (15 loci, A. geoffroyi and C. moloch had only three and four MHC-G-like genes, respectively, indicating that not all Platyrrhini species have expanded their MHC-I loci. We then sequenced MHC-G-like and -B cDNAs from nine Platyrrhini species, recovering two to five unique cDNAs per individual for both loci classes. In two Saguinus species, however, no MHC-B cDNAs were found. In phylogenetic trees, MHC-G-like cDNAs formed genus-specific clusters whereas the MHC-B cDNAs grouped by Platyrrhini families, suggesting a more rapid diversification of the former. Furthermore, cDNA sequencing in 12 capuchin monkeys showed that they transcribe at least four MHC-G-like and five MHC-B polymorphic genes, showing haplotypic diversity for gene copy number and signatures of positive natural selection at the peptide binding region. Finally, a quantitative index for MHC:KIR affinity was proposed and tested to predict putative interacting pairs. Altogether, our data indicate that i MHC-I genes has expanded differentially among Platyrrhini species, ii Callitrichinae (tamarins and marmosets MHC-B loci have limited or tissue-specific expression, iii MHC-G-like genes have diversified more rapidly than MHC-B genes, and iv the MHC-I diversity is generated mainly by genetic polymorphism and gene copy number variation, likely promoted by natural selection for ligand binding.

  6. T lymphocytes from irradiation chimeras repopulated with 13-day fetal liver cells recognize antigens only in association with self-MHC products

    International Nuclear Information System (INIS)

    Nisbet-Brown, E.; Diener, E.

    1986-01-01

    The restriction specificities of maturing thymocytes are determined by the Class II MHC antigens expressed by non-lymphoid thymic tissues. The proliferative response of mature T lymphocytes to antigen-presenting cells (APC) and antigen requires that the APC express the same MHC antigens as the thymus in which the T cells differentiated. Thus, in the two-way bone marrow chimera [A + B----(A x B)F1], T lymphocyte populations of A and B haplotypes have each acquired the potential to recognize antigens associated with either parental haplotype. In spite of the large body of work on MHC restriction, we still do not have a clear understanding of the mechanisms which impose self restriction. The chimeric model systems used previously to study MHC restriction have used adult bone marrow cells as the source of lymphoid precursors. During normal ontogeny, T cells are derived from precursors in the fetal liver and we felt that a direct comparison of T cells from fetal liver and bone marrow-repopulated animals would shed light on the development of MHC restriction specificities during T cell ontogeny in the thymus or prethymically. We found that parental T lymphocyte populations isolated from two-way fetal liver chimeras cooperated only with syngeneic APC, while those from bone marrow chimeras cooperated with APC of either parental haplotype. This suggests that fetal liver and bone marrow may not be equivalent sources of stem cells. Our results may be due to fundamental differences between thymocyte precursors in fetal liver and bone marrow, including the time course of their expression of T cell receptor gene products

  7. Data sharing system for lithography APC

    Science.gov (United States)

    Kawamura, Eiichi; Teranishi, Yoshiharu; Shimabara, Masanori

    2007-03-01

    We have developed a simple and cost-effective data sharing system between fabs for lithography advanced process control (APC). Lithography APC requires process flow, inter-layer information, history information, mask information and so on. So, inter-APC data sharing system has become necessary when lots are to be processed in multiple fabs (usually two fabs). The development cost and maintenance cost also have to be taken into account. The system handles minimum information necessary to make trend prediction for the lots. Three types of data have to be shared for precise trend prediction. First one is device information of the lots, e.g., process flow of the device and inter-layer information. Second one is mask information from mask suppliers, e.g., pattern characteristics and pattern widths. Last one is history data of the lots. Device information is electronic file and easy to handle. The electronic file is common between APCs and uploaded into the database. As for mask information sharing, mask information described in common format is obtained via Wide Area Network (WAN) from mask-vender will be stored in the mask-information data server. This information is periodically transferred to one specific lithography-APC server and compiled into the database. This lithography-APC server periodically delivers the mask-information to every other lithography-APC server. Process-history data sharing system mainly consists of function of delivering process-history data. In shipping production lots to another fab, the product-related process-history data is delivered by the lithography-APC server from the shipping site. We have confirmed the function and effectiveness of data sharing systems.

  8. The specificity of targeted vaccines for APC surface molecules influences the immune response phenotype.

    Directory of Open Access Journals (Sweden)

    Gunnveig Grødeland

    Full Text Available Different diseases require different immune responses for efficient protection. Thus, prophylactic vaccines should prime the immune system for the particular type of response needed for protection against a given infectious agent. We have here tested fusion DNA vaccines which encode proteins that bivalently target influenza hemagglutinins (HA to different surface molecules on antigen presenting cells (APC. We demonstrate that targeting to MHC class II molecules predominantly induced an antibody/Th2 response, whereas targeting to CCR1/3/5 predominantly induced a CD8(+/Th1 T cell response. With respect to antibodies, the polarizing effect was even more pronounced upon intramuscular (i.m delivery as compared to intradermal (i.d. vaccination. Despite these differences in induced immune responses, both vaccines protected against a viral challenge with influenza H1N1. Substitution of HA with ovalbumin (OVA demonstrated that polarization of immune responses, as a consequence of APC targeting specificity, could be extended to other antigens. Taken together, the results demonstrate that vaccination can be tailor-made to induce a particular phenotype of adaptive immune responses by specifically targeting different surface molecules on APCs.

  9. Human xenospecific T suppressor cells inhibit T helper cell proliferation to porcine aortic endothelial cells, and NF-kappaB activity in porcine APC.

    Science.gov (United States)

    Ciubotariu, R; Li, J; Colovai, A I; Platt, J L; Cortesini, R; Suciu Foca Cortesini, N

    2001-05-01

    Human T suppressor cells (Ts), capable of preventing autologous T helper cells (Th) from reacting against xenogeneic pig endothelial cells and pig APC can be generated in vitro. Ts derive from a population of CD3(+)CD8(+)CD28(-) T lymphocytes and specifically recognize the MHC class I antigens of the APC used for in vitro immunization. To study the mechanism that underlies suppression, we investigated whether Ts inhibit the expression of costimulatory molecules in xenogeneic professional and semiprofessional APC. We found that Ts down-regulate Th-induced expression of CD86 in pig APC, and that this effect occurs at the level of transcription, as indicated by nuclear run-on and Northern blot assays. EMSA results revealed that inhibition of CD86 expression is mediated by inactivation of transcription factor NF-kappaB. Furthermore, transfection of pig APC with a vector expressing NF-kappaB p65 partially rescued Th-induced expression of the CD86 molecule. These results strongly support the concept that xenospecific Ts inhibit the APC function of xenogeneic cells by preventing activation of NF-kappaB.

  10. MHC Class II epitope predictive algorithms

    DEFF Research Database (Denmark)

    Nielsen, Morten; Lund, Ole; Buus, S

    2010-01-01

    Major histocompatibility complex class II (MHC-II) molecules sample peptides from the extracellular space, allowing the immune system to detect the presence of foreign microbes from this compartment. To be able to predict the immune response to given pathogens, a number of methods have been...... developed to predict peptide-MHC binding. However, few methods other than the pioneering TEPITOPE/ProPred method have been developed for MHC-II. Despite recent progress in method development, the predictive performance for MHC-II remains significantly lower than what can be obtained for MHC-I. One reason...

  11. Mechanism of APC/CCDC20 activation by mitotic phosphorylation.

    Science.gov (United States)

    Qiao, Renping; Weissmann, Florian; Yamaguchi, Masaya; Brown, Nicholas G; VanderLinden, Ryan; Imre, Richard; Jarvis, Marc A; Brunner, Michael R; Davidson, Iain F; Litos, Gabriele; Haselbach, David; Mechtler, Karl; Stark, Holger; Schulman, Brenda A; Peters, Jan-Michael

    2016-05-10

    Chromosome segregation and mitotic exit are initiated by the 1.2-MDa ubiquitin ligase APC/C (anaphase-promoting complex/cyclosome) and its coactivator CDC20 (cell division cycle 20). To avoid chromosome missegregation, APC/C(CDC20) activation is tightly controlled. CDC20 only associates with APC/C in mitosis when APC/C has become phosphorylated and is further inhibited by a mitotic checkpoint complex until all chromosomes are bioriented on the spindle. APC/C contains 14 different types of subunits, most of which are phosphorylated in mitosis on multiple sites. However, it is unknown which of these phospho-sites enable APC/C(CDC20) activation and by which mechanism. Here we have identified 68 evolutionarily conserved mitotic phospho-sites on human APC/C bound to CDC20 and have used the biGBac technique to generate 47 APC/C mutants in which either all 68 sites or subsets of them were replaced by nonphosphorylatable or phospho-mimicking residues. The characterization of these complexes in substrate ubiquitination and degradation assays indicates that phosphorylation of an N-terminal loop region in APC1 is sufficient for binding and activation of APC/C by CDC20. Deletion of the N-terminal APC1 loop enables APC/C(CDC20) activation in the absence of mitotic phosphorylation or phospho-mimicking mutations. These results indicate that binding of CDC20 to APC/C is normally prevented by an autoinhibitory loop in APC1 and that its mitotic phosphorylation relieves this inhibition. The predicted location of the N-terminal APC1 loop implies that this loop controls interactions between the N-terminal domain of CDC20 and APC1 and APC8. These results reveal how APC/C phosphorylation enables CDC20 to bind and activate the APC/C in mitosis.

  12. Sumoylation promotes optimal APC/C Activation and Timely Anaphase.

    Science.gov (United States)

    Lee, Christine C; Li, Bing; Yu, Hongtao; Matunis, Michael J

    2018-03-08

    The Anaphase Promoting Complex/Cyclosome (APC/C) is a ubiquitin E3 ligase that functions as the gatekeeper to mitotic exit. APC/C activity is controlled by an interplay of multiple pathways during mitosis, including the spindle assembly checkpoint (SAC), that are not yet fully understood. Here, we show that sumoylation of the APC4 subunit of the APC/C peaks during mitosis and is critical for timely APC/C activation and anaphase onset. We have also identified a functionally important SUMO interacting motif in the cullin-homology domain of APC2 located near the APC4 sumoylation sites and APC/C catalytic core. Our findings provide evidence of an important regulatory role for SUMO modification and binding in affecting APC/C activation and mitotic exit. © 2018, Lee et al.

  13. APC functions at the centrosome to stimulate microtubule growth.

    Science.gov (United States)

    Lui, Christina; Ashton, Cahora; Sharma, Manisha; Brocardo, Mariana G; Henderson, Beric R

    2016-01-01

    The adenomatous polyposis coli (APC) tumor suppressor is multi-functional. APC is known to localize at the centrosome, and in mitotic cells contributes to formation of the mitotic spindle. To test whether APC contributes to nascent microtubule (MT) growth at interphase centrosomes, we employed MT regrowth assays in U2OS cells to measure MT assembly before and after nocodazole treatment and release. We showed that siRNA knockdown of full-length APC delayed both initial MT aster formation and MT elongation/regrowth. In contrast, APC-mutant SW480 cancer cells displayed a defect in MT regrowth that was unaffected by APC knockdown, but which was rescued by reconstitution of full-length APC. Our findings identify APC as a positive regulator of centrosome MT initial assembly and suggest that this process is disrupted by cancer mutations. We confirmed that full-length APC associates with the MT-nucleation factor γ-tubulin, and found that the APC cancer-truncated form (1-1309) also bound to γ-tubulin through APC amino acids 1-453. While binding to γ-tubulin may help target APC to the site of MT nucleation complexes, additional C-terminal sequences of APC are required to stimulate and stabilize MT growth. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. MHC variability in heritage breeds of chickens.

    Science.gov (United States)

    Fulton, J E; Lund, A R; McCarron, A M; Pinegar, K N; Korver, D R; Classen, H L; Aggrey, S; Utterbach, C; Anthony, N B; Berres, M E

    2016-02-01

    The chicken Major Histocompatibility Complex (MHC) is very strongly associated with disease resistance and thus is a very important region of the chicken genome. Historically, MHC (B locus) has been identified by the use of serology with haplotype specific alloantisera. These antisera can be difficult to produce and frequently cross-react with multiple haplotypes and hence their application is generally limited to inbred and MHC-defined lines. As a consequence, very little information about MHC variability in heritage chicken breeds is available. DNA-based methods are now available for examining MHC variability in these previously uncharacterized populations. A high density SNP panel consisting of 101 SNP that span a 230,000 bp region of the chicken MHC was used to examine MHC variability in 17 heritage populations of chickens from five universities from Canada and the United States. The breeds included 6 heritage broiler lines, 3 Barred Plymouth Rock, 2 New Hampshire and one each of Rhode Island Red, Light Sussex, White Leghorn, Dark Brown Leghorn, and 2 synthetic lines. These heritage breeds contained from one to 11 haplotypes per line. A total of 52 unique MHC haplotypes were found with only 10 of them identical to serologically defined haplotypes. Furthermore, nine MHC recombinants with their respective parental haplotypes were identified. This survey confirms the value of these non-commercially utilized lines in maintaining genetic diversity. The identification of multiple MHC haplotypes and novel MHC recombinants indicates that diversity is being generated and maintained within these heritage populations. © 2016 Poultry Science Association Inc.

  15. Analysis of APC allelic imbalance/loss of heterozygosity and APC protein expression in cutaneous squamous cell carcinomas.

    LENUS (Irish Health Repository)

    Gray, Sarah E

    2012-02-01

    BACKGROUND: The adenomatous polyposis coli (APC) gene is a tumor suppressor gene which is mutated in the hereditary disease, familial adenomatous polyposis (FAP). Somatic mutations of the APC gene have also been identified in the majority of sporadic colorectal carcinomas, and mutation of the APC gene appears to be an early step in the initiation of colon cancer. Loss of heterozygosity (LOH) of APC has been described in a variety of other cancer types, including renal cell carcinoma, gastric cancer, non-small cell lung cancer, endometrial cancer and oral squamous cell carcinomas (SCC). AIM: To determine the role played by APC gene in the genesis of cutaneous SCC. MATERIALS AND METHODS: Allelic imbalance\\/loss of heterozygosity (AI\\/LOH) was examined in twenty-two histologically confirmed cutaneous squamous cell carcinomas (SCC) using microsatellite markers, proximal to the APC gene. Immunohistochemical analysis of APC protein expression was also examined in the cutaneous SCC. RESULTS: AI\\/LOH was detected in 60% of the SCC samples using D5S346 marker (proximal to the APC gene). Ninty-five percent of the SCC samples showed positive reduced APC expression, however the localization of the APC protein was abnormal. CONCLUSION: The abnormal expression of APC suggests that APC gene may play a role in cutaneous SCC development.

  16. MHC Class II and CD9 in Human Eosinophils Localize to Detergent-Resistant Membrane Microdomains

    Science.gov (United States)

    Akuthota, Praveen; Melo, Rossana C. N.; Spencer, Lisa A.

    2012-01-01

    Eosinophils function in murine allergic airways inflammation as professional antigen-presenting cells (APCs). In murine professional APC cell types, optimal functioning of MHC Class II depends on its lateral association in plasma membranes and colocalization with the tetraspanin CD9 into detergent-resistant membrane microdomains (DRMs). With human eosinophils, we evaluated the localization of MHC Class II (HLA-DR) to DRMs and the functional significance of such localization. In granulocyte-macrophage colony-stimulating factor–stimulated human eosinophils, antibody cross-linked HLA-DR colocalized by immunofluorescence microscopy focally on plasma membranes with CD9 and the DRM marker ganglioside GM1. In addition, HLA-DR coimmunoprecipitates with CD9 after chemical cross-linking of CD9. HLA-DR and CD9 were localized by Western blotting in eosinophil DRM subcellular fractions. DRM disruption with the cholesterol-depleting agent methyl-β-cyclodextrin decreased eosinophil surface expression of HLA-DR and CD9. We show that CD9 is abundant on the surface of eosinophils, presenting the first electron microscopy data of the ultrastructural immunolocalization of CD9 in human eosinophils. Disruption of HLA-DR–containing DRMs decreased the ability of superantigen-loaded human eosinophils to stimulate CD4+ T-cell activation (CD69 expression), proliferation, and cytokine production. Our results, which demonstrate that eosinophil MHC Class II localizes to DRMs in association with CD9 in a functionally significant manner, represent a novel insight into the organization of the antigen presentation complex of human eosinophils. PMID:21885678

  17. MHC Class II and CD9 in human eosinophils localize to detergent-resistant membrane microdomains.

    Science.gov (United States)

    Akuthota, Praveen; Melo, Rossana C N; Spencer, Lisa A; Weller, Peter F

    2012-02-01

    Eosinophils function in murine allergic airways inflammation as professional antigen-presenting cells (APCs). In murine professional APC cell types, optimal functioning of MHC Class II depends on its lateral association in plasma membranes and colocalization with the tetraspanin CD9 into detergent-resistant membrane microdomains (DRMs). With human eosinophils, we evaluated the localization of MHC Class II (HLA-DR) to DRMs and the functional significance of such localization. In granulocyte-macrophage colony-stimulating factor-stimulated human eosinophils, antibody cross-linked HLA-DR colocalized by immunofluorescence microscopy focally on plasma membranes with CD9 and the DRM marker ganglioside GM1. In addition, HLA-DR coimmunoprecipitates with CD9 after chemical cross-linking of CD9. HLA-DR and CD9 were localized by Western blotting in eosinophil DRM subcellular fractions. DRM disruption with the cholesterol-depleting agent methyl-β-cyclodextrin decreased eosinophil surface expression of HLA-DR and CD9. We show that CD9 is abundant on the surface of eosinophils, presenting the first electron microscopy data of the ultrastructural immunolocalization of CD9 in human eosinophils. Disruption of HLA-DR-containing DRMs decreased the ability of superantigen-loaded human eosinophils to stimulate CD4(+) T-cell activation (CD69 expression), proliferation, and cytokine production. Our results, which demonstrate that eosinophil MHC Class II localizes to DRMs in association with CD9 in a functionally significant manner, represent a novel insight into the organization of the antigen presentation complex of human eosinophils.

  18. Prediction of MHC class II binding affinity using SMM-align, a novel stabilization matrix alignment method.

    Science.gov (United States)

    Nielsen, Morten; Lundegaard, Claus; Lund, Ole

    2007-07-04

    Antigen presenting cells (APCs) sample the extra cellular space and present peptides from here to T helper cells, which can be activated if the peptides are of foreign origin. The peptides are presented on the surface of the cells in complex with major histocompatibility class II (MHC II) molecules. Identification of peptides that bind MHC II molecules is thus a key step in rational vaccine design and developing methods for accurate prediction of the peptide:MHC interactions play a central role in epitope discovery. The MHC class II binding groove is open at both ends making the correct alignment of a peptide in the binding groove a crucial part of identifying the core of an MHC class II binding motif. Here, we present a novel stabilization matrix alignment method, SMM-align, that allows for direct prediction of peptide:MHC binding affinities. The predictive performance of the method is validated on a large MHC class II benchmark data set covering 14 HLA-DR (human MHC) and three mouse H2-IA alleles. The predictive performance of the SMM-align method was demonstrated to be superior to that of the Gibbs sampler, TEPITOPE, SVRMHC, and MHCpred methods. Cross validation between peptide data set obtained from different sources demonstrated that direct incorporation of peptide length potentially results in over-fitting of the binding prediction method. Focusing on amino terminal peptide flanking residues (PFR), we demonstrate a consistent gain in predictive performance by favoring binding registers with a minimum PFR length of two amino acids. Visualizing the binding motif as obtained by the SMM-align and TEPITOPE methods highlights a series of fundamental discrepancies between the two predicted motifs. For the DRB1*1302 allele for instance, the TEPITOPE method favors basic amino acids at most anchor positions, whereas the SMM-align method identifies a preference for hydrophobic or neutral amino acids at the anchors. The SMM-align method was shown to outperform other

  19. Prediction of MHC class II binding affinity using SMM-align, a novel stabilization matrix alignment method

    Directory of Open Access Journals (Sweden)

    Lund Ole

    2007-07-01

    Full Text Available Abstract Background Antigen presenting cells (APCs sample the extra cellular space and present peptides from here to T helper cells, which can be activated if the peptides are of foreign origin. The peptides are presented on the surface of the cells in complex with major histocompatibility class II (MHC II molecules. Identification of peptides that bind MHC II molecules is thus a key step in rational vaccine design and developing methods for accurate prediction of the peptide:MHC interactions play a central role in epitope discovery. The MHC class II binding groove is open at both ends making the correct alignment of a peptide in the binding groove a crucial part of identifying the core of an MHC class II binding motif. Here, we present a novel stabilization matrix alignment method, SMM-align, that allows for direct prediction of peptide:MHC binding affinities. The predictive performance of the method is validated on a large MHC class II benchmark data set covering 14 HLA-DR (human MHC and three mouse H2-IA alleles. Results The predictive performance of the SMM-align method was demonstrated to be superior to that of the Gibbs sampler, TEPITOPE, SVRMHC, and MHCpred methods. Cross validation between peptide data set obtained from different sources demonstrated that direct incorporation of peptide length potentially results in over-fitting of the binding prediction method. Focusing on amino terminal peptide flanking residues (PFR, we demonstrate a consistent gain in predictive performance by favoring binding registers with a minimum PFR length of two amino acids. Visualizing the binding motif as obtained by the SMM-align and TEPITOPE methods highlights a series of fundamental discrepancies between the two predicted motifs. For the DRB1*1302 allele for instance, the TEPITOPE method favors basic amino acids at most anchor positions, whereas the SMM-align method identifies a preference for hydrophobic or neutral amino acids at the anchors. Conclusion

  20. Innate lymphoid cells and the MHC.

    Science.gov (United States)

    Robinette, M L; Colonna, M

    2016-01-01

    Innate lymphoid cells (ILCs) are a new class of immune cells that include natural killer (NK) cells and appear to be the innate counterparts to CD4(+) helper T cells and CD8(+) cytotoxic T cells based on developmental and functional similarities. Like T cells, both NK cells and other ILCs also show connections to the major histocompatibility complex (MHC). In human and mouse, NK cells recognize and respond to classical and nonclassical MHC I molecules as well as structural homologues, whereas mouse ILCs have recently been shown to express MHC II. We describe the history of MHC I recognition by NK cells and discuss emerging roles for MHC II expression by ILC subsets, making comparisons between both mouse and human when possible. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. B lymphocytes as natural antigen-presenting cells (APC) of their own Ig receptor determinants

    International Nuclear Information System (INIS)

    Yurin, V.L.; Rudensky, A.Yu.; Rabinovich, O.R.; Kulakova, O.G.; Bobreneva, R.A.

    1986-01-01

    The authors use Igk-lb allotype-specific rat T cell proliferation(Pr) in vitro as a model of natural Ig determinants B cell presentation in Ig-specific T-B cell interactions. As shown before Igk-lb-specific responsiveness of AUG(RT-l/sup c/, Igk-la) and WAG (RT-l, Igk-la) rats is controlled by dominant Ir gene, linked to RT-l/sup c/. Only IgG(Igk-lb)-pulsed splenic APC of AUG(responder) but not WAG(non-responder) origin induce specific F 1 (WAGxAUG) T cell Pr. The same restriction was observed if purified B cells from Igk-l congeneic AUG-lb and WAG-lb rats were used as APC. B cell presentation was found to be sensitive to high irradiation dose(2000 rad). Anti-RT-l monoclonal antibody inhibition studies suggested RT-lB(I-A) molecule as a main restricting element of Igk-lb T cell recognition. B cell and splenic APC presentation of Igk-lb allotype was not inhibited by poly- and monoclonal anti-Igk-lb antibodies. Allelic exclusion of Igk-lb presentation by B cells from heterozygous F 1 (WAG-lbx AUG) rats was demonstrated by panning with antiallotypic reagents. Important, that irradiated anti-Igk-lb T cells induce specific Pr of normal Igk-lb-positive B cells. The data demonstrate MHC-restricted B cell presentation of their own receptor determinants, distinct from serologically-defined epitopes. T cell recognition of these determinants induce specific Pr of Ig-recognizing T cells and Ig-presenting B lymphocytes

  2. Cancer stemness in Apc- vs. Apc/KRAS-driven intestinal tumorigenesis.

    Directory of Open Access Journals (Sweden)

    Mehrnaz Ghazvini

    Full Text Available Constitutive activation of the Wnt pathway leads to adenoma formation, an obligatory step towards intestinal cancer. In view of the established role of Wnt in regulating stemness, we attempted the isolation of cancer stem cells (CSCs from Apc- and Apc/KRAS-mutant intestinal tumours. Whereas CSCs are present in Apc/KRAS tumours, they appear to be very rare (<10(-6 in the Apc-mutant adenomas. In contrast, the Lin(-CD24(hiCD29(+ subpopulation of adenocarcinoma cells appear to be enriched in CSCs with increased levels of active β-catenin. Expression profiling analysis of the CSC-enriched subpopulation confirmed their enhanced Wnt activity and revealed additional differential expression of other signalling pathways, growth factor binding proteins, and extracellular matrix components. As expected, genes characteristic of the Paneth cell lineage (e.g. defensins are co-expressed together with stem cell genes (e.g. Lgr5 within the CSC-enriched subpopulation. This is of interest as it may indicate a cancer stem cell niche role for tumor-derived Paneth-like cells, similar to their role in supporting Lgr5(+ stem cells in the normal intestinal crypt. Overall, our results indicate that oncogenic KRAS activation in Apc-driven tumours results in the expansion of the CSCs compartment by increasing ®-catenin intracellular stabilization.

  3. Molecular mechanism of APC/C activation by mitotic phosphorylation.

    Science.gov (United States)

    Zhang, Suyang; Chang, Leifu; Alfieri, Claudio; Zhang, Ziguo; Yang, Jing; Maslen, Sarah; Skehel, Mark; Barford, David

    2016-05-12

    In eukaryotes, the anaphase-promoting complex (APC/C, also known as the cyclosome) regulates the ubiquitin-dependent proteolysis of specific cell-cycle proteins to coordinate chromosome segregation in mitosis and entry into the G1 phase. The catalytic activity of the APC/C and its ability to specify the destruction of particular proteins at different phases of the cell cycle are controlled by its interaction with two structurally related coactivator subunits, Cdc20 and Cdh1. Coactivators recognize substrate degrons, and enhance the affinity of the APC/C for its cognate E2 (refs 4-6). During mitosis, cyclin-dependent kinase (Cdk) and polo-like kinase (Plk) control Cdc20- and Cdh1-mediated activation of the APC/C. Hyperphosphorylation of APC/C subunits, notably Apc1 and Apc3, is required for Cdc20 to activate the APC/C, whereas phosphorylation of Cdh1 prevents its association with the APC/C. Since both coactivators associate with the APC/C through their common C-box and Ile-Arg tail motifs, the mechanism underlying this differential regulation is unclear, as is the role of specific APC/C phosphorylation sites. Here, using cryo-electron microscopy and biochemical analysis, we define the molecular basis of how phosphorylation of human APC/C allows for its control by Cdc20. An auto-inhibitory segment of Apc1 acts as a molecular switch that in apo unphosphorylated APC/C interacts with the C-box binding site and obstructs engagement of Cdc20. Phosphorylation of the auto-inhibitory segment displaces it from the C-box-binding site. Efficient phosphorylation of the auto-inhibitory segment, and thus relief of auto-inhibition, requires the recruitment of Cdk-cyclin in complex with a Cdk regulatory subunit (Cks) to a hyperphosphorylated loop of Apc3. We also find that the small-molecule inhibitor, tosyl-l-arginine methyl ester, preferentially suppresses APC/C(Cdc20) rather than APC/C(Cdh1), and interacts with the binding sites of both the C-box and Ile-Arg tail motifs. Our

  4. Article Processing Charges and OpenAPC

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    The publication landscape is about to change. While being largely operated by subscription based journals in the past, recent political decisions force the publishing industry towards OpenAccess. Especially, the publication of the Finch report in 2012 put APC based Gold OpenAccess models almost everywhere on the agenda. These models also require quite some adoptions for library work flows to handle payments, bills and centralized funds for publication fees. Sometimes handled in specialized systems (e.g. first setups in Jülich) pretty early on discussions started to handle APCs in local repositories which would also hold the OpenAccess content resulting from these fees, e.g. the University of Regenburg uses ePrints for this purpose. Backed up by the OpenData movmement, libraries also saw opportunity to exchange data about fees payed. Thus, OpenAPC.de was born in 2014 on github to facilitate this exchange and aggregate large amounts of data for evaluation and comparison. Using the repository to hold payment d...

  5. Early diagnostic potential of APC hypermethylation in esophageal cancer

    Directory of Open Access Journals (Sweden)

    Wang B

    2018-02-01

    Full Text Available Bujiang Wang,1 Haojun Song,1 Haizhong Jiang,1 Yangbo Fu,1 Xiaoyun Ding,1 Chongchang Zhou2 1Department of Gastroenterology, Laboratory of Digestive Diseases, Ningbo First Hospital, Ningbo, 2Department of Otorhinolaryngology Head and Neck Surgery, Lihuili Hospital of Ningbo University, Ningbo, Zhejiang, People’s Republic of China Background: The hypermethylation of APC gene is observed in various cancers, including esophageal cancer (EC. However, the association between APC methylation and the initiation and progression of EC is poorly understood. Purpose and methods: The current study systematically reviewed studies on abnormal methylation of APC in EC and quantitatively synthesized 18 studies by meta-analysis involving 1008 ECs, 570 Barrett’s esophagus (BE, and 782 controls. Results: Our results showed higher methylation of APC in EC (OR = 23.33, P < 0.001 and BE (OR = 9.34, P < 0.001 than in normal controls. Whereas APC methylation in EC was similar to that in BE (P = 0.052, it was not associated with tumor stage (P = 0.204. Additionally, APC methylation was not significantly associated with overall survival (OS and relapse-free survival (RFS in patients with EC. The performance of APC methylation for the detection of EC and BE achieved areas under the receiver operating characteristic curves of 0.94 and 0.88, respectively. Conclusion: Our results imply that APC methylation detection is a potential diagnostic biomarker for EC and BE. Keywords: esophageal cancer, Barrett’s esophagus, methylation, APC

  6. Analysis of APC mutation in human ameloblastoma and clinical significance.

    Science.gov (United States)

    Li, Ning; Liu, Bing; Sui, Chengguang; Jiang, Youhong

    2016-01-01

    As a highly conserved signaling pathway, Wnt/β-catenin signal transduction pathway plays an important role in many processes. Either in the occurrence or development of tumor, activation of this pathway takes an important place. APC inhibits Wnt/β-catenin pathway to regulate cell proliferation and differentiation. This study aimed to investigate the function of cancer suppressor gene. PCR amplification and sequencing method was used to analyze APC mutations of human clinical specimens. The pathological specimens were collected for PCR and clear electrophoretic bands were obtained after electrophoresis. The gene sequence obtained after purification and sequencing analysis was compared with the known APC gene sequence (NM_000038.5). Base mutations at APC 1543 (T → C), APC-4564 (G → A), APC-5353 (T → G), APC-5550 (T → A) and APC-5969 (G → A) locus existed in 22 (27.5 %), 12 (15 %), 5 (6.25 %), 13 (16.25 %) and 12 patients (15 %), respectively. Gene mutations existed in ameloblastoma, and the mutation loci were 1543 locus (T → C), 4564 locus (G → A), 5353 locus (T → G), 5550 locus (T → A) and 5969 locus (G → A) 15 %, respectively. APC mutation plays a certain role in monitoring the tumor malignant degree as it may indicate the transition process of ameloblastoma malignant phenotype.

  7. Structural properties of MHC class II ligands, implications for the prediction of MHC class II epitopes.

    Directory of Open Access Journals (Sweden)

    Kasper Winther Jørgensen

    2010-12-01

    Full Text Available Major Histocompatibility class II (MHC-II molecules sample peptides from the extracellular space allowing the immune system to detect the presence of foreign microbes from this compartment. Prediction of MHC class II ligands is complicated by the open binding cleft of the MHC class II molecule, allowing binding of peptides extending out of the binding groove. Furthermore, only a few HLA-DR alleles have been characterized with a sufficient number of peptides (100-200 peptides per allele to derive accurate description of their binding motif. Little work has been performed characterizing structural properties of MHC class II ligands. Here, we perform one such large-scale analysis. A large set of SYFPEITHI MHC class II ligands covering more than 20 different HLA-DR molecules was analyzed in terms of their secondary structure and surface exposure characteristics in the context of the native structure of the corresponding source protein. We demonstrated that MHC class II ligands are significantly more exposed and have significantly more coil content than other peptides in the same protein with similar predicted binding affinity. We next exploited this observation to derive an improved prediction method for MHC class II ligands by integrating prediction of MHC- peptide binding with prediction of surface exposure and protein secondary structure. This combined prediction method was shown to significantly outperform the state-of-the-art MHC class II peptide binding prediction method when used to identify MHC class II ligands. We also tried to integrate N- and O-glycosylation in our prediction methods but this additional information was found not to improve prediction performance. In summary, these findings strongly suggest that local structural properties influence antigen processing and/or the accessibility of peptides to the MHC class II molecule.

  8. Analysis of APC allelic imbalance/loss of heterozygosity and APC protein expression in cutaneous squamous cell carcinomas.

    LENUS (Irish Health Repository)

    Gray, Sarah E

    2011-05-01

    The adenomatous polyposis coli (APC) gene is a tumor suppressor gene which is mutated in the hereditary disease, familial adenomatous polyposis (FAP). Somatic mutations of the APC gene have also been identified in the majority of sporadic colorectal carcinomas, and mutation of the APC gene appears to be an early step in the initiation of colon cancer. Loss of heterozygosity (LOH) of APC has been described in a variety of other cancer types, including renal cell carcinoma, gastric cancer, non-small cell lung cancer, endometrial cancer and oral squamous cell carcinomas (SCC).

  9. Structure of an APC3-APC16 complex: Insights into assembly of the Anaphase Promoting Complex/Cyclosome

    OpenAIRE

    Yamaguchi, Masaya; Yu, Shanshan; Qiao, Renping; Weissmann, Florian; Miller, Darcie J.; VanderLinden, Ryan; Brown, Nicholas G.; Frye, Jeremiah J.; Peters, Jan-Michael; Schulman, Brenda A.

    2014-01-01

    The Anaphase Promoting Complex/Cyclosome (APC/C) is a massive E3 ligase that controls mitosis by catalyzing ubiquitination of key cell cycle regulatory proteins. The APC/C assembly contains two subcomplexes: the “Platform” centers around a cullin-RING-like E3 ligase catalytic core; the “Arc Lamp” is a hub that mediates transient association with regulators and ubiquitination substrates. The Arc Lamp contains the small subunits APC16, CDC26, and APC13, and tetratricopeptide repeat (TPR) protei...

  10. The MHC motif viewer: a visualization tool for MHC binding motifs

    DEFF Research Database (Denmark)

    Rapin, Nicolas; Hoof, Ilka; Lund, Ole

    2010-01-01

    is hampered by the lack of tools for browsing and comparing specificity of these molecules. We have developed a Web server, MHC Motif Viewer, which allows the display of the binding motif for MHC class I proteins for human, chimpanzee, rhesus monkey, mouse, and swine, as well as HLA-DR protein sequences...

  11. Rejection of class I MHC-deficient haemopoietic cells by irradiated MHC-matched mice

    International Nuclear Information System (INIS)

    Bix, M.; Nanshih Liao; Raulet, D.; Zijlstra, M.; Loring, J.; Jaenisch, R.

    1991-01-01

    Irradiated MHC-heterozygous mice often reject bone marrow cells transplanted from one of the homozygous parental strains, a phenomenon ('hybrid resistance') that appears to violate the laws of transplantation. Rejection of parental and allogeneic marrow cells also differs from conventional T cell-mediated rejection mechanisms as it is effected by NK1.1 + cells. To account for the unusual specificity of bone marrow rejection, it has been proposed that NK1.1 + cells destroy marrow cells that fail to express the full complement of self MHC class I (MHC-I) molecules. We show here that NK1.1 + cells in normal mice reject haemopoietic transplants from mice that are deficient for normal cell-surface MHC-I expression because of a targeted mutation in the β 2 -microglobulin gene. These findings demonstrate that deficient expression of MHC-I molecules renders marrow cells susceptible to rejection. (author)

  12. WD40 domain of Apc1 is critical for the coactivator-induced allosteric transition that stimulates APC/C catalytic activity.

    Science.gov (United States)

    Li, Qiuhong; Chang, Leifu; Aibara, Shintaro; Yang, Jing; Zhang, Ziguo; Barford, David

    2016-09-20

    The anaphase-promoting complex/cyclosome (APC/C) is a large multimeric cullin-RING E3 ubiquitin ligase that orchestrates cell-cycle progression by targeting cell-cycle regulatory proteins for destruction via the ubiquitin proteasome system. The APC/C assembly comprises two scaffolding subcomplexes: the platform and the TPR lobe that together coordinate the juxtaposition of the catalytic and substrate-recognition modules. The platform comprises APC/C subunits Apc1, Apc4, Apc5, and Apc15. Although the role of Apc1 as an APC/C scaffolding subunit has been characterized, its specific functions in contributing toward APC/C catalytic activity are not fully understood. Here, we report the crystal structure of the N-terminal domain of human Apc1 (Apc1N) determined at 2.2-Å resolution and provide an atomic-resolution description of the architecture of its WD40 (WD40 repeat) domain (Apc1(WD40)). To understand how Apc1(WD40) contributes to APC/C activity, a mutant form of the APC/C with Apc1(WD40) deleted was generated and evaluated biochemically and structurally. We found that the deletion of Apc1(WD40) abolished the UbcH10-dependent ubiquitination of APC/C substrates without impairing the Ube2S-dependent ubiquitin chain elongation activity. A cryo-EM structure of an APC/C-Cdh1 complex with Apc1(WD40) deleted showed that the mutant APC/C is locked into an inactive conformation in which the UbcH10-binding site of the catalytic module is inaccessible. Additionally, an EM density for Apc15 is not visible. Our data show that Apc1(WD40) is required to mediate the coactivator-induced conformational change of the APC/C that is responsible for stimulating APC/C catalytic activity by promoting UbcH10 binding. In contrast, Ube2S activity toward APC/C substrates is not dependent on the initiation-competent conformation of the APC/C.

  13. The SysteMHC Atlas project.

    Science.gov (United States)

    Shao, Wenguang; Pedrioli, Patrick G A; Wolski, Witold; Scurtescu, Cristian; Schmid, Emanuel; Vizcaíno, Juan A; Courcelles, Mathieu; Schuster, Heiko; Kowalewski, Daniel; Marino, Fabio; Arlehamn, Cecilia S L; Vaughan, Kerrie; Peters, Bjoern; Sette, Alessandro; Ottenhoff, Tom H M; Meijgaarden, Krista E; Nieuwenhuizen, Natalie; Kaufmann, Stefan H E; Schlapbach, Ralph; Castle, John C; Nesvizhskii, Alexey I; Nielsen, Morten; Deutsch, Eric W; Campbell, David S; Moritz, Robert L; Zubarev, Roman A; Ytterberg, Anders Jimmy; Purcell, Anthony W; Marcilla, Miguel; Paradela, Alberto; Wang, Qi; Costello, Catherine E; Ternette, Nicola; van Veelen, Peter A; van Els, Cécile A C M; Heck, Albert J R; de Souza, Gustavo A; Sollid, Ludvig M; Admon, Arie; Stevanovic, Stefan; Rammensee, Hans-Georg; Thibault, Pierre; Perreault, Claude; Bassani-Sternberg, Michal; Aebersold, Ruedi; Caron, Etienne

    2018-01-04

    Mass spectrometry (MS)-based immunopeptidomics investigates the repertoire of peptides presented at the cell surface by major histocompatibility complex (MHC) molecules. The broad clinical relevance of MHC-associated peptides, e.g. in precision medicine, provides a strong rationale for the large-scale generation of immunopeptidomic datasets and recent developments in MS-based peptide analysis technologies now support the generation of the required data. Importantly, the availability of diverse immunopeptidomic datasets has resulted in an increasing need to standardize, store and exchange this type of data to enable better collaborations among researchers, to advance the field more efficiently and to establish quality measures required for the meaningful comparison of datasets. Here we present the SysteMHC Atlas (https://systemhcatlas.org), a public database that aims at collecting, organizing, sharing, visualizing and exploring immunopeptidomic data generated by MS. The Atlas includes raw mass spectrometer output files collected from several laboratories around the globe, a catalog of context-specific datasets of MHC class I and class II peptides, standardized MHC allele-specific peptide spectral libraries consisting of consensus spectra calculated from repeat measurements of the same peptide sequence, and links to other proteomics and immunology databases. The SysteMHC Atlas project was created and will be further expanded using a uniform and open computational pipeline that controls the quality of peptide identifications and peptide annotations. Thus, the SysteMHC Atlas disseminates quality controlled immunopeptidomic information to the public domain and serves as a community resource toward the generation of a high-quality comprehensive map of the human immunopeptidome and the support of consistent measurement of immunopeptidomic sample cohorts. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  14. NLRC5: a newly discovered MHC class I transactivator (CITA)

    OpenAIRE

    Meissner, Torsten B.; Li, Amy; Kobayashi, Koichi S.

    2011-01-01

    Major histocompatibility complex (MHC) class I and class II are crucial for the function of the human adaptive immune system. An NLR protein, CIITA (MHC class II transactivator), is a master regulator of MHC class II gene expression as well as of some of the genes involved in MHC class II antigen presentation. It has recently been discovered that another member of the NLR protein family, NLRC5, transcriptionally activates MHC class I genes, and thus acts as “CITA” (MHC class I transactivator)...

  15. APC gene mutations and extraintestinal phenotype of familial adenomatous polyposis

    NARCIS (Netherlands)

    Giardiello, F. M.; Petersen, G. M.; Piantadosi, S.; Gruber, S. B.; Traboulsi, E. I.; Offerhaus, G. J.; Muro, K.; Krush, A. J.; Booker, S. V.; Luce, M. C.; Laken, S. J.; Kinzler, K. W.; Vogelstein, B.; Hamilton, S. R.

    1997-01-01

    Familial adenomatous polyposis (FAP) is caused by germline mutation of the adenomatous polyposis coli (APC) gene on chromosome 5q. This study assessed genotype-phenotype correlations for extraintestinal lesions in FAP. Mutations of the APC gene were compared with the occurrence of seven

  16. Myc deletion rescues Apc deficiency in the small intestine

    NARCIS (Netherlands)

    Sansom, O.J.; Meniel, V.S.; Muncan, V.; Phesse, T.J.; Wilkins, J.A.; Reed, K.R.; Vass, J.K.; Athineos, D.; Clevers, J.C.; Clarke, A.R.

    2007-01-01

    The APC gene encodes the adenomatous polyposis coli tumour suppressor protein, germline mutation of which characterizes familial adenomatous polyposis (FAP), an autosomal intestinal cancer syndrome. Inactivation of APC is also recognized as the key early event in the development of sporadic

  17. Dietary factors and Truncating APC Mutations in Sporadic Colorectal Adenomas

    NARCIS (Netherlands)

    Diergaarde, B.; Tiemersma, E.W.; Braam, H.; Muijen, van G.N.P.; Nagengast, F.M.; Kok, F.J.; Kampman, E.

    2005-01-01

    Inactivating mutations in APC are thought to be early, initiating events in colorectal carcinogenesis. To gain insight into the relationship between diet and inactivating APC mutations, we evaluated associations between dietary factors and the occurrence of these mutations in a Dutch case-control

  18. Dietary factors and truncating APC mutations in sporadic colorectal adenomas.

    NARCIS (Netherlands)

    Diergaarde, B.; Tiemersma, E.W.; Braam, H.; Muijen, G.N.P. van; Nagengast, F.M.; Kok, F.J.; Kampman, E.

    2005-01-01

    Inactivating mutations in APC are thought to be early, initiating events in colorectal carcinogenesis. To gain insight into the relationship between diet and inactivating APC mutations, we evaluated associations between dietary factors and the occurrence of these mutations in a Dutch case-control

  19. Measuring APC/C-Dependent Ubiquitylation In Vitro.

    Science.gov (United States)

    Jarvis, Marc A; Brown, Nicholas G; Watson, Edmond R; VanderLinden, Ryan; Schulman, Brenda A; Peters, Jan-Michael

    2016-01-01

    The anaphase-promoting complex/cyclosome (APC/C) is a 1.2 MDa ubiquitin ligase complex with important functions in both proliferating and post-mitotic differentiated cells. In proliferating cells, APC/C controls cell cycle progression by targeting inhibitors of chromosome segregation and mitotic exit for degradation by the 26S proteasome. To understand how APC/C recruits and ubiquitylates its substrate proteins and how these processes are controlled, it is essential to analyze APC/C activity in vitro. In the past, such experiments have been limited by the fact that large quantities of purified APC/C were difficult to obtain and that mutated versions of the APC/C could not be easily generated. In this chapter we review recent advances in generating and purifying recombinant forms of the human APC/C and its co-activators, using methods that are scalable and compatible with mutagenesis. We also describe a method that allows the quantitative analysis of APC/C activity using fluorescently labeled substrate proteins.

  20. Early diagnostic potential of APC hypermethylation in esophageal cancer.

    Science.gov (United States)

    Wang, Bujiang; Song, Haojun; Jiang, Haizhong; Fu, Yangbo; Ding, Xiaoyun; Zhou, Chongchang

    2018-01-01

    The hypermethylation of APC gene is observed in various cancers, including esophageal cancer (EC). However, the association between APC methylation and the initiation and progression of EC is poorly understood. The current study systematically reviewed studies on abnormal methylation of APC in EC and quantitatively synthesized 18 studies by meta-analysis involving 1008 ECs, 570 Barrett's esophagus (BE), and 782 controls. Our results showed higher methylation of APC in EC (OR = 23.33, P APC methylation in EC was similar to that in BE ( P = 0.052), it was not associated with tumor stage ( P = 0.204). Additionally, APC methylation was not significantly associated with overall survival (OS) and relapse-free survival (RFS) in patients with EC. The performance of APC methylation for the detection of EC and BE achieved areas under the receiver operating characteristic curves of 0.94 and 0.88, respectively. Our results imply that APC methylation detection is a potential diagnostic biomarker for EC and BE.

  1. More than two decades of Apc modeling in rodents

    Science.gov (United States)

    Zeineldin, Maged; Neufeld, Kristi L.

    2013-01-01

    Mutation of tumor suppressor gene Adenomatous polyposis coli (APC) is an initiating step in most colon cancers. This review summarizes Apc models in mice and rats, with particular concentration on those most recently developed, phenotypic variation among different models, and genotype/ phenotype correlations. PMID:23333833

  2. APC selectively mediates response to chemotherapeutic agents in breast cancer

    International Nuclear Information System (INIS)

    VanKlompenberg, Monica K.; Bedalov, Claire O.; Soto, Katia Fernandez; Prosperi, Jenifer R.

    2015-01-01

    The Adenomatous Polyposis Coli (APC) tumor suppressor is mutated or hypermethylated in up to 70 % of sporadic breast cancers depending on subtype; however, the effects of APC mutation on tumorigenic properties remain unexplored. Using the Apc Min/+ mouse crossed to the Polyoma middle T antigen (PyMT) transgenic model, we identified enhanced breast tumorigenesis and alterations in genes critical in therapeutic resistance independent of Wnt/β-catenin signaling. Apc mutation changed the tumor histopathology from solid to squamous adenocarcinomas, resembling the highly aggressive human metaplastic breast cancer. Mechanistic studies in tumor-derived cell lines demonstrated that focal adhesion kinase (FAK)/Src/JNK signaling regulated the enhanced proliferation downstream of Apc mutation. Despite this mechanistic information, the role of APC in mediating breast cancer chemotherapeutic resistance is currently unknown. We have examined the effect of Apc loss in MMTV-PyMT mouse breast cancer cells on gene expression changes of ATP-binding cassette transporters and immunofluorescence to determine proliferative and apoptotic response of cells to cisplatin, doxorubicin and paclitaxel. Furthermore we determined the added effect of Src or JNK inhibition by PP2 and SP600125, respectively, on chemotherapeutic response. We also used the Aldefluor assay to measure the population of tumor initiating cells. Lastly, we measured the apoptotic and proliferative response to APC knockdown in MDA-MB-157 human breast cancer cells after chemotherapeutic treatment. Cells obtained from MMTV-PyMT;Apc Min/+ tumors express increased MDR1 (multidrug resistance protein 1), which is augmented by treatment with paclitaxel or doxorubicin. Furthermore MMTV-PyMT;Apc Min/+ cells are more resistant to cisplatin and doxorubicin-induced apoptosis, and show a larger population of ALDH positive cells. In the human metaplastic breast cancer cell line MDA-MB-157, APC knockdown led to paclitaxel and cisplatin

  3. APC-II: an electron beam propagation code

    International Nuclear Information System (INIS)

    Iwan, D.C.; Freeman, J.R.

    1984-05-01

    The computer code APC-II simulates the propagation of a relativistic electron beam through air. APC-II is an updated version of the APC envelope model code. It incorporates an improved conductivity model which significantly extends the range of stable calculations. A number of test cases show that these new models are capable of reproducing the simulations of the original APC code. As the result of a major restructuring and reprogramming of the code, APC-II is now friendly to both the occasional user and the experienced user who wishes to make modifications. Most of the code is in standard ANS-II Fortran 77 so that it can be easily transported between machines

  4. Panta rhei: The APC/C at steady state

    Science.gov (United States)

    2013-01-01

    The anaphase-promoting complex or cyclosome (APC/C) is a conserved, multisubunit E3 ubiquitin (Ub) ligase that is active both in dividing and in postmitotic cells. Its contributions to life are especially well studied in the domain of cell division, in which the APC/C lies at the epicenter of a regulatory network that controls the directionality and timing of cell cycle events. Biochemical and structural work is shedding light on the overall organization of APC/C subunits and on the mechanism of substrate recognition and Ub chain initiation and extension as well as on the molecular mechanisms of a checkpoint that seizes control of APC/C activity during mitosis. Here, we review how these recent advancements are modifying our understanding of the APC/C. PMID:23589490

  5. Quantitative framework for ordered degradation of APC/C substrates.

    Science.gov (United States)

    Lu, Dan; Girard, Juliet R; Li, Weihan; Mizrak, Arda; Morgan, David O

    2015-11-16

    During cell-cycle progression, substrates of a single master regulatory enzyme can be modified in a specific order. Here, we used experimental and computational approaches to dissect the quantitative mechanisms underlying the ordered degradation of the substrates of the ubiquitin ligase APC/C(Cdc20), a key regulator of chromosome segregation in mitosis. We show experimentally that the rate of catalysis varies with different substrates of APC/C(Cdc20). Using a computational model based on multi-step ubiquitination, we then show how changes in the interaction between a single substrate and APC/C(Cdc20) can alter the timing of degradation onset relative to APC/C(Cdc20) activation, while ensuring a fast degradation rate. Degradation timing and dynamics depend on substrate affinity for the enzyme as well as the catalytic rate at which the substrate is modified. When two substrates share the same pool of APC/C(Cdc20), their relative enzyme affinities and rates of catalysis influence the partitioning of APC/C(Cdc20) among substrates, resulting in substrate competition. Depending on how APC/C(Cdc20) is partitioned among its substrates, competition can have minor or major effects on the degradation of certain substrates. We show experimentally that increased expression of the early APC/C(Cdc20) substrate Clb5 does not delay the degradation of the later substrate securin, arguing against a role for competition with Clb5 in establishing securin degradation timing. The degradation timing of APC/C(Cdc20) substrates depends on the multi-step nature of ubiquitination, differences in substrate-APC/C(Cdc20) interactions, and competition among substrates. Our studies provide a conceptual framework for understanding how ordered modification can be established among substrates of the same regulatory enzyme, and facilitate our understanding of how precise temporal control is achieved by a small number of master regulators to ensure a successful cell division cycle.

  6. Interaction between APC and Fen1 during breast carcinogenesis.

    Science.gov (United States)

    Narayan, Satya; Jaiswal, Aruna S; Law, Brian K; Kamal, Mohammad A; Sharma, Arun K; Hromas, Robert A

    2016-05-01

    Aberrant DNA base excision repair (BER) contributes to malignant transformation. However, inter-individual variations in DNA repair capacity plays a key role in modifying breast cancer risk. We review here emerging evidence that two proteins involved in BER - adenomatous polyposis coli (APC) and flap endonuclease 1 (Fen1) - promote the development of breast cancer through novel mechanisms. APC and Fen1 expression and interaction is increased in breast tumors versus normal cells, APC interacts with and blocks Fen1 activity in Pol-β-directed LP-BER, and abrogation of LP-BER is linked with cigarette smoke condensate-induced transformation of normal breast epithelial cells. Carcinogens increase expression of APC and Fen1 in spontaneously immortalized human breast epithelial cells, human colon cancer cells, and mouse embryonic fibroblasts. Since APC and Fen1 are tumor suppressors, an increase in their levels could protect against carcinogenesis; however, this does not seem to be the case. Elevated Fen1 levels in breast and lung cancer cells may reflect the enhanced proliferation of cancer cells or increased DNA damage in cancer cells compared to normal cells. Inactivation of the tumor suppressor functions of APC and Fen1 is due to their interaction, which may act as a susceptibility factor for breast cancer. The increased interaction of APC and Fen1 may occur due to polypmorphic and/or mutational variation in these genes. Screening of APC and Fen1 polymorphic and/or mutational variations and APC/Fen1 interaction may permit assessment of individual DNA repair capability and the risk for breast cancer development. Such individuals might lower their breast cancer risk by reducing exposure to carcinogens. Stratifying individuals according to susceptibility would greatly assist epidemiologic studies of the impact of suspected environmental carcinogens. Additionally, a mechanistic understanding of the interaction of APC and Fen1 may provide the basis for developing new and

  7. IMGT unique numbering for MHC groove G-DOMAIN and MHC superfamily (MhcSF) G-LIKE-DOMAIN

    DEFF Research Database (Denmark)

    Lefranc, Marie-Paule; Duprat, E.; Kaas, Quentin

    2005-01-01

    IMGT, the international ImMunoGeneTics information system® (http://imgt.cines.fr) provides a common access to expertly annotated data on the genome, proteome, genetics and structure of immunoglobulins (IG), T cell receptors (TR), major histocompatibility complex (MHC), and related proteins...

  8. APC/C--the master controller of origin licensing?

    Science.gov (United States)

    Sivaprasad, Umasundari; Machida, Yuichi J; Dutta, Anindya

    2007-02-23

    DNA replication must be tightly controlled to prevent initiation of a second round of replication until mitosis is complete. So far, components of the pre-replicative complex (Cdt1, Cdc6 and geminin) were considered key players in this regulation. In a new study, Machida and Dutta have shown that depletion of Emi1 caused cells to replicate their DNA more than once per cell cycle 1. This effect was dependent on the ability of Emi1 to inhibit the APC/C. In addition to its role in regulating entry into mitosis, oscillation of APC/C activity regulates pre-RC formation: high APC/C activity in late M/G1 allows pre-RC formation and low APC/C activity in S/G2 prevents pre-RC formation for a second time thereby preventing rereplication. Each redundant pathway to prevent rereplication is dependent on regulating one of the pre-RC components, and all of the pathways are co-regulated by Emi1 through the APC/C. In this commentary we discuss how this new role of Emi1 adds to our understanding of the regulation of replication initiation. We also review the literature to analyze whether APC/C has a role in regulating endoreduplication (a normal state of polyploidy in some differentiated cells). Similarly a role of premature APC/C activation in genomic instability of tumors is discussed.

  9. APC/C – the master controller of origin licensing?

    Directory of Open Access Journals (Sweden)

    Dutta Anindya

    2007-02-01

    Full Text Available Abstract DNA replication must be tightly controlled to prevent initiation of a second round of replication until mitosis is complete. So far, components of the pre-replicative complex (Cdt1, Cdc6 and geminin were considered key players in this regulation. In a new study, Machida and Dutta have shown that depletion of Emi1 caused cells to replicate their DNA more than once per cell cycle 1. This effect was dependent on the ability of Emi1 to inhibit the APC/C. In addition to its role in regulating entry into mitosis, oscillation of APC/C activity regulates pre-RC formation: high APC/C activity in late M/G1 allows pre-RC formation and low APC/C activity in S/G2 prevents pre-RC formation for a second time thereby preventing rereplication. Each redundant pathway to prevent rereplication is dependent on regulating one of the pre-RC components, and all of the pathways are co-regulated by Emi1 through the APC/C. In this commentary we discuss how this new role of Emi1 adds to our understanding of the regulation of replication initiation. We also review the literature to analyze whether APC/C has a role in regulating endoreduplication (a normal state of polyploidy in some differentiated cells. Similarly a role of premature APC/C activation in genomic instability of tumors is discussed.

  10. State of the APC/C: Organization, function, and structure

    Science.gov (United States)

    McLean, Janel R.; Chaix, Denis; Ohi, Melanie D.; Gould, Kathleen L.

    2016-01-01

    The ubiquitin-proteasome protein degradation system is involved in many essential cellular processes including cell cycle regulation, cell differentiation, and the unfolded protein response.The anaphase-promoting complex/cyclosome (APC/C), an evolutionary conserved E3 ubiquitin ligase, was discovered 15 years ago because of its pivotal role in cyclin degradation and mitotic progression. Since then, we have learned that the APC/C is a very large, complex E3 ligase composed of 13 subunits, yielding a molecular machine of approximately 1 MDa. The intricate regulation of the APC/C is mediated by the Cdc20 family of activators, pseudosubstrate inhibitors, protein kinases and phosphatases and the spindle assembly checkpoint. The large size, complexity, and dynamic nature of the APC/C represent significant obstacles toward high-resolution structural techniques; however, over the last decade, there have been a number of lower resolution APC/C structures determined using single particle electron microscopy. These structures, when combined with data generated from numerous genetic and biochemical studies, have begun to shed light on how APC/C activity is regulated. Here, we discuss the most recent developments in the APC/C field concerning structure, substrate recognition, and catalysis. PMID:21261459

  11. A hybrid approach for predicting promiscuous MHC class I restricted ...

    Indian Academy of Sciences (India)

    Prakash

    2006-09-15

    Sep 15, 2006 ... with existing MHC binder prediction methods for alleles studied by both ... in locating the promiscuous MHC binding regions from antigen sequence. ... Artificial neural network; MHC class I alleles; promiscuous binders; ... this problem by developing methods for prediction for ... In case equal number of.

  12. Prediction of antigenic epitopes and MHC binders of neurotoxin ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-01

    Dec 1, 2009 ... scorpion chlorotoxin-like short-chain neurotoxins (SCNs). *Corresponding ... Protein sequence analysis. Here we ... MHC/peptide binding is a log-transformed value related to the IC50 values in nM ..... porter. Adducts of MHC and peptide complexes are the ligands for T cell receptors (TCR) (Table-1). MHC.

  13. MHC classⅠ gene in two duck lines

    Indian Academy of Sciences (India)

    Navya

    Weishan Ma duck (WS) is the eugenic endemic breed, one of the four famous ducks in China, as well Cherry Valley duck (CV) is the largest number of breeding variety. WS is egg strain and CV is meat type. The two duck lines mainly support the. Chinese waterfowl industry. In this study, MHC class Ⅰ genes of WS and CV ...

  14. MHC Region and Its Related Disease Study

    DEFF Research Database (Denmark)

    Cao, Hongzhi

    The major histocompatibility complex (MHC) is one of the most gene dense regions in the human genome and many disorders, including primary immune deficiencies, autoimmune conditions, infections, cancers and mental disorder have been found to be associated with this region. However, due to a high ...

  15. It's the peptide-MHC affinity, stupid.

    Science.gov (United States)

    Kammertoens, Thomas; Blankenstein, Thomas

    2013-04-15

    Adoptively transferred T cells can reject large established tumors, but recurrence due to escape variants frequently occurs. In this issue of Cancer Cell, Engels et al. demonstrate that the affinity of the target peptide to the MHC molecule determines whether large tumors will relapse following adoptive T cell therapy. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. The MHC molecules of nonmammalian vertebrates

    DEFF Research Database (Denmark)

    Kaufman, J; Skjoedt, K; Salomonsen, J

    1990-01-01

    class II distribution. The axolotl has a very poor immune response (as though there are no helper T cells), a wide class II distribution and, for most animals, no cell surface class I molecule. It would be enlightening to understand both the mechanisms for the regulation of the MHC molecules during...

  17. 42 CFR 419.31 - Ambulatory payment classification (APC) system and payment weights.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Ambulatory payment classification (APC) system and... Outpatient Services § 419.31 Ambulatory payment classification (APC) system and payment weights. (a) APC... of resource use into APC groups. Except as specified in paragraph (a)(2) of this section, items and...

  18. APC Inhibits Ligand-Independent Wnt Signaling by the Clathrin Endocytic Pathway.

    Science.gov (United States)

    Saito-Diaz, Kenyi; Benchabane, Hassina; Tiwari, Ajit; Tian, Ai; Li, Bin; Thompson, Joshua J; Hyde, Annastasia S; Sawyer, Leah M; Jodoin, Jeanne N; Santos, Eduardo; Lee, Laura A; Coffey, Robert J; Beauchamp, R Daniel; Williams, Christopher S; Kenworthy, Anne K; Robbins, David J; Ahmed, Yashi; Lee, Ethan

    2018-03-12

    Adenomatous polyposis coli (APC) mutations cause Wnt pathway activation in human cancers. Current models for APC action emphasize its role in promoting β-catenin degradation downstream of Wnt receptors. Unexpectedly, we find that blocking Wnt receptor activity in APC-deficient cells inhibits Wnt signaling independently of Wnt ligand. We also show that inducible loss of APC is rapidly followed by Wnt receptor activation and increased β-catenin levels. In contrast, APC2 loss does not promote receptor activation. We show that APC exists in a complex with clathrin and that Wnt pathway activation in APC-deficient cells requires clathrin-mediated endocytosis. Finally, we demonstrate conservation of this mechanism in Drosophila intestinal stem cells. We propose a model in which APC and APC2 function to promote β-catenin degradation, and APC also acts as a molecular "gatekeeper" to block receptor activation via the clathrin pathway. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. OpenAPC. Open-Access-Publikationskosten als Open Data

    OpenAIRE

    Tullney, Marco

    2015-01-01

    Präsentationsfolien zum Vortrag „OpenAPC. Open-Access-Publikationskosten als Open Data“ in der Session „Ausgestaltung eines wissenschaftsadäquaten APC-Marktes: Grundsätze, Finanzierungsansätze und Management“ der Open-Access-Tage 2015 in Zürich (https://www.open-access.net/community/open-access-tage/open-access-tage-2015-zuerich/programm/#c1974)

  20. The combination of major histocompatibility complex (MHC) and non-MHC genes influences murine lymphocytic choriomeningitis virus pathogenesis

    DEFF Research Database (Denmark)

    Eyler, Y L; Pfau, C J; Broomhall, K S

    1989-01-01

    with the recessive disease phenotype. In all cases, susceptibility was dominant. In backcross progeny obtained from matings of parental strains differing in both major histocompatibility complex (MHC) and non-MHC (SWR; C3H), 90% of the challenged mice died, indicating that at least three loci controlled...... susceptibility to the disease. When the parental strains carried similar MHC haplotypes but dissimilar background genes (B10.BR; CBA), 78% of the backcross mice succumbed, indicating that at least two non-MHC loci influenced disease susceptibility. It is unlikely, however, that the same two non-MHC loci...... are critical in all genetic combinations, since F1 produced from two H-2 identical, resistant strains (B10.BR; C3H) were found to be fully susceptible. When congenic mice, differing only in the D-end of the MHC region, were analysed, 50% of the backcross animals died, indicating that one gene in the MHC region...

  1. Differential RNA-seq analysis comparing APC-defective and APC-restored SW480 colorectal cancer cells.

    Science.gov (United States)

    King, Lauren E; Love, Christopher G; Sieber, Oliver M; Faux, Maree C; Burgess, Antony W

    2016-03-01

    The adenomatous polyposis coli (APC) tumour suppressor gene is mutated in about 80% of colorectal cancers (CRC) Brannon et al. (2014) [1]. APC is a large multifunctional protein that regulates many biological functions including Wnt signalling (through the regulation of beta-catenin stability) Reya and Clevers (2005) [2], cell migration Kroboth et al. (2007), Sansom et al. (2004) [3], [4], mitosis Kaplan et al. (2001) [5], cell adhesion Faux et al. (2004), Carothers et al. (2001) [6], [7] and differentiation Sansom et al. (2004) [4]. Although the role of APC in CRC is often described as the deregulation of Wnt signalling, its other biological functions suggest that there are other factors at play that contribute to the onset of adenomas and the progression of CRC upon the truncation of APC. To identify genes and pathways that are dysregulated as a consequence of loss of function of APC, we compared the gene expression profiles of the APC mutated human CRC cell line SW480 following reintroduction of wild-type APC (SW480 + APC) or empty control vector (SW480 + vector control) Faux et al. (2004) . Here we describe the RNA-seq data derived for three biological replicates of parental SW480, SW480 + vector control and SW480 + APC cells, and present the bioinformatics pipeline used to test for differential gene expression and pathway enrichment analysis. A total of 1735 genes showed significant differential expression when APC was restored and were enriched for genes associated with cell polarity, Wnt signalling and the epithelial to mesenchymal transition. There was additional enrichment for genes involved in cell-cell adhesion, cell-matrix junctions, angiogenesis, axon morphogenesis and cell movement. The raw and analysed RNA-seq data have been deposited in the Gene Expression Omnibus (GEO) database under accession number GSE76307. This dataset is useful for further investigations of the impact of APC mutation on the properties of colorectal cancer cells.

  2. APC/C Dysfunction Limits Excessive Cancer Chromosomal Instability.

    Science.gov (United States)

    Sansregret, Laurent; Patterson, James O; Dewhurst, Sally; López-García, Carlos; Koch, André; McGranahan, Nicholas; Chao, William Chong Hang; Barry, David J; Rowan, Andrew; Instrell, Rachael; Horswell, Stuart; Way, Michael; Howell, Michael; Singleton, Martin R; Medema, René H; Nurse, Paul; Petronczki, Mark; Swanton, Charles

    2017-02-01

    Intercellular heterogeneity, exacerbated by chromosomal instability (CIN), fosters tumor heterogeneity and drug resistance. However, extreme CIN correlates with improved cancer outcome, suggesting that karyotypic diversity required to adapt to selection pressures might be balanced in tumors against the risk of excessive instability. Here, we used a functional genomics screen, genome editing, and pharmacologic approaches to identify CIN-survival factors in diploid cells. We find partial anaphase-promoting complex/cyclosome (APC/C) dysfunction lengthens mitosis, suppresses pharmacologically induced chromosome segregation errors, and reduces naturally occurring lagging chromosomes in cancer cell lines or following tetraploidization. APC/C impairment caused adaptation to MPS1 inhibitors, revealing a likely resistance mechanism to therapies targeting the spindle assembly checkpoint. Finally, CRISPR-mediated introduction of cancer somatic mutations in the APC/C subunit cancer driver gene CDC27 reduces chromosome segregation errors, whereas reversal of an APC/C subunit nonsense mutation increases CIN. Subtle variations in mitotic duration, determined by APC/C activity, influence the extent of CIN, allowing cancer cells to dynamically optimize fitness during tumor evolution. We report a mechanism whereby cancers balance the evolutionary advantages associated with CIN against the fitness costs caused by excessive genome instability, providing insight into the consequence of CDC27 APC/C subunit driver mutations in cancer. Lengthening of mitosis through APC/C modulation may be a common mechanism of resistance to cancer therapeutics that increase chromosome segregation errors. Cancer Discov; 7(2); 218-33. ©2017 AACR.See related commentary by Burkard and Weaver, p. 134This article is highlighted in the In This Issue feature, p. 115. ©2017 American Association for Cancer Research.

  3. DNA sequence of the Peromyscus leucopus MHC class II gene Aa (MhcPeleAa)

    Energy Technology Data Exchange (ETDEWEB)

    Crew, M.D.; Bates, L.M. [Univ. of Arkansas for Medical Sciences, Little Rock, AR (United States)

    1996-09-01

    The genus Peromyscus has been extensively studied by populations biologists and ecologists for over eighty years, with P. leucopus (the white-footed mouse) being one of the most intensively investigated species. Polymorphic major histocompatibility complex (MHC) genes have proven useful in population genetic studies and might be helpful in understanding the population dynamics of Peromyscus species which are ubiquitously distributed over North and Central America. Polymorphism of P. leucopus MHC (MhcPele) class II genes was evident by restriction fragment length polymorphism (RFLP) analyses using human and mouse probes and Pele class II loci exhibited degrees of polymorphism similar to H2 class II genes (A-like>E-like). 8 refs., 2 figs.

  4. MHC class II expression through a hitherto unknown pathway supports T helper cell-dependent immune responses: implications for MHC class II deficiency.

    Science.gov (United States)

    Buch, Thorsten; Polic, Bojan; Clausen, Björn E; Weiss, Susanne; Akilli-Ozturk, Ozlem; Chang, Cheong-Hee; Flavell, Richard; Schulz, Ansgar; Jonjic, Stipan; Waisman, Ari; Förster, Irmgard

    2006-02-15

    MHC class II (MHCII) deficiency or bare lymphocyte syndrome (BLS) is a severe immunodeficiency characterized by deficient T helper (Th)-cell-dependent immunity. The disease is caused by defects of the MHCII promoter complex resulting in low or absent MHCII expression. We demonstrate in a murine model of MHCII deficiency (RFX5- or CIITA-deficient mice) that residual MHCII expression by professional antigen-presenting cells (APCs) is sufficient to support activation of adoptively transferred Th cells. Furthermore, upon transplantation of WT thymic epithelium, we observed development of endogenous Th cells with restoration of Th-cell-dependent antibody responses and immunity to cytomegalovirus infection, thus opening the possibility of an alternative treatment regimen for BLS. Residual MHCII expression was further induced by the presence of Th cells and also other stimuli. Analysis of CIITA/RFX5 double-deficient animals revealed that this inducible MHCII expression is genetically independent of the known promoter complex and thus constitutes an alternative MHCII expression pathway. In these experiments, we also detected a novel repressive function of the RFX complex in the absence of CIITA.

  5. MHC class II-derived peptides can bind to class II molecules, including self molecules, and prevent antigen presentation

    DEFF Research Database (Denmark)

    Rosloniec, E F; Vitez, L J; Buus, S

    1990-01-01

    the alpha k-3 peptide binds slightly less well. These combined data, suggesting that class II-derived peptides can bind to MHC class II molecules, including the autologous molecule from which they are derived, have important implications for the molecular basis of alloreactivity and autoreactivity. Further...... found in the first and third polymorphic regions (PMR) of the A alpha k chain (alpha k-1 and alpha k-3) were capable of inhibiting the presentation of three different HEL-derived peptide antigens to their appropriate T cells. In addition, the alpha k-1 peptide inhibited the presentation of the OVA(323......-339) immunodominant peptide to the I-Ad-restricted T cell hybridomas specific for it. Prepulsing experiments demonstrated that the PMR peptides were interacting with the APC and not with the T cell hybridomas. These observations were confirmed and extended by the demonstration that the alpha k-1 and alpha k-3...

  6. Primordial linkage of β2-microglobulin to the MHC.

    Science.gov (United States)

    Ohta, Yuko; Shiina, Takashi; Lohr, Rebecca L; Hosomichi, Kazuyoshi; Pollin, Toni I; Heist, Edward J; Suzuki, Shingo; Inoko, Hidetoshi; Flajnik, Martin F

    2011-03-15

    β2-Microglobulin (β2M) is believed to have arisen in a basal jawed vertebrate (gnathostome) and is the essential L chain that associates with most MHC class I molecules. It contains a distinctive molecular structure called a constant-1 Ig superfamily domain, which is shared with other adaptive immune molecules including MHC class I and class II. Despite its structural similarity to class I and class II and its conserved function, β2M is encoded outside the MHC in all examined species from bony fish to mammals, but it is assumed to have translocated from its original location within the MHC early in gnathostome evolution. We screened a nurse shark bacterial artificial chromosome library and isolated clones containing β2M genes. A gene present in the MHC of all other vertebrates (ring3) was found in the bacterial artificial chromosome clone, and the close linkage of ring3 and β2M to MHC class I and class II genes was determined by single-strand conformational polymorphism and allele-specific PCR. This study satisfies the long-held conjecture that β2M was linked to the primordial MHC (Ur MHC); furthermore, the apparent stability of the shark genome may yield other genes predicted to have had a primordial association with the MHC specifically and with immunity in general.

  7. MHCcluster, a method for functional clustering of MHC molecules

    DEFF Research Database (Denmark)

    Thomsen, Martin Christen Frølund; Lundegaard, Claus; Buus, Søren

    2013-01-01

    The identification of peptides binding to major histocompatibility complexes (MHC) is a critical step in the understanding of T cell immune responses. The human MHC genomic region (HLA) is extremely polymorphic comprising several thousand alleles, many encoding a distinct molecule. The potentially...... binding specificity. The method has a flexible web interface that allows the user to include any MHC of interest in the analysis. The output consists of a static heat map and graphical tree-based visualizations of the functional relationship between MHC variants and a dynamic TreeViewer interface where...

  8. High performance APCS conceptual design and evaluation scoping study

    International Nuclear Information System (INIS)

    Soelberg, N.; Liekhus, K.; Chambers, A.; Anderson, G.

    1998-02-01

    This Air Pollution Control System (APCS) Conceptual Design and Evaluation study was conducted to evaluate a high-performance (APC) system for minimizing air emissions from mixed waste thermal treatment systems. Seven variations of high-performance APCS designs were conceptualized using several design objectives. One of the system designs was selected for detailed process simulation using ASPEN PLUS to determine material and energy balances and evaluate performance. Installed system capital costs were also estimated. Sensitivity studies were conducted to evaluate the incremental cost and benefit of added carbon adsorber beds for mercury control, specific catalytic reduction for NO x control, and offgas retention tanks for holding the offgas until sample analysis is conducted to verify that the offgas meets emission limits. Results show that the high-performance dry-wet APCS can easily meet all expected emission limits except for possibly mercury. The capability to achieve high levels of mercury control (potentially necessary for thermally treating some DOE mixed streams) could not be validated using current performance data for mercury control technologies. The engineering approach and ASPEN PLUS modeling tool developed and used in this study identified APC equipment and system performance, size, cost, and other issues that are not yet resolved. These issues need to be addressed in feasibility studies and conceptual designs for new facilities or for determining how to modify existing facilities to meet expected emission limits. The ASPEN PLUS process simulation with current and refined input assumptions and calculations can be used to provide system performance information for decision-making, identifying best options, estimating costs, reducing the potential for emission violations, providing information needed for waste flow analysis, incorporating new APCS technologies in existing designs, or performing facility design and permitting activities

  9. Regulated degradation of the APC coactivator Cdc20

    Directory of Open Access Journals (Sweden)

    Robbins Jonathan A

    2010-09-01

    Full Text Available Abstract Background Cdc20 is a highly conserved activator of the anaphase-promoting complex (APC, promoting cell-cycle-regulated ubiquitination and proteolysis of a number of critical cell-cycle-regulatory targets including securin and mitotic cyclins. APC-Cdc20 activity is tightly regulated, and this regulation is likely important for accurate cell cycle control. One significant component of Cdc20 regulation is thought to be Cdc20 proteolysis. However, published literature suggests different mechanisms and requirements for Cdc20 proteolysis. The degree to which Cdc20 proteolysis is cell-cycle regulated, the dependence of Cdc20 proteolysis on Cdc20 destruction boxes (recognition sequences for APC-mediated ubiqutination, either by Cdc20 or by the related Cdh1 APC activator, and the need for APC itself for Cdc20 proteolysis all have been disputed to varying extents. In animals, Cdc20 proteolysis is thought to be mediated by Cdh1, contributing an intrinsic order of APC activation by Cdc20 and then by Cdh1. One report suggests a Cdh1 requirement for Cdc20 proteolysis in budding yeast; this idea has not been tested further. Results We characterized Cdc20 proteolysis using Cdc20 expressed from its endogenous locus; previous studies generally employed strongly overexpressed Cdc20, which can cause significant artifacts. We analyzed Cdc20 proteolysis with or without mutations in previously identified destruction box sequences, using varying methods of cell cycle synchronization, and in the presence or absence of Cdh1. Cdc20 instability is only partially dependent on destruction boxes. A much stronger dependence on Cdh1 for Cdc20 proteolysis was observed, but Cdh1-independent proteolysis was also clearly observed. Cdc20 proteolysis independent of both destruction boxes and Cdh1 was especially detectable around the G1/S transition; Cdh1-dependent proteolysis was most notable in late mitosis and G1. Conclusions Cdc20 proteolysis is under complex control

  10. MPID-T2: a database for sequence-structure-function analyses of pMHC and TR/pMHC structures.

    Science.gov (United States)

    Khan, Javed Mohammed; Cheruku, Harish Reddy; Tong, Joo Chuan; Ranganathan, Shoba

    2011-04-15

    Sequence-structure-function information is critical in understanding the mechanism of pMHC and TR/pMHC binding and recognition. A database for sequence-structure-function information on pMHC and TR/pMHC interactions, MHC-Peptide Interaction Database-TR version 2 (MPID-T2), is now available augmented with the latest PDB and IMGT/3Dstructure-DB data, advanced features and new parameters for the analysis of pMHC and TR/pMHC structures. http://biolinfo.org/mpid-t2. shoba.ranganathan@mq.edu.au Supplementary data are available at Bioinformatics online.

  11. Inhibition of HLA-DM mediated MHC class II peptide loading by HLA-DO promotes self tolerance

    Directory of Open Access Journals (Sweden)

    Lisa K. Denzin

    2013-12-01

    Full Text Available Major histocompatibility class II (MHCII molecules are loaded with peptides derived from foreign and self-proteins within the endosomes and lysosomes of antigen presenting cells (APCs. This process is mediated by interaction of MHCII with the conserved, nonpolymorphic MHCII-like molecule HLA-DM (DM. DM activity is directly opposed by HLA-DO (DO, another conserved, non-polymorphic MHCII like molecule. DO is an MHCII substrate mimic. Binding of DO to DM prevents MHCII from binding to DM, thereby inhibiting peptide loading. Inhibition of DM function enables low stability MHC complexes to survive and populate the surface of APCS. As a consequence, DO promotes the display of a broader pool of low abundance self-peptides. Broadening the peptide repertoire theoretically reduces the likelihood of inadvertently acquiring a density of self-ligands that is sufficient to activate self-reactive T cells. One function of DO, therefore, is to promote T cell tolerance by shaping the visible image of self. Recent data also shows that DO influences the adaptive immune response by controlling B cell entry into the germinal center reaction. This review explores the data supporting these concepts.

  12. The SysteMHC Atlas project

    DEFF Research Database (Denmark)

    Shao, Wenguang; Pedrioli, Patrick G. A.; Wolski, Witold

    2018-01-01

    consisting of consensus spectra calculated from repeat measurements of the same peptide sequence, and links to other proteomics and immunology databases. The SysteMHC Atlas project was created and will be further expanded using a uniform and open computational pipeline that controls the quality of peptide......-scale generation of immunopeptidomic datasets and recent developments in MS-based peptide analysis technologies now support the generation of the required data. Importantly, the availability of diverse immunopeptidomic datasets has resulted in an increasing need to standardize, store and exchange this type of data...

  13. Epigenetic regulation of APC in the molecular pathogenesis of gallbladder cancer

    Directory of Open Access Journals (Sweden)

    Dinesh Singh Tekcham

    2016-01-01

    Interpretation & conclusions: The present findings indicate epigenetic silencing of APC in advanced GBC. The methylation pattern, followed by expression analysis of APC may be suggested for diagnostic, prognostic and therapeutic purposes in GBC in future.

  14. MHC class II molecules and tumour immunotherapy

    International Nuclear Information System (INIS)

    Oven, I.

    2005-01-01

    Background. Tumour immunotherapy attempts to use the specificity and capability of the immune system to kill malignant cells with a minimum damage to normal tissue. Increasing knowledge of the identity of tumour antigens should help us design more effective therapeutic vaccines. Increasing evidence has demonstrated that MHC class II molecules and CD4+ T cells play important roles in generating and maintaining antitumour immune responses in animal models. These data suggest that it may be necessary to involve both CD4+ and CD8+ T cells for more effective antitumour therapy. Novel strategies have been developed for enhancing T cell responses against cancer by prolonging antigen presentation of dendritic cells to T cells, by the inclusion of MHC class II-restricted tumour antigens and by genetically modifying tumour cells to present antigen to T lymphocytes directly. Conclusions. Vaccines against cancers aim to induce tumour-specific effector T cells that can reduce tumour mass and induce development of tumour-specific T cell memory, that can control tumour relapse. (author)

  15. Apc Restoration Promotes Cellular Differentiation and Reestablishes Crypt Homeostasis in Colorectal Cancer

    NARCIS (Netherlands)

    Dow, Lukas E; O'Rourke, Kevin P; Simon, Janelle; Tschaharganeh, Darjus F; van Es, Johan H; Clevers, Hans; Lowe, Scott W

    2015-01-01

    The adenomatous polyposis coli (APC) tumor suppressor is mutated in the vast majority of human colorectal cancers (CRC) and leads to deregulated Wnt signaling. To determine whether Apc disruption is required for tumor maintenance, we developed a mouse model of CRC whereby Apc can be conditionally

  16. Colonizing the world in spite of reduced MHC variation

    Science.gov (United States)

    Gangoso, L.; Alcaide, M.; Grande, J.M.; Muñoz, J.; Talbot, Sandra L.; Sonsthagen, Sarah A.; Sage, Kevin; Figuerola, J.

    2012-01-01

    Reduced immune gene diversity is thought to negatively affect the capacity of organisms to adapt to pathogen challenges, which represent a major force in natural selection. Genes of the Major Histocompatibility Complex (MHC) are the most widely invoked adaptive loci in conservation biology, and have become the most popular genetic markers to investigate pathogen-host interactions in vertebrates. Although MHC genes are the most polymorphic genes described in the vertebrate genome, the extent to which MHC diversity determines the long-term persistence of populations is, unclear and often debated, as recent studies have documented the occurrence of natural populations thriving even after a depletion of MHC diversity caused by genetic drift. Here, we show that some phylogenetically related species belonging to the Falco genus (Aves: Falconidae) present a dramatically low MHC variability that has not precluded, nevertheless, the successful colonization of almost all existing regions and habitats worldwide. We found evidence for two remarkably different patterns of MHC variation within the genus. While kestrels show a high MHC variation according to the general theory, falcons exhibit an ancestrally low intra- and inter-specific MHC allelic diversity. We provide compelling evidence that this pattern is not caused by the degeneration of functional genes into pseudogenes, the inadvertent analyses of paralogous MHC genes, or the devastating action of genetic drift. Instead, our results strongly support the idea of an evolutionary transition driven and maintained by natural selection from primarily highly variable towards low polymorphic, but functional and expressed, MHC genes with species-specific pathogen-recognition capabilities.

  17. Sympatric and allopatric divergence of MHC genes in threespine stickleback.

    Directory of Open Access Journals (Sweden)

    Blake Matthews

    2010-06-01

    Full Text Available Parasites can strongly affect the evolution of their hosts, but their effects on host diversification are less clear. In theory, contrasting parasite communities in different foraging habitats could generate divergent selection on hosts and promote ecological speciation. Immune systems are costly to maintain, adaptable, and an important component of individual fitness. As a result, immune system genes, such as those of the Major Histocompatibility Complex (MHC, can change rapidly in response to parasite-mediated selection. In threespine stickleback (Gasterosteus aculeatus, as well as in other vertebrates, MHC genes have been linked with female mating preference, suggesting that divergent selection acting on MHC genes might influence speciation. Here, we examined genetic variation at MHC Class II loci of sticklebacks from two lakes with a limnetic and benthic species pair, and two lakes with a single species. In both lakes with species pairs, limnetics and benthics differed in their composition of MHC alleles, and limnetics had fewer MHC alleles per individual than benthics. Similar to the limnetics, the allopatric population with a pelagic phenotype had few MHC alleles per individual, suggesting a correlation between MHC genotype and foraging habitat. Using a simulation model we show that the diversity and composition of MHC alleles in a sympatric species pair depends on the amount of assortative mating and on the strength of parasite-mediated selection in adjacent foraging habitats. Our results indicate parallel divergence in the number of MHC alleles between sympatric stickleback species, possibly resulting from the contrasting parasite communities in littoral and pelagic habitats of lakes.

  18. MHC class II molecules deliver costimulatory signals in human T cells through a functional linkage with IL-2-receptors

    DEFF Research Database (Denmark)

    Odum, Niels; Kanner, S B; Ledbetter, J A

    1993-01-01

    MHC class II-positive T cells are found in tissues involved in autoimmune and infectious disorders. Because stimulation of class II molecules by mAb or bacterial superantigens induces protein tyrosine phosphorylation through activation of PTK3 in T cells, we hypothesized that class II signals play...... tyrosine phosphorylation of specific substrates including PLC-gamma 1. Combined stimulation of IL-2R and class II molecules had an additive effect on tyrosine phosphorylation. Pretreatment of T cells with a protein tyrosine kinase inhibitor, herbimycin A, inhibited IL-2 and class II-induced proliferation...... a regulatory function in T cell activation. Here, we show that cross-linking HLA-DR and -DP but not -DQ molecules by immobilized mAb enhanced proliferative T cell responses to IL-2. In contrast, class II stimulation had no effect on IL-4-induced proliferation. The costimulatory effect was most pronounced...

  19. Simulation of Major Histocompatibility Complex (MHC Structure and Peptide Loading into an MHC Binding Pocket with Teachers’Hands

    Directory of Open Access Journals (Sweden)

    Mojtaba Sankian

    2013-10-01

    Full Text Available Molecular understanding of three-dimensional (3D peptide: MHC models require both basic knowledge of computational modeling and skilled visual perception, which are not possessed by all students. The present model aims to simulate MHC molecular structure with the hands and make a profound impression on the students.

  20. The Anaphase-Promoting Complex (APC) ubiquitin ligase affects chemosensory behavior in C. elegans.

    Science.gov (United States)

    Wang, Julia; Jennings, Alexandra K; Kowalski, Jennifer R

    2016-01-01

    The regulation of fundamental aspects of neurobiological function has been linked to the ubiquitin signaling system (USS), which regulates the degradation and activity of proteins and is catalyzed by E1, E2, and E3 enzymes. The Anaphase-Promoting Complex (APC) is a multi-subunit E3 ubiquitin ligase that controls diverse developmental and signaling processes in post-mitotic neurons; however, potential roles for the APC in sensory function have yet to be explored. In this study, we examined the effect of the APC ubiquitin ligase on chemosensation in Caenorhabditis elegans by testing chemotaxis to the volatile odorants, diacetyl, pyrazine, and isoamyl alcohol, to which wild-type worms are attracted. Animals with loss of function mutations in either of two alleles (g48 and ye143) of the gene encoding the APC subunit EMB-27 APC6 showed increased chemotaxis towards diacetyl and pyrazine, odorants sensed by AWA neurons, but exhibited normal chemotaxis to isoamyl alcohol, which is sensed by AWC neurons. The statistically significant increase in chemotaxis in the emb-27 APC6 mutants suggests that the APC inhibits AWA-mediated chemosensation in C. elegans. Increased chemotaxis to pyrazine was also seen with mutants lacking another essential APC subunit, MAT-2 APC1; however, mat-2 APC1 mutants exhibited wild type responses to diacetyl. The difference in responsiveness of these two APC subunit mutants may be due to differential strength of these hypomorphic alleles or may indicate the presence of functional sub-complexes of the APC at work in this process. These findings are the first evidence for APC-mediated regulation of chemosensation and lay the groundwork for further studies aimed at identifying the expression levels, function, and targets of the APC in specific sensory neurons. Because of the similarity between human and C. elegans nervous systems, the role of the APC in sensory neurons may also advance our understanding of human sensory function and disease.

  1. Fission Yeast Apc15 Stabilizes MCC-Cdc20-APC/C Complexes, Ensuring Efficient Cdc20 Ubiquitination and Checkpoint Arrest.

    Science.gov (United States)

    May, Karen M; Paldi, Flora; Hardwick, Kevin G

    2017-04-24

    During mitosis, cells must segregate the replicated copies of their genome to their daughter cells with extremely high fidelity. Segregation errors lead to an abnormal chromosome number (aneuploidy), which typically results in disease or cell death [1]. Chromosome segregation and anaphase onset are initiated through the action of the multi-subunit E3 ubiquitin ligase known as the anaphase-promoting complex or cyclosome (APC/C [2]). The APC/C is inhibited by the spindle checkpoint in the presence of kinetochore attachment defects [3, 4]. Here we demonstrate that two non-essential APC/C subunits (Apc14 and Apc15) regulate association of spindle checkpoint proteins, in the form of the mitotic checkpoint complex (MCC), with the APC/C. apc14Δ mutants display increased MCC association with the APC/C and are unable to silence the checkpoint efficiently. Conversely, apc15Δ mutants display reduced association between the MCC and APC/C, are defective in poly-ubiquitination of Cdc20, and are checkpoint defective. In vitro reconstitution studies have shown that human MCC-APC/C can contain two molecules of Cdc20 [5-7]. Using a yeast strain expressing two Cdc20 genes with different epitope tags, we show by co-immunoprecipitation that this is true in vivo. MCC binding to the second molecule of Cdc20 is mediated via the C-terminal KEN box in Mad3. Somewhat surprisingly, complexes containing both molecules of Cdc20 accumulate in apc15Δ cells, and the implications of this observation are discussed. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  2. Effects of the APC materials on c-axis correlated pinning effects in a-axis oriented Y123/2D APC multilayer films

    International Nuclear Information System (INIS)

    Takamura, M.; Mukaida, M.; Horii, S.; Ichinose, A.; Kita, R.; Namba, M.; Awaji, S.; Watanabe, K.; Matsumoto, K.; Yoshida, Y.; Teranishi, R.; Yamada, K.; Mori, N.

    2009-01-01

    For a-axis oriented and c-axis in-plane aligned YBa 2 Cu 3 O 7-δ /artificial pinning center (Y123/APC) alternately-layered thin films, effects of the APC materials on the multilayer structures are discussed. Pr123, (Y 1-x Pr x )123 and Gd 2 CuO 4 (Gd214) were used as APCs. The multilayer structure was observed for Y123/Pr123 films and Y123/Gd214 films. However, some grains are also grown in the Y123/Gd214 film. For the Y123/Pr123 multilayer film, each Pr123 layer act as two-dimensional APCs (2D APCs) in the magnetic field angular dependences of the critical current density. The growth mechanism of the multilayer structure in the Y123/2D APC films is discussed by a transmission electron microscopy and an atomic force microscope. It is found that two conditions are needed to obtain the c-axis correlated pinning effects by 2D APC in the a-axis oriented and c-axis in-plane aligned Y123/APC multilayer films: the same structure as Y123; Y-free APC materials.

  3. Correlation between the methylation of APC gene promoter and colon cancer.

    Science.gov (United States)

    Li, Bing-Qiang; Liu, Peng-Peng; Zhang, Cai-Hua

    2017-08-01

    The present study was planned to explore the correlation between the methylation of APC (adenomatous polyposis coli) and colon carcinogenesis. Colon cancer tissues and tumor-adjacent normal tissues of 60 colon cancer patients (who received surgical operation in our hospital from January 2012 to December 2014) were collected. SW1116 cells in human colon cancer tissues were selected for culturing. 5-aza-2c-deoxycytidine (5-aza-dC) was utilized as an inhibitor of the methylation for APC gene. Methylation specific PCR (MSP) was utilized for detection of APC methylation in SW1116 cells. The MTT and Transwell assays were performed to detect the effect of the methylation of APC gene on the proliferation and invasive abilities of SW1116 cells. The correlation between the methylation of APC gene and pathological parameters of colon cancer patients was analyzed. MSP results revealed that 41 cases (68.33%) showed methylation of APC gene in colon cancer tissues. No methylation of APC gene was found in tumor-adjacent normal tissues. 5-aza-dC was able to inhibit the methylation of APC gene in SW1116 cells. APC gene methylation was correlated with tumor size, differentiation degree, lymph node metastasis and Dukes staging. In conclusion, the levels of the methylation of APC in colon cancer tissues and SW1116 cells are relatively high. The methylation of APC promoted the proliferation and invasion abilities of SW1116 cells. Furthermore, methylation is correlated with a variety of clinicopathological features of colon cancer patients.

  4. The APC tumor suppressor is required for epithelial cell polarization and three-dimensional morphogenesis

    Science.gov (United States)

    Lesko, Alyssa C.; Goss, Kathleen H.; Yang, Frank F.; Schwertner, Adam; Hulur, Imge; Onel, Kenan; Prosperi, Jenifer R.

    2015-01-01

    The Adenomatous Polyposis Coli (APC) tumor suppressor has been previously implicated in the control of apical-basal polarity; yet, the consequence of APC loss-of-function in epithelial polarization and morphogenesis has not been characterized. To test the hypothesis that APC is required for the establishment of normal epithelial polarity and morphogenesis programs, we generated APC-knockdown epithelial cell lines. APC depletion resulted in loss of polarity and multi-layering on permeable supports, and enlarged, filled spheroids with disrupted polarity in 3D culture. Importantly, these effects of APC knockdown were independent of Wnt/β-catenin signaling, but were rescued with either full-length or a carboxy (c)-terminal segment of APC. Moreover, we identified a gene expression signature associated with APC knockdown that points to several candidates known to regulate cell-cell and cell-matrix communication. Analysis of epithelial tissues from mice and humans carrying heterozygous APC mutations further support the importance of APC as a regulator of epithelial behavior and tissue architecture. These data also suggest that the initiation of epithelial-derived tumors as a result of APC mutation or gene silencing may be driven by loss of polarity and dysmorphogenesis. PMID:25578398

  5. Methods for MHC genotyping in non-model vertebrates.

    Science.gov (United States)

    Babik, W

    2010-03-01

    Genes of the major histocompatibility complex (MHC) are considered a paradigm of adaptive evolution at the molecular level and as such are frequently investigated by evolutionary biologists and ecologists. Accurate genotyping is essential for understanding of the role that MHC variation plays in natural populations, but may be extremely challenging. Here, I discuss the DNA-based methods currently used for genotyping MHC in non-model vertebrates, as well as techniques likely to find widespread use in the future. I also highlight the aspects of MHC structure that are relevant for genotyping, and detail the challenges posed by the complex genomic organization and high sequence variation of MHC loci. Special emphasis is placed on designing appropriate PCR primers, accounting for artefacts and the problem of genotyping alleles from multiple, co-amplifying loci, a strategy which is frequently necessary due to the structure of the MHC. The suitability of typing techniques is compared in various research situations, strategies for efficient genotyping are discussed and areas of likely progress in future are identified. This review addresses the well established typing methods such as the Single Strand Conformation Polymorphism (SSCP), Denaturing Gradient Gel Electrophoresis (DGGE), Reference Strand Conformational Analysis (RSCA) and cloning of PCR products. In addition, it includes the intriguing possibility of direct amplicon sequencing followed by the computational inference of alleles and also next generation sequencing (NGS) technologies; the latter technique may, in the future, find widespread use in typing complex multilocus MHC systems. © 2009 Blackwell Publishing Ltd.

  6. A multigene mutation classification of 468 colorectal cancers reveals a prognostic role for APC

    Science.gov (United States)

    Schell, Michael J.; Yang, Mingli; Teer, Jamie K.; Lo, Fang Yin; Madan, Anup; Coppola, Domenico; Monteiro, Alvaro N. A.; Nebozhyn, Michael V.; Yue, Binglin; Loboda, Andrey; Bien-Willner, Gabriel A.; Greenawalt, Danielle M.; Yeatman, Timothy J.

    2016-01-01

    Colorectal cancer (CRC) is a highly heterogeneous disease, for which prognosis has been relegated to clinicopathologic staging for decades. There is a need to stratify subpopulations of CRC on a molecular basis to better predict outcome and assign therapies. Here we report targeted exome-sequencing of 1,321 cancer-related genes on 468 tumour specimens, which identified a subset of 17 genes that best classify CRC, with APC playing a central role in predicting overall survival. APC may assume 0, 1 or 2 truncating mutations, each with a striking differential impact on survival. Tumours lacking any APC mutation carry a worse prognosis than single APC mutation tumours; however, two APC mutation tumours with mutant KRAS and TP53 confer the poorest survival among all the subgroups examined. Our study demonstrates a prognostic role for APC and suggests that sequencing of APC may have clinical utility in the routine staging and potential therapeutic assignment for CRC. PMID:27302369

  7. Improved pan-specific MHC class I peptide-binding predictions using a novel representation of the MHC-binding cleft environment

    DEFF Research Database (Denmark)

    Carrasco Pro, S.; Zimic, M.; Nielsen, Morten

    2014-01-01

    of the current state-of-the-art methods for MHC class I is NetMHCpan, which has a core ingredient for the representation of the MHC class I molecule using a pseudo-sequence representation of the binding cleft amino acid environment. New and large MHC-peptide-binding data sets are constantly being made available...... of different MHC data sets including human leukocyte antigen (HLA), non-human primates (chimpanzee, macaque and gorilla) and other animal alleles (cattle, mouse and swine). From these constructs, we showed that by focusing on MHC sequence positions found to be polymorphic across the MHC molecules used to train...

  8. A Genome-wide multidimensional RNAi screen reveals pathways controlling MHC class II antigen presentation

    NARCIS (Netherlands)

    Paul, Petra; van den Hoorn, Tineke; Jongsma, Marlieke L. M.; Bakker, Mark J.; Hengeveld, Rutger; Janssen, Lennert; Cresswell, Peter; Egan, David A.; van Ham, Marieke; ten Brinke, Anja; Ovaa, Huib; Beijersbergen, Roderick L.; Kuijl, Coenraad; Neefjes, Jacques

    2011-01-01

    MHC class II molecules (MHC-II) present peptides to T helper cells to facilitate immune responses and are strongly linked to autoimmune diseases. To unravel processes controlling MHC-II antigen presentation, we performed a genome-wide flow cytometry-based RNAi screen detecting MHC-II expression and

  9. Occult progression by Apc-deficient intestinal crypts as a target for chemoprevention

    Science.gov (United States)

    Liskay, R.Michael

    2014-01-01

    Although Apc mutation is widely considered an initiating event in colorectal cancer, little is known about the earliest stages of tumorigenesis following sporadic Apc loss. Therefore, we have utilized a novel mouse model that facilitates the sporadic inactivation of Apc via frameshift reversion of Cre in single, isolated cells and subsequently tracks the fates of Apc-deficient intestinal cells. Our results suggest that consistent with Apc being a ‘gatekeeper’, loss of Apc early in life during intestinal growth leads to adenomas or increased crypt fission, manifested by fields of mutant but otherwise normal-appearing crypts. In contrast, Apc loss occurring later in life has minimal consequences, with mutant crypts being less prone to either increased crypt fission or adenoma formation. Using the stem cell-specific Lgr5-CreER mouse, we generated different sized fields of Apc-deficient crypts via independent recombination events and found that field size correlates with progression to adenoma. To evaluate this early stage prior to adenoma formation as a therapeutic target, we examined the chemopreventive effects of sulindac on Apc-deficient occult crypt fission. We found that sulindac treatment started early in life inhibits the morphologically occult spread of Apc-deficient crypts and thus reduces adenoma numbers. Taken together these results suggest that: (i) earlier Apc loss promotes increased crypt fission, (ii) a field of Apc-deficient crypts, which can form via occult crypt fission or independent neighboring events, is an important intermediate between loss of Apc and adenoma formation and (iii) normal-appearing Apc-deficient crypts are potential unappreciated targets for cancer screening and chemoprevention. PMID:23996931

  10. Timing of APC/C substrate degradation is determined by fzy/fzr specificity of destruction boxes

    OpenAIRE

    Zur, Amit; Brandeis, Michael

    2002-01-01

    The anaphase promoting complex/cyclosome (APC/C), activated by fzy and fzr, degrades cell cycle proteins that carry RXXL or KEN destruction boxes (d-boxes). APC/C substrates regulate sequential events and must be degraded in the correct order during mitosis and G1. We studied how d-boxes determine APC/Cfzy/APC/Cfzr specificity and degradation timing. Cyclin B1 has an RXXL box and is degraded by both APC/Cfzy and APC/Cfzr; fzy has a KEN box and is degraded by APC/Cfzr only. We characterized th...

  11. APC: A new code for Atmospheric Polarization Computations

    International Nuclear Information System (INIS)

    Korkin, Sergey V.; Lyapustin, Alexei I.; Rozanov, Vladimir V.

    2013-01-01

    A new polarized radiative transfer code Atmospheric Polarization Computations (APC) is described. The code is based on separation of the diffuse light field into anisotropic and smooth (regular) parts. The anisotropic part is computed analytically. The smooth regular part is computed numerically using the discrete ordinates method. Vertical stratification of the atmosphere, common types of bidirectional surface reflection and scattering by spherical particles or spheroids are included. A particular consideration is given to computation of the bidirectional polarization distribution function (BPDF) of the waved ocean surface. -- Highlights: •A new code, APC, has been developed. •The code was validated against well-known codes. •The BPDF for an arbitrary Mueller matrix is computed

  12. Period 2 Mutation Accelerates ApcMin/+ Tumorigenesis

    Science.gov (United States)

    Wood, Patricia A.; Yang, Xiaoming; Taber, Andrew; Oh, Eun-Young; Ansell, Christine; Ayers, Stacy E.; Al-Assaad, Ziad; Carnevale, Kevin; Berger, Franklin G.; Peña, Maria Marjorette O.; Hrushesky, William J.M.

    2014-01-01

    Colorectal cancer risk is increased in shift workers with presumed circadian disruption. Intestinal epithelial cell proliferation is gated throughout each day by the circadian clock. Period 2 (Per2) is a key circadian clock gene. Per2 mutant (Per2m/m) mice show an increase in lymphomas and deregulated expression of cyclin D and c-Myc genes that are key to proliferation control. We asked whether Per2 clock gene inactivation would accelerate intestinal and colonic tumorigenesis. The effects of PER2 on cell proliferation and β-catenin were studied in colon cancer cell lines by its down-regulation following RNA interference. The effects of Per2 inactivation in vivo on β-catenin and on intestinal and colonic polyp formation were studied in mice with Per2 mutation alone and in combination with an Apc mutation using polyp-prone ApcMin/+ mice. Down-regulation of PER2 in colon cell lines (HCT116 and SW480) increases β-catenin, cyclin D, and cell proliferation. Down-regulation of β-catenin along with Per2 blocks the increase in cyclin D and cell proliferation. Per2m/m mice develop colonic polyps and show an increase in small intestinal mucosa β-catenin and cyclin D protein levels compared with wild-type mice. ApcMin/+Per2m/m mice develop twice the number of small intestinal and colonic polyps, with more severe anemia and splenomegaly, compared with ApcMin/+ mice. These data suggest that Per2 gene product suppresses tumorigenesis in the small intestine and colon by down-regulation of β-catenin and β-catenin target genes, and this circadian core clock gene may represent a novel target for colorectal cancer prevention and control. PMID:19010825

  13. lemmingA encodes the Apc11 subunit of the APC/C in Drosophila melanogaster that forms a ternary complex with the E2-C type ubiquitin conjugating enzyme, Vihar and Morula/Apc2

    Directory of Open Access Journals (Sweden)

    Nagy Olga

    2012-03-01

    Full Text Available Abstract Background Ubiquitin-dependent protein degradation is a critical step in key cell cycle events, such as metaphase-anaphase transition and mitotic exit. The anaphase promoting complex/cyclosome (APC/C plays a pivotal role in these transitions by recognizing and marking regulatory proteins for proteasomal degradation. Its overall structure and function has been elucidated mostly in yeasts and mammalian cell lines. The APC/C is, however, a multisubunit assembly with at least 13 subunits and their function and interaction within the complex is still relatively uncharacterized, particularly in metazoan systems. Here, lemming (lmg mutants were used to study the APC/C subunit, Apc11, and its interaction partners in Drosophila melanogaster. Results The lmg gene was initially identified through a pharate adult lethal P element insertion mutation expressing developmental abnormalities and widespread apoptosis in larval imaginal discs and pupal abdominal histoblasts. Larval neuroblasts were observed to arrest mitosis in a metaphase-like state with highly condensed, scattered chromosomes and frequent polyploidy. These neuroblasts contain high levels of both cyclin A and cyclin B. The lmg gene was cloned by virtue of the lmg03424 P element insertion which is located in the 5' untranslated region. The lemming locus is transcribed to give a 2.0 kb mRNA that contains two ORFs, lmgA and lmgB. The lmgA ORF codes for a putative protein with more than 80% sequence homology to the APC11 subunit of the human APC/C. The 85 amino acid protein also contains a RING-finger motif characteristic of known APC11 subunits. The lmgA ORF alone was sufficient to rescue the lethal and mitotic phenotypes of the lmg138 null allele and to complement the temperature sensitive lethal phenotype of the APC11-myc9 budding yeast mutant. The LmgA protein interacts with Mr/Apc2, and they together form a binding site for Vihar, the E2-C type ubiquitin conjugating enzyme. Despite

  14. Reduced expression of APC-1B but not APC-1A by the deletion of promoter 1B is responsible for familial adenomatous polyposis.

    Science.gov (United States)

    Yamaguchi, Kiyoshi; Nagayama, Satoshi; Shimizu, Eigo; Komura, Mitsuhiro; Yamaguchi, Rui; Shibuya, Tetsuo; Arai, Masami; Hatakeyama, Seira; Ikenoue, Tsuneo; Ueno, Masashi; Miyano, Satoru; Imoto, Seiya; Furukawa, Yoichi

    2016-05-24

    Germline mutations in the tumor suppressor gene APC are associated with familial adenomatous polyposis (FAP). Here we applied whole-genome sequencing (WGS) to the DNA of a sporadic FAP patient in which we did not find any pathological APC mutations by direct sequencing. WGS identified a promoter deletion of approximately 10 kb encompassing promoter 1B and exon1B of APC. Additional allele-specific expression analysis by deep cDNA sequencing revealed that the deletion reduced the expression of the mutated APC allele to as low as 11.2% in the total APC transcripts, suggesting that the residual mutant transcripts were driven by other promoter(s). Furthermore, cap analysis of gene expression (CAGE) demonstrated that the deleted promoter 1B region is responsible for the great majority of APC transcription in many tissues except the brain. The deletion decreased the transcripts of APC-1B to 39-45% in the patient compared to the healthy controls, but it did not decrease those of APC-1A. Different deletions including promoter 1B have been reported in FAP patients. Taken together, our results strengthen the evidence that analysis of structural variations in promoter 1B should be considered for the FAP patients whose pathological mutations are not identified by conventional direct sequencing.

  15. Clinical application of Assessment of Parenting Competencies (APC)

    DEFF Research Database (Denmark)

    Jacobsen, Stine Lindahl

    This paper is part of a symposium on music therapy with families with Kirsi Tuomi as Chair. It revolves around the clinical application of a new music therapy assessment model on parent-child interaction and parenting competencies. APC was developed for emotional neglected children and their pare......This paper is part of a symposium on music therapy with families with Kirsi Tuomi as Chair. It revolves around the clinical application of a new music therapy assessment model on parent-child interaction and parenting competencies. APC was developed for emotional neglected children......, child somatic hospitals, centers for refuges and other populations where it would be clinical relevant to assess the parent-child interaction. APC is an observational and improvisational based assessment model evaluating dyads of parent and child (child age range is 5-12). It produces information...... (numbers, graphs, and descriptions) of parent-child interaction and parenting competencies including nonverbal communication, level of attunement in the dyad, and level of emotional support from the parent. It is based on video analysis and a fixed assessment protocol. It was developed through a completed...

  16. Human immunodeficiencies related to APC/T cell interaction

    Directory of Open Access Journals (Sweden)

    Marinos eKallikourdis

    2015-08-01

    Full Text Available The primary event for initiating adaptive immune responses is the encounter between T lymphocytes and antigen presenting cells (APC in the T cell area of secondary lymphoid organs and the formation of highly organized inter-cellular junctions referred to as the immune synapses. In vivo live-cell imaging of APC-T cell interactions combined to functional studies unveiled that T cell fate is dictated, in large part, by the stability of the initial contact. Immune cell interaction is equally important during delivery of T cell help to B cells and for the killing of target cells by cytotoxic T cells and NK cells. The critical role of contact dynamics and synapse stability on the immune response is well illustrated by human immune deficiencies in which disease pathogenesis is linked to altered adhesion or defective cross-talk between the synaptic partners. Here we will discuss in details the mechanisms of defective APC-T cell communications in Wiskott-Aldrich syndrome (WAS and in warts, hypogammaglobulinemia, infections, myelokathexis syndrome (WHIM. In addition, we will summarize the evidences pointing to a compromised conjugate formation in WIP deficiency, DOCK8 deficiency and X-linked lymphoproliferative syndrome.

  17. Molecular basis of APC/C regulation by the spindle assembly checkpoint

    Science.gov (United States)

    Zhang, Ziguo; Yang, Jing; Maslen, Sarah; Skehel, Mark; Barford, David

    2016-01-01

    In the dividing eukaryotic cell the spindle assembly checkpoint (SAC) ensures each daughter cell inherits an identical set of chromosomes. The SAC coordinates the correct attachment of sister chromatid kinetochores to the mitotic spindle with activation of the anaphase-promoting complex/cyclosome (APC/C), the E3 ubiquitin ligase that initiates chromosome separation. In response to unattached kinetochores, the SAC generates the mitotic checkpoint complex (MCC), a multimeric assembly that inhibits the APC/C, delaying chromosome segregation. Here, using cryo-electron microscopy we determined the near-atomic resolution structure of an APC/C-MCC complex (APC/CMCC). We reveal how degron-like sequences of the MCC subunit BubR1 block degron recognition sites on Cdc20, the APC/C coactivator subunit (Cdc20APC/C) responsible for substrate interactions. BubR1 also obstructs binding of UbcH10 (APC/C’s initiating E2) to repress APC/C ubiquitination activity. Conformational variability of the complex allows for UbcH10 association, and we show from a structure of APC/CMCC in complex with UbcH10 how the Cdc20 subunit intrinsic to the MCC (Cdc20MCC) is ubiquitinated, a process that results in APC/C reactivation when the SAC is silenced. PMID:27509861

  18. Epigenetic regulation of APC in the molecular pathogenesis of gallbladder cancer.

    Science.gov (United States)

    Tekcham, Dinesh Singh; Poojary, Satish S; Bhunia, Shushruta; Barbhuiya, Mustafa Ahmed; Gupta, Sanjeev; Shrivastav, Braj Raj; Tiwari, Pramod Kumar

    2016-05-01

    Loss of function of adenomatous polyposis coli (APC) has been reported in cancer. The two promoters of APC, 1A and 1B also have roles in cancer. But, the epigenetic role of APC promoters is not yet clear in gallbladder cancer (GBC) and gallstone diseases (GSD). We undertook this study to determine the epigenetic role of APC in GBC and GSD. Methylation-specific (MS)-PCR was used to analyze the methylation of APC gene. The expression of APC gene was studied by semi-quantitative PCR, real-time PCR and immunohistochemistry (IHC) in GBC, GSD and adjacent normal tissues. Of the two promoters, APC 1A promoter was found methylated in 96 per cent GBC ( P=0.0155) and 80 per cent GSD (P=0.015). Exon 1 was downregulated in grade II (P=0.002) and grade III (P=0.0001) of GBC, while exon 2 was normally expressed. Scoring analysis of IHC revealed 0 or negativity in 34.48 per cent (P=0.057) and 1+ in 24.14 per cent (P=0.005) GBC cases suggesting loss of APC expression. The present findings indicate epigenetic silencing of APC in advanced GBC. The methylation pattern, followed by expression analysis of APC may be suggested for diagnostic, prognostic and therapeutic purposes in GBC in future.

  19. APC hypermethylation for early diagnosis of colorectal cancer: a meta-analysis and literature review.

    Science.gov (United States)

    Liang, Tie-Jun; Wang, Hong-Xu; Zheng, Yan-Yan; Cao, Ying-Qing; Wu, Xiaoyu; Zhou, Xin; Dong, Shu-Xiao

    2017-07-11

    Adenomatous polyposis coli (APC) promoter hypermethylation has been frequently observed in colorectal cancer (CRC). The association between APC promoter methylation and clinicopathological significance in CRC is under investigation. We performed a meta-analysis to quantitatively evaluate the significance of APC methylation in CRC. The study included a total of 24 articles and 2025 CRC patients. The frequency of APC promoter hypermethylation was significantly higher in colorectal adenoma than in normal colorectal tissue, OR was 5.76, 95% CI, 2.45-13.56; pAPC promoter more frequently hypermethylated in CRC stage I compared to normal colorectal tissue, OR was 13.42, 95% CI, 3.66-49.20; pAPC promoter hypermethylation, pooled OR was 9.80, 95%CI, 6.07-15.81; pAPC methylation was not associated with grade, stage of CRC as well as tumor location, patients' gender, and smoking behavior. The results indicate that APC promoter hypermethylation is an early event in carcinogenesis of CRC, could be a valuable diagnostic marker for early-stage CRC. APC methylation is not significantly associated with overall survival in patients with CRC. APC is a potential drug target for development of personalized treatment.

  20. Application examples of APC-03-2 and APC-03-2A airborne particle counters under various contamination conditions

    International Nuclear Information System (INIS)

    Czitrovszky, A.; Jani, P.

    1997-01-01

    Several application examples of the airborne particle counters APC-03-2 and APC-03-2A for monitoring particle size distribution and concentration in air and other gases are described. The computer controlled fast data evaluation and storage provide efficient presentation of the measured data in a variety of table- and histogram-forms, presenting of alarm levels for each size range, observation of alarm history, etc. The device can be applied not only for clean room monitoring and laminar box testing, but also for measuring contamination in health care facilities in workshops using hazardous airborne compounds (e.g. in pharmacology), and in toxicology where the concentration of the contamination may be very high. (author)

  1. Complex Mhc-based mate choice in a wild passerine

    Science.gov (United States)

    Bonneaud, Camille; Chastel, Olivier; Federici, Pierre; Westerdahl, Helena; Sorci, Gabriele

    2006-01-01

    The extreme polymorphism of the vertebrate major histocompatibility complex (Mhc) is famous for protecting hosts against constantly evolving pathogens. Mate choice is often evoked as a means of maintaining Mhc variability through avoidance of partners with similar Mhc alleles or preference for heterozygotes. Evidence for these two hypotheses mostly comes from studies on humans and laboratory mice. Here, we tested these hypotheses in a wild outbred population of house sparrows (Passer domesticus). Females were not more or less closely related to the males they paired with when considering neutral genetic variation. However, males failed to form breeding pairs when they had too few Mhc alleles and when they were too dissimilar from females at Mhc loci (i.e. had no common alleles). Furthermore, pairs did not form at random as Mhc diversity positively correlated in mating pairs. These results suggest that mate choice evolves in response to (i) benefits in terms of parasite resistance acquired from allelic diversity, and (ii) costs associated with the disruption of co-adapted genes. PMID:16600889

  2. MHC class II polymorphisms, autoreactive T-cells and autoimmunity

    Directory of Open Access Journals (Sweden)

    Sue eTsai

    2013-10-01

    Full Text Available Major histocompatibility complex (MHC genes, also known as human leukocyte antigen genes (HLA in humans, are the prevailing contributors of genetic susceptibility to autoimmune diseases such as Type 1 Diabetes (T1D, Multiple Sclerosis (MS, and Rheumatoid arthritis (RA, among others (Todd and Wicker, 2001;MacKay et al., 2002;Hafler et al., 2007. Although the pathways through which MHC molecules afford autoimmune risk or resistance remain to be fully mapped out, it is generally accepted that they do so by shaping the central and peripheral T cell repertoires of the host towards autoimmune proclivity or resistance, respectively. Disease-predisposing MHC alleles would both spare autoreactive thymocytes from central tolerance and bias their development towards a pathogenic phenotype. Protective MHC alleles, on the other hand, would promote central deletion of autoreactive thymocytes and skew their development towards non-pathogenic phenotypes. This interpretation of the data is at odds with two other observations: that in MHC-heterozygous individuals, resistance is dominant over susceptibility; and that it is difficult to understand how deletion of one or a few clonal autoreactive T cell types would suffice to curb autoimmune responses driven by hundreds if not thousands of autoreactive T cell specificities. This review provides an update on current advances in our understanding of the mechanisms underlying MHC class II-associated autoimmune disease susceptibility and/or resistance and attempts to reconcile these seemingly opposing concepts.

  3. Electrodialytically treated MSWI APC residue as substitute for cement in mortar

    DEFF Research Database (Denmark)

    Kirkelund, Gunvor Marie; Geiker, Mette Rica; Jensen, Pernille Erland

    2014-01-01

    Air pollution control (APC) residues from municipal solid waste incineration (MSWI) are considered hazardous waste and need pretreatment prior to possible reuse. Here, two MSWI APC residues, from which the most mobile fraction of heavy metals and salts has been removed by carbonation and/or elect......Air pollution control (APC) residues from municipal solid waste incineration (MSWI) are considered hazardous waste and need pretreatment prior to possible reuse. Here, two MSWI APC residues, from which the most mobile fraction of heavy metals and salts has been removed by carbonation and....../or electrodialytic remediation, were used in Portland cement mortar. Mortar bars with 15 % weight replacement of cement by APC residues showed compressive strengths up to 40 MPa after 28/32 days. Heavy metal and salt leaching from both crushed and monolithic mortars with APC residues was generally similar...

  4. A metabolic switch controls intestinal differentiation downstream of Adenomatous polyposis coli (APC).

    Science.gov (United States)

    Sandoval, Imelda T; Delacruz, Richard Glenn C; Miller, Braden N; Hill, Shauna; Olson, Kristofor A; Gabriel, Ana E; Boyd, Kevin; Satterfield, Christeena; Remmen, Holly Van; Rutter, Jared; Jones, David A

    2017-04-11

    Elucidating signaling pathways that regulate cellular metabolism is essential for a better understanding of normal development and tumorigenesis. Recent studies have shown that mitochondrial pyruvate carrier 1 (MPC1) , a crucial player in pyruvate metabolism, is downregulated in colon adenocarcinomas. Utilizing zebrafish to examine the genetic relationship between MPC1 and Adenomatous polyposis coli (APC), a key tumor suppressor in colorectal cancer, we found that apc controls the levels of mpc1 and that knock down of mpc1 recapitulates phenotypes of impaired apc function including failed intestinal differentiation. Exogenous human MPC1 RNA rescued failed intestinal differentiation in zebrafish models of apc deficiency. Our data demonstrate a novel role for apc in pyruvate metabolism and that pyruvate metabolism dictates intestinal cell fate and differentiation decisions downstream of apc .

  5. Contrasting patterns of selection between MHC I and II across populations of Humboldt and Magellanic penguins.

    Science.gov (United States)

    Sallaberry-Pincheira, Nicole; González-Acuña, Daniel; Padilla, Pamela; Dantas, Gisele P M; Luna-Jorquera, Guillermo; Frere, Esteban; Valdés-Velásquez, Armando; Vianna, Juliana A

    2016-10-01

    The evolutionary and adaptive potential of populations or species facing an emerging infectious disease depends on their genetic diversity in genes, such as the major histocompatibility complex (MHC). In birds, MHC class I deals predominantly with intracellular infections (e.g., viruses) and MHC class II with extracellular infections (e.g., bacteria). Therefore, patterns of MHC I and II diversity may differ between species and across populations of species depending on the relative effect of local and global environmental selective pressures, genetic drift, and gene flow. We hypothesize that high gene flow among populations of Humboldt and Magellanic penguins limits local adaptation in MHC I and MHC II, and signatures of selection differ between markers, locations, and species. We evaluated the MHC I and II diversity using 454 next-generation sequencing of 100 Humboldt and 75 Magellanic penguins from seven different breeding colonies. Higher genetic diversity was observed in MHC I than MHC II for both species, explained by more than one MHC I loci identified. Large population sizes, high gene flow, and/or similar selection pressures maintain diversity but limit local adaptation in MHC I. A pattern of isolation by distance was observed for MHC II for Humboldt penguin suggesting local adaptation, mainly on the northernmost studied locality. Furthermore, trans-species alleles were found due to a recent speciation for the genus or convergent evolution. High MHC I and MHC II gene diversity described is extremely advantageous for the long-term survival of the species.

  6. Stable MCC binding to the APC/C is required for a functional spindle assembly checkpoint

    DEFF Research Database (Denmark)

    Hein, Jamin B; Nilsson, Jakob

    2014-01-01

    stably to the APC/C. Whether MCC formation per se is sufficient for a functional SAC or MCC association with the APC/C is required remains unclear. Here, we analyze the role of two conserved motifs in Cdc20, IR and C-Box, in binding of the MCC to the APC/C. Mutants in both motifs assemble the MCC....../C is critical for a functional SAC....

  7. Detection of microsatellite instability but not truncating APC mutations in gastric adenocarcinomas in Brazilian patients

    OpenAIRE

    Bevilacqua Roberta A.U.; Corvello Cassandra M.; Duarte Ana Paula; Simpson Andrew J.G.

    2000-01-01

    A crucial role for the adenomatous polyposis colonic (APC) gene in colorectal carcinogenesis has been conclusively established, but, the role of APC in gastric tumors remains controversial. APC mutations have been detected at a relatively high frequency in gastric tumors of Japanese patients, yet such mutations have been reported to be extremely rare in British patients and patients from north-central-Italy. We here report the analysis of 40 primary sporadic gastric adenocarcinomas and 35 pri...

  8. Extensive metabolic disorders are present in APC(min) tumorigenesis mice.

    Science.gov (United States)

    Liu, Zhenzhen; Xiao, Yi; Zhou, Zhengxiang; Mao, Xiaoxiao; Cai, Jinxing; Xiong, Lu; Liao, Chaonan; Huang, Fulian; Liu, Zehao; Ali Sheikh, Md Sayed; Plutzky, Jorge; Huang, He; Yang, Tianlun; Duan, Qiong

    2016-05-15

    Wnt signaling plays essential role in mesenchymal stem cell (MSC) differentiation. Activation of Wnt signaling suppresses adipogenesis, but promotes osteogenesis in MSC. Adenomatous polyposis coli (APC) is a negative regulator of β-catenin and Wnt signaling activity. The mutation of APC gene leads to the activation of Wnt signaling and is responsible for tumorigenesis in APC(min) mouse; however, very few studies focused on its metabolic abnormalities. The present study reports a widespread metabolic disorder phenotype in APC(min) mice. The old APC(min) mice have decreased body weight and impaired adipogenesis, but severe hyperlipidemia, which mimic the phenotypes of Familial Adenomatous Polyposis (FAP), an inherited disease also caused by APC gene mutation in human. We found that the expression of lipid metabolism and free fat acids (FA) use genes in the white adipose tissue (WAT) of the APC(min) mice is much lower than those of control. The changed gene expression pattern may lead to the disability of circulatory lipid transportation and storage at WAT. Moreover, the APC(min) mice could not maintain the core body temperature in cold condition. PET-CT determination revealed that the BAT of APC(min) mice has significantly impaired ability to take up (18)FDG from the blood. Morphological studies identified that the brown adipocytes of APC(min) mice were filled with lipid droplets but fewer mitochondria. These results matched with the findings of impaired BAT function in APC(min) mice. Collectively, our study explores a new mechanism that explains abnormal metabolism in APC(min) mice and provides insights into studying the metabolic disorders of FAP patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Sex-specific selection for MHC variability in Alpine chamois

    Directory of Open Access Journals (Sweden)

    Schaschl Helmut

    2012-02-01

    Full Text Available Abstract Background In mammals, males typically have shorter lives than females. This difference is thought to be due to behavioural traits which enhance competitive abilities, and hence male reproductive success, but impair survival. Furthermore, in many species males usually show higher parasite burden than females. Consequently, the intensity of selection for genetic factors which reduce susceptibility to pathogens may differ between sexes. High variability at the major histocompatibility complex (MHC genes is believed to be advantageous for detecting and combating the range of infectious agents present in the environment. Increased heterozygosity at these immune genes is expected to be important for individual longevity. However, whether males in natural populations benefit more from MHC heterozygosity than females has rarely been investigated. We investigated this question in a long-term study of free-living Alpine chamois (Rupicapra rupicapra, a polygynous mountain ungulate. Results Here we show that male chamois survive significantly (P = 0.022 longer if heterozygous at the MHC class II DRB locus, whereas females do not. Improved survival of males was not a result of heterozygote advantage per se, as background heterozygosity (estimated across twelve microsatellite loci did not change significantly with age. Furthermore, reproductively active males depleted their body fat reserves earlier than females leading to significantly impaired survival rates in this sex (P Conclusions Increased MHC class II DRB heterozygosity with age in males, suggests that MHC heterozygous males survive longer than homozygotes. Reproductively active males appear to be less likely to survive than females most likely because of the energetic challenge of the winter rut, accompanied by earlier depletion of their body fat stores, and a generally higher parasite burden. This scenario renders the MHC-mediated immune response more important for males than for females

  10. APC/C-Cdh1-dependent anaphase and telophase progression during mitotic slippage

    Directory of Open Access Journals (Sweden)

    Toda Kazuhiro

    2012-02-01

    Full Text Available Abstract Background The spindle assembly checkpoint (SAC inhibits anaphase progression in the presence of insufficient kinetochore-microtubule attachments, but cells can eventually override mitotic arrest by a process known as mitotic slippage or adaptation. This is a problem for cancer chemotherapy using microtubule poisons. Results Here we describe mitotic slippage in yeast bub2Δ mutant cells that are defective in the repression of precocious telophase onset (mitotic exit. Precocious activation of anaphase promoting complex/cyclosome (APC/C-Cdh1 caused mitotic slippage in the presence of nocodazole, while the SAC was still active. APC/C-Cdh1, but not APC/C-Cdc20, triggered anaphase progression (securin degradation, separase-mediated cohesin cleavage, sister-chromatid separation and chromosome missegregation, in addition to telophase onset (mitotic exit, during mitotic slippage. This demonstrates that an inhibitory system not only of APC/C-Cdc20 but also of APC/C-Cdh1 is critical for accurate chromosome segregation in the presence of insufficient kinetochore-microtubule attachments. Conclusions The sequential activation of APC/C-Cdc20 to APC/C-Cdh1 during mitosis is central to accurate mitosis. Precocious activation of APC/C-Cdh1 in metaphase (pre-anaphase causes mitotic slippage in SAC-activated cells. For the prevention of mitotic slippage, concomitant inhibition of APC/C-Cdh1 may be effective for tumor therapy with mitotic spindle poisons in humans.

  11. Controlling the response to DNA damage by the APC/C-Cdh1.

    Science.gov (United States)

    de Boer, H Rudolf; Guerrero Llobet, S; van Vugt, Marcel A T M

    2016-03-01

    Proper cell cycle progression is safeguarded by the oscillating activities of cyclin/cyclin-dependent kinase complexes. An important player in the regulation of mitotic cyclins is the anaphase-promoting complex/cyclosome (APC/C), a multi-subunit E3 ubiquitin ligase. Prior to entry into mitosis, the APC/C remains inactive, which allows the accumulation of mitotic regulators. APC/C activation requires binding to either the Cdc20 or Cdh1 adaptor protein, which sequentially bind the APC/C and facilitate targeting of multiple mitotic regulators for proteasomal destruction, including Securin and Cyclin B, to ensure proper chromosome segregation and mitotic exit. Emerging data have indicated that the APC/C, particularly in association with Cdh1, also functions prior to mitotic entry. Specifically, the APC/C-Cdh1 is activated in response to DNA damage in G2 phase cells. These observations are in line with in vitro and in vivo genetic studies, in which cells lacking Cdh1 expression display various defects, including impaired DNA repair and aberrant cell cycle checkpoints. In this review, we summarize the current literature on APC/C regulation in response to DNA damage, the functions of APC/C-Cdh1 activation upon DNA damage, and speculate how APC/C-Cdh1 can control cell fate in the context of persistent DNA damage.

  12. Apc bridges Wnt/{beta}-catenin and BMP signaling during osteoblast differentiation of KS483 cells

    Energy Technology Data Exchange (ETDEWEB)

    Miclea, Razvan L., E-mail: R.L.Miclea@lumc.nl [Department of Pediatrics, Leiden University Medical Centre (LUMC), Leiden (Netherlands); Horst, Geertje van der, E-mail: G.van_der_Horst@lumc.nl [Department of Urology, LUMC, Leiden (Netherlands); Robanus-Maandag, Els C., E-mail: E.C.Robanus@lumc.nl [Department of Human Genetics, LUMC, Leiden (Netherlands); Loewik, Clemens W.G.M., E-mail: C.W.G.M.Lowik@lumc.nl [Department of Endocrinology and Metabolic Diseases, LUMC, Leiden (Netherlands); Oostdijk, Wilma, E-mail: W.Oostdijk@lumc.nl [Department of Pediatrics, Leiden University Medical Centre (LUMC), Leiden (Netherlands); Wit, Jan M., E-mail: J.M.Wit@lumc.nl [Department of Pediatrics, Leiden University Medical Centre (LUMC), Leiden (Netherlands); Karperien, Marcel, E-mail: H.B.J.Karperien@tnw.utwente.nl [MIRA Institute for Biomedical Technology and Technical Medicine, Department of Tissue Regeneration, University of Twente, Zuidhorst Room ZH 144, Drienerlolaan 5, 7522 NB Enschede (Netherlands)

    2011-06-10

    The canonical Wnt signaling pathway influences the differentiation of mesenchymal cell lineages in a quantitative and qualitative fashion depending on the dose of {beta}-catenin signaling. Adenomatous polyposis coli (Apc) is the critical intracellular regulator of {beta}-catenin turnover. To better understand the molecular mechanisms underlying the role of Apc in regulating the differentiation capacity of skeletal progenitor cells, we have knocked down Apc in the murine mesenchymal stem cell-like KS483 cells by stable expression of Apc-specific small interfering RNA. In routine culture, KSFrt-Apc{sub si} cells displayed a mesenchymal-like spindle shape morphology, exhibited markedly decreased proliferation and increased apoptosis. Apc knockdown resulted in upregulation of the Wnt/{beta}-catenin and the BMP/Smad signaling pathways, but osteogenic differentiation was completely inhibited. This effect could be rescued by adding high concentrations of BMP-7 to the differentiation medium. Furthermore, KSFrt-Apc{sub si} cells showed no potential to differentiate into chondrocytes or adipocytes. These results demonstrate that Apc is essential for the proliferation, survival and differentiation of KS483 cells. Apc knockdown blocks the osteogenic differentiation of skeletal progenitor cells, a process that can be overruled by high BMP signaling.

  13. Synergistic inhibition of the APC/C by the removal of APC15 in HCT116 cells lacking UBE2C.

    Science.gov (United States)

    Garvanska, Dimitriya H; Larsen, Marie Sofie Yoo; Nilsson, Jakob

    2016-10-15

    The spindle assembly checkpoint (SAC) inhibits the anaphase-promoting complex/cyclosome (APC/C) in response to unattached kinetochores by generating a diffusible inhibitor termed the mitotic checkpoint complex (MCC). At metaphase, rapid activation of the APC/C requires removal of the MCC, a process that has been shown to depend on the APC/C E2 enzymes, UBE2C and UBE2S. Here we investigate the in vivo role of the APC/C E2 enzymes in SAC silencing using CRISPR/Cas9 genetically engineered HCT116 UBE2C or UBE2S null cell lines. Using live cell assays, we show that UBE2C and UBE2S make a minor contribution to SAC silencing in HCT116 cells. Strikingly, in cells specifically lacking UBE2C, we observe a strong synergistic inhibition of mitotic progression when we stabilize the MCC on the APC/C by depleting APC15, potentially reflecting increased competition between the MCC and the remaining initiating E2 enzyme UBE2D. In conclusion, we provide in vivo insight into the APC/C E2 module and its interplay with SAC silencing components. © 2016. Published by The Company of Biologists Ltd.

  14. NLRC5: a key regulator of MHC class I-dependent immune responses.

    Science.gov (United States)

    Kobayashi, Koichi S; van den Elsen, Peter J

    2012-12-01

    The expression of MHC class I molecules is crucial for the initiation and regulation of adaptive immune responses against pathogens. NOD-, LRR- and CARD-containing 5 (NLRC5) was recently identified as a specific transactivator of MHC class I genes (CITA). NLRC5 and the master regulator for MHC class II genes, class II transactivator (CIITA), interact with similar MHC promoter-bound factors. Here, we provide a broad overview of the molecular mechanisms behind MHC class I transcription and the role of the class I transactivator NLRC5 in MHC class I-dependent immune responses.

  15. Recurrent APC gene mutations in Polish FAP families

    Directory of Open Access Journals (Sweden)

    Pławski Andrzej

    2007-12-01

    Full Text Available Abstract The molecular diagnostics of genetically conditioned disorders is based on the identification of the mutations in the predisposing genes. Hereditary cancer disorders of the gastrointestinal tracts are caused by mutations of the tumour suppressor genes or the DNA repair genes. Occurrence of recurrent mutation allows improvement of molecular diagnostics. The mutation spectrum in the genes causing hereditary forms of colorectal cancers in the Polish population was previously described. In the present work an estimation of the frequency of the recurrent mutations of the APC gene was performed. Eight types of mutations occurred in 19.4% of our FAP families and these constitute 43% of all Polish diagnosed families.

  16. APC: A New Code for Atmospheric Polarization Computations

    Science.gov (United States)

    Korkin, Sergey V.; Lyapustin, Alexei I.; Rozanov, Vladimir V.

    2014-01-01

    A new polarized radiative transfer code Atmospheric Polarization Computations (APC) is described. The code is based on separation of the diffuse light field into anisotropic and smooth (regular) parts. The anisotropic part is computed analytically. The smooth regular part is computed numerically using the discrete ordinates method. Vertical stratification of the atmosphere, common types of bidirectional surface reflection and scattering by spherical particles or spheroids are included. A particular consideration is given to computation of the bidirectional polarization distribution function (BPDF) of the waved ocean surface.

  17. Detection of irradiated foods by the DEFT/APC method

    International Nuclear Information System (INIS)

    Yuecel, P. K.; Koeseoglu, T.; Halkman, H. B. D.

    2009-01-01

    Irradiation technology is used to prevent the spoilage losses and to improve the hygienic quality of foods. Appropriate techniques for the detection of irradiated foods are needed to guarantee the proper consumer information and to facilitate the trade of irradiated foods. The characteristics of the microbial population of irradiated foods have been used for developing detection methods for irradiated foods. This microbiological method is based on the comparison of an aerobic plate count (APC) with a count obtained with the direct epifluorescent filter technique (DEFT) for the detection of irradiation of foodstuffs.

  18. Understanding TR binding to pMHC complexes: how does a TR scan many pMHC complexes yet preferentially bind to one.

    Directory of Open Access Journals (Sweden)

    Javed Mohammed Khan

    Full Text Available Understanding the basis of the binding of a T cell receptor (TR to the peptide-MHC (pMHC complex is essential due to the vital role it plays in adaptive immune response. We describe the use of computed binding (free energy (BE, TR paratope, pMHC epitope, molecular surface electrostatic potential (MSEP and calculated TR docking angle (θ to analyse 61 TR/pMHC crystallographic structures to comprehend TR/pMHC interaction. In doing so, we have successfully demonstrated a novel/rational approach for θ calculation, obtained a linear correlation between BE and θ without any "codon" or amino acid preference, provided an explanation for TR ability to scan many pMHC ligands yet specifically bind one, proposed a mechanism for pMHC recognition by TR leading to T cell activation and illustrated the importance of the peptide in determining TR specificity, challenging the "germline bias" theory.

  19. Comparative genome analyses reveal distinct structure in the saltwater crocodile MHC.

    Directory of Open Access Journals (Sweden)

    Weerachai Jaratlerdsiri

    Full Text Available The major histocompatibility complex (MHC is a dynamic genome region with an essential role in the adaptive immunity of vertebrates, especially antigen presentation. The MHC is generally divided into subregions (classes I, II and III containing genes of similar function across species, but with different gene number and organisation. Crocodylia (crocodilians are widely distributed and represent an evolutionary distinct group among higher vertebrates, but the genomic organisation of MHC within this lineage has been largely unexplored. Here, we studied the MHC region of the saltwater crocodile (Crocodylus porosus and compared it with that of other taxa. We characterised genomic clusters encompassing MHC class I and class II genes in the saltwater crocodile based on sequencing of bacterial artificial chromosomes. Six gene clusters spanning ∼452 kb were identified to contain nine MHC class I genes, six MHC class II genes, three TAP genes, and a TRIM gene. These MHC class I and class II genes were in separate scaffold regions and were greater in length (2-6 times longer than their counterparts in well-studied fowl B loci, suggesting that the compaction of avian MHC occurred after the crocodilian-avian split. Comparative analyses between the saltwater crocodile MHC and that from the alligator and gharial showed large syntenic areas (>80% identity with similar gene order. Comparisons with other vertebrates showed that the saltwater crocodile had MHC class I genes located along with TAP, consistent with birds studied. Linkage between MHC class I and TRIM39 observed in the saltwater crocodile resembled MHC in eutherians compared, but absent in avian MHC, suggesting that the saltwater crocodile MHC appears to have gene organisation intermediate between these two lineages. These observations suggest that the structure of the saltwater crocodile MHC, and other crocodilians, can help determine the MHC that was present in the ancestors of archosaurs.

  20. Functions of the APC tumor suppressor protein dependent and independent of canonical WNT signaling: implications for therapeutic targeting.

    Science.gov (United States)

    Hankey, William; Frankel, Wendy L; Groden, Joanna

    2018-03-01

    The acquisition of biallelic mutations in the APC gene is a rate-limiting step in the development of most colorectal cancers and occurs in the earliest lesions. APC encodes a 312-kDa protein that localizes to multiple subcellular compartments and performs diverse functions. APC participates in a cytoplasmic complex that promotes the destruction of the transcriptional licensing factor β-catenin; APC mutations that abolish this function trigger constitutive activation of the canonical WNT signaling pathway, a characteristic found in almost all colorectal cancers. By negatively regulating canonical WNT signaling, APC counteracts proliferation, promotes differentiation, facilitates apoptosis, and suppresses invasion and tumor progression. APC further antagonizes canonical WNT signaling by interacting with and counteracting β-catenin in the nucleus. APC also suppresses tumor initiation and progression in the colorectal epithelium through functions that are independent of canonical WNT signaling. APC regulates the mitotic spindle to facilitate proper chromosome segregation, localizes to the cell periphery and cell protrusions to establish cell polarity and appropriate directional migration, and inhibits DNA replication by interacting directly with DNA. Mutations in APC are often frameshifts, insertions, or deletions that introduce premature stop codons and lead to the production of truncated APC proteins that lack its normal functions and possess tumorigenic properties. Therapeutic approaches in development for the treatment of APC-deficient tumors are focused on the inhibition of canonical WNT signaling, especially through targets downstream of APC in the pathway, or on the restoration of wild-type APC expression.

  1. Circumvention of MHC class II restriction by genetic immunization.

    Science.gov (United States)

    Schuler, K; Lu, C; Chang, H D; Croft, M; Zanetti, M; Gerloni, M

    2001-11-12

    The fate of T cell responses to peptide-based vaccination is subject to constraints by the major histocompatibility complex (MHC), MHC restriction. Using as a model system of T and B cell epitopes from the circumsporozoite protein of Plasmodium falciparum malaria parasite, we show that vaccination by somatic transgene immunization readily primes Balb/c mice (H-2(d)) a strain previously reported to be non-responder to immunization with a synthetic peptide vaccine encompassing these epitopes. Following genetic vaccination Balb/c mice developed a primary T cell response comparable to that of the responder strain C57Bl/6 (H-2(b)). Following booster immunization on day 45 Balb/c mice responded with a typical T cell memory response. Priming induced the formation of specific antibodies, which rose sharply after booster immunization. These findings suggests that genetic immunization can circumvent MHC class II restriction.

  2. Synergistic inhibition of the APC/C by the removal of APC15 in HCT116 cells lacking UBE2C

    DEFF Research Database (Denmark)

    Garvanska, Dimitriya H; Larsen, Marie Sofie Yoo; Nilsson, Jakob

    2016-01-01

    that has been shown to depend on the APC/C E2 enzymes, UBE2C and UBE2S. Here we investigate the in vivo role of the APC/C E2 enzymes in SAC silencing using CRISPR/Cas9 genetically engineered HCT116 UBE2C or UBE2S null cell lines. Using live cell assays, we show that UBE2C and UBE2S make a minor...... contribution to SAC silencing in HCT116 cells. Strikingly in cells specifically lacking UBE2C, we observe a strong synergistic inhibition of mitotic progression when we stabilize the MCC on the APC/C by depleting APC15, potentially reflecting increased competition between the MCC and the remaining initiating E...

  3. Apc1 is required for maintenance of local brain organizers and dorsal midbrain survival.

    NARCIS (Netherlands)

    Paridaen, J.T.M.; Danesin, C.; Elas, A.T.; van de Water, S.G.P.; Houart, C.; Zivkovic, D.

    2009-01-01

    The tumor suppressor Apc1 is an intracellular antagonist of the Wnt/beta-catenin pathway, which is vital for induction and patterning of the early vertebrate brain. However, its role in later brain development is less clear. Here, we examined the mechanisms underlying effects of an Apc1

  4. Effect of drying on leaching testing of treated municipal solid waste incineration APC-residues

    DEFF Research Database (Denmark)

    Hu, Y.; Hyks, Jiri; Astrup, Thomas

    2008-01-01

    Air-pollution-control (APC) residues from waste incinerators are hazardous waste according to European legislation and must be treated prior to landfilling. Batch and column leaching data determine which type of landfill can receive the treated APC-residues. CEN standards are prescribed...

  5. REMOVAL OF ARSENIC IN DRINKING WATER: ARS CFU-50 APC ELECTROFLOCCULATION AND FILTRATION WATER TREATMENT SYSTEM

    Science.gov (United States)

    ETV testing of the ARS CFU-50 APC Electroflocculation and Filtration Water Treatment System (ARS CFU-50 APC) for arsenic removal was conducted at the Town of Bernalillo Well #3 site from April 18 through May 2, 2006. The source water was chlorinated groundwater from two supply w...

  6. Chir99021 and Valproic acid reduce the proliferative advantage of Apc mutant cells.

    Science.gov (United States)

    Langlands, Alistair J; Carroll, Thomas D; Chen, Yu; Näthke, Inke

    2018-02-15

    More than 90% of colorectal cancers carry mutations in Apc that drive tumourigenesis. A 'just-right' signalling model proposes that Apc mutations stimulate optimal, but not excessive Wnt signalling, resulting in a growth advantage of Apc mutant over wild-type cells. Reversal of this growth advantage constitutes a potential therapeutic approach. We utilised intestinal organoids to compare the growth of Apc mutant and wild-type cells. Organoids derived from Apc Min/+ mice recapitulate stages of intestinal polyposis in culture. They eventually form spherical cysts that reflect the competitive growth advantage of cells that have undergone loss of heterozygosity (LOH). We discovered that this emergence of cysts was inhibited by Chiron99021 and Valproic acid, which potentiates Wnt signalling. Chiron99021 and Valproic acid restrict the growth advantage of Apc mutant cells while stimulating that of wild-type cells, suggesting that excessive Wnt signalling reduces the relative fitness of Apc mutant cells. As a proof of concept, we demonstrated that Chiron99021-treated Apc mutant organoids were rendered susceptible to TSA-induced apoptosis, while wild-type cells were protected.

  7. APC sets the Wnt tone necessary for cerebral cortical progenitor development.

    Science.gov (United States)

    Nakagawa, Naoki; Li, Jingjun; Yabuno-Nakagawa, Keiko; Eom, Tae-Yeon; Cowles, Martis; Mapp, Tavien; Taylor, Robin; Anton, E S

    2017-08-15

    Adenomatous polyposis coli (APC) regulates the activity of β-catenin, an integral component of Wnt signaling. However, the selective role of the APC-β-catenin pathway in cerebral cortical development is unknown. Here we genetically dissected the relative contributions of APC-regulated β-catenin signaling in cortical progenitor development, a necessary early step in cerebral cortical formation. Radial progenitor-specific inactivation of the APC-β-catenin pathway indicates that the maintenance of appropriate β-catenin-mediated Wnt tone is necessary for the orderly differentiation of cortical progenitors and the resultant formation of the cerebral cortex. APC deletion deregulates β-catenin, leads to high Wnt tone, and disrupts Notch1 signaling and primary cilium maintenance necessary for radial progenitor functions. β-Catenin deregulation directly disrupts cilium maintenance and signaling via Tulp3, essential for intraflagellar transport of ciliary signaling receptors. Surprisingly, deletion of β-catenin or inhibition of β-catenin activity in APC-null progenitors rescues the APC-null phenotype. These results reveal that APC-regulated β-catenin activity in cortical progenitors sets the appropriate Wnt tone necessary for normal cerebral cortical development. © 2017 Nakagawa et al.; Published by Cold Spring Harbor Laboratory Press.

  8. Contribution of APC and MUTYH mutations to familial adenomatous polyposis susceptibility in Hungary.

    Science.gov (United States)

    Papp, Janos; Kovacs, Marietta Eva; Matrai, Zoltan; Orosz, Enikő; Kásler, Miklós; Børresen-Dale, Anne-Lise; Olah, Edith

    2016-01-01

    Familial adenomatous polyposis (FAP) is a colorectal cancer predisposition syndrome with considerable genetic and phenotypic heterogeneity, defined by the development of multiple adenomas throughout the colorectum. FAP is caused either by monoallelic mutations in the adenomatous polyposis coli gene APC, or by biallelic germline mutations of MUTYH, this latter usually presenting with milder phenotype. The aim of the present study was to characterize the genotype and phenotype of Hungarian FAP patients. Mutation screening of 87 unrelated probands from FAP families (21 of them presented as the attenuated variant of the disease, showing APC were identified in 65 patients (75 %), including nine cases (37.5 %) with large genomic alterations. Twelve of the point mutations were novel. In addition, APC-negative samples were also tested for MUTYH mutations and we were able to identify biallelic pathogenic mutations in 23 % of these cases (5/22). Correlations between the localization of APC mutations and the clinical manifestations of the disease were observed, cases with a mutation in the codon 1200-1400 region showing earlier age of disease onset (p APC- and MUTYH-associated FAP in our cohort: the age at onset of polyposis was significantly delayed for biallelic MUTYH mutation carriers as compared to patients with an APC mutation. Our data represent the first comprehensive study delineating the mutation spectra of both APC and MUTYH in Hungarian FAP families, and underscore the overlap between the clinical characteristics of APC- and MUTYH-associated phenotypes, necessitating a more appropriate clinical characterization of FAP families.

  9. Tumour Suppressor Adenomatous Polyposis Coli (APC) localisation is regulated by both Kinesin-1 and Kinesin-2

    NARCIS (Netherlands)

    Ruane, Peter T; Gumy, Laura F; Bola, Becky; Anderson, Beverley; Wozniak, Marcin J; Hoogenraad, Casper C; Allan, Victoria J

    2016-01-01

    Microtubules and their associated proteins (MAPs) underpin the polarity of specialised cells. Adenomatous polyposis coli (APC) is one such MAP with a multifunctional agenda that requires precise intracellular localisations. Although APC has been found to associate with kinesin-2 subfamily members,

  10. Peptidomimetic inhibitors of APC-Asef interaction block colorectal cancer migration.

    Science.gov (United States)

    Jiang, Haiming; Deng, Rong; Yang, Xiuyan; Shang, Jialin; Lu, Shaoyong; Zhao, Yanlong; Song, Kun; Liu, Xinyi; Zhang, Qiufen; Chen, Yu; Chinn, Y Eugene; Wu, Geng; Li, Jian; Chen, Guoqiang; Yu, Jianxiu; Zhang, Jian

    2017-09-01

    The binding of adenomatous polyposis coli (APC) to its receptor Asef relieves the negative intramolecular regulation of Asef and leads to aberrant cell migration in human colorectal cancer. Because of its crucial role in metastatic dissemination, the interaction between APC and Asef is an attractive target for anti-colorectal-cancer therapy. We rationally designed a series of peptidomimetics that act as potent inhibitors of the APC interface. Crystal structures and biochemical and cellular assays showed that the peptidomimetics in the APC pocket inhibited the migration of colorectal cells by disrupting APC-Asef interaction. By using the peptidomimetic inhibitor as a chemical probe, we found that CDC42 was the downstream GTPase involved in APC-stimulated Asef activation in colorectal cancer cells. Our work demonstrates the feasibility of exploiting APC-Asef interaction to regulate the migration of colorectal cancer cells, and provides what to our knowledge is the first class of protein-protein interaction inhibitors available for the development of cancer therapeutics targeting APC-Asef signaling.

  11. The aPC treatment improves microcirculation in severe sepsis/septic shock syndrome

    NARCIS (Netherlands)

    Donati, Abele; Damiani, Elisa; Botticelli, Laura; Adrario, Erica; Lombrano, Maria Rita; Domizi, Roberta; Marini, Benedetto; van Teeffelen, Jurgen W. G. E.; Carletti, Paola; Girardis, Massimo; Pelaia, Paolo; Ince, Can

    2013-01-01

    The role of recombinant activated protein C (aPC) during sepsis is still controversial. It showed anti-inflammatory effect and improved the microvascular perfusion in experimental models of septic shock. The present study was aimed at testing the hypothesis that recombinant aPC therapy improves the

  12. Evolution of MHC class I in the Order Crocodylia

    DEFF Research Database (Denmark)

    Jaratlerdsiri, Weerachai; Isberg, Sally R; Higgins, Damien P

    2014-01-01

    have mostly focused on model species. However, the investigation of this region in non-avian reptiles is still in its infancy. To provide insights into the evolutionary mechanisms that have shaped the diversity of this region in the Order Crocodylia, we investigated MHC class I exon 3, intron 3...... events of gene duplication, particularly in Crocodilidae. These findings enhance our understanding of MHC class I evolution and provide a preliminary framework for comparative studies of other non-avian reptiles as well as diversity assessment within Crocodylia....

  13. MHC molecules protect T cell epitopes against proteolytic destruction

    DEFF Research Database (Denmark)

    Mouritsen, S; Meldal, M; Werdelin, O

    1992-01-01

    There is a subtle duality in the role of proteolytic enzymes in Ag processing. They are required to fragment protein Ag ingested by APC. However, prolonged exposure to proteolytic enzymes may lead to a complete degradation of the Ag, leaving nothing for the T cell system to recognize. What ensures...

  14. Modeling the Effect of APC Truncation on Destruction Complex Function in Colorectal Cancer Cells

    Science.gov (United States)

    Barua, Dipak; Hlavacek, William S.

    2013-01-01

    In colorectal cancer cells, APC, a tumor suppressor protein, is commonly expressed in truncated form. Truncation of APC is believed to disrupt degradation of β—catenin, which is regulated by a multiprotein complex called the destruction complex. The destruction complex comprises APC, Axin, β—catenin, serine/threonine kinases, and other proteins. The kinases and , which are recruited by Axin, mediate phosphorylation of β—catenin, which initiates its ubiquitination and proteosomal degradation. The mechanism of regulation of β—catenin degradation by the destruction complex and the role of truncation of APC in colorectal cancer are not entirely understood. Through formulation and analysis of a rule-based computational model, we investigated the regulation of β—catenin phosphorylation and degradation by APC and the effect of APC truncation on function of the destruction complex. The model integrates available mechanistic knowledge about site-specific interactions and phosphorylation of destruction complex components and is consistent with an array of published data. We find that the phosphorylated truncated form of APC can outcompete Axin for binding to β—catenin, provided that Axin is limiting, and thereby sequester β—catenin away from Axin and the Axin-recruited kinases and . Full-length APC also competes with Axin for binding to β—catenin; however, full-length APC is able, through its SAMP repeats, which bind Axin and which are missing in truncated oncogenic forms of APC, to bring β—catenin into indirect association with Axin and Axin-recruited kinases. Because our model indicates that the positive effects of truncated APC on β—catenin levels depend on phosphorylation of APC, at the first 20-amino acid repeat, and because phosphorylation of this site is mediated by , we suggest that is a potential target for therapeutic intervention in colorectal cancer. Specific inhibition of is predicted to limit binding of β—catenin to truncated

  15. Contrasting patterns of selection between MHC I and II across populations of Humboldt and Magellanic penguins

    OpenAIRE

    Sallaberry?Pincheira, Nicole; Gonz?lez?Acu?a, Daniel; Padilla, Pamela; Dantas, Gisele P. M.; Luna?Jorquera, Guillermo; Frere, Esteban; Vald?s?Vel?squez, Armando; Vianna, Juliana A.

    2016-01-01

    Abstract The evolutionary and adaptive potential of populations or species facing an emerging infectious disease depends on their genetic diversity in genes, such as the major histocompatibility complex (MHC). In birds, MHC class I deals predominantly with intracellular infections (e.g., viruses) and MHC class II with extracellular infections (e.g., bacteria). Therefore, patterns of MHC I and II diversity may differ between species and across populations of species depending on the relative e...

  16. APC senses cell-cell contacts and moves to the nucleus upon their disruption.

    Science.gov (United States)

    Brocardo, M G; Bianchini, M; Radrizzani, M; Reyes, G B; Dugour, A V; Taminelli, G L; Gonzalez Solveyra, C; Santa-Coloma, T A

    2001-06-22

    The adenomatous polyposis coli (APC) tumor suppressor protein is involved in the Wnt/wingless pathway, modulating beta-catenin activity. We report the development of a highly specific, chemically synthesized oligobody (oligonucleotide-based synthetic antibody), directed against the N-terminal region of APC. Using this reagent, we found that within 16 h of disrupting HT-29 cell-cell contacts by harvesting cells with trypsin/EDTA treatment and replating, APC was translocated from the cytoplasm to the nucleus. Five days after plating the cells, when the cells had returned to their normal confluent phenotype and cell-cell contacts were reestablished, APC returned to the cytoplasm. These results suggest that APC functions as part of a "sensor" system, and responds to the loss of cell-cell contacts by moving to the nucleus, and returning to the cytoplasm when the contacts are fully restored. Copyright 2001 Academic Press.

  17. Familial adenomatous polyposis patients without an identified APC germline mutation have a severe phenotype

    DEFF Research Database (Denmark)

    Bisgaard, M L; Ripa, R; Knudsen, Anne Louise

    2004-01-01

    BACKGROUND: Development of more than 100 colorectal adenomas is diagnostic of the dominantly inherited autosomal disease familial adenomatous polyposis (FAP). Germline mutations can be identified in the adenomatous polyposis coli (APC) gene in approximately 80% of patients. The APC protein...... comprises several regions and domains for interaction with other proteins, and specific clinical manifestations are associated with the mutation assignment to one of these regions or domains. AIMS: The phenotype in patients without an identified causative APC mutation was compared with the phenotype...... in patients with a known APC mutation and with the phenotypes characteristic of patients with mutations in specific APC regions and domains. PATIENTS: Data on 121 FAP probands and 149 call up patients from 70 different families were extracted from the Danish Polyposis register. METHODS: Differences in 16...

  18. Critical Current Properties in Longitudinal Magnetic Field of YBCO Superconductor with APC

    Science.gov (United States)

    Kido, R.; Kiuchi, M.; Otabe, E. S.; Matsushita, T.; Jha, A. K.; Matsumoto, K.

    The critical current density (Jc) properties of the Artificial Pinning Center (APC) introduced YBa2Cu3O7 (YBCO) films in the longitudinal magnetic field were measured. Y2O3 or Y2BaCuO5 (Y211) was introduced as APCs to YBCO, and YBCO films with APC were fabricated on SrTiO3 single crystal substrate. The sizes of Y2O3 and Y211 were 5-10 nm and 10-20 nm, respectively. As a result, Jc enhancement in the longitudinal magnetic field was observed in Y2O3 introduced YBCO films. However, it was not observed in Y211 introduced YBCO films. Therefore, it was considered that Jc properties in the longitudinal magnetic field were affected by introducing of small size APC, and it was necessary that APC does not disturb the current pathway in the superconductor.

  19. MHC class II B diversity in blue tits : A preliminary study

    NARCIS (Netherlands)

    Rivero-de Aguilar, Juan; Schut, Elske; Merino, Santiago; Martinez, Javier; Komdeur, Jan; Westerdahl, Helena

    In this study, we partly characterize major histocompatibility complex (MHC) class II B in the blue tit (Cyanistes caeruleus). A total of 22 individuals from three different European locations: Spain, The Netherlands, and Sweden were screened for MHC allelic diversity. The MHC genes were

  20. A comparative analysis of viral peptides presented by contemporary human and chimpanzee MHC class I molecules

    NARCIS (Netherlands)

    van Deutekom, Hanneke W. M.; Hoof, Ilka; Bontrop, Ronald E.; Keşmir, Can

    2011-01-01

    Genetic factors such as the MHC influence the immunocompetence of an individual. MHC genes are the most polymorphic genes in primates, which is often interpreted as an adaptation to establish good T cell responses to a wide range of (evolving) pathogens. Chimpanzee MHC (Patr) genes are less

  1. Germline Missense Changes in the APC Gene and Their Relationship to Disease.

    Science.gov (United States)

    Scott, Rodney J; Crooks, Renee; Rose, Lindy; Attia, John; Thakkinstian, Ammarin; Thomas, Lesley; Spigelman, Allan D; Meldrum, Cliff J

    2004-05-15

    Familial adenomatous polyposis (FAP) is characterized by the presence of hundreds to thousands of adenomas that carpet the entire colon and rectum. Nonsense and frameshift mutations in the adenomatous polyposis coli (APC) gene account for the majority of mutations identified to date and predispose primarily to the typical disease phenotype. Some APC mutations are associated with a milder form of the disease known as attenuated FAP. Virtually all mutations that have been described in the APC gene result in the formation of a premature stop codon and very little is known about missense mutations apart from a common Ashkenazi Jewish mutation (1307 K) and a British E1317Q missense change. The incidence of missense mutations in the APC gene has been underreported since the APC gene lends itself to analysis using an artificial transcription and translation assay known as the Protein Truncation Test (PTT) or the In Vitro Synthetic Protein assay (IVSP).In this report we have used denaturing high performance liquid chromatography to analyse the entire coding sequence of the APC gene to determine if a cohort of patients adhering to the diagnostic criteria of FAP to assess the frequency of missense mutations in the APC gene. Altogether 112 patients were studied and 22 missense mutations were identified. From the total of 22 missense changes, 13 were silent changes and the remaining 9 resulted in amino acid substitutions. One or more of these changes were identified multiple times in 62.5% of the population under study.The results reveal that missense mutations in the APC gene appear not to radically alter protein function but may be associated with more subtle processing of RNA transcripts which in turn could result in the expression of differentially spliced forms of the APC gene which may interfere with the functional activity of the APC protein.

  2. Germline Missense Changes in the APC Gene and Their Relationship to Disease

    Directory of Open Access Journals (Sweden)

    Scott Rodney J

    2004-05-01

    Full Text Available Abstract Familial adenomatous polyposis (FAP is characterized by the presence of hundreds to thousands of adenomas that carpet the entire colon and rectum. Nonsense and frameshift mutations in the adenomatous polyposis coli (APC gene account for the majority of mutations identified to date and predispose primarily to the typical disease phenotype. Some APC mutations are associated with a milder form of the disease known as attenuated FAP. Virtually all mutations that have been described in the APC gene result in the formation of a premature stop codon and very little is known about missense mutations apart from a common Ashkenazi Jewish mutation (1307 K and a British E1317Q missense change. The incidence of missense mutations in the APC gene has been underreported since the APC gene lends itself to analysis using an artificial transcription and translation assay known as the Protein Truncation Test (PTT or the In Vitro Synthetic Protein assay (IVSP. In this report we have used denaturing high performance liquid chromatography to analyse the entire coding sequence of the APC gene to determine if a cohort of patients adhering to the diagnostic criteria of FAP to assess the frequency of missense mutations in the APC gene. Altogether 112 patients were studied and 22 missense mutations were identified. From the total of 22 missense changes, 13 were silent changes and the remaining 9 resulted in amino acid substitutions. One or more of these changes were identified multiple times in 62.5% of the population under study. The results reveal that missense mutations in the APC gene appear not to radically alter protein function but may be associated with more subtle processing of RNA transcripts which in turn could result in the expression of differentially spliced forms of the APC gene which may interfere with the functional activity of the APC protein.

  3. A targeted constitutive mutation in the APC tumor suppressor gene underlies mammary but not intestinal tumorigenesis.

    Directory of Open Access Journals (Sweden)

    Claudia Gaspar

    2009-07-01

    Full Text Available Germline mutations in the adenomatous polyposis coli (APC gene are responsible for familial adenomatous polyposis (FAP, an autosomal dominant hereditary predisposition to the development of multiple colorectal adenomas and of a broad spectrum of extra-intestinal tumors. Moreover, somatic APC mutations play a rate-limiting and initiating role in the majority of sporadic colorectal cancers. Notwithstanding its multifunctional nature, the main tumor suppressing activity of the APC gene resides in its ability to regulate Wnt/beta-catenin signaling. Notably, genotype-phenotype correlations have been established at the APC gene between the length and stability of the truncated proteins encoded by different mutant alleles, the corresponding levels of Wnt/beta-catenin signaling activity they encode for, and the incidence and distribution of intestinal and extra-intestinal tumors. Here, we report a novel mouse model, Apc1572T, obtained by targeting a truncated mutation at codon 1572 in the endogenous Apc gene. This hypomorphic mutant allele results in intermediate levels of Wnt/beta-catenin signaling activation when compared with other Apc mutations associated with multifocal intestinal tumors. Notwithstanding the constitutive nature of the mutation, Apc(+/1572T mice have no predisposition to intestinal cancer but develop multifocal mammary adenocarcinomas and subsequent pulmonary metastases in both genders. The histology of the Apc1572T primary mammary tumours is highly heterogeneous with luminal, myoepithelial, and squamous lineages and is reminiscent of metaplastic carcinoma of the breast in humans. The striking phenotype of Apc(+/1572T mice suggests that specific dosages of Wnt/beta-catenin signaling activity differentially affect tissue homeostasis and initiate tumorigenesis in an organ-specific fashion.

  4. The role of APC in WNT pathway activation in serrated neoplasia.

    Science.gov (United States)

    Borowsky, Jennifer; Dumenil, Troy; Bettington, Mark; Pearson, Sally-Ann; Bond, Catherine; Fennell, Lochlan; Liu, Cheng; McKeone, Diane; Rosty, Christophe; Brown, Ian; Walker, Neal; Leggett, Barbara; Whitehall, Vicki

    2018-03-01

    Conventional adenomas are initiated by APC gene mutation that activates the WNT signal. Serrated neoplasia is commonly initiated by BRAF or KRAS mutation. WNT pathway activation may also occur, however, to what extent this is owing to APC mutation is unknown. We examined aberrant nuclear β-catenin immunolocalization as a surrogate for WNT pathway activation and analyzed the entire APC gene coding sequence in serrated and conventional pathway polyps and cancers. WNT pathway activation was a common event in conventional pathway lesions with aberrant nuclear immunolocalization of β-catenin and truncating APC mutations in 90% and 89% of conventional adenomas and 82% and 70% of BRAF wild-type cancers, respectively. WNT pathway activation was seen to a lesser extent in serrated pathway lesions. It occurred at the transition to dysplasia in serrated polyps with a significant increase in nuclear β-catenin labeling from sessile serrated adenomas (10%) to sessile serrated adenomas with dysplasia (55%) and traditional serrated adenomas (9%) to traditional serrated adenomas with dysplasia (39%) (P=0.0001). However, unlike the conventional pathway, truncating APC mutations were rare in the serrated pathway lesions especially sessile serrated adenomas even when dysplastic (15%) and in the BRAF mutant cancers with microsatellite instability that arise from them (8%). In contrast, APC missense mutations that were rare in conventional pathway adenomas and cancers (3% in BRAF wild-type cancers) were more frequent in BRAF mutant cancers with microsatellite instability (32%). We conclude that increased WNT signaling is important in the transition to malignancy in the serrated pathway but that APC mutation is less common and the spectrum of mutations is different than in conventional colorectal carcinogenesis. Moderate impact APC mutations and non-APC-related causes of increased WNT signaling may have a more important role in serrated neoplasia than the truncating APC mutations

  5. CpG methylation of APC promoter 1A in sporadic and familial breast cancer patients.

    Science.gov (United States)

    Debouki-Joudi, Saoussen; Trifa, Fatma; Khabir, Abdelmajid; Sellami-Boudawara, Tahia; Frikha, Mounir; Daoud, Jamel; Mokdad-Gargouri, Raja

    2017-01-01

    Tumour suppressor gene (TSG) silencing through promoter hypermethylation plays an important role in cancer initiation. The aim of this study was to assess the extent of methylation of APC gene promoter in 91 sporadic and 44 familial cases of Tunisian patients with breast cancer (BC) in. The frequency of APC promoter methylation is somewhat similar for sporadic and familial breast cancer cases, (52.1%, and 54.5% respectively). For sporadic breast cancer patients, there was a significant correlation of APC promoter hypermethylation with TNM stage (p = 0.024) and 3-year survival (p = 0.025). Regarding the hormonal status (HR), we found significant association between negativity to PR and unmethylated APC (p= 0.005) while ER and Her2/neu are not correlated. Moreover, unmethylated APC promoter is more frequent in tumours expressing at least one out the 3 proteins compared to triple negative cases (p= 0.053). On the other hand, aberrant methylation of APC was associated with tumour size (p = 0.036), lymph node (p = 0.028), distant metastasis (p = 0.031), and 3-year survival (p = 0.046) in the group of patients with familial breast cancer. Moreover, patients with sporadic breast cancer displaying the unmethylated profile have a significant prolonged overall survival compared to those with the methylated pattern of APC promoter (p log rank = 0.008). Epigenetic change at the CpG islands in the APC promoter was associated with the silence of its transcript and the loss of protein expression suggesting that this event is the main mechanism regulating the APC expression in breast cancer. In conclusion, our data showed that the loss of APC through aberrant methylation is associated with the aggressive behavior of both sporadic and familial breast cancer in Tunisian patients.

  6. Downregulation of the anaphase-promoting complex (APC)7 in invasive ductal carcinomas of the breast and its clinicopathologic relationships

    International Nuclear Information System (INIS)

    Park, Kwang-Hwa; Choi, Sung-E; Eom, Minseob; Kang, Yup

    2005-01-01

    The anaphase-promoting complex (APC) is a multiprotein complex with E3 ubiquitin ligase activity, which is required for the ubiquitination of securin and cyclin-B. Moreover, the mitotic spindle checkpoint is activated if APC activation is prevented. In addition, several APC-targeting molecules such as securin, polo-like kinase, aurora kinase, and SnoN have been reported to be oncogenes. Therefore, dysregulation of APC may be associated with tumorigenesis. However, the clinical significance and the involvement of APC in tumorigenesis have not been investigated. The expression of APC7 was immunohistochemically investigated in 108 invasive ductal carcinomas of the breast and its relationship with clinicopathologic parameters was examined. The expression of APC7 was defined as positive when the summed scores of staining intensities (0 to 3+) and stained proportions (0 to 3+) exceeded 3+. Positive APC7 expression was less frequent than its negative expression when histologic (P = 0.009) or nuclear grade (P = 0.009), or mitotic number (P = 0.0016) was elevated. The frequency of APC7 negative expression was higher in high Ki-67 or aneuploid groups than in low Ki-67 or diploid groups. These data show that loss of APC7 expression is more common in breast carcinoma cases with poor prognostic parameters or malignant characteristics. They therefore suggest that dysregulation of APC activity, possibly through downregulation of APC7, may be associated with tumorigenesis in breast cancer

  7. 75 FR 78246 - Medicare Program; Re-Chartering of the Advisory Panel on Ambulatory Payment Classification (APC...

    Science.gov (United States)

    2010-12-15

    ...] Medicare Program; Re-Chartering of the Advisory Panel on Ambulatory Payment Classification (APC) Groups... announces the re-chartering of the Advisory Panel on Ambulatory Payment Classification (APC) Groups (the... (APC) groups and their associated weights established under the Medicare hospital Outpatient...

  8. Prospects for immunotherapy of MHC class I-deficient tumours

    Czech Academy of Sciences Publication Activity Database

    Bubeník, Jan

    2003-01-01

    Roč. 49, č. 3 (2003), s. 95-99 ISSN 0015-5500 Institutional research plan: CEZ:AV0Z5052915 Keywords : MHC class I * immunotherapy Subject RIV: FD - Oncology ; Hematology Impact factor: 0.527, year: 2003

  9. Exosomal cancer immunotherapy is independent of MHC molecules on exosomes.

    Science.gov (United States)

    Hiltbrunner, Stefanie; Larssen, Pia; Eldh, Maria; Martinez-Bravo, Maria-Jose; Wagner, Arnika K; Karlsson, Mikael C I; Gabrielsson, Susanne

    2016-06-21

    Peptide-loaded exosomes are promising cancer treatment vehicles; however, moderate T cell responses in human clinical trials indicate a need to further understand exosome-induced immunity. We previously demonstrated that antigen-loaded exosomes carry whole protein antigens and require B cells for inducing antigen-specific T cells. Therefore, we investigated the relative importance of exosomal major histocompatibility complex (MHC) class I for the induction of antigen-specific T cell responses and tumour protection. We show that ovalbumin-loaded dendritic cell-derived exosomes from MHCI-/- mice induce antigen-specific T cells at the same magnitude as wild type exosomes. Furthermore, exosomes lacking MHC class I, as well as exosomes with both MHC class I and II mismatch, induced tumour infiltrating T cells and increased overall survival to the same extent as syngeneic exosomes in B16 melanoma. In conclusion, T cell responses are independent of exosomal MHC/peptide complexes if whole antigen is present. This establishes the prospective of using impersonalised exosomes, and will greatly increase the feasibility of designing exosome-based vaccines or therapeutic approaches in humans.

  10. Cutting Edge: Impaired MHC Class I Expression in Mice Deficient for Nlrc5/CITA

    OpenAIRE

    Biswas, Amlan; Meissner, Torsten B.; Taro Kawai,; Kobayashi, Koichi S.

    2012-01-01

    MHC class I and class II are crucial for the adaptive immune system. Although regulation of MHC class II expression by CIITA (class II transactivator) has long been recognized, the mechanism of MHC class I transactivation has been largely unknown until the recent discovery of NLRC5/CITA. Here we show using Nlrc5-deficient mice that NLRC5 is required for both constitutive and inducible MHC class I expression. Loss of Nlrc5 resulted in severe reduction in the expression of MHC class I and relat...

  11. MHC Class II and Non-MHC Class II Genes Differentially Influence Humoral Immunity to Bacillus anthracis Lethal Factor and Protective Antigen

    Directory of Open Access Journals (Sweden)

    Judith A. James

    2012-12-01

    Full Text Available Anthrax Lethal Toxin consists of Protective Antigen (PA and Lethal Factor (LF, and current vaccination strategies focus on eliciting antibodies to PA. In human vaccination, the response to PA can vary greatly, and the response is often directed toward non-neutralizing epitopes. Variable vaccine responses have been shown to be due in part to genetic differences in individuals, with both MHC class II and other genes playing roles. Here, we investigated the relative contribution of MHC class II versus non-MHC class II genes in the humoral response to PA and LF immunization using three immunized strains of inbred mice: A/J (H-2k at the MHC class II locus, B6 (H-2b, and B6.H2k (H-2k. IgG antibody titers to LF were controlled primarily by the MHC class II locus, whereas IgG titers to PA were strongly influenced by the non-MHC class II genetic background. Conversely, the humoral fine specificity of reactivity to LF appeared to be controlled primarily through non-MHC class II genes, while the specificity of reactivity to PA was more dependent on MHC class II. Common epitopes, reactive in all strains, occurred in both LF and PA responses. These results demonstrate that MHC class II differentially influences humoral immune responses to LF and PA.

  12. Apc1 is required for maintenance of local brain organizers and dorsal midbrain survival.

    Science.gov (United States)

    Paridaen, Judith T M L; Danesin, Catherine; Elas, Abu Tufayal; van de Water, Sandra; Houart, Corinne; Zivkovic, Danica

    2009-07-15

    The tumor suppressor Apc1 is an intracellular antagonist of the Wnt/beta-catenin pathway, which is vital for induction and patterning of the early vertebrate brain. However, its role in later brain development is less clear. Here, we examined the mechanisms underlying effects of an Apc1 zygotic-effect mutation on late brain development in zebrafish. Apc1 is required for maintenance of established brain subdivisions and control of local organizers such as the isthmic organizer (IsO). Caudal expansion of Fgf8 from IsO into the cerebellum is accompanied by hyperproliferation and abnormal cerebellar morphogenesis. Loss of apc1 results in reduced proliferation and apoptosis in the dorsal midbrain. Mosaic analysis shows that Apc is required cell-autonomously for maintenance of dorsal midbrain cell fate. The tectal phenotype occurs independently of Fgf8-mediated IsO function and is predominantly caused by stabilization of beta-catenin and subsequent hyperactivation of Wnt/beta-catenin signalling, which is mainly mediated through LEF1 activity. Chemical activation of the Wnt/beta-catenin in wild-type embryos during late brain maintenance stages phenocopies the IsO and tectal phenotypes of the apc mutants. These data demonstrate that Apc1-mediated restriction of Wnt/beta-catenin signalling is required for maintenance of local organizers and tectal integrity.

  13. PLK1 has tumor-suppressive potential in APC-truncated colon cancer cells.

    Science.gov (United States)

    Raab, Monika; Sanhaji, Mourad; Matthess, Yves; Hörlin, Albrecht; Lorenz, Ioana; Dötsch, Christina; Habbe, Nils; Waidmann, Oliver; Kurunci-Csacsko, Elisabeth; Firestein, Ron; Becker, Sven; Strebhardt, Klaus

    2018-03-16

    The spindle assembly checkpoint (SAC) acts as a molecular safeguard in ensuring faithful chromosome transmission during mitosis, which is regulated by a complex interplay between phosphatases and kinases including PLK1. Adenomatous polyposis coli (APC) germline mutations cause aneuploidy and are responsible for familial adenomatous polyposis (FAP). Here we study the role of PLK1 in colon cancer cells with chromosomal instability promoted by APC truncation (APC-ΔC). The expression of APC-ΔC in colon cells reduces the accumulation of mitotic cells upon PLK1 inhibition, accelerates mitotic exit and increases the survival of cells with enhanced chromosomal abnormalities. The inhibition of PLK1 in mitotic, APC-∆C-expressing cells reduces the kinetochore levels of Aurora B and hampers the recruitment of SAC component suggesting a compromised mitotic checkpoint. Furthermore, Plk1 inhibition (RNAi, pharmacological compounds) promotes the development of adenomatous polyps in two independent Apc Min/+ mouse models. High PLK1 expression increases the survival of colon cancer patients expressing a truncated APC significantly.

  14. Epithelial-derived IL-33 promotes intestinal tumorigenesis in Apc Min/+ mice.

    Science.gov (United States)

    He, Zhengxiang; Chen, Lili; Souto, Fabricio O; Canasto-Chibuque, Claudia; Bongers, Gerold; Deshpande, Madhura; Harpaz, Noam; Ko, Huaibin M; Kelley, Kevin; Furtado, Glaucia C; Lira, Sergio A

    2017-07-14

    Increased expression of Interleukin (IL)-33 has been detected in intestinal samples of patients with ulcerative colitis, a condition associated with increased risk for colon cancer, but its role in the development of colorectal cancer has yet to be fully examined. Here, we investigated the role of epithelial expressed IL-33 during development of intestinal tumors. IL-33 expression was detected in epithelial cells in colorectal cancer specimens and in the Apc Min/+ mice. To better understand the role of epithelial-derived IL-33 in the intestinal tumorigenesis, we generated transgenic mice expressing IL-33 in intestinal epithelial cells (V33 mice). V33 Apc Min/+ mice, resulting from the cross of V33 with Apc Min/+ mice, had increased intestinal tumor burden compared with littermate Apc Min/+ mice. Consistently, Apc Min/+ mice deficient for IL-33 receptor (ST2), had reduced polyp burden. Mechanistically, overexpression of IL-33 promoted expansion of ST2 + regulatory T cells, increased Th2 cytokine milieu, and induced alternatively activated macrophages in the gut. IL-33 promoted marked changes in the expression of antimicrobial peptides, and antibiotic treatment of V33 Apc Min/+ mice abrogated the tumor promoting-effects of IL-33 in the colon. In conclusion, elevated IL-33 signaling increases tumor development in the Apc Min/+ mice.

  15. APC loss in breast cancer leads to doxorubicin resistance via STAT3 activation.

    Science.gov (United States)

    VanKlompenberg, Monica K; Leyden, Emily; Arnason, Anne H; Zhang, Jian-Ting; Stefanski, Casey D; Prosperi, Jenifer R

    2017-11-28

    Resistance to chemotherapy is one of the leading causes of death from breast cancer. We recently established that loss of Adenomatous Polyposis Coli (APC) in the Mouse Mammary Tumor Virus - Polyoma middle T (MMTV-PyMT) transgenic mouse model results in resistance to cisplatin or doxorubicin-induced apoptosis. Herein, we aim to establish the mechanism that is responsible for APC-mediated chemotherapeutic resistance. Our data demonstrate that MMTV-PyMT; Apc Min/+ cells have increased signal transducer and activator of transcription 3 (STAT3) activation. STAT3 can be constitutively activated in breast cancer, maintains the tumor initiating cell (TIC) population, and upregulates multidrug resistance protein 1 (MDR1). The activation of STAT3 in the MMTV-PyMT; Apc Min/+ model is independent of interleukin 6 (IL-6); however, enhanced EGFR expression in the MMTV-PyMT; Apc Min/+ cells may be responsible for the increased STAT3 activation. Inhibiting STAT3 with a small molecule inhibitor A69 in combination with doxorubicin, but not cisplatin, restores drug sensitivity. A69 also decreases doxorubicin enhanced MDR1 gene expression and the TIC population enhanced by loss of APC. In summary, these results have revealed the molecular mechanisms of APC loss in breast cancer that can guide future treatment plans to counteract chemotherapeutic resistance.

  16. Predicted MHC peptide binding promiscuity explains MHC class I 'hotspots' of antigen presentation defined by mass spectrometry eluted ligand data.

    Science.gov (United States)

    Jappe, Emma Christine; Kringelum, Jens; Trolle, Thomas; Nielsen, Morten

    2018-02-15

    Peptides that bind to and are presented by MHC class I and class II molecules collectively make up the immunopeptidome. In the context of vaccine development, an understanding of the immunopeptidome is essential, and much effort has been dedicated to its accurate and cost-effective identification. Current state-of-the-art methods mainly comprise in silico tools for predicting MHC binding, which is strongly correlated with peptide immunogenicity. However, only a small proportion of the peptides that bind to MHC molecules are, in fact, immunogenic, and substantial work has been dedicated to uncovering additional determinants of peptide immunogenicity. In this context, and in light of recent advancements in mass spectrometry (MS), the existence of immunological hotspots has been given new life, inciting the hypothesis that hotspots are associated with MHC class I peptide immunogenicity. We here introduce a precise terminology for defining these hotspots and carry out a systematic analysis of MS and in silico predicted hotspots. We find that hotspots defined from MS data are largely captured by peptide binding predictions, enabling their replication in silico. This leads us to conclude that hotspots, to a great degree, are simply a result of promiscuous HLA binding, which disproves the hypothesis that the identification of hotspots provides novel information in the context of immunogenic peptide prediction. Furthermore, our analyses demonstrate that the signal of ligand processing, although present in the MS data, has very low predictive power to discriminate between MS and in silico defined hotspots. © 2018 John Wiley & Sons Ltd.

  17. Identification of MHC class II restricted T‐cell‐mediated reactivity against MHC class I binding Mycobacterium tuberculosis peptides

    DEFF Research Database (Denmark)

    Wang, Mingjun; Tang, Sheila Tuyet; Stryhn, Anette

    2011-01-01

    Major histocompatibility complex (MHC) class I restricted cytotoxic T lymphocytes (CTL) are known to play an important role in the control of Mycobacterium tuberculosis infection so identification of CTL epitopes from M. tuberculosis is of importance for the development of effective peptide...

  18. Somatic APC mosaicism and oligogenic inheritance in genetically unsolved colorectal adenomatous polyposis patients.

    Science.gov (United States)

    Ciavarella, Michele; Miccoli, Sara; Prossomariti, Anna; Pippucci, Tommaso; Bonora, Elena; Buscherini, Francesco; Palombo, Flavia; Zuntini, Roberta; Balbi, Tiziana; Ceccarelli, Claudio; Bazzoli, Franco; Ricciardiello, Luigi; Turchetti, Daniela; Piazzi, Giulia

    2018-03-01

    Germline variants in the APC gene cause familial adenomatous polyposis. Inherited variants in MutYH, POLE, POLD1, NTHL1, and MSH3 genes and somatic APC mosaicism have been reported as alternative causes of polyposis. However, ~30-50% of cases of polyposis remain genetically unsolved. Thus, the aim of this study was to investigate the genetic causes of unexplained adenomatous polyposis. Eight sporadic cases with >20 adenomatous polyps by 35 years of age or >50 adenomatous polyps by 55 years of age, and no causative germline variants in APC and/or MutYH, were enrolled from a cohort of 56 subjects with adenomatous colorectal polyposis. APC gene mosaicism was investigated on DNA from colonic adenomas by Sanger sequencing or Whole Exome Sequencing (WES). Mosaicism extension to other tissues (peripheral blood, saliva, hair follicles) was evaluated using Sanger sequencing and/or digital PCR. APC second hit was investigated in adenomas from mosaic patients. WES was performed on DNA from peripheral blood to identify additional polyposis candidate variants. We identified APC mosaicism in 50% of patients. In three cases mosaicism was restricted to the colon, while in one it also extended to the duodenum and saliva. One patient without APC mosaicism, carrying an APC in-frame deletion of uncertain significance, was found to harbor rare germline variants in OGG1, POLQ, and EXO1 genes. In conclusion, our restrictive selection criteria improved the detection of mosaic APC patients. In addition, we showed for the first time that an oligogenic inheritance of rare variants might have a cooperative role in sporadic colorectal polyposis onset.

  19. The APC/C E3 Ligase Complex Activator FZR1 Restricts BRAF Oncogenic Function.

    Science.gov (United States)

    Wan, Lixin; Chen, Ming; Cao, Juxiang; Dai, Xiangpeng; Yin, Qing; Zhang, Jinfang; Song, Su-Jung; Lu, Ying; Liu, Jing; Inuzuka, Hiroyuki; Katon, Jesse M; Berry, Kelsey; Fung, Jacqueline; Ng, Christopher; Liu, Pengda; Song, Min Sup; Xue, Lian; Bronson, Roderick T; Kirschner, Marc W; Cui, Rutao; Pandolfi, Pier Paolo; Wei, Wenyi

    2017-04-01

    BRAF drives tumorigenesis by coordinating the activation of the RAS/RAF/MEK/ERK oncogenic signaling cascade. However, upstream pathways governing BRAF kinase activity and protein stability remain undefined. Here, we report that in primary cells with active APC FZR1 , APC FZR1 earmarks BRAF for ubiquitination-mediated proteolysis, whereas in cancer cells with APC-free FZR1, FZR1 suppresses BRAF through disrupting BRAF dimerization. Moreover, we identified FZR1 as a direct target of ERK and CYCLIN D1/CDK4 kinases. Phosphorylation of FZR1 inhibits APC FZR1 , leading to elevation of a cohort of oncogenic APC FZR1 substrates to facilitate melanomagenesis. Importantly, CDK4 and/or BRAF/MEK inhibitors restore APC FZR1 E3 ligase activity, which might be critical for their clinical effects. Furthermore, FZR1 depletion cooperates with AKT hyperactivation to transform primary melanocytes, whereas genetic ablation of Fzr1 synergizes with Pten loss, leading to aberrant coactivation of BRAF/ERK and AKT signaling in mice. Our findings therefore reveal a reciprocal suppression mechanism between FZR1 and BRAF in controlling tumorigenesis. Significance: FZR1 inhibits BRAF oncogenic functions via both APC-dependent proteolysis and APC-independent disruption of BRAF dimers, whereas hyperactivated ERK and CDK4 reciprocally suppress APC FZR1 E3 ligase activity. Aberrancies in this newly defined signaling network might account for BRAF hyperactivation in human cancers, suggesting that targeting CYCLIN D1/CDK4, alone or in combination with BRAF/MEK inhibition, can be an effective anti-melanoma therapy. Cancer Discov; 7(4); 424-41. ©2017 AACR. See related commentary by Zhang and Bollag, p. 356 This article is highlighted in the In This Issue feature, p. 339 . ©2017 American Association for Cancer Research.

  20. Kaiso overexpression promotes intestinal inflammation and potentiates intestinal tumorigenesis in Apc(Min/+) mice.

    Science.gov (United States)

    Pierre, Christina C; Longo, Joseph; Mavor, Meaghan; Milosavljevic, Snezana B; Chaudhary, Roopali; Gilbreath, Ebony; Yates, Clayton; Daniel, Juliet M

    2015-09-01

    Constitutive Wnt/β-catenin signaling is a key contributor to colorectal cancer (CRC). Although inactivation of the tumor suppressor adenomatous polyposis coli (APC) is recognized as an early event in CRC development, it is the accumulation of multiple subsequent oncogenic insults facilitates malignant transformation. One potential contributor to colorectal carcinogenesis is the POZ-ZF transcription factor Kaiso, whose depletion extends lifespan and delays polyp onset in the widely used Apc(Min/+) mouse model of intestinal cancer. These findings suggested that Kaiso potentiates intestinal tumorigenesis, but this was paradoxical as Kaiso was previously implicated as a negative regulator of Wnt/β-catenin signaling. To resolve Kaiso's role in intestinal tumorigenesis and canonical Wnt signaling, we generated a transgenic mouse model (Kaiso(Tg/+)) expressing an intestinal-specific myc-tagged Kaiso transgene. We then mated Kaiso(Tg/+) and Apc(Min/+) mice to generate Kaiso(Tg/+):Apc(Min/+) mice for further characterization. Kaiso(Tg/+):Apc(Min/+) mice exhibited reduced lifespan and increased polyp multiplicity compared to Apc(Min/+) mice. Consistent with this murine phenotype, we found increased Kaiso expression in human CRC tissue, supporting a role for Kaiso in human CRC. Interestingly, Wnt target gene expression was increased in Kaiso(Tg/+):Apc(Min/+) mice, suggesting that Kaiso's function as a negative regulator of canonical Wnt signaling, as seen in Xenopus, is not maintained in this context. Notably, Kaiso(Tg/+):Apc(Min/+) mice exhibited increased inflammation and activation of NFκB signaling compared to their Apc(Min/+) counterparts. This phenotype was consistent with our previous report that Kaiso(Tg/+) mice exhibit chronic intestinal inflammation. Together our findings highlight a role for Kaiso in promoting Wnt signaling, inflammation and tumorigenesis in the mammalian intestine. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Tapasin-related protein TAPBPR is an additional component of the MHC class I presentation pathway

    DEFF Research Database (Denmark)

    Boyle, Louise H; Hermann, Clemens; Boname, Jessica M

    2013-01-01

    Tapasin is an integral component of the peptide-loading complex (PLC) important for efficient peptide loading onto MHC class I molecules. We investigated the function of the tapasin-related protein, TAPBPR. Like tapasin, TAPBPR is widely expressed, IFN-γ-inducible, and binds to MHC class I coupled...... with β2-microglobulin in the endoplasmic reticulum. In contrast to tapasin, TAPBPR does not bind ERp57 or calreticulin and is not an integral component of the PLC. β2-microglobulin is essential for the association between TAPBPR and MHC class I. However, the association between TAPBPR and MHC class I...... occurs in the absence of a functional PLC, suggesting peptide is not required. Expression of TAPBPR decreases the rate of MHC class I maturation through the secretory pathway and prolongs the association of MHC class I on the PLC. The TAPBPR:MHC class I complex trafficks through the Golgi apparatus...

  2. Pan-specific prediction of peptide-MHC Class I complex stability, a correlate of T cell immunogenicity

    DEFF Research Database (Denmark)

    Rasmussen, Michael; Fenoy, Emilio; Harndahl, Mikkel

    2016-01-01

    Binding of peptides to MHC class I (MHC-I) molecules is the most selective event in the processing and presentation of Ags to CTL, and insights into the mechanisms that govern peptide-MHC-I binding should facilitate our understanding of CTL biology. Peptide-MHC-I interactions have traditionally b...

  3. Apc-Mutant Kyoto Apc Delta (KAD) Rats Are Susceptible to 4-NQO-Induced Tongue Carcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Takuji, E-mail: tmntt08@gmail.com [Department of Diagnostic Pathology (DDP) & Research Center of Diagnostic Pathology (RC-DiP), Gifu Municipal Hospital, 7-1 Kashima-Cho, Gifu 500-8513 (Japan); Department of Tumor Pathology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Shimizu, Masahito; Kochi, Takahiro; Shirakami, Yohei [Department of Internal Medicine/Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Mori, Takayuki [Department of Pharmacy, Ogaki Municipal Hospital, 4-86 Minaminokawa-cho, Ogaki 503-8502 (Japan); Watanabe, Naoki [Department of Diagnostic Pathology (DDP) & Research Center of Diagnostic Pathology (RC-DiP), Gifu Municipal Hospital, 7-1 Kashima-Cho, Gifu 500-8513 (Japan); Naiki, Takafumi [Department of Clinical Laboratory, Gifu Municipal Hospital, 7-1 Kashima-cho, Gifu 500-8513 (Japan); Moriwaki, Hisataka [Department of Internal Medicine/Gastroenterology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194 (Japan); Yoshimi, Kazuto; Serikawa, Tadao; Kuramoto, Takashi [The Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501 (Japan)

    2014-07-21

    Despite widening interest in the possible association between infection/inflammation and cancer development, knowledge of this issue in relation to oral cancer remains inadequate. This study aimed to determine the susceptibility of Apc-mutant Kyoto Apc Delta (KAD) rats, which are vulnerable to developing inflammation-associated colorectal carcinogenesis, to 4-nitroquinoline 1-oxide (4-NQO)-induced tongue carcinogenesis in order to clarify the role of inflammation in oral cancer. KAD (20 males and 22 females) and F344/NS1c (22 males and 23 females) rats received drinking water with or without 4-NQO (20 ppm) for eight weeks. Histopathological and immunohistochemical analyses of the tongue were performed at week 20. Additionally, the mRNA expression of inflammatory cytokines in the tongue mucosa was determined at week 8. Tongue squamous cell carcinoma (SCC) developed in the KAD and F344/NS1c rats that received 4-NQO. Regardless of gender, the incidence and multiplicity of tongue SCC were greater in the KAD rats than in the F344/NS1c rats. In addition, the multiplicity of tongue SCC in the female KAD rats was significantly greater than that observed in the male KAD (p < 0.01) and female F344/NS1c rats (p < 0.05). The levels of inflammation and the mRNA expression of inflammatory cytokines in the tongue in the 4-NQO-treated female KAD rats were the highest among the rats given 4-NQO. These results show that KAD rats, particularly females, are susceptible to 4-NQO-induced tongue carcinogenesis, suggesting the utility of models employing KAD rats for investigating the pathobiology of oral (tongue) carcinogenesis associated with inflammation.

  4. Apc-Mutant Kyoto Apc Delta (KAD) Rats Are Susceptible to 4-NQO-Induced Tongue Carcinogenesis

    International Nuclear Information System (INIS)

    Tanaka, Takuji; Shimizu, Masahito; Kochi, Takahiro; Shirakami, Yohei; Mori, Takayuki; Watanabe, Naoki; Naiki, Takafumi; Moriwaki, Hisataka; Yoshimi, Kazuto; Serikawa, Tadao; Kuramoto, Takashi

    2014-01-01

    Despite widening interest in the possible association between infection/inflammation and cancer development, knowledge of this issue in relation to oral cancer remains inadequate. This study aimed to determine the susceptibility of Apc-mutant Kyoto Apc Delta (KAD) rats, which are vulnerable to developing inflammation-associated colorectal carcinogenesis, to 4-nitroquinoline 1-oxide (4-NQO)-induced tongue carcinogenesis in order to clarify the role of inflammation in oral cancer. KAD (20 males and 22 females) and F344/NS1c (22 males and 23 females) rats received drinking water with or without 4-NQO (20 ppm) for eight weeks. Histopathological and immunohistochemical analyses of the tongue were performed at week 20. Additionally, the mRNA expression of inflammatory cytokines in the tongue mucosa was determined at week 8. Tongue squamous cell carcinoma (SCC) developed in the KAD and F344/NS1c rats that received 4-NQO. Regardless of gender, the incidence and multiplicity of tongue SCC were greater in the KAD rats than in the F344/NS1c rats. In addition, the multiplicity of tongue SCC in the female KAD rats was significantly greater than that observed in the male KAD (p < 0.01) and female F344/NS1c rats (p < 0.05). The levels of inflammation and the mRNA expression of inflammatory cytokines in the tongue in the 4-NQO-treated female KAD rats were the highest among the rats given 4-NQO. These results show that KAD rats, particularly females, are susceptible to 4-NQO-induced tongue carcinogenesis, suggesting the utility of models employing KAD rats for investigating the pathobiology of oral (tongue) carcinogenesis associated with inflammation

  5. Stabilization of APC residues from waste incineration with ferrous sulfate on a semi-industrial scale

    DEFF Research Database (Denmark)

    Lundtorp, Kasper; Jensen, Dorthe Lærke; Christensen, Thomas Højlund

    2002-01-01

    A stabilization method for air pollution control (APC) residues from municipal solid waste incineration (MSWI) involving mixing of the residue with water and FeSO4 has been demonstrated on a semi-industrial scale on three types of APC residues: a semidy (SD) APC residue, a fly ash (FA), and an FA...... mixed with sludge (FAS) from a wet flue gas cleaning system. The process was performed in batches of 165-175 kg residue. It generates a wastewater that is highly saline but has a low content of heavy metals such as Cd, Cr, and Pb. The stabilized and raw residues have been subject to a range of leaching...

  6. Fine-mapping analysis of the MHC region for vitiligo based on a new Han-MHC reference panel.

    Science.gov (United States)

    Yang, Chao; Wu, Juan; Zhang, Xuelei; Wen, Leilei; Sun, Jingying; Cheng, Yuyan; Tang, Xianfa; Liang, Bo; Chen, Gang; Zhou, Fusheng; Cui, Yong; Zhang, Anping; Zhang, Xuejun; Zheng, Xiaodong; Yang, Sen; Sun, Liangdan

    2018-03-30

    Vitiligo is an immune-related disease with patchy depigmentation of skin and hair caused by selective destruction of melanocytes. In recent decades, many studies have shown the association between vitiligo and HLA genes; however, the results of Han Chinese are scarce. In this study, we performed a fine-mapping analysis of the MHC region in 2818 Han Chinese subjects through a widely used HLA imputation method with a newly built large-scale Han-MHC reference panel. Three new four-digit HLA alleles (HLA-DQB1 ∗ 02:02, HLA-DQA1 ∗ 02:01 and HLA-DPB1 ∗ 17:01) were identified to be associated with the risk of vitiligo, and four previously reported alleles were confirmed. Further conditional analysis revealed that two important variants, HLA-DQβ1 amino acid position 135 (OR = 1.79, P = 1.87 × 10 -11 ) and HLA-B amino acid positions 45-46 (OR = 1.44, P = 5.61 × 10 -11 ), conferred most of the MHC associations. Three-dimension ribbon models showed that the former is located within the β2 domain of the HLA-DQβ1 molecule, and the latter lies in the α1 domain of the HLA-B molecule, while both are involved in specific antigen presenting process. Finally, we summarized all significant signals in the MHC region to clarify their complex relationships, and 8.60% of phenotypic variance could be explained based on all reported variants in Han Chinese so far. Our findings highlight the complex genetic architecture of the MHC region for vitiligo in Han Chinese population and expand our understanding of the roles of HLA coding variants in the etiology of vitiligo. Copyright © 2018. Published by Elsevier B.V.

  7. β-Catenin destruction complex-independent regulation of Hippo–YAP signaling by APC in intestinal tumorigenesis

    Science.gov (United States)

    Cai, Jing; Maitra, Anirban; Anders, Robert A.; Taketo, Makoto M.; Pan, Duojia

    2015-01-01

    Mutations in Adenomatous polyposis coli (APC) underlie familial adenomatous polyposis (FAP), an inherited cancer syndrome characterized by the widespread development of colorectal polyps. APC is best known as a scaffold protein in the β-catenin destruction complex, whose activity is antagonized by canonical Wnt signaling. Whether other effector pathways mediate APC's tumor suppressor function is less clear. Here we report that activation of YAP, the downstream effector of the Hippo signaling pathway, is a general hallmark of tubular adenomas from FAP patients. We show that APC functions as a scaffold protein that facilitates the Hippo kinase cascade by interacting with Sav1 and Lats1. Consistent with the molecular link between APC and the Hippo signaling pathway, genetic analysis reveals that YAP is absolutely required for the development of APC-deficient adenomas. These findings establish Hippo–YAP signaling as a critical effector pathway downstream from APC, independent from its involvement in the β-catenin destruction complex. PMID:26193883

  8. Apoptosis in neural crest cells by functional loss of APC tumor suppressor gene

    Science.gov (United States)

    Hasegawa, Sumitaka; Sato, Tomoyuki; Akazawa, Hiroshi; Okada, Hitoshi; Maeno, Akiteru; Ito, Masaki; Sugitani, Yoshinobu; Shibata, Hiroyuki; Miyazaki, Jun-ichi; Katsuki, Motoya; Yamauchi, Yasutaka; Yamamura, Ken-ichi; Katamine, Shigeru; Noda, Tetsuo

    2002-01-01

    Apc is a gene associated with familial adenomatous polyposis coli (FAP) and its inactivation is a critical step in colorectal tumor formation. The protein product, adenomatous polyposis coli (APC), acts to down-regulate intracellular levels of β-catenin, a key signal transducer in the Wnt signaling. Conditional targeting of Apc in the neural crest of mice caused massive apoptosis of cephalic and cardiac neural crest cells at about 11.5 days post coitum, resulting in craniofacial and cardiac anomalies at birth. Notably, the apoptotic cells localized in the regions where β-catenin had accumulated. In contrast to its role in colorectal epithelial cells, inactivation of APC leads to dysregulation of β-catenin/Wnt signaling with resultant apoptosis in certain tissues including neural crest cells. PMID:11756652

  9. Visualizing the complex functions and mechanisms of the anaphase promoting complex/cyclosome (APC/C)

    Science.gov (United States)

    Alfieri, Claudio; Zhang, Suyang

    2017-01-01

    The anaphase promoting complex or cyclosome (APC/C) is a large multi-subunit E3 ubiquitin ligase that orchestrates cell cycle progression by mediating the degradation of important cell cycle regulators. During the two decades since its discovery, much has been learnt concerning its role in recognizing and ubiquitinating specific proteins in a cell-cycle-dependent manner, the mechanisms governing substrate specificity, the catalytic process of assembling polyubiquitin chains on its target proteins, and its regulation by phosphorylation and the spindle assembly checkpoint. The past few years have witnessed significant progress in understanding the quantitative mechanisms underlying these varied APC/C functions. This review integrates the overall functions and properties of the APC/C with mechanistic insights gained from recent cryo-electron microscopy (cryo-EM) studies of reconstituted human APC/C complexes. PMID:29167309

  10. Interferon beta 1, an intermediate in the tumor necrosis factor alpha- induced increased MHC class I expression and an autocrine regulator of the constitutive MHC class I expression

    OpenAIRE

    1987-01-01

    In conclusion, our observations indicate that the constitutive MHC class I expression is regulated by autocrine production of IFN-beta 1. TNF-alpha acts as an enhancer of the autocrine production of IFN-beta 1, and consequently as an enhancer of the MHC class I expression and viral protection.

  11. NetMHC-3.0: accurate web accessible predictions of human, mouse and monkey MHC class I affinities for peptides of length 8-11

    DEFF Research Database (Denmark)

    Lundegaard, Claus; Lamberth, K; Harndahl, M

    2008-01-01

    NetMHC-3.0 is trained on a large number of quantitative peptide data using both affinity data from the Immune Epitope Database and Analysis Resource (IEDB) and elution data from SYFPEITHI. The method generates high-accuracy predictions of major histocompatibility complex (MHC): peptide binding...

  12. Novel APC gene mutations associated with protein alteration in diffuse type gastric cancer.

    Science.gov (United States)

    Ghatak, Souvik; Chakraborty, Payel; Sarkar, Sandeep Roy; Chowdhury, Biswajit; Bhaumik, Arup; Kumar, Nachimuthu Senthil

    2017-06-02

    The role of adenomatous polyposis coli (APC) gene in mitosis might be critical for regulation of genomic stability and chromosome segregation. APC gene mutations have been associated to have a role in colon cancer and since gastric and colon tumors share some common genetic lesions, it is relevant to investigate the role of APC tumor suppressor gene in gastric cancer. We investigated for somatic mutations in the Exons 14 and 15 of APC gene from 40 diffuse type gastric cancersamples. Rabbit polyclonal anti-APC antibody was used, which detects the wild-type APC protein and was recommended for detection of the respective protein in human tissues. Cell cycle analysis was done from tumor and adjacent normal tissue. APC immunoreactivity showed positive expression of the protein in stages I, II, III and negative expression in Stages III and IV. Two novel deleterious variations (g.127576C > A, g.127583C > T) in exon 14 sequence were found to generate stop codon (Y622* and Q625*)in the tumor samples. Due to the generation of stop codon, the APC protein might be truncated and all the regulatory features could be lost which has led to the down-regulation of protein expression. Our results indicate that aneuploidy might occurdue to the codon 622 and 625 APC-driven gastric tumorigenesis, in agreement with our cell cycle analysis. The APC gene function in mitosis and chromosomal stability might be lost and G1 might be arrested with high quantity of DNA in the S phase. Six missense somatic mutations in tumor samples were detected in exon 15 A-B, twoof which showed pathological and disease causing effects based on SIFT, Polyphen2 and SNPs & GO score and were not previously reported in the literature or the public mutation databases. The two novel pathological somatic mutations (g.127576C > A, g.127583C > T) in exon 14 might be altering the protein expression leading to development of gastric cancer in the study population. Our study showed that mutations in the APC

  13. Neuronal MHC Class I Expression Is Regulated by Activity Driven Calcium Signaling.

    Directory of Open Access Journals (Sweden)

    Dan Lv

    Full Text Available MHC class I (MHC-I molecules are important components of the immune system. Recently MHC-I have been reported to also play important roles in brain development and synaptic plasticity. In this study, we examine the molecular mechanism(s underlying activity-dependent MHC-I expression using hippocampal neurons. Here we report that neuronal expression level of MHC-I is dynamically regulated during hippocampal development after birth in vivo. Kainic acid (KA treatment significantly increases the expression of MHC-I in cultured hippocampal neurons in vitro, suggesting that MHC-I expression is regulated by neuronal activity. In addition, KA stimulation decreased the expression of pre- and post-synaptic proteins. This down-regulation is prevented by addition of an MHC-I antibody to KA treated neurons. Further studies demonstrate that calcium-dependent protein kinase C (PKC is important in relaying KA simulation activation signals to up-regulated MHC-I expression. This signaling cascade relies on activation of the MAPK pathway, which leads to increased phosphorylation of CREB and NF-κB p65 while also enhancing the expression of IRF-1. Together, these results suggest that expression of MHC-I in hippocampal neurons is driven by Ca2+ regulated activation of the MAPK signaling transduction cascade.

  14. MHC I stabilizing potential of computer-designed octapeptides.

    Science.gov (United States)

    Wisniewska, Joanna M; Jäger, Natalie; Freier, Anja; Losch, Florian O; Wiesmüller, Karl-Heinz; Walden, Peter; Wrede, Paul; Schneider, Gisbert; Hiss, Jan A

    2010-01-01

    Experimental results are presented for 180 in silico designed octapeptide sequences and their stabilizing effects on the major histocompatibility class I molecule H-2K(b). Peptide sequence design was accomplished by a combination of an ant colony optimization algorithm with artificial neural network classifiers. Experimental tests yielded nine H-2K(b) stabilizing and 171 nonstabilizing peptides. 28 among the nonstabilizing octapeptides contain canonical motif residues known to be favorable for MHC I stabilization. For characterization of the area covered by stabilizing and non-stabilizing octapeptides in sequence space, we visualized the distribution of 100,603 octapeptides using a self-organizing map. The experimental results present evidence that the canonical sequence motives of the SYFPEITHI database on their own are insufficient for predicting MHC I protein stabilization.

  15. MHC I Stabilizing Potential of Computer-Designed Octapeptides

    Directory of Open Access Journals (Sweden)

    Joanna M. Wisniewska

    2010-01-01

    Full Text Available Experimental results are presented for 180 in silico designed octapeptide sequences and their stabilizing effects on the major histocompatibility class I molecule H-2Kb. Peptide sequence design was accomplished by a combination of an ant colony optimization algorithm with artificial neural network classifiers. Experimental tests yielded nine H-2Kb stabilizing and 171 nonstabilizing peptides. 28 among the nonstabilizing octapeptides contain canonical motif residues known to be favorable for MHC I stabilization. For characterization of the area covered by stabilizing and non-stabilizing octapeptides in sequence space, we visualized the distribution of 100,603 octapeptides using a self-organizing map. The experimental results present evidence that the canonical sequence motives of the SYFPEITHI database on their own are insufficient for predicting MHC I protein stabilization.

  16. Complex assembly, crystallization and preliminary X-ray crystallographic studies of duck MHC class I molecule

    International Nuclear Information System (INIS)

    Zhang, Jianhua; Chen, Yong; Gao, Feng; Chen, Weihong; Qi, Jianxun; Xia, Chun

    2009-01-01

    Using a peptide derived from H5N1, a complex of duck MHC class I molecule (DuMHC I) with duck β 2 -microglobulin (Duβ 2 m) was assembled and crystallized. Initial structure analysis indicated that the crystals did not contain the complete DuMHC I complex but instead contained DuMHC I α3-domain and Duβ 2 m subunits. In order to understand the biological properties of the immune systems of waterfowl and to establish a system for structural studies of duck class I major histocompatibility complex (DuMHC I), a complex of DuMHC I with duck β 2 -microglobulin (Duβ 2 m) and the peptide AEIEDLIF (AF8) derived from H5N1 NP residues 251–258 was assembled. The complex was crystallized; the crystals belonged to space group C222 1 , with unit-cell parameters a = 54.7, b = 72.4, c = 102.2 Å, and diffracted to 2.3 Å resolution. Matthews coefficient calculation and initial structure determination by molecular replacement showed that the crystals did not contain the whole DuMHC I complex, but instead contained the DuMHC I α3 domain and a Duβ2m molecule (DuMHC I α3+β2m). Another complex of DuMHC I with the peptide IDWFDGKE derived from a chicken fusion protein also generated the same results. The stable structure of DuMHC I α3+β2m may reflect some unique characteristics of DuMHC I and pave the way for novel MHC structure-related studies in the future

  17. The interrelationship between APC/C and Plk1 activities in centriole disengagement

    Directory of Open Access Journals (Sweden)

    Toshiyuki Hatano

    2012-09-01

    Mother–daughter centriole disengagement, the necessary first step in centriole duplication, involves Plk1 activity in early mitosis and separase activity after APC/C activity mediates securin degradation. Plk1 activity is thought to be essential and sufficient for centriole disengagement with separase activity playing a supporting but non-essential role. In separase null cells, however, centriole disengagement is substantially delayed. The ability of APC/C activity alone to mediate centriole disengagement has not been directly tested. We investigate the interrelationship between Plk1 and APC/C activities in disengaging centrioles in S or G2 HeLa and RPE1 cells, cell types that do not reduplicate centrioles when arrested in S phase. Knockdown of the interphase APC/C inhibitor Emi1 leads to centriole disengagement and reduplication of the mother centrioles, though this is slow. Strong inhibition of Plk1 activity, if any, during S does not block centriole disengagement and mother centriole reduplication in Emi1 depleted cells. Centriole disengagement depends on APC/C–Cdh1 activity, not APC/C–Cdc20 activity. Also, Plk1 and APC/C–Cdh1 activities can independently promote centriole disengagement in G2 arrested cells. Thus, Plk1 and APC/C–Cdh1 activities are independent but slow pathways for centriole disengagement. By having two slow mechanisms for disengagement working together, the cell ensures that centrioles will not prematurely separate in late G2 or early mitosis, thereby risking multipolar spindle assembly, but rather disengage in a timely fashion only late in mitosis.

  18. APC fly ashes stabilized with Portland cement for further development of road sub-base aggregates

    Science.gov (United States)

    Formosa, J.; Giro-Paloma, J.; Maldonado-Alameda, A.; Huete-Hernández, S.; Chimenos, J. M.

    2017-10-01

    Although waste-to-energy plants allow reducing the mass and volume of municipal solid waste (MSW) incinerated, an average around 30 % of the total content remains as bottom ash (BA) and air pollution control (APC) ashes at the end of combustion process. While weathered bottom ash (WBA) is considered a non-hazardous residue that can be revalorized as a secondary aggregate, APC fly ashes generated during the flue gas treatment are classified as hazardous waste and are handled in landfill disposal after stabilization, usually with Portland cement (OPC). However, taking into account the amount of APC residues produced and the disposing cost in landfill, their revalorization is an important issue that could be effectively addressed. As MSW can be incinerated producing bottom ashes (BA) or air pollutant control (APC) residues, the development of a mortar formulated with APC fly ash as secondary building material is a significant risk to the environment for their content of heavy metals. In this way, Design of Experiment (DoE) was used for the improvement of granular material (GM) formulation composed by APC and OPC for further uses as road sub-base aggregate. DoE analysis was successful in the modelling and optimization the formulation as function of the mechanical properties and APC amount. Consequently, an optimal mortar formulation (OMF) of around 50 wt.% APC and 50 wt.% OPC was considered. The OMF leachates and abrasion resistance have been analyzed. These results have demonstrated the viability of OMF as non-hazardous material feasible to be used as secondary aggregate. Moreover, it would be possible to consider the environmental assessment of a GM composed by ≈20 wt.% of OMF and ≈80 wt.% of WBA in order to improve mechanical properties and heavy metals stabilization.

  19. Use of operator training and simulating complexes for development of NPP APCS

    International Nuclear Information System (INIS)

    Malkin, S.D.; Rakitin, I.D.; Sivokon', V.P.

    2002-01-01

    The evolution of NPP educational facilities - from systems of training of personnel to power simulating systems for the development of Automatic Process Control System (APCS) and safety analysis is followed. High efficiency of simulating systems application for the development of NPP APCS including optimization of man-machine system interface was shown by experiments of USA, France, Japan, United Kingdom, conforming examples were given [ru

  20. Irradiated Foods Detection by Thermoluminescence (TL) and DEFT/APC Analysis

    International Nuclear Information System (INIS)

    Choi, I.D.; Kang, E.K.; Yang, J.S.

    2004-01-01

    Irradiated food detection methods such as Thermoluminescence (TL) and Direct Epifluorescent Filter Technique and Aerobic Plate Count (DEFT/APC) methods were evaluated. Fresh green-onion, onion, and ginger were irradiated at 0, 0.3, 0.6, and 0.9 kGy. Difference in log DEFT/APC units between irradiated and un-irradiated samples was less than 2 long units, below the average threshold value (3-4 long units) of international researches

  1. Prevalence of Resistence to Activated Protein C (Apc-Resistance in Blood Donors in Kosovo

    Directory of Open Access Journals (Sweden)

    Ymer Mekaj

    2009-11-01

    Full Text Available AbstractOne of the most frequent hereditary causes of thrombophilia is, without a doubt, resistance to Activated Protein C (APC-resistance, which is a consequence of point mutation in gene coding for coagulation Factor V (Factor V Leiden in 90-95% of cases.The aim of this paper was to determine prevalence of APC-resistance in a group of healthy blood donors. The size of the group is quite representative of Kosovo Albanians.A total of 944 blood donors were examined (537 males and 407 females, for whom APC-resistance was determined by functional methods of coagulation using the kit ACTICLOT® Protein C Resistance. Method is based on the test of APTT determined twice: first in the presence and second in the absence of activated Protein C (APC. The ratio of these two values constitutes is called Activated Protein C - Sensitivity Ratio (APC-SR.From 944 examined donors, pathologic values of APC-SR (1,3-1,9 were found in 32 persons (3,4% of the total number. The distribution among sexes was 3,35% (18/537 in male and 3,43% (14/407 in female subjects. The mean values of APC-SR (1,64 in male and 1,71 in female subjects were not significantly different (P = 0,22.Based on these results, we conclude that the prevalence of APC resistance in Albanian population of Kosovo is within the lower limit of prevalence in general population in different countries of European countries, which, according to some authors ranges is from 3 to 7%.

  2. Tumour MHC class I downregulation and immunotherapy (Review)

    Czech Academy of Sciences Publication Activity Database

    Bubeník, Jan

    2003-01-01

    Roč. 10, č. 6 (2003), s. 2005-2008 ISSN 1021-335X R&D Projects: GA MZd NC7148; GA ČR GA301/01/0985; GA AV ČR IAA5052203 Institutional research plan: CEZ:AV0Z5052915 Keywords : tumour vaccines * MHC class I downregulation Subject RIV: FD - Oncology ; Hematology Impact factor: 1.256, year: 2003

  3. Automated benchmarking of peptide-MHC class I binding predictions

    Science.gov (United States)

    Trolle, Thomas; Metushi, Imir G.; Greenbaum, Jason A.; Kim, Yohan; Sidney, John; Lund, Ole; Sette, Alessandro; Peters, Bjoern; Nielsen, Morten

    2015-01-01

    Motivation: Numerous in silico methods predicting peptide binding to major histocompatibility complex (MHC) class I molecules have been developed over the last decades. However, the multitude of available prediction tools makes it non-trivial for the end-user to select which tool to use for a given task. To provide a solid basis on which to compare different prediction tools, we here describe a framework for the automated benchmarking of peptide-MHC class I binding prediction tools. The framework runs weekly benchmarks on data that are newly entered into the Immune Epitope Database (IEDB), giving the public access to frequent, up-to-date performance evaluations of all participating tools. To overcome potential selection bias in the data included in the IEDB, a strategy was implemented that suggests a set of peptides for which different prediction methods give divergent predictions as to their binding capability. Upon experimental binding validation, these peptides entered the benchmark study. Results: The benchmark has run for 15 weeks and includes evaluation of 44 datasets covering 17 MHC alleles and more than 4000 peptide-MHC binding measurements. Inspection of the results allows the end-user to make educated selections between participating tools. Of the four participating servers, NetMHCpan performed the best, followed by ANN, SMM and finally ARB. Availability and implementation: Up-to-date performance evaluations of each server can be found online at http://tools.iedb.org/auto_bench/mhci/weekly. All prediction tool developers are invited to participate in the benchmark. Sign-up instructions are available at http://tools.iedb.org/auto_bench/mhci/join. Contact: mniel@cbs.dtu.dk or bpeters@liai.org Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25717196

  4. Ubiquitination of Cdc20 by the APC occurs through an intramolecular mechanism

    Science.gov (United States)

    Foe, Ian T.; Foster, Scott A.; Cheung, Stephanie K.; DeLuca, Steven Z.; Morgan, David O.; Toczyski, David P.

    2012-01-01

    SUMMARY Background Cells control progression through late mitosis by regulating Cdc20 and Cdh1, the two mitotic activators of the Anaphase Promoting Complex (APC). The control of Cdc20 protein levels during the cell cycle is not well understood. Results Here, we demonstrate that Cdc20 is degraded in budding yeast by multiple APC-dependent mechanisms. We find that the majority of Cdc20 turnover does not involve a second activator molecule, but instead depends on in cis Cdc20 autoubiquitination while it is bound to its activator-binding site on the APC core. Unlike in trans ubiquitination of Cdc20 substrates, the APC ubiquitinates Cdc20 independent of APC activation by Cdc20’s C-box. Cdc20 turnover by this intramolecular mechanism is cell cycle-regulated, contributing to the decline in Cdc20 levels that occurs after anaphase. Interestingly, high substrate levels in vitro significantly reduce Cdc20 autoubiquitination. Conclusion We show here that Cdc20 fluctuates through the cell cycle via a distinct form of APC-mediated ubiquitination. This in cis autoubiquitination may preferentially occur in early anaphase, following depletion of Cdc20 substrates. This suggests that distinct mechanisms are able to target Cdc20 for ubiquitination at different points during the cell cycle. PMID:22079111

  5. The APC/C Ubiquitin Ligase: From Cell Biology to Tumorigenesis

    Energy Technology Data Exchange (ETDEWEB)

    Penas, Clara; Ramachandran, Vimal [John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL (United States); Ayad, Nagi George, E-mail: nayad@med.miami.edu [John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL (United States); Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL (United States)

    2012-01-09

    The ubiquitin proteasome system (UPS) is required for normal cell proliferation, vertebrate development, and cancer cell transformation. The UPS consists of multiple proteins that work in concert to target a protein for degradation via the 26S proteasome. Chains of an 8.5-kDa protein called ubiquitin are attached to substrates, thus allowing recognition by the 26S proteasome. Enzymes called ubiquitin ligases or E3s mediate specific attachment to substrates. Although there are over 600 different ubiquitin ligases, the Skp1–Cullin–F-box (SCF) complexes and the anaphase promoting complex/cyclosome (APC/C) are the most studied. SCF involvement in cancer has been known for some time while APC/C’s cancer role has recently emerged. In this review we will discuss the importance of APC/C to normal cell proliferation and development, underscoring its possible contribution to transformation. We will also examine the hypothesis that modulating a specific interaction of the APC/C may be therapeutically attractive in specific cancer subtypes. Finally, given that the APC/C pathway is relatively new as a cancer target, therapeutic interventions affecting APC/C activity may be beneficial in cancers that are resistant to classical chemotherapy.

  6. Disruption of estrogen receptor signaling enhances intestinal neoplasia in ApcMin/+ mice

    Science.gov (United States)

    Cleveland, Alicia G.; Oikarinen, Seija I.; Bynoté, Kimberly K.; Marttinen, Maija; Rafter, Joseph J.; Gustafsson, Jan-Åke; Roy, Shyamal K.; Pitot, Henry C.; Korach, Kenneth S.; Lubahn, Dennis B.; Mutanen, Marja; Gould, Karen A.

    2009-01-01

    Estrogen receptors (ERs) [ERα (Esr1) and ERβ (Esr2)] are expressed in the human colon, but during the multistep process of colorectal carcinogenesis, expression of both ERα and ERβ is lost, suggesting that loss of ER function might promote colorectal carcinogenesis. Through crosses between an ERα knockout and ApcMin mouse strains, we demonstrate that ERα deficiency is associated with a significant increase in intestinal tumor multiplicity, size and burden in ApcMin/+ mice. Within the normal intestinal epithelium of ApcMin/+ mice, ERα deficiency is associated with an accumulation of nuclear β-catenin, an indicator of activation of the Wnt–β-catenin-signaling pathway, which is known to play a critical role in intestinal cancers. Consistent with the hypothesis that ERα deficiency is associated with activation of Wnt–β-catenin signaling, ERα deficiency in the intestinal epithelium of ApcMin/+ mice also correlated with increased expression of Wnt–β-catenin target genes. Through crosses between an ERβ knockout and ApcMin mouse strains, we observed some evidence that ERβ deficiency is associated with an increased incidence of colon tumors in ApcMin/+ mice. This effect of ERβ deficiency does not involve modulation of Wnt–β-catenin signaling. Our studies suggest that ERα and ERβ signaling modulate colorectal carcinogenesis, and ERα does so, at least in part, by regulating the activity of the Wnt–β-catenin pathway. PMID:19520794

  7. Upregulation of miR-3607 promotes lung adenocarcinoma proliferation by suppressing APC expression.

    Science.gov (United States)

    Lin, Yong; Gu, Qiangye; Sun, Zongwen; Sheng, Baowei; Qi, Congcong; Liu, Bing; Fu, Tian; Liu, Cun; Zhang, Yan

    2017-11-01

    Lung cancer is the leading cause of worldwide cancer-related deaths, although many drugs and new therapeutic approaches have been used, the 5-years survival rate is still low for lung cancer patients. microRNAs have been shown to regulate lung cancer initiation and development, here we studied the role of miR-3607 in lung cancer cell proliferation. We found miR-3607 was upregulated in lung cancer tissues and cells, miR-3607 overexpression promoted lung cancer cell A549 proliferation determined by MTT assay, colony formation assay, anchorage-independent growth ability assay and bromodeoxyuridine incorporation assay, while the opposite phenotypes were shown when miR-3607 was knocked down. Predicted analysis suggested a Wnt signaling pathway regulator adenomatous polyposis coli (APC) was the target of miR-3607, miR-3607 could directly bind to the 3'UTR of APC, and promoted Cyclin D1 and c-Myc expression which can be suppressed by APC. Double knockdown of miR-3607 and APC copied the phenotypes of miR-3607 overexpression, suggesting miR-3607 promoted lung cancer cell A549 proliferation by targeting APC. In conclusion, our study suggested miR-3607 contributes to lung cancer cell proliferation by inhibiting APC. Copyright © 2017. Published by Elsevier Masson SAS.

  8. The APC/C Ubiquitin Ligase: From Cell Biology to Tumorigenesis

    International Nuclear Information System (INIS)

    Penas, Clara; Ramachandran, Vimal; Ayad, Nagi George

    2012-01-01

    The ubiquitin proteasome system (UPS) is required for normal cell proliferation, vertebrate development, and cancer cell transformation. The UPS consists of multiple proteins that work in concert to target a protein for degradation via the 26S proteasome. Chains of an 8.5-kDa protein called ubiquitin are attached to substrates, thus allowing recognition by the 26S proteasome. Enzymes called ubiquitin ligases or E3s mediate specific attachment to substrates. Although there are over 600 different ubiquitin ligases, the Skp1–Cullin–F-box (SCF) complexes and the anaphase promoting complex/cyclosome (APC/C) are the most studied. SCF involvement in cancer has been known for some time while APC/C’s cancer role has recently emerged. In this review we will discuss the importance of APC/C to normal cell proliferation and development, underscoring its possible contribution to transformation. We will also examine the hypothesis that modulating a specific interaction of the APC/C may be therapeutically attractive in specific cancer subtypes. Finally, given that the APC/C pathway is relatively new as a cancer target, therapeutic interventions affecting APC/C activity may be beneficial in cancers that are resistant to classical chemotherapy.

  9. Atomic structure of the APC/C and its mechanism of protein ubiquitination

    Science.gov (United States)

    Yang, Jing; McLaughlin, Stephen H.; Barford, David

    2015-01-01

    The anaphase-promoting complex (APC/C) is a multimeric RING E3 ubiquitin ligase that controls chromosome segregation and mitotic exit. Its regulation by coactivator subunits, phosphorylation, the mitotic checkpoint complex, and interphase inhibitor Emi1 ensures the correct order and timing of distinct cell cycle transitions. Here, we used cryo-electron microscopy to determine atomic structures of APC/C-coactivator complexes with either Emi1 or a UbcH10-ubiquitin conjugate. These structures define the architecture of all APC/C subunits, the position of the catalytic module, and explain how Emi1 mediates inhibition of the two E2s UbcH10 and Ube2S. Definition of Cdh1 interactions with the APC/C indicates how they are antagonized by Cdh1 phosphorylation. The structure of the APC/C with UbcH10-ubiquitin reveals insights into the initiating ubiquitination reaction. Our results provide a quantitative framework for the design of experiments to further investigate APC/C functions in vivo. PMID:26083744

  10. The APC/C Ubiquitin Ligase: From Cell Biology to Tumorigenesis

    Science.gov (United States)

    Penas, Clara; Ramachandran, Vimal; Ayad, Nagi George

    2011-01-01

    The ubiquitin proteasome system (UPS) is required for normal cell proliferation, vertebrate development, and cancer cell transformation. The UPS consists of multiple proteins that work in concert to target a protein for degradation via the 26S proteasome. Chains of an 8.5-kDa protein called ubiquitin are attached to substrates, thus allowing recognition by the 26S proteasome. Enzymes called ubiquitin ligases or E3s mediate specific attachment to substrates. Although there are over 600 different ubiquitin ligases, the Skp1–Cullin–F-box (SCF) complexes and the anaphase promoting complex/cyclosome (APC/C) are the most studied. SCF involvement in cancer has been known for some time while APC/C’s cancer role has recently emerged. In this review we will discuss the importance of APC/C to normal cell proliferation and development, underscoring its possible contribution to transformation. We will also examine the hypothesis that modulating a specific interaction of the APC/C may be therapeutically attractive in specific cancer subtypes. Finally, given that the APC/C pathway is relatively new as a cancer target, therapeutic interventions affecting APC/C activity may be beneficial in cancers that are resistant to classical chemotherapy. PMID:22655255

  11. MHC Class II haplotypes of Colombian Amerindian tribes

    Science.gov (United States)

    Yunis, Juan J.; Yunis, Edmond J.; Yunis, Emilio

    2013-01-01

    We analyzed 1041 individuals belonging to 17 Amerindian tribes of Colombia, Chimila, Bari and Tunebo (Chibcha linguistic family), Embera, Waunana (Choco linguistic family), Puinave and Nukak (Maku-Puinave linguistic families), Cubeo, Guanano, Tucano, Desano and Piratapuyo (Tukano linguistic family), Guahibo and Guayabero (Guayabero Linguistic Family), Curripaco and Piapoco (Arawak linguistic family) and Yucpa (Karib linguistic family). for MHC class II haplotypes (HLA-DRB1, DQA1, DQB1). Approximately 90% of the MHC class II haplotypes found among these tribes are haplotypes frequently encountered in other Amerindian tribes. Nonetheless, striking differences were observed among Chibcha and non-Chibcha speaking tribes. The DRB1*04:04, DRB1*04:11, DRB1*09:01 carrying haplotypes were frequently found among non-Chibcha speaking tribes, while the DRB1*04:07 haplotype showed significant frequencies among Chibcha speaking tribes, and only marginal frequencies among non-Chibcha speaking tribes. Our results suggest that the differences in MHC class II haplotype frequency found among Chibcha and non-Chibcha speaking tribes could be due to genetic differentiation in Mesoamerica of the ancestral Amerindian population into Chibcha and non-Chibcha speaking populations before they entered into South America. PMID:23885196

  12. APC binds the Miro/Milton motor complex to stimulate transport of mitochondria to the plasma membrane.

    Science.gov (United States)

    Mills, Kate M; Brocardo, Mariana G; Henderson, Beric R

    2016-02-01

    Mutations in adenomatous polyposis coli (APC) disrupt regulation of Wnt signaling, mitosis, and the cytoskeleton. We describe a new role for APC in the transport of mitochondria. Silencing of wild-type APC by small interfering RNA caused mitochondria to redistribute from the cell periphery to the perinuclear region. We identified novel APC interactions with the mitochondrial kinesin-motor complex Miro/Milton that were mediated by the APC C-terminus. Truncating mutations in APC abolished its ability to bind Miro/Milton and reduced formation of the Miro/Milton complex, correlating with disrupted mitochondrial distribution in colorectal cancer cells that could be recovered by reconstitution of wild-type APC. Using proximity ligation assays, we identified endogenous APC-Miro/Milton complexes at mitochondria, and live-cell imaging showed that loss of APC slowed the frequency of anterograde mitochondrial transport to the membrane. We propose that APC helps drive mitochondria to the membrane to supply energy for cellular processes such as directed cell migration, a process disrupted by cancer mutations. © 2016 Mills et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  13. The TLR3/TICAM-1 signal constitutively controls spontaneous polyposis through suppression of c-Myc in Apc Min/+ mice.

    Science.gov (United States)

    Ono, Junya; Shime, Hiroaki; Takaki, Hiromi; Takashima, Ken; Funami, Kenji; Yoshida, Sumito; Takeda, Yohei; Matsumoto, Misako; Kasahara, Masanori; Seya, Tsukasa

    2017-10-17

    Intestinal tumorigenesis is promoted by myeloid differentiation primary response gene 88 (MyD88) activation in response to the components of microbiota in Apc Min/+ mice. Microbiota also contains double-stranded RNA (dsRNA), a ligand for TLR3, which activates the toll-like receptor adaptor molecule 1 (TICAM-1, also known as TRIF) pathway. We established Apc Min/+ Ticam1 -/- mice and their survival was compared to survival of Apc Min/+ Myd88 -/- and wild-type (WT) mice. The properties of polyps were investigated using immunofluorescence staining and RT-PCR analysis. We demonstrate that TICAM-1 is essential for suppression of polyp formation in Apc Min/+ mice. TICAM-1 knockout resulted in shorter survival of mice compared to WT mice or mice with knockout of MyD88 in the Apc Min/+ background. Polyps were more frequently formed in the distal intestine of Apc Min/+ Ticam1 -/- mice than in Apc Min/+ mice. Infiltration of immune cells such as CD11b + and CD8α + cells into the polyps was detected histologically. CD11b and CD8α mRNAs were increased in polyps of Apc Min/+ Ticam1 -/- mice compared to Apc Min/+ mice. Gene expression of inducible nitric oxide synthase (iNOS), interferon (IFN)-γ, CXCL9 and IL-12p40 was increased in polyps of Apc Min/+ Ticam1 -/- mice. mRNA and protein expression of c-Myc, a critical transcription factor for inflammation-associated polyposis, were increased in polyps of Apc Min/+ Ticam1 -/- mice. A Lactobacillus strain producing dsRNA was detected in feces of Apc Min/+ mice. These results imply that the TLR3/TICAM-1 pathway inhibits polyposis through suppression of c-Myc expression and supports long survival in Apc Min/+ mice.

  14. Immunotherapy of MHC class I-deficient tumours and epigenetic upregulation of MHC class I molecules on tumour cells

    Czech Academy of Sciences Publication Activity Database

    Reiniš, Milan; Manning, Jasper; Indrová, Marie; Přibylová, Hana; Bieblová, Jana; Šímová, Jana; Bubeník, Jan

    2007-01-01

    Roč. 20, Suppl. 1 (2007), S29-S29 ISSN 1107-3756. [World Congress on Advances in Oncology /12./ and International Symposium on Molecular Medicine /10./. 11.10.2007-12.10.2007, Hernissos] R&D Projects: GA ČR GA301/04/0492; GA ČR GA301/07/1410 Institutional research plan: CEZ:AV0Z50520514 Keywords : Immunotherapy * MHC I-deficient tumours * epigenetics Subject RIV: EB - Genetics ; Molecular Biology

  15. MHC class II deficiency: Report of a novel mutation and special review.

    Science.gov (United States)

    Farrokhi, S; Shabani, M; Aryan, Z; Zoghi, S; Krolo, A; Boztug, K; Rezaei, N

    The MHC II deficiency is a rare autosomal recessive primary immunodeficiency syndrome with increased susceptibility to respiratory and gastrointestinal infections, failure to thrive and early mortality. This syndrome is caused by mutations in transcription regulators of the MHC II gene and results in development of blind lymphocytes due to the lack of indicatory MHC II molecules. Despite homogeneity of clinical manifestations of patients with MHC II deficiency, the genetic defects underlying this disease are heterogeneous. Herein, we report an Iranian patient with MHC II deficiency harbouring a novel mutation in RFXANK and novel misleading clinical features. He had ataxic gait and dysarthria from 30 months of age. Epidemiology, clinical and immunological features, therapeutic options and prognosis of patients with MHC II are reviewed in this paper. Copyright © 2017 SEICAP. Published by Elsevier España, S.L.U. All rights reserved.

  16. Association between cigarette smoking, APC mutations and the risk of developing sporadic colorectal adenomas and carcinomas

    International Nuclear Information System (INIS)

    Sæbø, Mona; Skjelbred, Camilla F; Breistein, Rebecca; Lothe, Inger Marie B; Hagen, Per Chr; Bock, Gunter; Hansteen, Inger-Lise; Kure, Elin H

    2006-01-01

    The association between colorectal cancer (CRC) and smoking has not been consistent. Incomplete smoking history and association to a specific subset of CRC tumors have been proposed as explanations. The adenomatous polyposis coli (APC) gene has been reported to have a 'gatekeeper' function in the colonic mucosa. To evaluate the hypothesis that cigarette smoking is associated with adenoma and carcinoma development and further to investigate whether this association is due to mutations in the APC gene, we used a study population consisting of 133 cases (45 adenomas and 88 carcinomas) and 334 controls. All tumors were sequenced in the mutation cluster region (MCR) of the APC gene. Cases and controls were drawn from a homogeneous cohort of Norwegian origin. The mutational spectra of the APC gene revealed no difference in frequencies of mutations in cases based on ever and never smoking status. An overall case-control association was detected for adenomas and 'ever smoking' OR = 1.73 (95% CI 0.83–3.58). For CRC cases several smoking parameters for dose and duration were used. We detected an association for all smoking parameters and 'duration of smoking > 30 years', yielded a statistically significant OR = 2.86 (1.06–7.7). When cases were divided based on APC truncation mutation status, an association was detected in adenomas without APC mutation in relation to 'ever smoking', with an OR = 3.97 (1.26–12.51). For CRC cases without APC mutation 'duration of smoking > 30 years', yielded a statistically significant OR = 4.06 (1.20–13.7). The smoking parameter 'starting smoking ≥ 40 years ago' was only associated with CRC cases with APC mutations, OR = 2.0 (0.34–11.95). A case-case comparison revealed similar findings for this parameter, OR = 2.24 (0.73–6.86). Our data suggest an association between smoking and adenoma and CRC development. This association was strongest for cases without APC truncation

  17. α2-Macroglobulin Is a Significant In Vivo Inhibitor of Activated Protein C and Low APC:α2M Levels Are Associated with Venous Thromboembolism.

    Science.gov (United States)

    Martos, Laura; Ramón, Luis Andrés; Oto, Julia; Fernández-Pardo, Álvaro; Bonanad, Santiago; Cid, Ana Rosa; Gruber, Andras; Griffin, John H; España, Francisco; Navarro, Silvia; Medina, Pilar

    2018-04-01

     Activated protein C (APC) is a major regulator of thrombin formation. Two major plasma inhibitors form complexes with APC, protein C inhibitor (PCI) and α 1 -antitrypsin (α 1 AT), and these complexes have been quantified by specific enzyme-linked immunosorbent assays (ELISAs). Also, complexes of APC with α 2 -macroglobulin (α 2 M) have been observed by immunoblotting. Here, we report an ELISA for APC:α 2 M complexes in plasma.  Plasma samples were pre-treated with dithiothreitol and then with iodoacetamide. The detection range of the newly developed APC:α 2 M assay was 0.031 to 8.0 ng/mL of complexed APC. Following infusions of APC in humans and baboons, complexes of APC with α 2 M, PCI and α 1 AT were quantified. These complexes as well as circulating APC were also measured in 121 patients with a history of venous thromboembolism (VTE) and 119 matched controls.  In all the in vivo experiments, α 2 M was a significant APC inhibitor. The VTE case-control study showed that VTE patients had significantly lower APC:α 2 M and APC levels than the controls ( p  APC:α 2 M or the lowest quartile of APC had approximately four times more VTE risk than those in the highest quartile of APC:α 2 M or of APC. The risk increased for individuals with low levels of both parameters.  The APC:α 2 M assay reported here may be useful to help monitor the in vivo fate of APC in plasma. In addition, our results show that a low APC:α 2 M level is associated with increased VTE risk. Schattauer GmbH Stuttgart.

  18. The Intensity of Human Body Odors and the MHC: Should We Expect a Link?

    OpenAIRE

    Claus Wedekind; Thomas Seebeck; Florence Bettens; Alexander J. Paepke

    2006-01-01

    It is now well established that genes within the major histocompatibility complex (MHC) somehow affect the production of body odors in several vertebrates, including humans. Here we discuss whether variation in the intensity of body odors may be influenced by the MHC. In order to examine this question, we have to control for MHC-linked odor perception on the smeller's side. Such a control is necessary because the perception of pleasantness and intensity seem to be confounded, a...

  19. Sibling rivalry: competition between MHC class II family members inhibits immunity.

    Science.gov (United States)

    Denzin, Lisa K; Cresswell, Peter

    2013-01-01

    Peptide loading of major histocompatibility complex (MHC) class II molecules in the endosomes and lysosomes of antigen-presenting cells is catalyzed by human leukocyte antigen-DM (HLA-DM) and modulated by HLA-DO. In a structural study in this issue, Guce et al. show that HLA-DO is an MHC class II mimic and functions as a competitive and essentially irreversible inhibitor of HLA-DM activity, thereby inhibiting MHC class II antigen presentation.

  20. Rca1 inhibits APC-Cdh1(Fzr) and is required to prevent cyclin degradation in G2.

    Science.gov (United States)

    Grosskortenhaus, Ruth; Sprenger, Frank

    2002-01-01

    We demonstrate that Rca1 is an essential inhibitor of the anaphase-promoting complex/cyclosome (APC) in Drosophila. APC activity is restricted to mitotic stages and G1 by its activators Cdc20-Fizzy (Cdc20(Fzy)) and Cdh1-Fizzy-related (Cdh1(Fzr)), respectively. In rca1 mutants, cyclins are degraded prematurely in G2 by APC-Cdh1(Fzr)-dependent proteolysis, and cells fail to execute mitosis. Overexpression of Cdh1(Fzr) mimics the rca1 phenotype, and coexpression of Rca1 blocks this Cdh1(Fzr) function. We show that Rca1 and Cdh1(Fzr) are in a complex that also includes the APC component Cdc27. Previous studies have shown that phosphorylation of Cdh1 prevents its interaction with the APC. Our data reveal a different mode of APC regulation by Rca1 at the G2 stage, when low Cdk activity is unable to inhibit Cdh1(Fzr) interaction.

  1. Human APC sequesters beta-catenin even in the absence of GSK-3beta in a Drosophila model.

    Science.gov (United States)

    Rao, P R; Makhijani, K; Shashidhara, L S

    2008-04-10

    There have been conflicting reports on the requirement of GSK-3beta-mediated phosphorylation of the tumor suppressor adenomatous polyposis coli (APC) vis-à-vis its ability to bind and degrade beta-catenin. Using a unique combination of loss of function for Shaggy/GSK-3beta and a gain of function for human APC in Drosophila, we show that misexpressed human APC (hAPC) can still sequester Armadillo/beta-catenin. In addition, human APC could suppress gain of Wnt/Wingless phenotypes associated with loss of Shaggy/GSK-3beta activity, suggesting that sequestered Armadillo/beta-catenin is non-functional. Based on these studies, we propose that binding per se of beta-catenin by APC does not require phosphorylation by GSK-3beta.

  2. Detection and Analysis of Cell Cycle-Associated APC/C-Mediated Cellular Ubiquitylation In Vitro and In Vivo.

    Science.gov (United States)

    Cedeño, Cesyen; La Monaca, Esther; Esposito, Mara; Gutierrez, Gustavo J

    2016-01-01

    The anaphase-promoting complex or cyclosome (APC/C) is one of the major orchestrators of the cell division cycle in mammalian cells. The APC/C acts as a ubiquitin ligase that triggers sequential ubiquitylation of a significant number of substrates which will be eventually degraded by proteasomes during major transitions of the cell cycle. In this chapter, we present accessible methodologies to assess both in in vitro conditions and in cellular systems ubiquitylation reactions mediated by the APC/C. In addition, we also describe techniques to evidence the changes in protein stability provoked by modulation of the activity of the APC/C. Finally, specific methods to analyze interactors or posttranslational modifications of particular APC/C subunits are also discussed. Given the crucial role played by the APC/C in the regulation of the cell cycle, this review only focuses on its action and effects in actively proliferating cells.

  3. Ubiquitination regulates MHC class II-peptide complex retention and degradation in dendritic cells

    OpenAIRE

    Walseng, Even; Furuta, Kazuyuki; Bosch, Berta; Weih, Karis A.; Matsuki, Yohei; Bakke, Oddmund; Ishido, Satoshi; Roche, Paul A.

    2010-01-01

    The expression and turnover of MHC class II-peptide complexes (pMHC-II) on the surface of dendritic cells (DCs) is essential for their ability to activate CD4 T cells efficiently. The half-life of surface pMHC-II is significantly greater in activated (mature) DCs than in resting (immature) DCs, but the molecular mechanism leading to this difference remains unknown. We now show that ubiquitination of pMHC-II by the E3 ubiquitin ligase membrane-associated RING-CH 1 (March-I) regulates surface e...

  4. High levels of diversity characterize mandrill (Mandrillus sphinx) Mhc-DRB sequences.

    Science.gov (United States)

    Abbott, Kristin M; Wickings, E Jean; Knapp, Leslie A

    2006-08-01

    The major histocompatibility complex (MHC) is highly polymorphic in most primate species studied thus far. The rhesus macaque (Macaca mulatta) has been studied extensively and the Mhc-DRB region demonstrates variability similar to humans. The extent of MHC diversity is relatively unknown for other Old World monkeys (OWM), especially among genera other than Macaca. A molecular survey of the Mhc-DRB region in mandrills (Mandrillus sphinx) revealed extensive variability, suggesting that other OWMs may also possess high levels of Mhc-DRB polymorphism. In the present study, 33 Mhc-DRB loci were identified from only 13 animals. Eleven were wild-born and presumed to be unrelated and two were captive-born twins. Two to seven different sequences were identified for each individual, suggesting that some mandrills may have as many as four Mhc-DRB loci on a single haplotype. From these sequences, representatives of at least six Mhc-DRB loci or lineages were identified. As observed in other primates, some new lineages may have arisen through the process of gene conversion. These findings indicate that mandrills have Mhc-DRB diversity not unlike rhesus macaques and humans.

  5. MHC2NNZ: A novel peptide binding prediction approach for HLA DQ molecules

    Science.gov (United States)

    Xie, Jiang; Zeng, Xu; Lu, Dongfang; Liu, Zhixiang; Wang, Jiao

    2017-07-01

    The major histocompatibility complex class II (MHC-II) molecule plays a crucial role in immunology. Computational prediction of MHC-II binding peptides can help researchers understand the mechanism of immune systems and design vaccines. Most of the prediction algorithms for MHC-II to date have made large efforts in human leukocyte antigen (HLA, the name of MHC in Human) molecules encoded in the DR locus. However, HLA DQ molecules are equally important and have only been made less progress because it is more difficult to handle them experimentally. In this study, we propose an artificial neural network-based approach called MHC2NNZ to predict peptides binding to HLA DQ molecules. Unlike previous artificial neural network-based methods, MHC2NNZ not only considers sequence similarity features but also captures the chemical and physical properties, and a novel method incorporating these properties is proposed to represent peptide flanking regions (PFR). Furthermore, MHC2NNZ improves the prediction accuracy by combining with amino acid preference at more specific positions of the peptides binding core. By evaluating on 3549 peptides binding to six most frequent HLA DQ molecules, MHC2NNZ is demonstrated to outperform other state-of-the-art MHC-II prediction methods.

  6. Structure of a Pheromone Receptor-Associated Mhc Molecule With An Open And Empty Groove

    Energy Technology Data Exchange (ETDEWEB)

    Olson, R.; Huey-Tubman, K.E.; Dulac, C.; Bjorkman, P.J.; /Caltech /Harvard U.

    2006-10-06

    Neurons in the murine vomeronasal organ (VNO) express a family of class Ib major histocompatibility complex (MHC) proteins (M10s) that interact with the V2R class of VNO receptors. This interaction may play a direct role in the detection of pheromonal cues that initiate reproductive and territorial behaviors. The crystal structure of M10.5, an M10 family member, is similar to that of classical MHC molecules. However, the M10.5 counterpart of the MHC peptide-binding groove is open and unoccupied, revealing the first structure of an empty class I MHC molecule. Similar to empty MHC molecules, but unlike peptide-filled MHC proteins and non-peptide-binding MHC homologs, M10.5 is thermally unstable, suggesting that its groove is normally occupied. However, M10.5 does not bind endogenous peptides when expressed in mammalian cells or when offered a mixture of class I-binding peptides. The F pocket side of the M10.5 groove is open, suggesting that ligands larger than 8-10-mer class I-binding peptides could fit by extending out of the groove. Moreover, variable residues point up from the groove helices, rather than toward the groove as in classical MHC structures. These data suggest that M10s are unlikely to provide specific recognition of class I MHC-binding peptides, but are consistent with binding to other ligands, including proteins such as the V2Rs.

  7. Structure of a pheromone receptor-associated MHC molecule with an open and empty groove.

    Directory of Open Access Journals (Sweden)

    2005-08-01

    Full Text Available Neurons in the murine vomeronasal organ (VNO express a family of class Ib major histocompatibility complex (MHC proteins (M10s that interact with the V2R class of VNO receptors. This interaction may play a direct role in the detection of pheromonal cues that initiate reproductive and territorial behaviors. The crystal structure of M10.5, an M10 family member, is similar to that of classical MHC molecules. However, the M10.5 counterpart of the MHC peptide-binding groove is open and unoccupied, revealing the first structure of an empty class I MHC molecule. Similar to empty MHC molecules, but unlike peptide-filled MHC proteins and non-peptide-binding MHC homologs, M10.5 is thermally unstable, suggesting that its groove is normally occupied. However, M10.5 does not bind endogenous peptides when expressed in mammalian cells or when offered a mixture of class I-binding peptides. The F pocket side of the M10.5 groove is open, suggesting that ligands larger than 8-10-mer class I-binding peptides could fit by extending out of the groove. Moreover, variable residues point up from the groove helices, rather than toward the groove as in classical MHC structures. These data suggest that M10s are unlikely to provide specific recognition of class I MHC-binding peptides, but are consistent with binding to other ligands, including proteins such as the V2Rs.

  8. Establishment of a quantitative ELISA capable of determining peptide - MHC class I interaction

    DEFF Research Database (Denmark)

    Sylvester-Hvid, C; Kristensen, N; Blicher, T

    2002-01-01

    dependent manner. Here, we exploit the availability of these molecules to generate a quantitative ELISA-based assay capable of measuring the affinity of the interaction between peptide and MHC-I. This assay is simple and sensitive, and one can easily envisage that the necessary reagents, standards......Many different assays for measuring peptide-MHC interactions have been suggested over the years. Yet, there is no generally accepted standard method available. We have recently generated preoxidized recombinant MHC class I molecules (MHC-I) which can be purified to homogeneity under denaturing...

  9. Meta-analysis of the association between APC promoter methylation and colorectal cancer.

    Science.gov (United States)

    Ding, Zhenyu; Jiang, Tong; Piao, Ying; Han, Tao; Han, Yaling; Xie, Xiaodong

    2015-01-01

    Previous studies investigating the association between adenomatous polyposis coli (APC) gene promoter methylation and colorectal cancer (CRC) have yielded conflicting results. The aim of this study was to comprehensively evaluate the potential application of the detection of APC promoter methylation to the prevention and treatment of CRC. PubMed, Embase, and MEDLINE (results updated to October 2014) were searched for relevant studies. The effect size was defined as the weighted odds ratio (OR), which was calculated using either the fixed-effects or random-effects model. Prespecified subgroup and sensitivity analyses were conducted to evaluate potential heterogeneity among the included studies. Nineteen studies comprising 2,426 participants were selected for our meta-analysis. The pooled results of nine studies comprising a total of 740 subjects indicated that APC promoter methylation was significantly associated with CRC risk (pooled OR 5.53; 95% confidence interval [CI] 3.50-8.76; PAPC promoter methylation and the presence of CRC metastasis, and the pooled OR was 0.80 (95% CI 0.44-1.46; P=0.47). A meta-analysis conducted with four studies with a total of 467 patients found no significant correlation between APC promoter methylation and the presence of colorectal adenoma (pooled OR 1.85; 95% CI 0.67-5.10; P=0.23). No significant correlation between APC promoter methylation and patients' Dukes' stage, TNM stage, differentiation grade, age, or sex was identified. In conclusion, APC promoter methylation was found to be significantly associated with a higher risk of developing CRC. The findings indicate that APC promoter methylation may be a potential biomarker for the carcinogenesis of CRC.

  10. Efficacy and safety of Hybrid-APC for the ablation of Barrett's esophagus.

    Science.gov (United States)

    Manner, Hendrik; May, Andrea; Kouti, Ioanna; Pech, Oliver; Vieth, Michael; Ell, Christian

    2016-04-01

    After thermal ablation of Barrett's esophagus (BE), stricture formation is reported in 5 to over 10% of patients. The question arises whether submucosal fluid injection prior to ablation may lower the risk of stricture formation. The aim of the present study was to evaluate the efficacy and safety of the new technique of Hybrid-APC which combines submucosal injection with APC. Patients who had a residual BE segment of at least 1 cm after endoscopic resection of early Barrett's neoplasia underwent thermal ablation of BE by Hybrid-APC. Prior to thermal ablation, submucosal injection of sodium chloride 0.9% was carried out using a flexible water-jet probe (Erbejet 2; Erbe Elektromedizin, Tuebingen, Germany). Check-up upper GI endoscopy was carried out 3 months after macroscopically complete ablation including biopsies from the neo-Z-line and the former BE segment, and recording of stricture formation. From May 2011 to November 2012, a total of 60 patients (pt) were included in the study [55 pt male (92%); mean age 62 ± 9 years, range 42-79]. Ten patients were excluded from the study. In the remaining 50 pt, Hybrid-APC ablation and check-up endoscopy at 3 months were carried out. Forty-eight out of 50 pt (96%; ITT: 49/60, 82%) achieved macroscopically complete remission after a median of 3.5 APC sessions [SD 2.4; range 1-10]. Freedom from BE was histopathologically observed in 39/50 patients (78%). There was one treatment-related stricture (2%). Minor adverse events of Hybrid-APC were observed in 11 patients (22%). According to this pilot series, Hybrid-APC was effective and safe for BE ablation in a tertiary referral center. The rate of stricture formation was only 2%. Further studies are required to confirm the present results. DRKS00003369.

  11. APC promoter is frequently methylated in pancreatic juice of patients with pancreatic carcinomas or periampullary tumors.

    Science.gov (United States)

    Ginesta, Mireia M; Diaz-Riascos, Zamira Vanessa; Busquets, Juli; Pelaez, Núria; Serrano, Teresa; Peinado, Miquel Àngel; Jorba, Rosa; García-Borobia, Francisco Javier; Capella, Gabriel; Fabregat, Joan

    2016-09-01

    Early detection of pancreatic and periampullary neoplasms is critical to improve their clinical outcome. The present authors previously demonstrated that DNA hypermethylation of adenomatous polyposis coli (APC), histamine receptor H2 (HRH2), cadherin 13 (CDH13), secreted protein acidic and cysteine rich (SPARC) and engrailed-1 (EN-1) promoters is frequently detected in pancreatic tumor cells. The aim of the present study was to assess their prevalence in pancreatic juice of carcinomas of the pancreas and periampullary area. A total of 135 pancreatic juices obtained from 85 pancreatic cancer (PC), 26 ampullary carcinoma (AC), 10 intraductal papillary mucinous neoplasm (IPMN) and 14 chronic pancreatitis (CP) patients were analyzed. The methylation status of the APC, HRH2, CDH13, SPARC and EN-1 promoters was analyzed using methylation specific-melting curve analysis (MS-MCA). Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations were also tested with allele-specific quantitative polymerase chain reaction amplification. Out of the 5 promoters analyzed, APC (71%) and HRH2 (65%) were the most frequently methylated in PC juice. APC methylation was also detected at a high frequency in AC (76%) and IPMN (80%), but only occasionally observed in CP (7%). APC methylation had a high sensitivity (71-80%) for all types of cancer analyzed. The panel (where a sample scored as positive when ≥2 markers were methylated) did not outperform APC as a single marker. Finally, KRAS detection in pancreatic juice offered a lower sensitivity (50%) and specificity (71%) for detection of any cancer. APC hypermethylation in pancreatic juice, as assessed by MS-MCA, is a frequent event of potential clinical usefulness in the diagnosis of pancreatic and periampullary neoplasms.

  12. NetMHC-3.0: accurate web accessible predictions of human, mouse and monkey MHC class I affinities for peptides of length 8-11.

    Science.gov (United States)

    Lundegaard, Claus; Lamberth, Kasper; Harndahl, Mikkel; Buus, Søren; Lund, Ole; Nielsen, Morten

    2008-07-01

    NetMHC-3.0 is trained on a large number of quantitative peptide data using both affinity data from the Immune Epitope Database and Analysis Resource (IEDB) and elution data from SYFPEITHI. The method generates high-accuracy predictions of major histocompatibility complex (MHC): peptide binding. The predictions are based on artificial neural networks trained on data from 55 MHC alleles (43 Human and 12 non-human), and position-specific scoring matrices (PSSMs) for additional 67 HLA alleles. As only the MHC class I prediction server is available, predictions are possible for peptides of length 8-11 for all 122 alleles. artificial neural network predictions are given as actual IC(50) values whereas PSSM predictions are given as a log-odds likelihood scores. The output is optionally available as download for easy post-processing. The training method underlying the server is the best available, and has been used to predict possible MHC-binding peptides in a series of pathogen viral proteomes including SARS, Influenza and HIV, resulting in an average of 75-80% confirmed MHC binders. Here, the performance is further validated and benchmarked using a large set of newly published affinity data, non-redundant to the training set. The server is free of use and available at: http://www.cbs.dtu.dk/services/NetMHC.

  13. An integrated tool to study MHC region: accurate SNV detection and HLA genes typing in human MHC region using targeted high-throughput sequencing.

    Directory of Open Access Journals (Sweden)

    Hongzhi Cao

    Full Text Available The major histocompatibility complex (MHC is one of the most variable and gene-dense regions of the human genome. Most studies of the MHC, and associated regions, focus on minor variants and HLA typing, many of which have been demonstrated to be associated with human disease susceptibility and metabolic pathways. However, the detection of variants in the MHC region, and diagnostic HLA typing, still lacks a coherent, standardized, cost effective and high coverage protocol of clinical quality and reliability. In this paper, we presented such a method for the accurate detection of minor variants and HLA types in the human MHC region, using high-throughput, high-coverage sequencing of target regions. A probe set was designed to template upon the 8 annotated human MHC haplotypes, and to encompass the 5 megabases (Mb of the extended MHC region. We deployed our probes upon three, genetically diverse human samples for probe set evaluation, and sequencing data show that ∼97% of the MHC region, and over 99% of the genes in MHC region, are covered with sufficient depth and good evenness. 98% of genotypes called by this capture sequencing prove consistent with established HapMap genotypes. We have concurrently developed a one-step pipeline for calling any HLA type referenced in the IMGT/HLA database from this target capture sequencing data, which shows over 96% typing accuracy when deployed at 4 digital resolution. This cost-effective and highly accurate approach for variant detection and HLA typing in the MHC region may lend further insight into immune-mediated diseases studies, and may find clinical utility in transplantation medicine research. This one-step pipeline is released for general evaluation and use by the scientific community.

  14. The Spindle Assembly Checkpoint Is Not Essential for Viability of Human Cells with Genetically Lowered APC/C Activity.

    Science.gov (United States)

    Wild, Thomas; Larsen, Marie Sofie Yoo; Narita, Takeo; Schou, Julie; Nilsson, Jakob; Choudhary, Chunaram

    2016-03-01

    The anaphase-promoting complex/cyclosome (APC/C) and the spindle assembly checkpoint (SAC), which inhibits the APC/C, are essential determinants of mitotic timing and faithful division of genetic material. Activation of the APC/C is known to depend on two APC/C-interacting E2 ubiquitin-conjugating enzymes-UBE2C and UBE2S. We show that APC/C activity in human cells is tuned by the combinatorial use of three E2s, namely UBE2C, UBE2S, and UBE2D. Genetic deletion of UBE2C and UBE2S, individually or in combination, leads to discriminative reduction in APC/C function and sensitizes cells to UBE2D depletion. Reduction of APC/C activity results in loss of switch-like metaphase-to-anaphase transition and, strikingly, renders cells insensitive to chemical inhibition of MPS1 and genetic ablation of MAD2, both of which are essential for the SAC. These results provide insights into the regulation of APC/C activity and demonstrate that the essentiality of the SAC is imposed by the strength of the APC/C. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Detection of irradiated food by using direct epifluorescent filter technique/aerobic plate count method (DEFT/APC)

    International Nuclear Information System (INIS)

    Zhao Yongfu; Li Lili; Wang Changbao; Ji Ping; Wang Chao; Wang Zhidong

    2010-01-01

    The Direct Epifluorescent Filter Technique/Aerobic Plate Count technique(DEFT/APC) can be used to identify the irradiated food by comparing the DEFT and APC counts of the samples prior to the irradiation and after. This technology was tested by using spice and dried marine fish as testing materials in this study. The results shows that the index, log (DEFT/APC) > 4.0, can indicate that the samples have been irradiated at a dose level higher than 1.0 kGy. It also indicates that the detecting sensitivity was affected by the initial value of APC and D 10 value of the samples. (authors)

  16. Proteomic analysis reveals APC-dependent post-translational modifications and identifies a novel regulator of β-catenin.

    Science.gov (United States)

    Blundon, Malachi A; Schlesinger, Danielle R; Parthasarathy, Amritha; Smith, Samantha L; Kolev, Hannah M; Vinson, David A; Kunttas-Tatli, Ezgi; McCartney, Brooke M; Minden, Jonathan S

    2016-07-15

    Wnt signaling generates patterns in all embryos, from flies to humans, and controls cell fate, proliferation and metabolic homeostasis. Inappropriate Wnt pathway activation results in diseases, including colorectal cancer. The adenomatous polyposis coli (APC) tumor suppressor gene encodes a multifunctional protein that is an essential regulator of Wnt signaling and cytoskeletal organization. Although progress has been made in defining the role of APC in a normal cellular context, there are still significant gaps in our understanding of APC-dependent cellular function and dysfunction. We expanded the APC-associated protein network using a combination of genetics and a proteomic technique called two-dimensional difference gel electrophoresis (2D-DIGE). We show that loss of Drosophila Apc2 causes protein isoform changes reflecting misregulation of post-translational modifications (PTMs), which are not dependent on β-catenin transcriptional activity. Mass spectrometry revealed that proteins involved in metabolic and biosynthetic pathways, protein synthesis and degradation, and cell signaling are affected by Apc2 loss. We demonstrate that changes in phosphorylation partially account for the altered PTMs in APC mutants, suggesting that APC mutants affect other types of PTM. Finally, through this approach Aminopeptidase P was identified as a new regulator of β-catenin abundance in Drosophila embryos. This study provides new perspectives on the cellular effects of APC that might lead to a deeper understanding of its role in development. © 2016. Published by The Company of Biologists Ltd.

  17. Adenomatous polyposis coli (APC) regulates miR17-92 cluster through β-catenin pathway in colorectal cancer.

    Science.gov (United States)

    Li, Yajuan; Lauriola, Mattia; Kim, Donghwa; Francesconi, Mirko; D'Uva, Gabriele; Shibata, Dave; Malafa, Mokenge P; Yeatman, Timothy J; Coppola, Domenico; Solmi, Rossella; Cheng, Jin Q

    2016-09-01

    Adenomatous polyposis coli (APC) mutation is the most common genetic change in sporadic colorectal cancer (CRC). Although deregulations of miRNAs have been frequently reported in this malignancy, APC-regulated miRNAs have not been extensively documented. Here, by using an APC-inducible cell line and array analysis, we identified a total of 26 deregulated miRNAs. Among them, members of miR-17-92 cluster were dramatically inhibited by APC and induced by enforced expression of β-catenin. Furthermore, we demonstrate that activated β-catenin resulted from APC loss binds to and activates the miR-17-92 promoter. Notably, enforced expression of miR-19a overrides APC tumor suppressor activity, and knockdown of miR-19a in cancer cells with compromised APC function reduced their aggressive features in vitro. Finally, we observed that expression of miR-19a significantly correlates with β-catenin levels in colorectal cancer specimens, and it is associated to the aggressive stage of tumor progression. Thus, our study reveals that miR-17-92 cluster is directly regulated by APC/β-catenin pathway and could be a potential therapeutic target in colon cancers with aberrant APC/β-catenin signaling.

  18. Hypermethylated APC in serous carcinoma based on a meta-analysis of ovarian cancer.

    Science.gov (United States)

    Shen, Chunyan; Sheng, Qifang; Zhang, Xiaojie; Fu, Yuling; Zhu, Kemiao

    2016-09-26

    The reduced expression of the Adenomatous polyposis coli (APC) gene, a tumor suppressor gene, through promoter hypermethylation has been reported to play a key role in the carcinogenesis. However, the correlation between APC promoter hypermethylation and ovarian cancer (OC) remains to be clarified. A comprehensive literature search was carried out in related research databases. The overall odds ratio (OR) and corresponding 95 % confidence interval (CI) were used to evaluate the effects of APC promoter hypermethylation on OC and clinicopathological characteristics. Ultimately, 12 eligible studies were used in our study, including 806 OC samples, 429 normal controls, 109 benign lesions and 75 LMP samples. The pooled OR showed that APC promoter hypermethylation was significantly higher in OC than in normal and benign controls (OR = 6.18 and OR = 3.26, respectively). No significant correlation was observed between OC and low malignant potential (LMP) tumors (P = 0.436). In the comparison of OC and normal controls, subgroup analysis based on race showed that the overall OR of APC promoter hypermethylation was significant and similar in Asians and Caucasians (OR = 8.34 and OR = 5.39, respectively). A subgroup analysis based on sample type found that the pooled OR was significantly higher in blood than in tissue (OR = 18.71 and OR = 5.74, respectively). A significant association was not observed between APC promoter hypermethylation and tumor grade or tumor stage. The pooled OR indicated that APC promoter hypermethylation was significantly lower in serous carcinoma than in non-serous carcinoma (OR = 0.56, P = 0.02). No obvious publication bias was detected by Egger's test (all P > 0.05). APC promoter hypermethylation may be linked to the increased risk of OC. It was associated with histological type, but not with tumor grade or tumor stage. Moreover, hypermethylated APC may be a noninvasive biomarker using blood samples. Future

  19. Polymorphism at Expressed DQ and DR Loci in Five Common Equine MHC Haplotypes

    Science.gov (United States)

    Miller, Donald; Tallmadge, Rebecca L.; Binns, Matthew; Zhu, Baoli; Mohamoud, Yasmin Ali; Ahmed, Ayeda; Brooks, Samantha A.; Antczak, Douglas F.

    2016-01-01

    The polymorphism of Major Histocompatibility Complex (MHC) class II DQ and DR genes in five common Equine Leukocyte Antigen (ELA) haplotypes was determined through sequencing of mRNA transcripts isolated from lymphocytes of eight ELA homozygous horses. Ten expressed MHC class II genes were detected in horses of the ELA-A3 haplotype carried by the donor horses of the equine Bacterial Artificial Chromosome (BAC) library and the reference genome sequence: four DR genes and six DQ genes. The other four ELA haplotypes contained at least eight expressed polymorphic MHC class II loci. Next Generation Sequencing (NGS) of genomic DNA of these four MHC haplotypes revealed stop codons in the DQA3 gene in the ELA-A2, ELA-A5, and ELA-A9 haplotypes. Few NGS reads were obtained for the other MHC class II genes that were not amplified in these horses. The amino acid sequences across haplotypes contained locus-specific residues, and the locus clusters produced by phylogenetic analysis were well supported. The MHC class II alleles within the five tested haplotypes were largely non-overlapping between haplotypes. The complement of equine MHC class II DQ and DR genes appears to be well conserved between haplotypes, in contrast to the recently described variation in class I gene loci between equine MHC haplotypes. The identification of allelic series of equine MHC class II loci will aid comparative studies of mammalian MHC conservation and evolution and may also help to interpret associations between the equine MHC class II region and diseases of the horse. PMID:27889800

  20. Cheetah paradigm revisited: MHC diversity in the world's largest free-ranging population.

    Science.gov (United States)

    Castro-Prieto, Aines; Wachter, Bettina; Sommer, Simone

    2011-04-01

    For more than two decades, the cheetah (Acinonyx jubatus) has been considered a paradigm of disease vulnerability associated with low genetic diversity, particularly at the immune genes of the major histocompatibility complex (MHC). Cheetahs have been used as a classic example in numerous conservation genetics textbooks as well as in many related scientific publications. However, earlier studies used methods with low resolution to quantify MHC diversity and/or small sample sizes. Furthermore, high disease susceptibility was reported only for captive cheetahs, whereas free-ranging cheetahs show no signs of infectious diseases and a good general health status. We examined whether the diversity at MHC class I and class II-DRB loci in 149 Namibian cheetahs was higher than previously reported using single-strand conformation polymorphism analysis, cloning, and sequencing. MHC genes were examined at the genomic and transcriptomic levels. We detected ten MHC class I and four class II-DRB alleles, of which nine MHC class I and all class II-DRB alleles were expressed. Phylogenetic analyses and individual genotypes suggested that the alleles belong to four MHC class I and three class II-DRB putative loci. Evidence of positive selection was detected in both MHC loci. Our study indicated that the low number of MHC class I alleles previously observed in cheetahs was due to a smaller sample size examined. On the other hand, the low number of MHC class II-DRB alleles previously observed in cheetahs was further confirmed. Compared with other mammalian species including felids, cheetahs showed low levels of MHC diversity, but this does not seem to influence the immunocompetence of free-ranging cheetahs in Namibia and contradicts the previous conclusion that the cheetah is a paradigm species of disease vulnerability.

  1. Function of the activated protein C (APC) autolysis loop in activated FVIII inactivation.

    Science.gov (United States)

    Cramer, Thomas J; Gale, Andrew J

    2011-06-01

    Activated protein C (APC) binds to its substrates activated factor V (FVa) and activated factor VIII (FVIIIa) with a basic exosite that consists of loops 37, 60, 70 and the autolysis loop. These loops have a high density of basic residues, resulting in a positive charge on the surface of APC. Many of these residues are important in the interaction of APC with FVa and FVIIIa. The current study focused on the function of the autolysis loop in the interaction with FVIIIa. This loop was previously shown to interact with FVa, and it inhibits APC inactivation by plasma serpins. Charged residues of the autolysis loop were individually mutated to alanine and the activity of these mutants was assessed in functional FVIIIa inactivation assays. The autolysis loop was functionally important for FVIIIa inactivation. Mutation of R306, K311 and R314 each resulted in significantly reduced FVIIIa inactivation. The inactivating cleavages of FVIIIa at R336 and R562 were affected equally by the mutations. Protein S and FV stimulated cleavage at R562 more than cleavage at R336, independent of mutations in the autolysis loop. Together, these results confirmed that the autolysis loop plays a significant role as part of the basic exosite on APC in the interaction with FVIIIa. © 2011 Blackwell Publishing Ltd.

  2. APC-PCI complex levels for screening of AAA in patients with peripheral atherosclerosis.

    Science.gov (United States)

    Zarrouk, Moncef; Keshavarz, Kave; Lindblad, Bengt; Gottsäter, Anders

    2013-11-01

    To evaluate the use of activated protein C-protein C inhibitor (APC-PCI) complex levels for detection of abdominal aortic aneurysm (AAA) in patients with peripheral atherosclerotic disease (PAD). APC-PCI levels and aortic diameter evaluated in 511 PAD patients without previously known AAA followed-up concerning survival for 4.8(0.5) years. AAA was found in 13% of patients. Aortic diameter correlated (r = 0.138; p = 0.002) with APC-PCI levels which were higher (0.40[0.45] vs. 0.30[0.49] μg/l; p = 0.004) in patients with AAA. This difference persisted in multivariate analysis (p = 0.029). A threshold value of APC-PCI ≥0.15 μg/L showed a specificity of 11%, a sensitivity of 97% and a negative predictive value of 96% for an AAA diagnosis. APC-PCI levels were higher in patients with AAA, and showed high sensitivity but low specificity for the diagnosis and can therefore not be considered as a screening tool in PAD patients. An AAA prevalence of 13% in patients with PAD indicates a need for AAA screening within this population.

  3. Naringin, a natural dietary compound, prevents intestinal tumorigenesis in Apc (Min/+) mouse model.

    Science.gov (United States)

    Zhang, Yu-Sheng; Li, Ye; Wang, Yan; Sun, Shi-Yue; Jiang, Tao; Li, Cong; Cui, Shu-Xiang; Qu, Xian-Jun

    2016-05-01

    Naringin is a natural dietary flavonoid compound. We aimed to evaluate the effects of naringin on intestinal tumorigenesis in the adenomatous polyposis coli multiple intestinal neoplasia (Apc (Min/+)) mouse model. Apc (Min/+) mice were given either naringin (150 mg/kg) or vehicle by p.o. gavage daily for 12 consecutive weeks. Mice were killed with ether, and blood samples were collected to assess the concentrations of IL-6 and PGE2. Total intestines were removed, and the number of polyps was examined. Tissue samples of intestinal polyps were subjected to the assays of histopathology, immunohistochemical analysis and Western blotting analysis. Apc (Min/+) mice fed with naringin developed less and smaller polyps in total intestines. Naringin prevented intestinal tumorigenesis without adverse effects. Histopathologic analysis revealed the reduction of dysplastic cells and dysplasia in the adenomatous polyps. The treatments' effects might arise from its anti-proliferation, induction of apoptosis and modulation of GSK-3β and APC/β-catenin signaling pathways. Naringin also exerted its effects on tumorigenesis through anti-chronic inflammation. Naringin prevented intestinal tumorigenesis likely through a collection of activities including anti-proliferation, induction of apoptosis, modulation of GSK-3β and APC/β-catenin pathways and anti-inflammation. Naringin is a potential chemopreventive agent for reducing the risk of colonic cancers.

  4. APC-PC Combined Scheme in Gilbert Two State Model: Proposal and Study

    Science.gov (United States)

    Bulo, Yaka; Saring, Yang; Bhunia, Chandan Tilak

    2017-04-01

    In an automatic repeat request (ARQ) scheme, a packet is retransmitted if it gets corrupted due to transmission errors caused by the channel. However, an erroneous packet may contain both erroneous bits and correct bits and hence it may still contain useful information. The receiver may be able to combine this information from multiple erroneous copies to recover the correct packet. Packet combining (PC) is a simple and elegant scheme of error correction in transmitted packet, in which two received copies are XORed to obtain the bit location of erroneous bits. Thereafter, the packet is corrected by bit inversion of bit located as erroneous. Aggressive packet combining (APC) is a logic extension of PC primarily designed for wireless communication with objective of correcting error with low latency. PC offers higher throughput than APC, but PC does not correct double bit errors if occur in same bit location of erroneous copies of the packet. A hybrid technique is proposed to utilize the advantages of both APC and PC while attempting to remove the limitation of both. In the proposed technique, applications of APC-PC on Gilbert two state model has been studied. The simulation results show that the proposed technique offers better throughput than the conventional APC and lesser packet error rate than PC scheme.

  5. APC promoter 1B deletion in seven American families with familial adenomatous polyposis.

    Science.gov (United States)

    Snow, A K; Tuohy, T M F; Sargent, N R; Smith, L J; Burt, R W; Neklason, D W

    2015-10-01

    Familial adenomatous polyposis (FAP) is a colorectal cancer predisposition syndrome caused by mutations in the adenomatous polyposis coli (APC) gene. Clinical genetic testing fails to identify disease causing mutations in up to 20% of clinically apparent FAP cases. Following the inclusion of multiplex ligation-dependent probe amplification (MLPA) probes specific for APC promoter 1B, seven probands were identified with a deletion of promoter 1B. Using haplotype analysis spanning the APC locus, the seven families appear to be identical by descent from a common founder. The clinical phenotype of 19 mutation carriers is classical FAP with colectomy at an average age of 24. The majority of cases had a large number of duodenal and gastric polyps. Measurements of allele-specific expression of APC mRNA using TaqMan assay confirmed that relative expression in the allele containing the promoter 1B deletion was reduced 42-98%, depending on tissue type. This study confirms the importance of APC promoter deletions as a cause of FAP and identifies a founder mutation in FAP patients from the United States. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Immunotherapy of MHC class I-deficient tumors

    Czech Academy of Sciences Publication Activity Database

    Reiniš, Milan

    2010-01-01

    Roč. 6, č. 10 (2010), s. 1577-1589 ISSN 1479-6694 R&D Projects: GA ČR GA301/07/1410; GA ČR GAP301/10/2174; GA AV ČR IAA500520807; GA AV ČR IAA500520605 EU Projects: European Commission(XE) 18933 - CLINIGENE Institutional research plan: CEZ:AV0Z50520514 Keywords : tumor vaccine * MHC class I expression * antigen presenting machinery Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.455, year: 2010

  7. AGILE integration into APC for high mix logic fab

    Science.gov (United States)

    Gatefait, M.; Lam, A.; Le Gratiet, B.; Mikolajczak, M.; Morin, V.; Chojnowski, N.; Kocsis, Z.; Smith, I.; Decaunes, J.; Ostrovsky, A.; Monget, C.

    2015-09-01

    mix logic Fab) in term of product and technology portfolio AGILE corrects for up to 120nm of product topography error on process layer with less than 50nm depth of focus Based on tool functionalities delivered by ASML and on high volume manufacturing requirement, AGILE integration is a real challenge. Regarding ST requirements "Automatic AGILE" functionality developed by ASML was not a turnkey solution and a dedicated functionality was needed. A "ST homemade AGILE integration" has been fully developed and implemented within ASML and ST constraints. This paper describes this integration in our Advanced Process Control platform (APC).

  8. A kinetic model to study the regulation of β-catenin, APC, and Axin in the human colonic crypt.

    Science.gov (United States)

    Emerick, Brooks; Schleiniger, Gilberto; Boman, Bruce M

    2017-11-01

    The Wnt/[Formula: see text]-catenin pathway plays a crucial role in stem cell renewal and differentiation in the normal human colonic crypt. The balance between [Formula: see text]-catenin and APC along the crypt axis determines its normal functionality. The mechanism that deregulates this balance may give insight into the initiation of colorectal cancer. This is significant because the spatial dysregulation of [Formula: see text]-catenin by the mutated tumor suppressor gene/protein APC in human colonic crypts is responsible for the initiation and growth of colorectal cancer. We consider a regulatory function that promotes APC synthesis within the cell and its effect on the accumulation of the Wnt target protein, [Formula: see text]-catenin. It is evident that an APC gradient exists along the crypt axis; however, the mechanism by which APC expression is regulated within the cell is not well known. We investigate the dynamics of an APC regulatory mechanism with an increased level of Axin at the subcellular level. Model output shows an increase of APC for a diminished Wnt signal, which explains the APC gradient along the crypt. We find that the dynamic interplay between [Formula: see text]-catenin, APC, and Axin produces oscillatory behavior, which is controlled by the Wnt stimulus. In the presence of reduced functional APC, the oscillations are amplified, which suggests that the cell remains in a more proliferative state for longer periods of time. Increased Axin levels (typical of mammalian cells) reduce oscillatory behavior and minimize the levels of [Formula: see text]-catenin within the cell while raising the levels of APC.

  9. Quantifying the importance of pMHC valency, total pMHC dose and frequency on nanoparticle therapeutic efficacy.

    Science.gov (United States)

    Sugarman, Jordan; Tsai, Sue; Santamaria, Pere; Khadra, Anmar

    2013-05-01

    Nanoparticles (NPs) coated with β-cell-specific peptide major histocompatibility complex (pMHC) class I molecules can effectively restore normoglycemia in spontaneously diabetic nonobese diabetic mice. They do so by expanding pools of cognate memory autoreactive regulatory CD8+ T cells that arise from naive low-avidity T-cell precursors to therapeutic levels. Here we develop our previously constructed mathematical model to explore the effects of compound design parameters (NP dose and pMHC valency) on therapeutic efficacy with the underlying hypothesis that the functional correlates of the therapeutic response (expansion of autoregulatory T cells and deletion of autoantigen-loaded antigen-presenting cells by these T cells) are biphasic. We show, using bifurcation analysis, that the model exhibits a 'resonance'-like behavior for a given range of NP dose in which bistability between the healthy state (possessing zero level of effector T-cell population) and autoimmune state (possessing elevated level of the same population) disappears. A heterogeneous population of model mice subjected to several treatment protocols under these new conditions is conducted to quantify both the average percentage of autoregulatory T cells in responsive and nonresponsive model mice, and the average valency-dependent minimal optimal dose needed for effective therapy. Our results reveal that a moderate increase (≥1.6-fold) in the NP-dependent expansion rate of autoregulatory T-cell population leads to a significant increase in the efficacy and the area corresponding to the effective treatment regimen, provided that NP dose ≥8 μg. We expect the model developed here to generalize to other autoimmune diseases and serve as a computational tool to understand and optimize pMHC-NP-based therapies.

  10. The prognostic role of classical and nonclassical MHC class I expression in endometrial cancer

    NARCIS (Netherlands)

    Bijen, C.B.; Bantema-Joppe, E.J.; de Jong, Renske; Leffers, N.; Mourits, M.J.; Eggink, Henk F.; van der Zee, A.G.; Hollema, H.; de Bock, G.H.; Nijman, H.W.

    2010-01-01

    The aim of this study was to investigate classical MHC class I and nonclassical MHC (human leukocyte antigen-G [HLA-GJ) expression in a large cohort of patients with endometrial cancer, to determine the prognostic value of these cell surface markers and their relation with clinicopathological

  11. Social pairing of Seychelles warblers under reduced constraints: MHC, neutral heterozygosity, and age.

    Science.gov (United States)

    Wright, David J; Brouwer, Lyanne; Mannarelli, Maria-Elena; Burke, Terry; Komdeur, Jan; Richardson, David S

    2016-01-01

    The prevalence and significance of precopulatory mate choice remains keenly debated. The major histocompatibility complex (MHC) plays a key role in vertebrate adaptive immunity, and variation at the MHC influences individual survival. Although MHC-dependent mate choice has been documented in certain species, many other studies find no such pattern. This may be, at least in part, because in natural systems constraints may reduce the choices available to individuals and prevent full expression of underlying preferences. We used translocations to previously unoccupied islands to experimentally reduce constraints on female social mate choice in the Seychelles warbler ( Acrocephalus sechellensis ), a species in which patterns of MHC-dependent extrapair paternity (EPP), but not social mate choice, have been observed. We find no evidence of MHC-dependent social mate choice in the new populations. Instead, we find that older males and males with more microsatellite heterozygosity are more likely to have successfully paired. Our data cannot resolve whether these patterns in pairing were due to male-male competition or female choice. However, our research does suggest that female Seychelles warblers do not choose social mates using MHC class I to increase fitness. It may also indicate that the MHC-dependent EPP observed in the source population is probably due to mechanisms other than female precopulatory mate choice based on MHC cues.

  12. NLRC5/MHC class I transactivator is a target for immune evasion in cancer.

    Science.gov (United States)

    Yoshihama, Sayuri; Roszik, Jason; Downs, Isaac; Meissner, Torsten B; Vijayan, Saptha; Chapuy, Bjoern; Sidiq, Tabasum; Shipp, Margaret A; Lizee, Gregory A; Kobayashi, Koichi S

    2016-05-24

    Cancer cells develop under immune surveillance, thus necessitating immune escape for successful growth. Loss of MHC class I expression provides a key immune evasion strategy in many cancers, although the molecular mechanisms remain elusive. MHC class I transactivator (CITA), known as "NLRC5" [NOD-like receptor (NLR) family, caspase recruitment (CARD) domain containing 5], has recently been identified as a critical transcriptional coactivator of MHC class I gene expression. Here we show that the MHC class I transactivation pathway mediated by CITA/NLRC5 constitutes a target for cancer immune evasion. In all the 21 tumor types we examined, NLRC5 expression was highly correlated with the expression of MHC class I, with cytotoxic T-cell markers, and with genes in the MHC class I antigen-presentation pathway, including LMP2/LMP7, TAP1, and β2-microglobulin. Epigenetic and genetic alterations in cancers, including promoter methylation, copy number loss, and somatic mutations, were most prevalent in NLRC5 among all MHC class I-related genes and were associated with the impaired expression of components of the MHC class I pathway. Strikingly, NLRC5 expression was significantly associated with the activation of CD8(+) cytotoxic T cells and patient survival in multiple cancer types. Thus, NLRC5 constitutes a novel prognostic biomarker and potential therapeutic target of cancers.

  13. Ligation of MHC class I molecules on peripheral blood T lymphocytes induces new phenotypes and functions

    DEFF Research Database (Denmark)

    Bregenholt, S; Röpke, M; Skov, S

    1996-01-01

    of T cell-mediated cytotoxicity. Immediately following MHC-I ligation, the T cells responded with increased protein tyrosine phosphorylation, with new bands appearing in the SDS-PAGE. Exposure of T cells to immobilized anti-MHC-I Ab for 24 h induced an increased surface expression of the TCR/CD3 and CD......28 molecules. MHC-I-induced proliferation of purified T cells was dependent on cellular interactions with non-T cells. Under certain conditions, in which MHC-I was ligated by picogram concentrations of immobilized anti-MHC-I Ab, anti-TCR/CD3 Ab-induced proliferation of T cells was strongly inhibited....... These data clearly demonstrate that ligation of the MHC-I complex on T cells may induce both positive and negative signals. Since the physiologic ligands for MHC-I molecules are TCR and the CD8 molecules, our data may suggest that MHC-I molecules are instrumental in cellular interactions between T cells....

  14. The Intensity of Human Body Odors and the MHC: Should We Expect a Link?

    Directory of Open Access Journals (Sweden)

    Claus Wedekind

    2006-01-01

    Full Text Available It is now well established that genes within the major histocompatibility complex (MHC somehow affect the production of body odors in several vertebrates, including humans. Here we discuss whether variation in the intensity of body odors may be influenced by the MHC. In order to examine this question, we have to control for MHC-linked odor perception on the smeller's side. Such a control is necessary because the perception of pleasantness and intensity seem to be confounded, and the causalities are still unsolved. It has previously been found that intense odors are scored as less pleasant if the signaler and the receiver are of MHC-dissimilar type, but not if they are of MHC similar type. We argue, and first data suggest, that an effect of the degree of MHC-heterozygosity and odor intensity is likely (MHC-homozygotes may normally smell more intense, while there is currently no strong argument for other possible links between the MHC and body odor intensity.

  15. Modes of salmonid MHC class I and II evolution differ from the primate paradigm

    NARCIS (Netherlands)

    Shum, B.P.; Guethlein, L.; Flodin, L.R.; Adkison, M.A.; Hedrick, R.P.; Nehring, R.B.; Stet, R.J.M.; Secombes, C.; Parham, P.

    2001-01-01

    Rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) represent two salmonid genera separated for 15-20 million years. cDNA sequences were determined for the classical MHC class I heavy chain gene UBA and the MHC class II β-chain gene DAB from 15 rainbow and 10 brown trout. Both genes

  16. Can Selective MHC Downregulation Explain the Specificity and Genetic Diversity of NK Cell Receptors?

    NARCIS (Netherlands)

    Carrillo-Bustamante, Paola; Kesmir, Can; de Boer, Rob J

    2015-01-01

    Natural killer (NK) cells express inhibiting receptors (iNKRs), which specifically bind MHC-I molecules on the surface of healthy cells. When the expression of MHC-I on the cell surface decreases, which might occur during certain viral infections and cancer, iNKRs lose inhibiting signals and the

  17. Fine mapping in the MHC region accounts for 18% additional genetic risk for celiac disease

    NARCIS (Netherlands)

    Gutierrez-Achury, Javier; Zhernakova, Alexandra; Pulit, Sara L.; Trynka, Gosia; Hunt, Karen A.; Romanos, Jihane; Raychaudhuri, Soumya; van Heel, David A.; Wijmenga, Cisca; de Balcker, Paul I. W.

    Although dietary gluten is the trigger for celiac disease, risk is strongly influenced by genetic variation in the major histocompatibility complex (MHC) region. We fine mapped the MHC association signal to identify additional risk factors independent of the HLA-DQA1 and HLA-DQB1 alleles and

  18. Evolution of MHC class I genes in the European badger (Meles meles)

    NARCIS (Netherlands)

    Sin, Yung Wa; Dugdale, Hannah L.; Newman, Chris; Macdonald, David W.; Burke, Terry

    The major histocompatibility complex (MHC) plays a central role in the adaptive immune system and provides a good model with which to understand the evolutionary processes underlying functional genes. Trans-species polymorphism and orthology are both commonly found in MHC genes; however, mammalian

  19. Peptide specific expansion of CD8(+) T cells by recombinant plate bound MHC/peptide complexes

    DEFF Research Database (Denmark)

    Schmidt, Esben G W; Buus, Soren; Thorn, Mette

    2009-01-01

    to in vitro T cell stimulation was investigated. By use of an antigenic peptide derived from the cytomegalovirus (CMVp) we tested the stimulatory efficacy of recombinant plate bound MHC molecules (PB-MHC), being immobilized in culture plates. A single stimulation of non-adherent peripheral blood mononuclear...

  20. MHC Class II and Non-MHC Class II Genes Differentially Influence Humoral Immunity to Bacillus anthracis Lethal Factor and Protective Antigen

    OpenAIRE

    Garman, Lori; Dumas, Eric K.; Kurella, Sridevi; Hunt, Jonathan J.; Crowe, Sherry R.; Nguyen, Melissa L.; Cox, Philip M.; James, Judith A.; Farris, A. Darise

    2012-01-01

    Anthrax Lethal Toxin consists of Protective Antigen (PA) and Lethal Factor (LF), and current vaccination strategies focus on eliciting antibodies to PA. In human vaccination, the response to PA can vary greatly, and the response is often directed toward non-neutralizing epitopes. Variable vaccine responses have been shown to be due in part to genetic differences in individuals, with both MHC class II and other genes playing roles. Here, we investigated the relative contribution of MHC class I...

  1. Population genetic segmentation of MHC-correlated perfume preferences.

    Science.gov (United States)

    Hämmerli, A; Schweisgut, C; Kaegi, M

    2012-04-01

    It has become difficult to find a matching perfume. An overwhelming number of 300 new perfumes launch each year, and marketing campaigns target pre-defined groups based on gender, age or income rather than on individual preferences. Recent evidence for a genetic basis of perfume preferences, however, could be the starting point for a novel population genetic approach to better match perfumes with people's preferences. With a total of 116 participants genotyped for alleles of three loci of the major histocompatibility complex (MHC), the aim of this study was to test whether common MHC alleles could be used as genetic markers to segment a given population into preference types. Significant deviations from random expectations for a set of 10 common perfume ingredients indicate how such segmentation could be achieved. In addition, preference patterns of participants confronted with images that contained a sexual communication context significantly differed in their ratings for some of the scents compared with participants confronted with images of perfume bottles. This strongly supports the assumption that genetically correlated perfume preferences evolved in the context of sexual communication. The results are discussed in the light of perfume customization. © 2011 The Authors. ICS © 2011 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  2. Functional recombinant MHC class II molecules and high-throughput peptide-binding assays

    DEFF Research Database (Denmark)

    Justesen, Sune; Harndahl, Mikkel; Lamberth, Kasper

    2009-01-01

    BACKGROUND: Molecules of the class II major histocompability complex (MHC-II) specifically bind and present exogenously derived peptide epitopes to CD4+ T helper cells. The extreme polymorphism of the MHC-II hampers the complete analysis of peptide binding. It is also a significant hurdle......-II molecules and accompanying HTS peptide-binding assay were successfully developed for nine different MHC-II molecules including the DPA1*0103/DPB1*0401 (DP401) and DQA1*0501/DQB1*0201, where both alpha and beta chains are polymorphic, illustrating the advantages of producing the two chains separately....... CONCLUSION: We have successfully developed versatile MHC-II resources, which may assist in the generation of MHC class II -wide reagents, data, and tools....

  3. Porcine major histocompatibility complex (MHC) class I molecules and analysis of their peptide-binding specificities

    DEFF Research Database (Denmark)

    Pedersen, Lasse Eggers; Harndahl, Mikkel; Rasmussen, Michael

    2011-01-01

    a HLA-I molecule (HLA-A*11:01), thereby generating recombinant human/swine chimeric MHC-I molecules as well as the intact SLA-1*0401 molecule. Biochemical peptide-binding assays and positional scanning combinatorial peptide libraries were used to analyze the peptide-binding motifs of these molecules....... A pan-specific predictor of peptide–MHC-I binding, NetMHCpan, which was originally developed to cover the binding specificities of all known HLA-I molecules, was successfully used to predict the specificities of the SLA-1*0401 molecule as well as the porcine/human chimeric MHC-I molecules. These data......In all vertebrate animals, CD8+ cytotoxic T lymphocytes (CTLs) are controlled by major histocompatibility complex class I (MHC-I) molecules. These are highly polymorphic peptide receptors selecting and presenting endogenously derived epitopes to circulating CTLs. The polymorphism of the MHC...

  4. Gapped sequence alignment using artificial neural networks: application to the MHC class I system

    DEFF Research Database (Denmark)

    Andreatta, Massimo; Nielsen, Morten

    2016-01-01

    . On this relatively simple system, we developed a sequence alignment method based on artificial neural networks that allows insertions and deletions in the alignment. Results: We show that prediction methods based on alignments that include insertions and deletions have significantly higher performance than methods...... trained on peptides of single lengths. Also, we illustrate how the location of deletions can aid the interpretation of the modes of binding of the peptide-MHC, as in the case of long peptides bulging out of the MHC groove or protruding at either terminus. Finally, we demonstrate that the method can learn...... the length profile of different MHC molecules, and quantified the reduction of the experimental effort required to identify potential epitopes using our prediction algorithm. Availability and implementation: The NetMHC-4.0 method for the prediction of peptide-MHC class I binding affinity using gapped...

  5. MHC class II+ (HLA-DP-like) cells in the cow reproductive tract: II. Immunolocalization of MHC class II+ cells in oviduct and vagina.

    Science.gov (United States)

    Eren, U; Kum, S; Sandikçi, M; Eren, V; Ilhan, F

    2009-08-01

    The aim of this study was to determine and examine the distribution of major frequency MHC II+ cells in the oviduct and vagina of cows during the oestrous and dioestrus phases. Right oviduct (ampulla, isthmus) and vaginal samples taken from a total of twenty seven multiparous cows were used. Tissue samples were processed to obtain both cryostat and paraffin sections. Sections were stained immunocytochemically using StreptABC method using a specific monoclonal antibody to MHC II+ cell population. Intra-epithelial and subepithelial areas along with lamina propria, muscularis mucosae and serosa of both ampulla and isthmus and intra-epithelial/subepithelial areas and mucosae of vagina were examined for the presence of MHC II+ cells. The density of immune positive cells was determined using a subjective scoring system. MHC II+ cells were demonstrated in all areas examined in both oestrus and dioestrus. In oestrus, the density of MHC II+ cells decreased in subepithelial areas (in between the epithelial cells and the basal membrane) of isthmus, whereas the density of immune positive cells was increased in muscularis mucosae of isthmus (P < 0.05), lamina propria and muscularis mucosae of ampulla (P < 0.05) as well as in the mucosae of vagina (P MHC II+ cells observed in the oviduct and vagina increases in the majority of areas examined due to the effect of oestrogen.

  6. Thermally induced transformations of iron oxide stabilised APC residues from waste incineration

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Koch, C.B.

    2001-01-01

    Air pollution control (APC) facilities at waste incinerator plants produce large quantities of solid residues rich in salts and heavy metals. Heavy metals are readily released to water from the residues and it has, therefore, been found suitable to apply a rapid co-precipitation/adsorption process...... as a means to immobilize the toxic elements. In the 'Ferrox process', this immobilization is based on co-precipitation with an Fe(III) oxide formed by oxidation of Fe(II) by air in an aqueous slurry with the APC residue at alkaline pH. In this work we have undertaken a Mossbauer spectroscopy study of the Fe...

  7. TLR signals induce phagosomal MHC-I delivery from the endosomal recycling compartment to allow cross-presentation

    NARCIS (Netherlands)

    Nair-Gupta, Priyanka; Baccarini, Alessia; Tung, Navpreet; Seyffer, Fabian; Florey, Oliver; Huang, Yunjie; Banerjee, Meenakshi; Overholtzer, Michael; Roche, Paul A.; Tampé, Robert; Brown, Brian D.; Amsen, Derk; Whiteheart, Sidney W.; Blander, J. Magarian

    2014-01-01

    Adaptation of the endoplasmic reticulum (ER) pathway for MHC class I (MHC-I) presentation in dendritic cells enables cross-presentation of peptides derived from phagocytosed microbes, infected cells, or tumor cells to CD8 T cells. How these peptides intersect with MHC-I molecules remains poorly

  8. Antibody Stabilization of Peptide–MHC Multimers Reveals Functional T Cells Bearing Extremely Low-Affinity TCRs

    DEFF Research Database (Denmark)

    Tungatt, Katie; Bianchi, Valentina; Crowther, Michael D

    2015-01-01

    Fluorochrome-conjugated peptide-MHC (pMHC) multimers are commonly used in combination with flow cytometry for direct ex vivo visualization and characterization of Ag-specific T cells, but these reagents can fail to stain cells when TCR affinity and/or TCR cell-surface density are low. pMHC multim...

  9. Gene transfer preferentially selects MHC class I positive tumour cells and enhances tumour immunogenicity.

    Science.gov (United States)

    Hacker, Ulrich T; Schildhauer, Ines; Barroso, Margarita Céspedes; Kofler, David M; Gerner, Franz M; Mysliwietz, Josef; Buening, Hildegard; Hallek, Michael; King, Susan B S

    2006-05-01

    The modulated expression of MHC class I on tumour tissue is well documented. Although the effect of MHC class I expression on the tumorigenicity and immunogenicity of MHC class I negative tumour cell lines has been rigorously studied, less is known about the validity of gene transfer and selection in cell lines with a mixed MHC class I phenotype. To address this issue we identified a C26 cell subline that consists of distinct populations of MHC class I (H-2D/K) positive and negative cells. Transient transfection experiments using liposome-based transfer showed a lower transgene expression in MHC class I negative cells. In addition, MHC class I negative cells were more sensitive to antibiotic selection. This led to the generation of fully MHC class I positive cell lines. In contrast to C26 cells, all transfectants were rejected in vivo and induced protection against the parental tumour cells in rechallenge experiments. Tumour cell specificity of the immune response was demonstrated in in vitro cytokine secretion and cytotoxicity assays. Transfectants expressing CD40 ligand and hygromycin phosphotransferase were not more immunogenic than cells expressing hygromycin resistance alone. We suggest that the MHC class I positive phenotype of the C26 transfectants had a bearing on their immunogenicity, because selected MHC class I positive cells were more immunogenic than parental C26 cells and could induce specific anti-tumour immune responses. These data demonstrate that the generation of tumour cell transfectants can lead to the selection of subpopulations that show an altered phenotype compared to the parental cell line and display altered immunogenicity independent of selection marker genes or other immune modulatory genes. Our results show the importance of monitoring gene transfer in the whole tumour cell population, especially for the evaluation of in vivo therapies targeted to heterogeneous tumour cell populations.

  10. H pylori receptor MHC class II contributes to the dynamic gastric epithelial apoptotic response

    Science.gov (United States)

    Bland, David A; Suarez, Giovanni; Beswick, Ellen J; Sierra, Johanna C; Reyes, Victor E

    2006-01-01

    AIM: To investigate the role of MHC class II in the modulation of gastric epithelial cell apoptosis induced by H pylori infection. METHODS: After stimulating a human gastric epithelial cell line with bacteria or agonist antibodies specific for MHC class II and CD95, the quantitation of apoptotic and anti-apoptotic events, including caspase activation, BCL-2 activation, and FADD recruitment, was performed with a fluorometric assay, a cytometric bead array, and confocal microscopy, respectively. RESULTS: Pretreatment of N87 cells with the anti-MHC class II IgM antibody RFD1 resulted in a reduction in global caspase activation at 24 h of H pylori infection. When caspase 3 activation was specifically measured, crosslinking of MHC class II resulted in a marked reduced caspase activation, while simple ligation of MHC class II did not. Crosslinking of MHC class II also resulted in an increased activation of the anti-apoptosis molecule BCL-2 compared to simple ligation. Confocal microscope analysis demonstrated that the pretreatment of gastric epithelial cells with a crosslinking anti-MHC class II IgM blocked the recruitment of FADD to the cell surface. CONCLUSION: The results presented here demonstrate that the ability of MHC class II to modulate gastric epithelial apoptosis is at least partially dependent on its crosslinking. Furthermore, while previous research has demonstrated that MHC class II signaling can be pro-apoptotic during extended ligation, we have shown that the crosslinking of this molecule has anti-apoptotic effects during the earlier time points of H pylori infection. This effect is possibly mediated by the ability of MHC class II to modulate the activation of the pro-apoptotic receptor Fas by blocking the recruitment of the accessory molecule FADD, and this delay in apoptosis induction could allow for prolonged cytokine secretion by H pylori-infected gastric epithelial cells. PMID:16981259

  11. MHC Intratumoral Heterogeneity May Predict Cancer Progression and Response to Immunotherapy

    Directory of Open Access Journals (Sweden)

    Irene Romero

    2018-01-01

    Full Text Available An individual tumor can present intratumoral phenotypic heterogeneity, containing tumor cells with different phenotypes that do not present irreversible genetic alterations. We have developed a mouse cancer model, named GR9, derived from a methylcholanthrene-induced fibrosarcoma that was adapted to tissue culture and cloned into different tumor cell lines. The clones showed diverse MHC-I phenotypes, ranging from highly positive to weakly positive MHC-I expression. These MHC-I alterations are due to reversible molecular mechanisms, because surface MHC-I could be recovered by IFN-γ treatment. Cell clones with high MHC-I expression demonstrated low local oncogenicity and high spontaneous metastatic capacity, whereas MHC-I-low clones showed high local oncogenicity and no spontaneous metastatic capacity. Although MHC-I-low clones did not metastasize, they produced MHC-I-positive dormant micrometastases controlled by the host immune system, i.e., in a state of immunodormancy. The metastatic capacity of each clone was directly correlated with the host T-cell subpopulations; thus, a strong decrease in cytotoxic and helper T lymphocytes was observed in mice with numerous metastases derived from MHC-I positive tumor clones but a strong increase was observed in those with dormant micrometastases. Immunotherapy was administered to the hosts after excision of the primary tumor, producing a recovery in their immune status and leading to the complete eradication of overt spontaneous metastases or their decrease. According to these findings, the combination of MHC-I surface expression in primary tumor and metastases with host T-cell subsets may be a decisive indicator of the clinical outcome and response to immunotherapy in metastatic disease, allowing the identification of responders to this approach.

  12. ER stress affects processing of MHC class I-associated peptides

    Directory of Open Access Journals (Sweden)

    Meloche Sylvain

    2009-02-01

    Full Text Available Abstract Background Viral infection and neoplastic transformation trigger endoplasmic reticulum (ER stress. Thus, a large proportion of the cells that must be recognized by the immune system are stressed cells. Cells respond to ER stress by launching the unfolded protein response (UPR. The UPR regulates the two key processes that control major histocompatibility complex class I (MHC I-peptide presentation: protein synthesis and degradation. We therefore asked whether and how the UPR impinges on MHC I-peptide presentation. Results We evaluated the impact of the UPR on global MHC I expression and on presentation of the H2Kb-associated SIINFEKL peptide. EL4 cells stably transfected with vectors coding hen egg lysozyme (HEL-SIINFEKL protein variants were stressed with palmitate or exposed to glucose deprivation. UPR decreased surface expression of MHC I but did not affect MHC I mRNA level nor the total amount of intracellular MHC I proteins. Impaired MHC I-peptide presentation was due mainly to reduced supply of peptides owing to an inhibition of overall protein synthesis. Consequently, generation of H2Kb-SIINFEKL complexes was curtailed during ER stress, illustrating how generation of MHC I peptide ligands is tightly coupled to ongoing protein synthesis. Notably, the UPR-induced decline of MHC I-peptide presentation was more severe when the protein source of peptides was localized in the cytosol than in the ER. This difference was not due to changes in the translation rates of the precursor proteins but to increased stability of the cytosolic protein during ER stress. Conclusion Our results demonstrate that ER stress impairs MHC I-peptide presentation, and that it differentially regulates expression of ER- vs. cytosol-derived peptides. Furthermore, this work illustrates how ER stress, a typical feature of infected and malignant cells, can impinge on cues for adaptive immune recognition.

  13. Test of electrodialytic upgrading of MSWI APC residue in pilot scale: focus on reduced metal and salt leaching

    DEFF Research Database (Denmark)

    Kirkelund, Gunvor Marie; Jensen, Pernille Erland; Villumsen, Arne

    2010-01-01

    that is adapted from conventional electrodialysis, e.g. used in desalination of solutions. The APC residue was treated in a suspension (8 kg APC residue and 80 L tap water) and circulated through an electrodialytic (ED) stack consisting of 50 cell pairs separated by ion exchange membranes. A direct current...

  14. The role of S100a4 (Mts1) in Apc- and Smad4-driven tumour onset and progression

    DEFF Research Database (Denmark)

    Atlasi, Yaser; Noori, Rubina; Marolin, Ivana

    2016-01-01

    burden characteristic of the Apc1638N model. In agreement with these results, S100a4 appears to be co-expressed together with mesenchymal stem cell (MSC) markers in desmoid tumours from Apc1638N/+ mice, as well as from sporadic and hereditary human desmoids. Conclusion Our data provide the first report...

  15. Different effection of p.1125Val>Ala and rs11954856 in APC on Wnt signaling pathway.

    Science.gov (United States)

    Li, Fei-Feng; Zhao, Zhi-Xun; Yan, Peng; Wang, Song; Liu, Zheng; Zhang, Qiong; Zhang, Xiao-Ning; Sun, Chang-Hao; Wang, Xi-Shan; Wang, Gui-Yu; Liu, Shu-Lin

    2017-09-19

    Colorectal cancer (CRC) is among the most common and fatal forms of solid tumors worldwide and more than two thirds of CRC and adenomas patients have APC gene mutations. APC is a key regulator in the Wnt/β-catenin signaling pathway but its roles in CRC remains to be elucidated. In this study, we compared APC genes between CRC patients and controls to determine possible associations of nucleotide changes in the APC gene with the pathways involved in CRC pathogenesis. All participants received physical and enteroscopic examinations. The APC gene was sequenced for 300 Chinese Han CRC patients and 411 normal controls, and the expression levels of genes in the signaling pathway were analyzed using Western Blotting. Statistical analyses were conducted using SPSS (version 19.0) software. We found that rs11954856 in the APC gene was associated with colorectal cancer and could increase the expression levels of APC , β-catenin , TCF7L1 , TCF7L2 and LEF1 genes in the pathway in the CRC patients, demonstrating the involvement of APC in the pathological processes leading to CRC.

  16. 77 FR 34455 - In the Matter of Aegis Assessments, Inc., APC Group, Inc., Aurelio Resource Corp., BioAuthorize...

    Science.gov (United States)

    2012-06-11

    ... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] In the Matter of Aegis Assessments, Inc., APC Group, Inc., Aurelio Resource Corp., BioAuthorize Holdings, Inc., and Fonix Corporation; Order of... securities of APC Group, Inc. because it has not filed any periodic reports since the period ended August 31...

  17. The Spindle Assembly Checkpoint Is Not Essential for Viability of Human Cells with Genetically Lowered APC/C Activity

    DEFF Research Database (Denmark)

    Wild, Thomas; Larsen, Marie Sofie Yoo; Narita, Takeo

    2016-01-01

    The anaphase-promoting complex/cyclosome (APC/C) and the spindle assembly checkpoint (SAC), which inhibits the APC/C, are essential determinants of mitotic timing and faithful division of genetic material. Activation of the APC/C is known to depend on two APC/C-interacting E2 ubiquitin......-conjugating enzymes-UBE2C and UBE2S. We show that APC/C activity in human cells is tuned by the combinatorial use of three E2s, namely UBE2C, UBE2S, and UBE2D. Genetic deletion of UBE2C and UBE2S, individually or in combination, leads to discriminative reduction in APC/C function and sensitizes cells to UBE2D...... depletion. Reduction of APC/C activity results in loss of switch-like metaphase-to-anaphase transition and, strikingly, renders cells insensitive to chemical inhibition of MPS1 and genetic ablation of MAD2, both of which are essential for the SAC. These results provide insights into the regulation of APC...

  18. An APC/C-Cdh1 Biosensor Reveals the Dynamics of Cdh1 Inactivation at the G1/S Transition.

    Science.gov (United States)

    Ondracka, Andrej; Robbins, Jonathan A; Cross, Frederick R

    2016-01-01

    B-type cyclin-dependent kinase activity must be turned off for mitotic exit and G1 stabilization. B-type cyclin degradation is mediated by the anaphase-promoting complex/cyclosome (APC/C); during and after mitotic exit, APC/C is dependent on Cdh1. Cdh1 is in turn phosphorylated and inactivated by cyclin-CDK at the Start transition of the new cell cycle. We developed a biosensor to assess the cell cycle dynamics of APC/C-Cdh1. Nuclear exit of the G1 transcriptional repressor Whi5 is a known marker of Start; APC/C-Cdh1 is inactivated 12 min after Whi5 nuclear exit with little measurable cell-to-cell timing variability. Multiple phosphorylation sites on Cdh1 act in a redundant manner to repress its activity. Reducing the number of phosphorylation sites on Cdh1 can to some extent be tolerated for cell viability, but it increases variability in timing of APC/C-Cdh1 inactivation. Mutants with minimal subsets of phosphorylation sites required for viability exhibit striking stochasticity in multiple responses including budding, nuclear division, and APC/C-Cdh1 activity itself. Multiple cyclin-CDK complexes, as well as the stoichiometric inhibitor Acm1, contribute to APC/C-Cdh1 inactivation; this redundant control is likely to promote rapid and reliable APC/C-Cdh1 inactivation immediately following the Start transition.

  19. New Functions of APC/C Ubiquitin Ligase in the Nervous System and Its Role in Alzheimer's Disease.

    Science.gov (United States)

    Fuchsberger, Tanja; Lloret, Ana; Viña, Jose

    2017-05-14

    The E3 ubiquitin ligase Anaphase Promoting Complex/Cyclosome (APC/C) regulates important processes in cells, such as the cell cycle, by targeting a set of substrates for degradation. In the last decade, APC/C has been related to several major functions in the nervous system, including axon guidance, synaptic plasticity, neurogenesis, and neuronal survival. Interestingly, some of the identified APC/C substrates have been related to neurodegenerative diseases. There is an accumulation of some degradation targets of APC/C in Alzheimer's disease (AD) brains, which suggests a dysregulation of the protein complex in the disorder. Moreover, recently evidence has been provided for an inactivation of APC/C in AD. It has been shown that oligomers of the AD-related peptide, Aβ, induce degradation of the APC/C activator subunit cdh1, in vitro in neurons in culture and in vivo in the mouse hippocampus. Furthermore, in the AD mouse model APP/PS1, lower cdh1 levels were observed in pyramidal neurons in CA1 when compared to age-matched wildtype mice. In this review, we provide a complete list of APC/C substrates that are involved in the nervous system and we discuss their functions. We also summarize recent studies that show neurobiological effects in cdh1 knockout mouse models. Finally, we discuss the role of APC/C in the pathophysiology of AD.

  20. 4-Hydroxy-2(E)-nonenal metabolism differs in Apc(+/+) cells and in Apc(Min/+) cells: it may explain colon cancer promotion by heme iron.

    Science.gov (United States)

    Baradat, Maryse; Jouanin, Isabelle; Dalleau, Sabine; Taché, Sylviane; Gieules, Mathilde; Debrauwer, Laurent; Canlet, Cécile; Huc, Laurence; Dupuy, Jacques; Pierre, Fabrice H F; Guéraud, Françoise

    2011-11-21

    Animal and epidemiological studies suggest that dietary heme iron would promote colorectal cancer. Oxidative properties of heme could lead to the formation of cytotoxic and genotoxic secondary lipid oxidation products, such as 4-hydroxy-2(E)-nonenal (HNE). This compound is more cytotoxic to mouse wild-type colon cells than to isogenic cells with a mutation on the adenomatous polyposis coli (APC) gene. The latter thus have a selective advantage, possibly leading to cancer promotion. This mutation is an early and frequent event in human colorectal cancer. To explain this difference, the HNE biotransformation capacities of the two cell types have been studied using radiolabeled and stable isotope-labeled HNE. Apc-mutated cells showed better biotransformation capacities than nonmutated cells did. Thiol compound conjugation capacities were higher for mutated cells, with an important advantage for the extracellular conjugation to cysteine. Both cells types were able to reduce HNE to 4-hydroxynonanal, a biotransformation pathway that has not been reported for other intestinal cells. Mutated cells showed higher capacities to oxidize 4-hydroxynonanal into 4-hydroxynonanoic acid. The mRNA expression of different enzymes involved in HNE metabolism such as aldehyde dehydrogenase 1A1, 2 and 3A1, glutathione transferase A4-4, or cystine transporter xCT was upregulated in mutated cells compared with wild-type cells. In conclusion, this study suggests that Apc-mutated cells are more efficient than wild-type cells in metabolizing HNE into thiol conjugates and 4-hydroxynonanoic acid due to the higher expression of key biotransformation enzymes. These differential biotransformation capacities would explain the differences of susceptibility between normal and Apc-mutated cells regarding secondary lipid oxidation products.

  1. The Regulation of the Angiogenic Factor FGF Binding Protein (FGF-BP) by the APC/Beta-Catenin Signaling Pathway in the Progression of Breast Cancer

    National Research Council Canada - National Science Library

    Stylianou, Dora

    2004-01-01

    ...) to study the expression of FGF-BP in mammary tumorigenesis progression of the APC/+ mouse and 2) to determine the mechanism of regulation of FGF-BP b the APC/beta-catenin signaling pathway in breast cancer...

  2. The Regulation of the Angiogenic Factor FGF Binding Protein (FGF-BP) by the APC/Beta-Catenin Signaling Pathway in the Progression of Breast Cancer

    National Research Council Canada - National Science Library

    Stylianou, Dora

    2003-01-01

    ...) to study the expression of FGF-BP in mammary tumorigenesis% progression of the APC/+ mouse and 2) to determine the mechanism of regulation of FGF-BP by the APC/beta- catenin signaling pathway in breast cancer...

  3. Functional characterization of Anaphase Promoting Complex/Cyclosome (APC/C) E3 ubiquitin ligases in tumorigenesis

    Science.gov (United States)

    Zhang, Jinfang; Wan, Lixin; Dai, Xiangpeng; Sun, Yi; Wei, Wenyi

    2014-01-01

    The Anaphase Promoting Complex/Cyclosome (APC/C) is a multi-subunit E3 ubiquitin ligase that primarily governs cell cycle progression. APC/C is composed of at least 14 core subunits and recruits its substrates for ubiquitination via one of the two adaptor proteins, Cdc20 or Cdh1, in M or M/early G1 phase, respectively. Furthermore, recent studies have shed light on crucial functions for APC/C in maintaining genomic integrity, neuronal differentiation, cellular metabolism and tumorigenesis. To gain better insight into the in vivo physiological functions of APC/C in regulating various cellular processes, particularly development and tumorigenesis, a number of mouse models of APC/C core subunits, coactivators or inhibitors have been established and characterized. However, due to their essential role in cell cycle regulation, most of the germline knockout mice targeting the APC/C pathway are embryonic lethal, indicating the need for generating conditional knockout mouse models to assess the role in tumorigenesis for each APC/C signaling component in specific tissues. In this review, we will first provide a brief introduction of the ubiquitin-proteasome system (UPS) and the biochemical activities and cellular functions of the APC/C E3 ligase. We will then focus primarily on characterizing genetic mouse models used to understand the physiological roles of each APC/C signaling component in embryogenesis, cell proliferation, development and carcinogenesis. Finally, we discuss future research directions to further elucidate the physiological contributions of APC/C components during tumorigenesis and validate their potentials as a novel class of anti-cancer targets. PMID:24569229

  4. Structures of the APC-ARM domain in complexes with discrete Amer1/WTX fragments reveal that it uses a consensus mode to recognize its binding partners.

    Science.gov (United States)

    Zhang, Zhenyi; Akyildiz, Senem; Xiao, Yafei; Gai, Zhongchao; An, Ying; Behrens, Jürgen; Wu, Geng

    2015-01-01

    The tumor suppressor APC employs its conserved armadillo repeat (ARM) domain to recognize many of its binding partners, including Amer1/WTX, which is mutated in Wilms' tumor and bone overgrowth syndrome. The APC-Amer1 complex has important roles in regulating Wnt signaling and cell adhesion. Three sites A1, A2, and A3 of Amer1 have been reported to mediate its interaction with APC-ARM. In this study, crystal structures of APC-ARM in complexes with Amer1-A1, -A2, and -A4, which is newly identified in this work, were determined. Combined with our GST pull-down, yeast two-hybrid, and isothermal titration calorimetry (ITC) assay results using mutants of APC and Amer1 interface residues, our structures demonstrate that Amer1-A1, -A2, and -A4, as well as other APC-binding proteins such as Asef and Sam68, all employ a common recognition pattern to associate with APC-ARM. In contrast, Amer1-A3 binds to the C-terminal side of APC-ARM through a bipartite interaction mode. Composite mutations on either APC or Amer1 disrupting all four interfaces abrogated their association in cultured cells and impaired the membrane recruitment of APC by Amer1. Our study thus comprehensively elucidated the recognition mechanism between APC and Amer1, and revealed a consensus recognition sequence employed by various APC-ARM binding partners.

  5. APC/C-Cdh1 coordinates neurogenesis and cortical size during development

    Science.gov (United States)

    Delgado-Esteban, Maria; García-Higuera, Irene; Maestre, Carolina; Moreno, Sergio; Almeida, Angeles

    2013-12-01

    The morphology of the adult brain is the result of a delicate balance between neural progenitor proliferation and the initiation of neurogenesis in the embryonic period. Here we assessed whether the anaphase-promoting complex/cyclosome (APC/C) cofactor, Cdh1—which regulates mitosis exit and G1-phase length in dividing cells—regulates neurogenesis in vivo. We use an embryo-restricted Cdh1 knockout mouse model and show that functional APC/C-Cdh1 ubiquitin ligase activity is required for both terminal differentiation of cortical neurons in vitro and neurogenesis in vivo. Further, genetic ablation of Cdh1 impairs the ability of APC/C to promote neurogenesis by delaying the exit of the progenitor cells from the cell cycle. This causes replicative stress and p53-mediated apoptotic death resulting in decreased number of cortical neurons and cortex size. These results demonstrate that APC/C-Cdh1 coordinates cortical neurogenesis and size, thus posing Cdh1 in the molecular pathogenesis of congenital neurodevelopmental disorders, such as microcephaly.

  6. Microbiological Method (DEFT/APC) For The Detection Of Irradiated Foods In Egypt

    International Nuclear Information System (INIS)

    Osman, M.E.; Abo El-Nasr, A.; Abo El Nour, S.A.; Hammad, A.; Ibrahim, H.M.A.

    2013-01-01

    The applicability of a microbiological screening method based on the comparison of the count obtained by the direct epi fluorescent filter technique (DEFT) with the count obtained by the conventional aerobic plate count (APC) for the detection of three kinds of irradiated foodstuffs (black pepper, strawberry, de-boned chicken meat) in Egypt was evaluated. The detection method was carried out immediately after irradiation and during subsequent storage. The results revealed that for irradiation doses of 5 kGy or higher, the DEFT/APC difference of around 2 log units or more could be a suitable criterion for judging black pepper samples as irradiated. DEFT/APC difference of around 2 log units or more could be used as a criterion for irradiation processing of strawberry at dose level of 2 kGy or higher. The DEFT/APC difference of around 2.5 log units or more could be indicated that fresh and frozen de-boned chicken meat samples had been irradiated at least at 3 and 6 kGy or higher, respectively. In general, the results showed that this method had the potential to detect irradiated food samples either immediately after irradiation or throughout the storage period.

  7. Opposite effects of modifiers of the Apc(Min) mutation in intestine and mammary gland

    Czech Academy of Sciences Publication Activity Database

    Czarnomska, A.; Krysiak, E.; Piskorowska, J.; Sitarz, M.; Pilčík, Tomáš; Demant, P.

    2003-01-01

    Roč. 2003, č. 63 (2003), s. 4533-4537 ISSN 0008-5472 Institutional research plan: CEZ:AV0Z5052915 Keywords : Recombinant congenic strains * primary breast cancers * APC gene Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 8.649, year: 2003

  8. Filtration Algorithms of Untrustworthy Analogous Information in APCS at TPP and NPP

    Directory of Open Access Journals (Sweden)

    V. I. Nazarov

    2012-01-01

    Full Text Available The paper considers filtration algorithms of untrustworthy analogous information in APCS at TTP and NPP that make it possible to identify credibility of information transmitted through communication channels in the form of signals and which are continuously changeable in the regime of real time.

  9. Virus encoded MHC-like decoys diversify the inhibitory KIR repertoire.

    Directory of Open Access Journals (Sweden)

    Paola Carrillo-Bustamante

    Full Text Available Natural killer (NK cells are circulating lymphocytes that play an important role in the control of viral infections and tumors. Their functions are regulated by several activating and inhibitory receptors. A subset of these receptors in human NK cells are the killer immunoglobulin-like receptors (KIRs, which interact with the highly polymorphic MHC class I molecules. One important function of NK cells is to detect cells that have down-regulated MHC expression (missing-self. Because MHC molecules have non polymorphic regions, their expression could have been monitored with a limited set of monomorphic receptors. Surprisingly, the KIR family has a remarkable genetic diversity, the function of which remains poorly understood. The mouse cytomegalovirus (MCMV is able to evade NK cell responses by coding "decoy" molecules that mimic MHC class I. This interaction was suggested to have driven the evolution of novel NK cell receptors. Inspired by the MCMV system, we develop an agent-based model of a host population infected with viruses that are able to evolve MHC down-regulation and decoy molecules. Our simulations show that specific recognition of MHC class I molecules by inhibitory KIRs provides excellent protection against viruses evolving decoys, and that the diversity of inhibitory KIRs will subsequently evolve as a result of the required discrimination between host MHC molecules and decoy molecules.

  10. Protective influences on experimental autoimmune encephalomyelitis by MHC class I and class II alleles

    DEFF Research Database (Denmark)

    Mustafa, M; Vingsbo, C; Olsson, T

    1994-01-01

    are resistant. Interestingly, rats with the MHC u haplotype develop an immune response to the MBP 63-88, but do not get EAE. In this study we have used intra-MHC recombinant rat strains to compare the influences of the MHC u with the a haplotype. We discovered the following: 1) The class II region of the MHC...... a haplotype permits EAE and a Th1 type of immune response as measured by IFN-gamma production after in vitro challenge of in vivo-primed T cells with MBP 63-88. 2) The class II region of the u haplotype is associated with a disease-protective immune response characterized by production of not only IFN......Experimental autoimmune encephalomyelitis (EAE) is influenced by polymorphism of the MHC. We have previously found that Lewis rats with certain MHC haplotypes are susceptible to disease induced with the myelin basic protein (MBP) peptide 63-88, whereas Lewis rats with other MHC haplotypes...

  11. Orf virus interferes with MHC class I surface expression by targeting vesicular transport and Golgi

    Directory of Open Access Journals (Sweden)

    Rohde Jörg

    2012-07-01

    Full Text Available Abstract Background The Orf virus (ORFV, a zoonotic Parapoxvirus, causes pustular skin lesions in small ruminants (goat and sheep. Intriguingly, ORFV can repeatedly infect its host, despite the induction of a specific immunity. These immune modulating and immune evading properties are still unexplained. Results Here, we describe that ORFV infection of permissive cells impairs the intracellular transport of MHC class I molecules (MHC I as a result of structural disruption and fragmentation of the Golgi apparatus. Depending on the duration of infection, we observed a pronounced co-localization of MHC I and COP-I vesicular structures as well as a reduction of MHC I surface expression of up to 50%. These subversion processes are associated with early ORFV gene expression and are accompanied by disturbed carbohydrate trimming of post-ER MHC I. The MHC I population remaining on the cell surface shows an extended half-life, an effect that might be partially controlled also by late ORFV genes. Conclusions The presented data demonstrate that ORFV down-regulates MHC I surface expression in infected cells by targeting the late vesicular export machinery and the structure and function of the Golgi apparatus, which might aid to escape cellular immune recognition.

  12. Disentangling the roles of natural selection and genetic drift in shaping variation at MHC immunity genes.

    Science.gov (United States)

    Sutton, Jolene T; Nakagawa, Shinichi; Robertson, Bruce C; Jamieson, Ian G

    2011-11-01

    The major histocompatibility complex (MHC) forms an integral component of the vertebrate immune response and, due to strong selection pressures, is one of the most polymorphic regions of the entire genome. Despite over 15 years of research, empirical studies offer highly contradictory explanations of the relative roles of different evolutionary forces, selection and genetic drift, acting on MHC genes during population bottlenecks. Here, we take a meta-analytical approach to quantify the results of studies into the effects of bottlenecks on MHC polymorphism. We show that the consequences of selection acting on MHC loci prior to a bottleneck event, combined with drift during the bottleneck, will result in overall loss of MHC polymorphism that is ∼15% greater than loss of neutral genetic diversity. These results are counter to general expectations that selection should maintain MHC polymorphism, but do agree with the results of recent simulation models and at least two empirical studies. Notably, our results suggest that negative frequency-dependent selection could be more important than overdominance for maintaining high MHC polymorphism in pre-bottlenecked populations. © 2011 Blackwell Publishing Ltd.

  13. Peptide and Peptide-Dependent Motions in MHC Proteins: Immunological Implications and Biophysical Underpinnings

    Directory of Open Access Journals (Sweden)

    Cory M. Ayres

    2017-08-01

    Full Text Available Structural biology of peptides presented by class I and class II MHC proteins has transformed immunology, impacting our understanding of fundamental immune mechanisms and allowing researchers to rationalize immunogenicity and design novel vaccines. However, proteins are not static structures as often inferred from crystallographic structures. Their components move and breathe individually and collectively over a range of timescales. Peptides bound within MHC peptide-binding grooves are no exception and their motions have been shown to impact recognition by T cell and other receptors in ways that influence function. Furthermore, peptides tune the motions of MHC proteins themselves, which impacts recognition of peptide/MHC complexes by other proteins. Here, we review the motional properties of peptides in MHC binding grooves and discuss how peptide properties can influence MHC motions. We briefly review theoretical concepts about protein motion and highlight key data that illustrate immunological consequences. We focus primarily on class I systems due to greater availability of data, but segue into class II systems as the concepts and consequences overlap. We suggest that characterization of the dynamic “energy landscapes” of peptide/MHC complexes and the resulting functional consequences is one of the next frontiers in structural immunology.

  14. Natural selection on MHC IIβ in parapatric lake and stream stickleback: Balancing, divergent, both or neither?

    Science.gov (United States)

    Stutz, William E; Bolnick, Daniel I

    2017-09-01

    Major histocompatibility complex (MHC) genes encode proteins that play a central role in vertebrates' adaptive immunity to parasites. MHC loci are among the most polymorphic in vertebrates' genomes, inspiring many studies to identify evolutionary processes driving MHC polymorphism within populations and divergence between populations. Leading hypotheses include balancing selection favouring rare alleles within populations, and spatially divergent selection. These hypotheses do not always produce diagnosably distinct predictions, causing many studies of MHC to yield inconsistent or ambiguous results. We suggest a novel strategy to distinguish balancing vs. divergent selection on MHC, taking advantage of natural admixture between parapatric populations. With divergent selection, individuals with immigrant alleles will be more infected and less fit because they are susceptible to novel parasites in their new habitat. With balancing selection, individuals with locally rare immigrant alleles will be more fit (less infected). We tested these contrasting predictions using three-spine stickleback from three replicate pairs of parapatric lake and stream habitats. We found numerous positive and negative associations between particular MHC IIβ alleles and particular parasite taxa. A few allele-parasite comparisons supported balancing selection, and others supported divergent selection between habitats. But, there was no overall tendency for fish with immigrant MHC alleles to be more or less heavily infected. Instead, locally rare MHC alleles (not necessarily immigrants) were associated with heavier infections. Our results illustrate the complex relationship between MHC IIβ allelic variation and spatially varying multispecies parasite communities: different hypotheses may be concurrently true for different allele-parasite combinations. © 2017 John Wiley & Sons Ltd.

  15. Leukocyte Ig-Like Receptors – a model for MHC class I disease associations

    Directory of Open Access Journals (Sweden)

    Rachel Louise Allen

    2016-07-01

    Full Text Available MHC class I (MHC-I polymorphisms are associated with the outcome of some viral infections and autoimmune diseases. MHC-I proteins present antigenic peptides and are recognised by receptors on Natural Killer cells and Cytotoxic T lymphocytes, thus enabling the immune system to detect self-antigens and eliminate targets lacking self or expressing foreign antigens. Recognition of MHC-I, however, extends beyond receptors on cytotoxic leukocytes. Members of the Leukocyte Ig-like receptor (LILR family are expressed on monocytic cells and can recognise both classical and non-classical MHC-I alleles. Despite their relatively broad specificity when compared to the T Cell Receptor or Killer Ig-like Receptors, variations in the strength of LILR binding between different MHC-I alleles have recently been shown to correlate with control of HIV infection. We suggest that LILR recognition may mediate MHC-I disease association in a manner that does not depend on a binary discrimination of self/non-self by cytotoxic cells. Instead, the effects of LILR activity following engagement by MHC-I may represent a degrees of self model, whereby strength of binding to different alleles determines the degree of influence exerted by these receptors on immune cell functions. LILR are expressed by myelomonocytic cells and lymphocytes, extending their influence across antigen presenting cell subsets including dendritic cells, macrophages and B cells. They have been identified as important players in the response to infection, inflammatory diseases and cancer, with recent literature to indicate that MHC-I recognition by these receptors and consequent allelic effects could extend an influence beyond the immune system.

  16. Crystal structure of a TAPBPR–MHC I complex reveals the mechanism of peptide editing in antigen presentation

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jiansheng; Natarajan, Kannan; Boyd, Lisa F.; Morozov, Giora I.; Mage, Michael G.; Margulies, David H. (NIH); (Hebrew)

    2017-10-12

    Central to CD8+ T cell–mediated immunity is the recognition of peptide–major histocompatibility complex class I (p–MHC I) proteins displayed by antigen-presenting cells. Chaperone-mediated loading of high-affinity peptides onto MHC I is a key step in the MHC I antigen presentation pathway. However, the structure of MHC I with a chaperone that facilitates peptide loading has not been determined. We report the crystal structure of MHC I in complex with the peptide editor TAPBPR (TAP-binding protein–related), a tapasin homolog. TAPBPR remodels the peptide-binding groove of MHC I, resulting in the release of low-affinity peptide. Changes include groove relaxation, modifications of key binding pockets, and domain adjustments. This structure captures a peptide-receptive state of MHC I and provides insights into the mechanism of peptide editing by TAPBPR and, by analogy, tapasin.

  17. Characterization of MHC-I in the blue tit (Cyanistes caeruleus) reveals low levels of genetic diversity and trans-population evolution across European populations

    NARCIS (Netherlands)

    Schut, Elske; Rivero-de Aguilar, Juan; Merino, Santiago; Magrath, Michael J. L.; Komdeur, Jan; Westerdahl, Helena

    The major histcompatibility complex (MHC) is a vital component of the adaptive immune system in all vertebrates. This study is the first to characterize MHC class I (MHC-I) in blue tits (Cyanistes caeruleus), and we use MHC-I exon 3 sequence data from individuals originating from three locations

  18. Curcumin suppresses intestinal polyps in APC Min mice fed a high fat diet

    Directory of Open Access Journals (Sweden)

    Christina Pettan-Brewer

    2011-06-01

    Full Text Available Colorectal cancer (CRC is a leading cause of cancer deaths in the United States. Various risk factors have been associated with CRC including increasing age and diet. Epidemiological and experimental studies have implicated a diet high in fat as an important risk factor for colon cancer. High fat diets can promote obesity resulting in insulin resistance and inflammation and the development of oxidative stress, increased cell proliferation, and suppression of apoptosis. Because of the high consumption of dietary fats, especially saturated fats, by Western countries, it is of interest to see if non-nutrient food factors might be effective in preventing or delaying CRC in the presence of high saturated fat intake. Curcumin (Curcuma longa, the main yellow pigment in turmeric, was selected to test because of its reported anti-tumor activity. APC Min mice, which develop intestinal polyps and have many molecular features of CRC, were fed a diet containing 35% pork fat, 33% sucrose, and a protein and vitamin mineral mixture (HFD with or without 0.5% curcumin. These cohorts were compared to APC Min mice receiving standard rodent chow (RC with 8% fat. APC Min mice fed the HFD for 3 months had a 23% increase in total number of polyps compared to APC Min mice on RC. Curcumin was able to significantly reverse the accelerated polyp development associated with the HFD suggesting it may be effective clinically in helping prevent colon cancer even when ingesting high amounts of fatty foods. The anti-tumor effect of curcumin was shown to be associated with enhanced apoptosis and increased efficiency of DNA repair. Since curcumin prevented the gain in body weight seen in APC Min mice ingesting the HFD, modulation of energy metabolism may also be a factor.

  19. Thymine DNA Glycosylase (TDG) is involved in the pathogenesis of intestinal tumors with reduced APC expression.

    Science.gov (United States)

    Xu, Jinfei; Cortellino, Salvatore; Tricarico, Rossella; Chang, Wen-Chi; Scher, Gabrielle; Devarajan, Karthik; Slifker, Michael; Moore, Robert; Bassi, Maria Rosaria; Caretti, Elena; Clapper, Margie; Cooper, Harry; Bellacosa, Alfonso

    2017-10-27

    Thymine DNA Glycosylase (TDG) is a base excision repair enzyme that acts as a thymine and uracil DNA N-glycosylase on G:T and G:U mismatches, thus protecting CpG sites in the genome from mutagenesis by deamination. In addition, TDG has an epigenomic function by removing the novel cytosine derivatives 5-formylcytosine and 5-carboxylcytosine (5caC) generated by Ten-Eleven Translocation (TET) enzymes during active DNA demethylation. We and others previously reported that TDG is essential for mammalian development. However, its involvement in tumor formation is unknown. To study the role of TDG in tumorigenesis, we analyzed the effects of its inactivation in a well-characterized model of tumor predisposition, the Apc Min mouse strain. Mice bearing a conditional Tdg flox allele were crossed with Fabpl ::Cre transgenic mice, in the context of the Apc Min mutation, in order to inactivate Tdg in the small intestinal and colonic epithelium. We observed an approximately 2-fold increase in the number of small intestinal adenomas in the test Tdg -mutant Apc Min mice in comparison to control genotypes (p=0.0001). This increase occurred in female mice, and is similar to the known increase in intestinal adenoma formation due to oophorectomy. In the human colorectal cancer (CRC) TCGA database, the subset of patients with TDG and APC expression in the lowest quartile exhibits an excess of female cases. We conclude that TDG inactivation plays a role in intestinal tumorigenesis initiated by mutation/underexpression of APC . Our results also indicate that TDG may be involved in sex-specific protection from CRC.

  20. Disruption of the APC gene by t(5;7) translocation in a Turcot family.

    Science.gov (United States)

    Sahnane, Nora; Bernasconi, Barbara; Carnevali, Ileana; Furlan, Daniela; Viel, Alessandra; Sessa, Fausto; Tibiletti, Maria Grazia

    2016-03-01

    Turcot syndrome (TS) refers to the combination of colorectal polyps and primary tumours of the central nervous system. TS is a heterogeneous genetic condition due to APC and/or mismatch repair germline mutations. When APC is involved the vast majority of mutations are truncating, but in approximately 20%-30% of patients with familial polyposis no germline mutation can be found. A 30-year-old Caucasian woman with a positive pedigree for TS was referred to our Genetic Counselling Service. She was negative for APC and MUTYH but showed a reciprocal balanced translocation t(5;7)(q22;p15) at chromosome analysis. FISH analysis using specific BAC probes demonstrated that 5q22 breakpoint disrupted the APC gene. Transcript analysis by MLPA and digital PCR revealed that the cytogenetic rearrangement involving the 3' end of the APC gene caused a defective expression of a truncated transcript. This result allowed cytogenetic analysis to be offered to all the other family members and segregation analysis clearly demonstrated that all the carriers were affected, whereas non-carriers did not have the polyposis. A cytogenetic approach permitted the identification of the mutation-causing disease in this family, and the segregation analysis together with the transcript study supported the pathogenetic role of this mutation. Karyotype analysis was used as a predictive test in all members of this family. This family suggests that clinically positive TS and FAP cases, which test negative with standard molecular analysis, could be easily and cost-effectively resolved by a classical and molecular cytogenetic approach. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. A novel mutation of adenomatous polyposis coli (APC) gene results in the formation of supernumerary teeth.

    Science.gov (United States)

    Yu, Fang; Cai, Wenping; Jiang, Beizhan; Xu, Laijun; Liu, Shangfeng; Zhao, Shouliang

    2018-01-01

    Supernumerary teeth are teeth that are present in addition to normal teeth. Although several hypotheses and some molecular signalling pathways explain the formation of supernumerary teeth, but their exact disease pathogenesis is unknown. To study the molecular mechanisms of supernumerary tooth-related syndrome (Gardner syndrome), a deeper understanding of the aetiology of supernumerary teeth and the associated syndrome is needed, with the goal of inhibiting disease inheritance via prenatal diagnosis. We recruited a Chinese family with Gardner syndrome. Haematoxylin and eosin staining of supernumerary teeth and colonic polyp lesion biopsies revealed that these patients exhibited significant pathological characteristics. APC gene mutations were detected by PCR and direct sequencing. We revealed the pathological pathway involved in human supernumerary tooth development and the mouse tooth germ development expression profile by RNA sequencing (RNA-seq). Sequencing analysis revealed that an APC gene mutation in exon 15, namely 4292-4293-Del GA, caused Gardner syndrome in this family. This mutation not only initiated the various manifestations typical of Gardner syndrome but also resulted in odontoma and supernumerary teeth in this case. Furthermore, RNA-seq analysis of human supernumerary teeth suggests that the APC gene is the key gene involved in the development of supernumerary teeth in humans. The mouse tooth germ development expression profile shows that the APC gene plays an important role in tooth germ development. We identified a new mutation in the APC gene that results in supernumerary teeth in association with Gardner syndrome. This information may shed light on the molecular pathogenesis of supernumerary teeth. Gene-based diagnosis and gene therapy for supernumerary teeth may become available in the future, and our study provides a high-resolution reference for treating other syndromes associated with supernumerary teeth. © 2017 The Authors. Journal of

  2. Intestinal tumor suppression in ApcMin/+ mice by prostaglandin D2 receptor PTGDR

    International Nuclear Information System (INIS)

    Tippin, Brigette L; Kwong, Alan M; Inadomi, Michael J; Lee, Oliver J; Park, Jae Man; Materi, Alicia M; Buslon, Virgilio S; Lin, Amy M; Kudo, Lili C; Karsten, Stanislav L; French, Samuel W; Narumiya, Shuh; Urade, Yoshihiro; Salido, Eduardo; Lin, Henry J

    2014-01-01

    Our earlier work showed that knockout of hematopoietic prostaglandin D synthase (HPGDS, an enzyme that produces prostaglandin D 2 ) caused more adenomas in Apc Min/+ mice. Conversely, highly expressed transgenic HPGDS allowed fewer tumors. Prostaglandin D 2 (PGD 2 ) binds to the prostaglandin D 2 receptor known as PTGDR (or DP1). PGD 2 metabolites bind to peroxisome proliferator-activated receptor γ (PPARG). We hypothesized that Ptgdr or Pparg knockouts may raise numbers of tumors, if these receptors take part in tumor suppression by PGD 2 . To assess, we produced Apc Min/+ mice with and without Ptgdr knockouts (147 mice). In separate experiments, we produced Apc Min/+ mice expressing transgenic lipocalin-type prostaglandin D synthase (PTGDS), with and without heterozygous Pparg knockouts (104 mice). Homozygous Ptgdr knockouts raised total numbers of tumors by 30–40% at 6 and 14 weeks. Colon tumors were not affected. Heterozygous Pparg knockouts alone did not affect tumor numbers in Apc Min/+ mice. As mentioned above, our Pparg knockout assessment also included mice with highly expressed PTGDS transgenes. Apc Min/+ mice with transgenic PTGDS had fewer large adenomas (63% of control) and lower levels of v-myc avian myelocytomatosis viral oncogene homolog (MYC) mRNA in the colon. Heterozygous Pparg knockouts appeared to blunt the tumor-suppressing effect of transgenic PTGDS. However, tumor suppression by PGD 2 was more clearly mediated by receptor PTGDR in our experiments. The suppression mechanism did not appear to involve changes in microvessel density or slower proliferation of tumor cells. The data support a role for PGD 2 signals acting through PTGDR in suppression of intestinal tumors

  3. An APC:WNT counter-current-like mechanism regulates cell division along the colonic crypt axis: a mechanism that explains how APC mutations induce proliferative abnormalities that drive colon cancer development.

    Directory of Open Access Journals (Sweden)

    Bruce M Boman

    2013-11-01

    Full Text Available APC normally down-regulates WNT signaling in human colon, and APC mutations cause proliferative abnormalities in premalignant crypts leading to colon cancer, but the mechanisms are unclear at the level of spatial and functional organization of the crypt. Accordingly, we postulated a counter-current-like mechanism based on gradients of factors (APC;WNT that regulate colonocyte proliferation along the crypt axis. During crypt renewal, stem cells (SCs at the crypt bottom generate non-SC daughter cells that proliferate and differentiate while migrating upwards. The APC concentration is low at the crypt bottom and high at the top (where differentiated cells reside. WNT signaling, in contrast, is high at the bottom (where SCs reside and low at the top. Given that WNT and APC gradients are counter to one another, we hypothesized that a counter-current-like mechanism exists. Since both APC and WNT signaling components (e.g. survivin are required for mitosis, this mechanism establishes a zone in the lower crypt where conditions are optimal for maximal cell division and mitosis orientation (symmetric versus asymmetric. APC haploinsufficiency diminishes the APC gradient, shifts the proliferative zone upwards, and increases symmetric division, which causes SC overpopulation. In homozygote mutant crypts, these changes are exacerbated. Thus, APC-mutation-induced changes in the counter-current-like mechanism cause expansion of proliferative populations (SCs, rapidly-proliferating cells during tumorigenesis. We propose this mechanism also drives crypt fission, functions in the crypt cycle, and underlies adenoma development. Novel chemoprevention approaches designed to normalize the two gradients and readjust the proliferative zone downwards, might thwart progression of these premalignant changes.

  4. An APC:WNT Counter-Current-Like Mechanism Regulates Cell Division Along the Human Colonic Crypt Axis: A Mechanism That Explains How APC Mutations Induce Proliferative Abnormalities That Drive Colon Cancer Development

    Science.gov (United States)

    Boman, Bruce M.; Fields, Jeremy Z.

    2013-01-01

    APC normally down-regulates WNT signaling in human colon, and APC mutations cause proliferative abnormalities in premalignant crypts leading to colon cancer, but the mechanisms are unclear at the level of spatial and functional organization of the crypt. Accordingly, we postulated a counter-current-like mechanism based on gradients of factors (APC;WNT) that regulate colonocyte proliferation along the crypt axis. During crypt renewal, stem cells (SCs) at the crypt bottom generate non-SC daughter cells that proliferate and differentiate while migrating upwards. The APC concentration is low at the crypt bottom and high at the top (where differentiated cells reside). WNT signaling, in contrast, is high at the bottom (where SCs reside) and low at the top. Given that WNT and APC gradients are counter to one another, we hypothesized that a counter-current-like mechanism exists. Since both APC and WNT signaling components (e.g., survivin) are required for mitosis, this mechanism establishes a zone in the lower crypt where conditions are optimal for maximal cell division and mitosis orientation (symmetric versus asymmetric). APC haploinsufficiency diminishes the APC gradient, shifts the proliferative zone upwards, and increases symmetric division, which causes SC overpopulation. In homozygote mutant crypts, these changes are exacerbated. Thus, APC-mutation-induced changes in the counter-current-like mechanism cause expansion of proliferative populations (SCs, rapidly proliferating cells) during tumorigenesis. We propose this mechanism also drives crypt fission, functions in the crypt cycle, and underlies adenoma development. Novel chemoprevention approaches designed to normalize the two gradients and readjust the proliferative zone downwards, might thwart progression of these premalignant changes. PMID:24224156

  5. pH dependence of MHC class I-restricted peptide presentation

    DEFF Research Database (Denmark)

    Stryhn, A; Pedersen, L O; Romme, T

    1996-01-01

    The function of MHC class I molecules is to bind and present antigenic peptides to cytotoxic T cells. Here, we report that class I-restricted peptide presentation is strongly pH dependent. The presentation of some peptides was enhanced at acidic pH, whereas the presentation of others was inhibited....... Biochemical peptide-MHC class I binding assays demonstrated that peptide-MHC class I complexes are more stable at neutral pH than at acidic pH. We suggest that acid-dependent peptide dissociation can generate empty class I molecules and that the resulting binding potential can be exploited by a subset...

  6. Systematic Characterisation of Cellular Localisation and Expression Profiles of Proteins Containing MHC Ligands

    DEFF Research Database (Denmark)

    Juncker, Agnieszka; Larsen, Mette Voldby; Weinhold, Nils

    2009-01-01

    Background: Presentation of peptides on Major Histocompatibility Complex (MHC) molecules is the cornerstone in immune system activation and increased knowledge of the characteristics of MHC ligands and their source proteins is highly desirable. Methodology/Principal Finding: In the present large......-scale study, we used a large data set of proteins containing experimentally identified MHC class I or II ligands and examined the proteins according to their expression profiles at the mRNA level and their Gene Ontology (GO) classification within the cellular component ontology. Proteins encoded by highly...

  7. Improved prediction of MHC class I and class II epitopes using a novel Gibbs sampling approach

    DEFF Research Database (Denmark)

    Nielsen, Morten; Lundegaard, Claus; Worning, Peder

    2004-01-01

    Prediction of which peptides will bind a specific major histocompatibility complex (MHC) constitutes an important step in identifying potential T-cell epitopes suitable as vaccine candidates. MHC class II binding peptides have a broad length distribution complicating such predictions. Thus......, identifying the correct alignment is a crucial part of identifying the core of an MHC class II binding motif. In this context, we wish to describe a novel Gibbs motif sampler method ideally suited for recognizing such weak sequence motifs. The method is based on the Gibbs sampling method, and it incorporates...

  8. Low genetic variation in the MHC class II DRB gene and MHC-linked microsatellites in endangered island populations of the leopard cat (Prionailurus bengalensis) in Japan.

    Science.gov (United States)

    Saka, Toshinori; Nishita, Yoshinori; Masuda, Ryuichi

    2018-02-01

    Isolated populations of the leopard cat (Prionailurus bengalensis) on Tsushima and Iriomote islands in Japan are classified as subspecies P. b. euptilurus and P. b. iriomotensis, respectively. Because both populations have decreased to roughly 100, an understanding of their genetic diversity is essential for conservation. We genotyped MHC class II DRB exon 2 and MHC-linked microsatellite loci to evaluate the diversity of MHC genes in the Tsushima and Iriomote cat populations. We detected ten and four DRB alleles in these populations, respectively. A phylogenetic analysis showed DRB alleles from both populations to be closely related to those in other felid DRB lineages, indicating trans-species polymorphism. The MHC-linked microsatellites were more polymorphic in the Tsushima than in the Iriomote population. The MHC diversity of both leopard cat populations is much lower than in the domestic cat populations on these islands, probably due to inbreeding associated with founder effects, geographical isolation, or genetic drift. Our results predict low resistance of the two endangered populations to new pathogens introduced to the islands.

  9. Role of heterozygous APC mutation in niche succession and initiation of colorectal cancer--a computational study.

    Directory of Open Access Journals (Sweden)

    Roschen Sasikumar

    Full Text Available Mutations in the adenomatous polyposis coli (APC gene are found in most colorectal cancers. They cause constitutive activation of proliferative pathways when both alleles of the gene are mutated. However studies on individuals with familial adenomatous polyposis (FAP have shown that a single mutated APC allele can also create changes in the precancerous colon crypt, like increased number of stem cells, increased crypt fission, greater variability of DNA methylation patterns, and higher somatic mutation rates. In this paper, using a computational model of colon crypt dynamics, we evolve and investigate a hypothesis on the effect of heterozygous APC mutation that explains these different observations. Based on previous reports and the results from the computational model we propose the hypothesis that heterozygous APC mutation has the effect of increasing the chances for a stem cell to divide symmetrically, producing two stem cell daughters. We incorporate this hypothesis into the model and perform simulation experiments to investigate the consequences of the hypothesis. Simulations show that this hypothesis links together the changes in FAP crypts observed in previous studies. The simulations also show that an APC(+/- stem cell gets selective advantages for dominating the crypt and progressing to cancer. This explains why most colon cancers are initiated by APC mutation. The results could have implications for preventing or retarding the onset of colon cancer in people with inherited or acquired mutation of one APC allele. Experimental validation of the hypothesis as well as investigation into the molecular mechanisms of this effect may therefore be worth undertaking.

  10. The combination of heteroduplex analysis and protein truncation test for exact detection of the APC gene mutations

    International Nuclear Information System (INIS)

    Tomka, M.; Kirchhoff, T.; Stefurkova, V.; Zajac, V.; Kulcsar, L.

    1998-01-01

    Familial adenomatous polyposis (FAP) is usually associated with mutation in the adenomatous polyposis coli (APC) gene. To examine the occurrence of these mutations in the number of FAP suspected families from the whole Slovakia effectively, we have applied heteroduplex analysis (HDA) and protein truncation test (PTT) for the analyses of 2-5 base pair deletions and point mutations of the APC gene. In the analyzed exon 15 of the APC gene determined by the primers 15Efor-15Grev for HDA and 15ET7-15J3 for PTT more than 70% of mutations should be deletions [3, 12], which are detectable by HDA. In our collection of 5 FAP families mutations in the APC gene were found in families 10, 27 and 41 using HDA. By PTT test the formation of truncated APC protein in FAP families 2, 10, 16 and 27 were revealed. The necessity of combination of at least HDA and PTT techniques for exact detection of APC mutations in analyzed APC region is discussed. (authors)

  11. Activated protein C (APC) can increase bone anabolism via a protease-activated receptor (PAR)1/2 dependent mechanism.

    Science.gov (United States)

    Shen, Kaitlin; Murphy, Ciara M; Chan, Ben; Kolind, Mille; Cheng, Tegan L; Mikulec, Kathy; Peacock, Lauren; Xue, Meilang; Park, Sang-Youel; Little, David G; Jackson, Chris J; Schindeler, Aaron

    2014-12-01

    Activated Protein C (APC) is an anticoagulant with strong cytoprotective properties that has been shown to promote wound healing. In this study APC was investigated for its potential orthopedic application using a Bone Morphogenetic Protein 2 (rhBMP-2) induced ectopic bone formation model. Local co-administration of 10 µg rhBMP-2 with 10 µg or 25 µg APC increased bone volume at 3 weeks by 32% (N.S.) and 74% (pAPC are largely mediated by its receptors endothelial protein C receptor (EPCR) and protease-activated receptors (PARs). Cultured pre-osteoblasts and bone nodule tissue sections were shown to express PAR1/2 and EPCR. When pre-osteoblasts were treated with APC, cell viability and phosphorylation of ERK1/2, Akt, and p38 were increased. Inhibition with PAR1 and sometimes PAR2 antagonists, but not with EPCR blocking antibodies, ameliorated the effects of APC on cell viability and kinase phosphorylation. These data indicate that APC can affect osteoblast viability and signaling, and may have in vivo applications with rhBMP-2 for bone repair. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  12. High-resolution Melting Analysis for Gene Scanning of Adenomatous Polyposis Coli (APC) Gene With Oral Squamous Cell Carcinoma Samples.

    Science.gov (United States)

    Chang, Ya-Sian; Lin, Chien-Yu; Yang, Shu-Fen; Ho, Cheng Mao; Chang, Jan-Gowth

    2016-02-01

    There have been many different mutations reported for the large adenomatous polyposis coli (APC) tumor suppressor gene. APC mutations result in inactivation of APC tumor suppressor action, allowing the progression of tumorigenesis. The present study utilized a highly efficient method to identify APC mutations and investigated the association between the APC genetic variants Y486Y, A545A, T1493T, and D1822V and susceptibility to oral squamous cell carcinoma (OSCC). High-resolution melting (HRM) analysis was used to characterize APC mutations. Genomic DNA was extracted from 83 patient specimens of OSCC and 50 blood samples from healthy control subjects. The 14 exons and mutation cluster region of exon 15 were screened by HRM analysis. All mutations were confirmed by direct DNA sequencing. Three mutations and 4 single nucleotide polymorphisms (SNPs) were found in this study. The mutations were c.573T>C (Y191Y) in exon 5, c.1005A>G (L335L) in exon 9, and c.1488A>T (T496T) in exon 11. Two SNPs, c.4479G>A (T1493T) and c.5465A>T (D1822V), were located in exon 15, whereas c.1458T>C (Y486Y) and c.1635G>A (A545A) were located in exon 11 and 13, respectively. There was no observed association between OSCC risk and genotype for any of the 4 APC SNPs. The mutation of APC is rare in Taiwanese patients with OSCC. HRM analysis is a reliable, accurate, and fast screening method for APC mutations.

  13. APC/β-catenin-rich complexes at membrane protrusions regulate mammary tumor cell migration and mesenchymal morphology

    International Nuclear Information System (INIS)

    Odenwald, Matthew A; Prosperi, Jenifer R; Goss, Kathleen H

    2013-01-01

    The APC tumor suppressor is mutated or downregulated in many tumor types, and is prominently localized to punctate clusters at protrusion tips in migratory cells, such as in astrocytes where it has been implicated in directed cell motility. Although APC loss is considered an initiating event in colorectal cancer, for example, it is less clear what role APC plays in tumor cell motility and whether loss of APC might be an important promoter of tumor progression in addition to initiation. The localization of APC and β-catenin was analyzed in multiple cell lines, including non-transformed epithelial lines treated with a proteasome inhibitor or TGFβ to induce an epithelial-to-mesenchymal transition (EMT), as well as several breast cancer lines, by immunofluorescence. APC expression was knocked down in 4T07 mammary tumor cells using lentiviral-mediated delivery of APC-specific short-hairpin (sh) RNAs, and assessed using quantitative (q) reverse-transcriptase (RT)-PCR and western blotting. Tumor cell motility was analyzed by performing wound-filling assays, and morphology via immunofluorescence (IF) and phase-contrast microscopy. Additionally, proliferation was measured using BrdU incorporation, and TCF reporter assays were performed to determine β-catenin/TCF-mediated transcriptional activity. APC/β-catenin-rich complexes were observed at protrusion ends of migratory epithelial cells treated with a proteasome inhibitor or when EMT has been induced and in tumor cells with a mesenchymal, spindle-like morphology. 4T07 tumor cells with reduced APC levels were significantly less motile and had a more rounded morphology; yet, they did not differ significantly in proliferation or β-catenin/TCF transcriptional activity. Furthermore, we found that APC/β-catenin-rich complexes at protrusion ends were dependent upon an intact microtubule cytoskeleton. These findings indicate that membrane protrusions with APC/β-catenin-containing puncta control the migratory potential and

  14. Molecular dissection of the APC/C inhibitor Rca1 shows a novel F-box-dependent function

    OpenAIRE

    Zielke, Norman; Querings, Silvia; Grosskortenhaus, Ruth; Reis, Tânia; Sprenger, Frank

    2006-01-01

    Rca1 (regulator of Cyclin A)/Emi (early mitotic inhibitor) proteins are essential inhibitors of the anaphase-promoting complex/cyclosome (APC/C). In Drosophila, Rca1 is required during G2 to prevent premature cyclin degradation by the Fizzy-related (Fzr)-dependent APC/C activity. Here, we present a structure and function analysis of Rca1 showing that a carboxy-terminal fragment is sufficient for APC/C inhibition. Rca1/Emi proteins contain a conserved F-box and interact with components of the ...

  15. APC/β-catenin-rich complexes at membrane protrusions regulate mammary tumor cell migration and mesenchymal morphology

    Science.gov (United States)

    2013-01-01

    Background The APC tumor suppressor is mutated or downregulated in many tumor types, and is prominently localized to punctate clusters at protrusion tips in migratory cells, such as in astrocytes where it has been implicated in directed cell motility. Although APC loss is considered an initiating event in colorectal cancer, for example, it is less clear what role APC plays in tumor cell motility and whether loss of APC might be an important promoter of tumor progression in addition to initiation. Methods The localization of APC and β-catenin was analyzed in multiple cell lines, including non-transformed epithelial lines treated with a proteasome inhibitor or TGFβ to induce an epithelial-to-mesenchymal transition (EMT), as well as several breast cancer lines, by immunofluorescence. APC expression was knocked down in 4T07 mammary tumor cells using lentiviral-mediated delivery of APC-specific short-hairpin (sh) RNAs, and assessed using quantitative (q) reverse-transcriptase (RT)-PCR and western blotting. Tumor cell motility was analyzed by performing wound-filling assays, and morphology via immunofluorescence (IF) and phase-contrast microscopy. Additionally, proliferation was measured using BrdU incorporation, and TCF reporter assays were performed to determine β-catenin/TCF-mediated transcriptional activity. Results APC/β-catenin-rich complexes were observed at protrusion ends of migratory epithelial cells treated with a proteasome inhibitor or when EMT has been induced and in tumor cells with a mesenchymal, spindle-like morphology. 4T07 tumor cells with reduced APC levels were significantly less motile and had a more rounded morphology; yet, they did not differ significantly in proliferation or β-catenin/TCF transcriptional activity. Furthermore, we found that APC/β-catenin-rich complexes at protrusion ends were dependent upon an intact microtubule cytoskeleton. Conclusions These findings indicate that membrane protrusions with APC/β-catenin-containing puncta

  16. Mutation analysis of the adenomatous polyposis coli (APC) gene in Danish patients with familial adenomatous polyposis (FAP)

    DEFF Research Database (Denmark)

    Bisgaard, Marie Luise; Ripa, Rasmus S; Bülow, Steffen

    2004-01-01

    Development of one hundred or more adenomas in the colon and rectum is diagnostic for the dominantly inherited, autosomal disease Familial Adenomatous Polyposis (FAP). It is possible to identify a mutation in the Adenomatous Polyposis Coli (APC) gene in approximately 80% of the patients, and almost...... 1,000 different pathogenic mutations have been identified in the APC gene up till now. We report 12 novel and 24' previously described germline APC mutations from 48 unrelated Danish families. Four families with the mutation localized in the 3' region of the gene showed great variance in phenotypic...

  17. High dose infusion of activated protein C (rhAPC) fails to improve neuronal damage and cognitive deficit after global cerebral ischemia in rats.

    Science.gov (United States)

    Brückner, Melanie; Lasarzik, Irina; Jahn-Eimermacher, Antje; Peetz, Dirk; Werner, Christian; Engelhard, Kristin; Thal, Serge C

    2013-09-13

    Recent studies demonstrated anticoagulatory, antiinflammatory, antiapoptotic, and neuroprotective properties of activated protein C (APC) in rodent models of acute neurodegenerative diseases, suggesting APC as promising broad acting therapeutic agent. Unfortunately, continuous infusion of recombinant human APC (rhAPC) failed to improve brain damage following cardiac arrest in rats. The present study was designed to investigate the neuroprotective effect after global cerebral ischemia (GI) with an optimized infusion protocol. Rats were subjected to bilateral clip occlusion of the common carotid arteries (BCAO) and controlled hemorrhagic hypotension to 40 mm Hg for 14 min and a subsequent 5h-infusion of rhAPC (2mg/kg bolus+6 mg/kg/h continuous IV) or vehicle (0.9% NaCl). The dosage was calculated to maintain plasma hAPC activity at 150%. Cerebral inflammation, apoptosis and neuronal survival was determined at day 10. rhAPC infusion did not influence cortical cerebral perfusion during reperfusion and failed to reduce neuronal cell loss, microglia activation, and caspase 3 activity. Even an optimized rhAPC infusion protocol designed to maintain a high level of APC plasma activity failed to improve the sequels following GI. Despite positive reports about protective effects of APC following, e.g., ischemic stroke, the present study supports the notion that infusion of APC during the early reperfusion phase does not result in sustained neuroprotection and fails to improve outcome after global cerebral ischemia. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. Reversible Modification of Adenomatous Polyposis Coli (APC) with K63-linked Polyubiquitin Regulates the Assembly and Activity of the β-Catenin Destruction Complex

    Science.gov (United States)

    Tran, Hoanh; Polakis, Paul

    2012-01-01

    The adenomatous polyposis coli (APC) tumor suppressor forms a complex with Axin and GSK3β to promote the phosphorylation and degradation of β-catenin, a key co-activator of Wnt-induced transcription. Here, we establish that APC is modified predominantly with K63-linked ubiquitin chains when it is bound to Axin in unstimulated HEK293 cells. Wnt3a stimulation induced a time-dependent loss of K63-polyubiquitin adducts from APC, an effect synchronous with the dissociation of Axin from APC and the stabilization of cytosolic β-catenin. RNAi-mediated depletion of Axin or β-catenin, which negated the association between APC and Axin, resulted in the absence of K63-adducts on APC. Overexpression of wild-type and phosphodegron-mutant β-catenin, combined with analysis of thirteen human cancer cell lines that harbor oncogenic mutations in APC, Axin, or β-catenin, support the hypothesis that a fully assembled APC-Axin-GSK3β-phospho-β-catenin complex is necessary for the K63-polyubiquitylation of APC. Intriguingly, the degree of this modification on APC appears to correlate inversely with the levels of β-catenin in cells. Together, our results indicate that K63-linked polyubiquitin adducts on APC regulate the assembly and/or efficiency of the β-catenin destruction complex. PMID:22761442

  19. USP7 Is a Tumor-Specific WNT Activator for APC-Mutated Colorectal Cancer by Mediating β-Catenin Deubiquitination

    Directory of Open Access Journals (Sweden)

    Laura Novellasdemunt

    2017-10-01

    Full Text Available The tumor suppressor gene adenomatous polyposis coli (APC is mutated in most colorectal cancers (CRCs, resulting in constitutive Wnt activation. To understand the Wnt-activating mechanism of the APC mutation, we applied CRISPR/Cas9 technology to engineer various APC-truncated isogenic lines. We find that the β-catenin inhibitory domain (CID in APC represents the threshold for pathological levels of Wnt activation and tumor transformation. Mechanistically, CID-deleted APC truncation promotes β-catenin deubiquitination through reverse binding of β-TrCP and USP7 to the destruction complex. USP7 depletion in APC-mutated CRC inhibits Wnt activation by restoring β-catenin ubiquitination, drives differentiation, and suppresses xenograft tumor growth. Finally, the Wnt-activating role of USP7 is specific to APC mutations; thus, it can be used as a tumor-specific therapeutic target for most CRCs.

  20. USP7 Is a Tumor-Specific WNT Activator for APC-Mutated Colorectal Cancer by Mediating β-Catenin Deubiquitination.

    Science.gov (United States)

    Novellasdemunt, Laura; Foglizzo, Valentina; Cuadrado, Laura; Antas, Pedro; Kucharska, Anna; Encheva, Vesela; Snijders, Ambrosius P; Li, Vivian S W

    2017-10-17

    The tumor suppressor gene adenomatous polyposis coli (APC) is mutated in most colorectal cancers (CRCs), resulting in constitutive Wnt activation. To understand the Wnt-activating mechanism of the APC mutation, we applied CRISPR/Cas9 technology to engineer various APC-truncated isogenic lines. We find that the β-catenin inhibitory domain (CID) in APC represents the threshold for pathological levels of Wnt activation and tumor transformation. Mechanistically, CID-deleted APC truncation promotes β-catenin deubiquitination through reverse binding of β-TrCP and USP7 to the destruction complex. USP7 depletion in APC-mutated CRC inhibits Wnt activation by restoring β-catenin ubiquitination, drives differentiation, and suppresses xenograft tumor growth. Finally, the Wnt-activating role of USP7 is specific to APC mutations; thus, it can be used as a tumor-specific therapeutic target for most CRCs. Copyright © 2017 The Francis Crick Institute. Published by Elsevier Inc. All rights reserved.

  1. Molecular Basis of Natural Killer Cell Tumor Target Recognition: The NKr/MHC Class I Complex

    National Research Council Canada - National Science Library

    Hasemann, Charles

    1999-01-01

    .... We have pursued this via the heterologous expression of wild type and mutant NK receptors for the purpose of the determination of the atomic structure of an NK receptor/ class I MHC complex via X-ray crystallography...

  2. A Novel Therapeutic Vaccine for Metastatic Mammary Carcinoma: Focusing MHC/Peptide Complexes to Lipid Rafts

    National Research Council Canada - National Science Library

    Dolan, Brian

    2004-01-01

    Genetic engineering of tumor cells to express MHC class and subsequent use of said cells for treatment of established and metastatic tumors has yielded promising results in animal models for treatment of breast cancer...

  3. ZAP-70 and p72syk are signaling response elements through MHC class II molecules

    DEFF Research Database (Denmark)

    Kanner, S B; Grosmaire, L S; Blake, J

    1995-01-01

    Ligation of major histocompatibility complex (MHC) class II antigens expressed on antigen-activated human CD4+ T-lymphocytes induces early signal transduction events including the activation of tyrosine kinases, the tyrosine phosphorylation of phospholipase-C gamma 1 and the mobilization...... of intracellular calcium. Similar responses have been observed in B-cells following stimulation of MHC class II molecules, including the increased production of intracellular cAMP. In this report, we demonstrate that the ZAP-70 tyrosine kinase is a responsive signaling element following cross-linking of HLA...... by herbimycin A. MHC class II ligation on B-lymphocytes resulted in cell death, which was both qualitatively distinct from Fas-induced apoptosis and partially protected by herbimycin A pretreatment. Thus, ligation of MHC class II molecules expressed on human lymphocytes stimulates the ZAP-70/p72syk family...

  4. Barrett associated MHC and FOXF1 variants also increase esophageal carcinoma risk

    NARCIS (Netherlands)

    Dura, P.; Veen, E.M. van; Salomon, J.; Morsche, R.H.M. te; Roelofs, H.M.J.; Kristinsson, J.O.; Wobbes, T.; Witteman, B.J.; Tan, A.C.; Drenth, J.P.H.; Peters, W.H.M.

    2013-01-01

    Barrett's esophagus, with gastroesophageal reflux disease and obesity as risk factors, predisposes to esophageal adenocarcinoma (EAC). Recently a British genome wide association study identified two Barrett's esophagus susceptibility loci mapping within the major histocompatibility complex (MHC;

  5. Forming a complex with MHC class I molecules interferes with mouse CD1d functional expression.

    Directory of Open Access Journals (Sweden)

    Renukaradhya J Gourapura

    Full Text Available CD1d molecules are structurally similar to MHC class I, but present lipid antigens as opposed to peptides. Here, we show that MHC class I molecules physically associate with (and regulate the functional expression of mouse CD1d on the surface of cells. Low pH (3.0 acid stripping of MHC class I molecules resulted in increased surface expression of murine CD1d on antigen presenting cells as well as augmented CD1d-mediated antigen presentation to NKT cells. Consistent with the above results, TAP1-/- mice were found to have a higher percentage of type I NKT cells as compared to wild type mice. Moreover, bone marrow-derived dendritic cells from TAP1-/- mice showed increased antigen presentation by CD1d compared to wild type mice. Together, these results suggest that MHC class I molecules can regulate NKT cell function, in part, by masking CD1d.

  6. MHC class I is functionally associated with antigen receptors in human T and B lymphomas

    DEFF Research Database (Denmark)

    Pedersen, Anders Elm; Jacoby, B F; Skov, S

    1996-01-01

    lines the increase in [Ca2+]i after MHC-I cross-linking caused upregulation of CD69, an early marker of activation. When studying the effect of MHC-I cross-linking on the TCR- and B cell antigen receptor (BCR)- mediated increase in [Ca2+]i, respectively, we observed that MHC-I had a costimulatory effect...... on the TCR-mediated increase in [Ca2+]i in Jurkat cells but not on the anti-IgM-mediated activity of Solubo cells. Studies of subpopulations of Jurkat and Solubo cells expressing different levels of MHC-I on their cell surfaces revealed that the TCR- and BCR-mediated increases in [Ca2+]i, respectively, were...

  7. Semi-empirical quantum evaluation of peptide - MHC class II binding

    Science.gov (United States)

    González, Ronald; Suárez, Carlos F.; Bohórquez, Hugo J.; Patarroyo, Manuel A.; Patarroyo, Manuel E.

    2017-01-01

    Peptide presentation by the major histocompatibility complex (MHC) is a key process for triggering a specific immune response. Studying peptide-MHC (pMHC) binding from a structural-based approach has potential for reducing the costs of investigation into vaccine development. This study involved using two semi-empirical quantum chemistry methods (PM7 and FMO-DFTB) for computing the binding energies of peptides bonded to HLA-DR1 and HLA-DR2. We found that key stabilising water molecules involved in the peptide binding mechanism were required for finding high correlation with IC50 experimental values. Our proposal is computationally non-intensive, and is a reliable alternative for studying pMHC binding interactions.

  8. Structural requirements for the interaction between class II MHC molecules and peptide antigens

    DEFF Research Database (Denmark)

    Sette, A; Buus, S; Appella, E

    1990-01-01

    of binding, it is possible to define certain structural features of peptides that are associated with the capacity to bind to a particular MHC specificity (IA(d) or IE(d)); 3) IA(d) and IE(d) molecules recognize different and independent structures on the antigen molecule; 4) only about 10% of the single...... IA(d) and IE(d) molecules and their peptide ligands, we found that some structural characteristics apply to both antigen-MHC interactions. In particular, we found: 1) each MHC molecule is capable of binding many unrelated peptides through the same peptide-binding site; 2) despite this permissiveness...... amino acid substitutions tested on two IA(d)- and IE(d)-binding peptides had significant effect on their MHC-binding capacities, while over 80% of these substitutions significantly impaired T cell recognition of the Ia-peptide complex; 5) based on the segregation between residues that are crucial for T...

  9. Diagnostic value of MHC class I staining in idiopathic inflammatory myopathies.

    NARCIS (Netherlands)

    Pas, J. van der; Hengstman, G.J.D.; Laak, H.J. ter; Borm, G.F.; Engelen, B.G.M. van

    2004-01-01

    BACKGROUND: Identification of mononuclear cellular infiltrates in skeletal muscle tissue is the histological cornerstone of the diagnosis of idiopathic inflammatory myopathy (IIM). However, these infiltrates are not always present. OBJECTIVE: To determine whether MHC class I antigen expression on

  10. IRF-4-mediated CIITA transcription is blocked by KSHV encoded LANA to inhibit MHC II presentation.

    Directory of Open Access Journals (Sweden)

    Qiliang Cai

    2013-10-01

    Full Text Available Peptides presentation to T cells by MHC class II molecules is of importance in initiation of immune response to a pathogen. The level of MHC II expression directly influences T lymphocyte activation and is often targeted by various viruses. Kaposi's sarcoma-associated herpesvirus (KSHV encoded LANA is known to evade MHC class I peptide processing, however, the effect of LANA on MHC class II remains unclear. Here, we report that LANA down-regulates MHC II expression and presentation by inhibiting the transcription of MHC II transactivator (CIITA promoter pIII and pIV in a dose-dependent manner. Strikingly, although LANA knockdown efficiently disrupts the inhibition of CIITA transcripts from its pIII and pIV promoter region, the expression of HLA-DQβ but no other MHC II molecules was significantly restored. Moreover, we revealed that the presentation of HLA-DQβ enhanced by LANA knockdown did not help LANA-specific CD4+ T cell recognition of PEL cells, and the inhibition of CIITA by LANA is independent of IL-4 or IFN-γ signaling but dependent on the direct interaction of LANA with IRF-4 (an activator of both the pIII and pIV CIITA promoters. This interaction dramatically blocked the DNA-binding ability of IRF-4 on both pIII and pIV promoters. Thus, our data implies that LANA can evade MHC II presentation and suppress CIITA transcription to provide a unique strategy of KSHV escape from immune surveillance by cytotoxic T cells.

  11. Drosophila homologues of adenomatous polyposis coli (APC) and the formin diaphanous collaborate by a conserved mechanism to stimulate actin filament assembly.

    Science.gov (United States)

    Jaiswal, Richa; Stepanik, Vince; Rankova, Aneliya; Molinar, Olivia; Goode, Bruce L; McCartney, Brooke M

    2013-05-10

    Vertebrate APC collaborates with Dia through its Basic domain to assemble actin filaments. Despite limited sequence homology between the vertebrate and Drosophila APC Basic domains, Drosophila APC1 collaborates with Dia to stimulate actin assembly in vitro. The mechanism of actin assembly is highly conserved over evolution. APC-Dia collaborations may be crucial in a wide range of animal cells. Adenomatous polyposis coli (APC) is a large multidomain protein that regulates the cytoskeleton. Recently, it was shown that vertebrate APC through its Basic domain directly collaborates with the formin mDia1 to stimulate actin filament assembly in the presence of nucleation barriers. However, it has been unclear whether these activities extend to homologues of APC and Dia in other organisms. Drosophila APC and Dia are each required to promote actin furrow formation in the syncytial embryo, suggesting a potential collaboration in actin assembly, but low sequence homology between the Basic domains of Drosophila and vertebrate APC has left their functional and mechanistic parallels uncertain. To address this question, we purified Drosophila APC1 and Dia and determined their individual and combined effects on actin assembly using both bulk fluorescence assays and total internal reflection fluorescence microscopy. Our data show that APC1, similar to its vertebrate homologue, bound to actin monomers and nucleated and bundled filaments. Further, Drosophila Dia nucleated actin assembly and protected growing filament barbed ends from capping protein. Drosophila APC1 and Dia directly interacted and collaborated to promote actin assembly in the combined presence of profilin and capping protein. Thus, despite limited sequence homology, Drosophila and vertebrate APCs exhibit highly related activities and mechanisms and directly collaborate with formins. These results suggest that APC-Dia interactions in actin assembly are conserved and may underlie important in vivo functions in a broad

  12. Identification of the cognate peptide-MHC target of T cell receptors using molecular modeling and force field scoring

    DEFF Research Database (Denmark)

    Lanzarotti, Esteban; Marcatili, Paolo; Nielsen, Morten

    2018-01-01

    Interactions of T cell receptors (TCR) to peptides in complex with MHC (p:MHC) are key features that mediate cellular immune responses. While MHC binding is required for a peptide to be presented to T cells, not all MHC binders are immunogenic. The interaction of a TCR to the p:MHC complex holds...... terms. Building a benchmark of TCR:p:MHC complexes where epitopes and non-epitopes are modelled using state-of-the-art molecular modelling tools, scoring p:MHC to a given TCR using force-fields, optimized in a cross-validation setup to evaluate TCR inter atomic interactions involved with each p:MHC, we...... and model the TCR:p:MHC complex structure. In summary, we conclude that it is possible to identify the TCR cognate target among different candidate peptides by using a force-field based model, and believe this works could lay the foundation for future work within prediction of TCR:p:MHC interactions....

  13. MHC and non-MHC genes regulate elimination of lymphocytic choriomeningitis virus and antiviral cytotoxic T lymphocyte and delayed-type hypersensitivity mediating T lymphocyte activity in parallel

    DEFF Research Database (Denmark)

    Thomsen, Allan Randrup; Marker, O

    1989-01-01

    with regard to all three parameters was recessive, indicating that natural tolerance is not the mechanism explaining non-MHC dependent low responsiveness in this system. The implications of these findings are discussed with specific reference to the role of MHC genes in controlling resistance to infectious......, indicating that both H-2 and non-H-2 genes may influence the elimination of this virus. Differences in virus spread prior to appearance of the immune response could not explain the observed differences in clearance rate. On the other hand, inefficient clearance always correlated with low T cell...

  14. Characterization of MHC class I in a long distance migratory wader, the Icelandic black-tailed godwit.

    Science.gov (United States)

    Pardal, Sara; Drews, Anna; Alves, José A; Ramos, Jaime A; Westerdahl, Helena

    2017-07-01

    The major histocompatibility complex (MHC) encodes proteins that are central for antigen presentation and pathogen elimination. MHC class I (MHC-I) genes have attracted a great deal of interest among researchers in ecology and evolution and have been partly characterized in a wide range of bird species. So far, the main focus has been on species within the bird orders Galliformes and Passeriformes, while Charadriiformes remain vastly underrepresented with only two species studied to date. These two Charadriiformes species exhibit striking differences in MHC-I characteristics and MHC-I diversity. We therefore set out to study a third species within Charadriiformes, the Icelandic subspecies of black-tailed godwits (Limosa limosa islandica). This subspecies is normally confined to parasite-poor environments, and we hence expected low MHC diversity. MHC-I was partially characterized first using Sanger sequencing and then using high-throughput sequencing (MiSeq) in 84 individuals. We verified 47 nucleotide alleles in open reading frame with classical MHC-I characteristics, and each individual godwit had two to seven putatively classical MHC alleles. However, in contrast to previous MHC-I data within Charadriiformes, we did not find any evidence of alleles with low sequence diversity, believed to represent non-classical MHC genes. The diversity and divergence of the godwits MHC-I genes to a large extent fell between the previous estimates within Charadriiformes. However, the MHC genes of the migratory godwits had few sites subject to positive selection, and one possible explanation could be a low exposure to pathogens.

  15. Characterization of MHC class I and II genes in a subantarctic seabird, the blue petrel, Halobaena caerulea (Procellariiformes).

    Science.gov (United States)

    Strandh, Maria; Lannefors, Mimi; Bonadonna, Francesco; Westerdahl, Helena

    2011-10-01

    The great polymorphism observed in the major histocompatibility complex (MHC) genes is thought to be maintained by pathogen-mediated selection possibly combined with MHC-disassortative mating, guided by MHC-determined olfactory cues. Here, we partly characterize the MHC class I and II B of the blue petrel, Halobaena caerulea (Procellariiformes), a bird with significant olfactory abilities that lives under presumably low pathogen burdens in Subantarctica. Blue petrels are long-lived, monogamous birds which suggest the necessity of an accurate mate choice process. The species is ancestral to songbirds (Passeriformes; many MHC loci), although not to gamefowls (Galliformes; few MHC loci). Considering the phylogenetic relationships and the low subantarctic pathogen burden, we expected few rather than many MHC loci in the blue petrel. However, when we analysed partial MHC class I and class II B cDNA and gDNA sequences we found evidence for as many as at least eight MHC class I loci and at least two class II B loci. These class I and II B sequences showed classical MHC characteristics, e.g. high nucleotide diversity, especially in putative peptide-binding regions where signatures of positive selection was detected. Trans-species polymorphism was found between MHC class II B sequences of the blue petrel and those of thin-billed prion, Pachyptila belcheri, two species that diverged ∼25 MYA. The observed MHC allele richness in the blue petrel may well serve as a basis for mate choice, especially since olfactory discrimination of MHC types may be possible in this species.

  16. Statistical deconvolution of enthalpic energetic contributions to MHC-peptide binding affinity

    Directory of Open Access Journals (Sweden)

    Drew Michael GB

    2006-03-01

    Full Text Available Abstract Background MHC Class I molecules present antigenic peptides to cytotoxic T cells, which forms an integral part of the adaptive immune response. Peptides are bound within a groove formed by the MHC heavy chain. Previous approaches to MHC Class I-peptide binding prediction have largely concentrated on the peptide anchor residues located at the P2 and C-terminus positions. Results A large dataset comprising MHC-peptide structural complexes was created by re-modelling pre-determined x-ray crystallographic structures. Static energetic analysis, following energy minimisation, was performed on the dataset in order to characterise interactions between bound peptides and the MHC Class I molecule, partitioning the interactions within the groove into van der Waals, electrostatic and total non-bonded energy contributions. Conclusion The QSAR techniques of Genetic Function Approximation (GFA and Genetic Partial Least Squares (G/PLS algorithms were used to identify key interactions between the two molecules by comparing the calculated energy values with experimentally-determined BL50 data. Although the peptide termini binding interactions help ensure the stability of the MHC Class I-peptide complex, the central region of the peptide is also important in defining the specificity of the interaction. As thermodynamic studies indicate that peptide association and dissociation may be driven entropically, it may be necessary to incorporate entropic contributions into future calculations.

  17. Variation in MHC genotypes in two populations of house sparrow (Passer domesticus) with different population histories.

    Science.gov (United States)

    Borg, Asa Alexandra; Pedersen, Sindre Andre; Jensen, Henrik; Westerdahl, Helena

    2011-10-01

    Small populations are likely to have a low genetic ability for disease resistance due to loss of genetic variation through inbreeding and genetic drift. In vertebrates, the highest genetic diversity of the immune system is located at genes within the major histocompatibility complex (MHC). Interestingly, parasite-mediated selection is thought to potentially maintain variation at MHC loci even in populations that are monomorphic at other loci. Therefore, general loss of genetic variation in the genome may not necessarily be associated with low variation at MHC loci. We evaluated inter- and intrapopulation variation in MHC genotypes between an inbred (Aldra) and a relatively outbred population (Hestmannøy) of house sparrows (Passer domesticus) in a metapopulation at Helgeland, Norway. Genomic (gDNA) and transcribed (cDNA) alleles of functional MHC class I and IIB loci, along with neutral noncoding microsatellite markers, were analyzed to obtain relevant estimates of genetic variation. We found lower allelic richness in microsatellites in the inbred population, but high genetic variation in MHC class I and IIB loci in both populations. This suggests that also the inbred population could be under balancing selection to maintain genetic variation for pathogen resistance.

  18. An MHC class I immune evasion gene of Marek׳s disease virus.

    Science.gov (United States)

    Hearn, Cari; Preeyanon, Likit; Hunt, Henry D; York, Ian A

    2015-01-15

    Marek׳s disease virus (MDV) is a widespread α-herpesvirus of chickens that causes T cell tumors. Acute, but not latent, MDV infection has previously been shown to lead to downregulation of cell-surface MHC class I (Virology 282:198-205 (2001)), but the gene(s) involved have not been identified. Here we demonstrate that an MDV gene, MDV012, is capable of reducing surface expression of MHC class I on chicken cells. Co-expression of an MHC class I-binding peptide targeted to the endoplasmic reticulum (bypassing the requirement for the TAP peptide transporter) partially rescued MHC class I expression in the presence of MDV012, suggesting that MDV012 is a TAP-blocking MHC class I immune evasion protein. This is the first unique non-mammalian MHC class I immune evasion gene identified, and suggests that α-herpesviruses have conserved this function for at least 100 million years. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. No evidence for the effect of MHC on male mating success in the brown bear.

    Science.gov (United States)

    Kuduk, Katarzyna; Babik, Wieslaw; Bellemain, Eva; Valentini, Alice; Zedrosser, Andreas; Taberlet, Pierre; Kindberg, Jonas; Swenson, Jon E; Radwan, Jacek

    2014-01-01

    Mate choice is thought to contribute to the maintenance of the spectacularly high polymorphism of the Major Histocompatibility Complex (MHC) genes, along with balancing selection from parasites, but the relative contribution of the former mechanism is debated. Here, we investigated the association between male MHC genotype and mating success in the brown bear. We analysed fragments of sequences coding for the peptide-binding region of the highly polymorphic MHC class I and class II DRB genes, while controlling for genome-wide effects using a panel of 18 microsatellite markers. Male mating success did not depend on the number of alleles shared with the female or amino-acid distance between potential mates at either locus. Furthermore, we found no indication of female mating preferences for MHC similarity being contingent on the number of alleles the females carried. Finally, we found no significant association between the number of MHC alleles a male carried and his mating success. Thus, our results provided no support for the role of mate choice in shaping MHC polymorphism in the brown bear.

  20. Termination of T cell priming relies on a phase of unresponsiveness promoting disengagement from APCs and T cell division.

    Science.gov (United States)

    Bohineust, Armelle; Garcia, Zacarias; Beuneu, Hélène; Lemaître, Fabrice; Bousso, Philippe

    2018-05-07

    T cells are primed in secondary lymphoid organs by establishing stable interactions with antigen-presenting cells (APCs). However, the cellular mechanisms underlying the termination of T cell priming and the initiation of clonal expansion remain largely unknown. Using intravital imaging, we observed that T cells typically divide without being associated to APCs. Supporting these findings, we demonstrate that recently activated T cells have an intrinsic defect in establishing stable contacts with APCs, a feature that was reflected by a blunted capacity to stop upon T cell receptor (TCR) engagement. T cell unresponsiveness was caused, in part, by a general block in extracellular calcium entry. Forcing TCR signals in activated T cells antagonized cell division, suggesting that T cell hyporesponsiveness acts as a safeguard mechanism against signals detrimental to mitosis. We propose that transient unresponsiveness represents an essential phase of T cell priming that promotes T cell disengagement from APCs and favors effective clonal expansion. © 2018 Bohineust et al.

  1. Cell cycle- and cell growth-regulated proteolysis of mammalian CDC6 is dependent on APC-CDH1

    DEFF Research Database (Denmark)

    Petersen, B O; Wagener, C; Marinoni, F

    2000-01-01

    is targeted for ubiquitin-mediated proteolysis by the anaphase promoting complex (APC)/cyclosome in G(1). A combination of point mutations in the destruction box and KEN-box motifs in CDC6 stabilizes the protein in G(1) and in quiescent cells. Furthermore, APC, in association with CDH1, ubiquitinates CDC6...... in vitro, and both APC and CDH1 are required and limiting for CDC6 proteolysis in vivo. Although a stable mutant of CDC6 is biologically active, overexpression of this mutant or wild-type CDC6 is not sufficient to induce multiple rounds of DNA replication in the same cell cycle. The APC-CDH1-dependent...

  2. Role of APC and DNA mismatch repair genes in the development of colorectal cancers

    Directory of Open Access Journals (Sweden)

    Roy Deodutta

    2003-12-01

    Full Text Available Abstract Colorectal cancer is the third most common cause of cancer-related death in both men and women in the western hemisphere. According to the American Cancer Society, an estimated 105,500 new cases of colon cancer with 57,100 deaths will occur in the U.S. in 2003, accounting for about 10% of cancer deaths. Among the colon cancer patients, hereditary risk contributes approximately 20%. The main inherited colorectal cancers are the familial adenomatous polyposis (FAP and the hereditary nonpolyposis colorectal cancers (HNPCC. The FAP and HNPCC are caused due to mutations in the adenomatous polyposis coli (APC and DNA mismatch repair (MMR genes. The focus of this review is to summarize the functions of APC and MMR gene products in the development of colorectal cancers.

  3. IFN-beta inhibits T cell activation capacity of central nervous system APCs

    DEFF Research Database (Denmark)

    Teige, Ingrid; Liu, Yawei; Issazadeh-Navikas, Shohreh

    2006-01-01

    We have previously investigated the physiological effects of IFN-beta on chronic CNS inflammation and shown that IFN-beta(-/-) mice develop a more severe experimental autoimmune encephalomyelitis than their IFN-beta(+/-) littermates. This result was shown to be associated with a higher activation...... state of the glial cells and a higher T cell cytokine production in the CNS. Because this state suggested a down-regulatory effect of IFN-beta on CNS-specific APCs, these results were investigated further. We report that IFN-beta pretreatment of astrocytes and microglia (glial cells) indeed down......-modulate their capacity to activate autoreactive Th1 cells. First, we investigated the intrinsic ability of glial cells as APCs and report that glial cells prevent autoreactive Th1 cells expansion while maintaining Ag-specific T cell effector functions. However, when the glial cells are treated with IFN-beta before...

  4. Differential regulation of microtubule severing by APC underlies distinct patterns of projection neuron and interneuron migration

    Science.gov (United States)

    Eom, Tae-Yeon; Stanco, Amelia; Guo, Jiami; Wilkins, Gary; Deslauriers, Danielle; Yan, Jessica; Monckton, Chase; Blair, Josh; Oon, Eesim; Perez, Abby; Salas, Eduardo; Oh, Adrianna; Ghukasyan, Vladimir; Snider, William D.; Rubenstein, John L. R.; Anton, E. S.

    2014-01-01

    Coordinated migration of distinct classes of neurons to appropriate positions leads to the formation of functional neuronal circuitry in the cerebral cortex. Two major classes of cortical neurons, interneurons and projection neurons, utilize distinctly different modes (radial vs. tangential) and routes of migration to arrive at their final positions in the cerebral cortex. Here, we show that adenomatous polyposis coli (APC) modulates microtubule (MT) severing in interneurons to facilitate tangential mode of interneuron migration, but not the glial-guided, radial migration of projection neurons. APC regulates the stability and activity of the MT severing protein p60-katanin in interneurons to promote the rapid remodeling of neuronal processes necessary for interneuron migration. These findings reveal how severing and restructuring of MTs facilitate distinct modes of neuronal migration necessary for laminar organization of neurons in the developing cerebral cortex. PMID:25535916

  5. ABERRANT METHYLATION OF THE PROMOTER OF APC, CDH13 AND MGMT GENES IN COLORECTAL CANCER PATIENTS

    Directory of Open Access Journals (Sweden)

    O. I. Kit

    2016-01-01

    Full Text Available Aberrant methylation of gene promoter regions is the main epigenetic change characterizing colorectal cancer. Methylation levels of 42 CpG-sites of promoter regions of the MGMT, APC and CDH13 genes in colorectal cancer were studied in comparison with methylation levels of the adjacent normal tissue in 25 patients. Pyrosequencing showed an increase in methylation levels of promoter regions of the MGMT, APC and CDH13 genes in tumor samples by 3 to 5 times. These tumor samples were screened for activating SNP-mutations in the KRAS (40 %, NRAS (0 % and BRAF (0 % oncogenes. SNP-mutations in the KRAS gene were accompanied by hypermethylation of one or more promoters of the studied genes. Association of this epigenetic index with tumor metastasis was proved. The data on an increase in methylation of the promoter regions of oncosupressor genes can be used as sensitive prognostic markers of progression and metastasis of colorectal cancer.

  6. Chlorinated Water Modulates the Development of Colorectal Tumors with Chromosomal Instability and Gut Microbiota in Apc-Deficient Mice.

    Science.gov (United States)

    Sasada, Tatsunari; Hinoi, Takao; Saito, Yasufumi; Adachi, Tomohiro; Takakura, Yuji; Kawaguchi, Yasuo; Sotomaru, Yusuke; Sentani, Kazuhiro; Oue, Naohide; Yasui, Wataru; Ohdan, Hideki

    2015-01-01

    The gastrointestinal tract is continuously exposed to a variety of chemicals and commensal bacteria. Recent studies have shown that changes in gut microbial populations caused by chlorine or other chemicals in the drinking water influence the development of human colorectal cancer, although the mechanism of tumorigenesis in the gut epithelium is obfuscated by the diversity of microflora and complexity of the tumor microenvironment. In this regard, mouse models that recapitulate human colorectal cancer are an invaluable tool. In this study, we used two conditional adenomatous polyposis coli (Apc) knockout mouse models to investigate the effect of chlorinated water on tumorigenesis in the digestive tract. Mice with colon-specific carcinoma--caused by either chromosomal (CDX2P 9.5-NLS Cre;Apc(+/flox), abbreviated to CPC;Apc) or microsatellite (CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox)) instability, respectively--were administered chlorinated (10.0 mg/L chlorine) or tap (0.7 mg/L chlorine) water and evaluated for colon polyp formation. In CPC;Apc mice given chlorinated drinking water, tumors tended to develop in the colon, whereas in those that drank tap water, tumors were mostly observed in the small intestine. There was no difference in the rate of tumor formation of CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox) mice consuming chlorinated as compared to tap water, suggesting that microsatellite instability in the Apc gene does not significantly affect tumorigenesis. Chlorinated water altered the enteric environment by reducing the fecal populations of the obligatory anaerobes Clostridium perfringens and C. difficile, as well as species belonging to the Atopobium cluster, including Enterobacteriaceae and Staphylococcus sp., which was associated with colon tumorigenesis in CPC;Apc mice. These results suggest that differences in tumorigenesis among CPC;Apc mice consuming chlorinated versus tap water may be due to differences

  7. APC/C-mediated degradation of dsRNA-binding protein 4 (DRB4 involved in RNA silencing.

    Directory of Open Access Journals (Sweden)

    Katia Marrocco

    Full Text Available Selective protein degradation via the ubiquitin-26S proteasome is a major mechanism underlying DNA replication and cell division in all Eukaryotes. In particular, the APC/C (Anaphase Promoting Complex or Cyclosome is a master ubiquitin protein ligase (E3 that targets regulatory proteins for degradation allowing sister chromatid separation and exit from mitosis. Interestingly, recent work also indicates that the APC/C remains active in differentiated animal and plant cells. However, its role in post-mitotic cells remains elusive and only a few substrates have been characterized.In order to identify novel APC/C substrates, we performed a yeast two-hybrid screen using as the bait Arabidopsis APC10/DOC1, one core subunit of the APC/C, which is required for substrate recruitment. This screen identified DRB4, a double-stranded RNA binding protein involved in the biogenesis of different classes of small RNA (sRNA. This protein interaction was further confirmed in vitro and in plant cells. Moreover, APC10 interacts with DRB4 through the second dsRNA binding motif (dsRBD2 of DRB4, which is also required for its homodimerization and binding to its Dicer partner DCL4. We further showed that DRB4 protein accumulates when the proteasome is inactivated and, most importantly, we found that DRB4 stability depends on APC/C activity. Hence, depletion of Arabidopsis APC/C activity by RNAi leads to a strong accumulation of endogenous DRB4, far beyond its normal level of accumulation. However, we could not detect any defects in sRNA production in lines where DRB4 was overexpressed.Our work identified a first plant substrate of the APC/C, which is not a regulator of the cell cycle. Though we cannot exclude that APC/C-dependent degradation of DRB4 has some regulatory roles under specific growth conditions, our work rather points to a housekeeping function of APC/C in maintaining precise cellular-protein concentrations and homeostasis of DRB4.

  8. The PP2AB56 phosphatase promotes the association of Cdc20 with APC/C in mitosis.

    Science.gov (United States)

    Lee, Sun Joo; Rodriguez-Bravo, Veronica; Kim, Hyunjung; Datta, Sutirtha; Foley, Emily A

    2017-05-15

    PP2A comprising B56 regulatory subunit isoforms (PP2A B56 ) is a serine/threonine phosphatase essential for mitosis. At the kinetochore, PP2A B56 both stabilizes microtubule binding and promotes silencing of the spindle assembly checkpoint (SAC) through its association with the SAC protein BubR1. Cells depleted of the B56 regulatory subunits of PP2A are delayed in activation of Cdc20-containing APC/C (APC/C Cdc20 ), which is an essential step for mitotic exit. It has been hypothesized that this delay arises from increased production of the mitotic checkpoint complex (MCC), an APC/C Cdc20 inhibitor formed at unattached kinetochores through SAC signaling. In contrast to this prediction, we show that depletion of B56 subunits does not increase the amount or stability of the MCC. Rather, delays in APC/C Cdc20 activation in B56-depleted cells correlate with impaired Cdc20 binding to APC/C. Stimulation of APC/C Cdc20 assembly does not require binding between PP2A B56 and BubR1, and thus this contribution of PP2A B56 towards mitotic exit is distinct from its functions at kinetochores. PP2A B56 associates with APC/C constitutively in a BubR1-independent manner. A mitotic phosphorylation site on Cdc20, known to be a substrate of PP2A B56 , modulates APC/C Cdc20 assembly. These results elucidate the contributions of PP2A B56 towards completion of mitosis. © 2017. Published by The Company of Biologists Ltd.

  9. Transforming activity and therapeutic targeting of C-terminal-binding protein 2 in Apc-mutated neoplasia.

    Science.gov (United States)

    Sumner, E T; Chawla, A T; Cororaton, A D; Koblinski, J E; Kovi, R C; Love, I M; Szomju, B B; Korwar, S; Ellis, K C; Grossman, S R

    2017-08-17

    Overexpression of the transcriptional coregulators C-terminal binding proteins 1 and 2 (CtBP1 and 2) occurs in many human solid tumors and is associated with poor prognosis. CtBP modulates oncogenic gene expression programs and is an emerging drug target, but its oncogenic role is unclear. Consistent with this oncogenic potential, exogenous CtBP2 transformed primary mouse and human cells to anchorage independence similarly to mutant H-Ras. To investigate CtBP's contribution to in vivo tumorigenesis, Apc min/+ mice, which succumb to massive intestinal polyposis, were bred to Ctbp2 +/- mice. CtBP interacts with adenomatous polyposis coli (APC) protein, and is stabilized in both APC-mutated human colon cancers and Apc min/+ intestinal polyps. Ctbp2 heterozygosity increased the median survival of Apc min/+ mice from 21 to 48 weeks, and reduced polyp formation by 90%, with Ctbp2 +/- polyps exhibiting reduced levels of β-catenin and its oncogenic transcriptional target, cyclin D1. CtBP's potential as a therapeutic target was studied by treating Apc min/+ mice with the CtBP small-molecule inhibitors 4-methylthio-2-oxobutyric acid and 2-hydroxy-imino phenylpyruvic acid, both of which reduced polyposis by more than half compared with vehicle treatment. Phenocopying Ctbp2 deletion, both Ctbp inhibitors caused substantial decreases in the protein level of Ctbp2, as well its oncogenic partner β-catenin, and the effects of the inhibitors on CtBP and β-catenin levels could be modeled in an APC-mutated human colon cancer cell line. CtBP2 is thus a druggable transforming oncoprotein critical for the evolution of neoplasia driven by Apc mutation.

  10. Low-level APC mutational mosaicism is the underlying cause in a substantial fraction of unexplained colorectal adenomatous polyposis cases.

    Science.gov (United States)

    Spier, Isabel; Drichel, Dmitriy; Kerick, Martin; Kirfel, Jutta; Horpaopan, Sukanya; Laner, Andreas; Holzapfel, Stefanie; Peters, Sophia; Adam, Ronja; Zhao, Bixiao; Becker, Tim; Lifton, Richard P; Perner, Sven; Hoffmann, Per; Kristiansen, Glen; Timmermann, Bernd; Nöthen, Markus M; Holinski-Feder, Elke; Schweiger, Michal R; Aretz, Stefan

    2016-03-01

    In 30-50% of patients with colorectal adenomatous polyposis, no germline mutation in the known genes APC, causing familial adenomatous polyposis, MUTYH, causing MUTYH-associated polyposis, or POLE or POLD1, causing polymerase-proofreading-associated polyposis can be identified, although a hereditary aetiology is likely. This study aimed to explore the impact of APC mutational mosaicism in unexplained polyposis. To comprehensively screen for somatic low-level APC mosaicism, high-coverage next-generation sequencing of the APC gene was performed using DNA from leucocytes and a total of 53 colorectal tumours from 20 unrelated patients with unexplained sporadic adenomatous polyposis. APC mosaicism was assumed if the same loss-of-function APC mutation was present in ≥ 2 anatomically separated colorectal adenomas/carcinomas per patient. All mutations were validated using diverse methods. In 25% (5/20) of patients, somatic mosaicism of a pathogenic APC mutation was identified as underlying cause of the disease. In 2/5 cases, the mosaic level in leucocyte DNA was slightly below the sensitivity threshold of Sanger sequencing; while in 3/5 cases, the allelic fraction was either very low (0.1-1%) or no mutations were detectable. The majority of mosaic mutations were located outside the somatic mutation cluster region of the gene. The present data indicate a high prevalence of pathogenic mosaic APC mutations below the detection thresholds of routine diagnostics in adenomatous polyposis, even if high-coverage sequencing of leucocyte DNA alone is taken into account. This has important implications for both routine work-up and strategies to identify new causative genes in this patient group. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  11. Multi-scale modeling of APC and [Formula: see text]-catenin regulation in the human colonic crypt.

    Science.gov (United States)

    Emerick, Brooks; Schleiniger, Gilberto; Boman, Bruce M

    2018-06-01

    Stem cell renewal and differentiation in the human colonic crypt are linked to the [Formula: see text]-catenin pathway. The spatial balance of Wnt factors in proliferative cells within the crypt maintain an appropriate level of cellular reproduction needed for normal crypt homeostasis. Mutational events at the gene level are responsible for deregulating the balance of Wnt factors along the crypt, causing an overpopulation of proliferative cells, a loss of structure of the crypt domain, and the initiation of colorectal carcinomas. We formulate a PDE model describing cell movement and reproduction in a static crypt domain. We consider a single cell population whose proliferative capabilities are determined by stemness, a quantity defined by intracellular levels of adenomatous polyposis coli (APC) scaffold protein and [Formula: see text]-catenin. We fit APC regulation parameters to biological data that describe normal protein gradients in the crypt. We also fit cell movement and protein flux parameters to normal crypt characteristics such as renewal time, total cell count, and proportion of proliferating cells. The model is used to investigate abnormal crypt dynamics when subjected to a diminished APC gradient, a scenario synonymous to mutations in the APC gene. We find that a 25% decrease in APC synthesis leads to a fraction of 0.88 proliferative, which is reflective of normal-appearing FAP crypts. A 50% drop in APC activity yields a fully proliferative crypt showing a doubling of the level of stemness, which characterizes the initial stages of colorectal cancer development. A sensitivity analysis of APC regulation parameters shows the perturbation of factors that is required to restore crypt dynamics to normal in the case of APC mutations.

  12. Association of APC I1307K and E1317Q polymorphisms with colorectal cancer among Egyptian subjects.

    Science.gov (United States)

    Abdel-Malak, Camelia; Darwish, Hossam; Elsaid, Afaf; El-Tarapely, Fatma; Elshazli, Rami

    2016-01-01

    Colorectal cancer is a multifactorial disease that involves both environmental and genetic factors. The gene encoding adenomatous polyposis coli (APC) has been reported to be associated with colorectal cancer (CRC) risk in several ethnic populations. The aim of this work is to assess the association of the APC I1307K and E1317Q polymorphisms with CRC risk among Egyptian subjects. This study included 120 unrelated CRC Egyptian patients who were compared to 100 healthy controls from the same locality. For all subjects, DNA was genotyped for APC I1307K and E1317Q polymorphisms using the PCR-ARMS technique. The frequency of APC I1307K carrier (TA+AA genotypes) was noted to be significantly higher among cases with CRC compared to controls (18.3 vs. 9.0 %, OR 2.58, 95 % CI 1.09-6.09, p = 0.03). Also the frequency of the APC I1307K A allele was significantly higher among cases compared to controls (10.4 vs. 4.5 %, OR 2.47; 95 % CI 1.12-5.42, p = 0.03). On the contrast, the frequencies of APC E1317Q GC genotype and C allele showed no significant difference among CRC patients compared to controls (3.3 vs. 2.0 %, OR 1.69; 95 % CI 0.30-9.42, p = 0.69 and 2.1 vs. 1.0 %, OR 2.11; 95 % CI 0.40-10.97, p = 0.46, respectively). Cases of the APC I1307K and E1317Q carriers (TA+AA and GC) showed no significant difference compared to those with I1307K and E1317Q non-carriers (TT and GG) regarding their clinical and laboratory markers. APC I1307K variant was associated with an increased risk of CRC among Egyptian subjects.

  13. Complete Genome Sequence of the Gamma-Aminobutyric Acid-Producing Strain Streptococcus thermophilus APC151.

    Science.gov (United States)

    Linares, Daniel M; Arboleya, Silvia; Ross, R Paul; Stanton, Catherine

    2017-04-27

    Here is presented the whole-genome sequence of Streptococcus thermophilus APC151, isolated from a marine fish. This bacterium produces gamma-aminobutyric acid (GABA) in high yields and is biotechnologically suitable to produce naturally GABA-enriched biofunctional yogurt. Its complete genome comprises 2,097 genes and 1,839,134 nucleotides, with an average G+C content of 39.1%. Copyright © 2017 Linares et al.

  14. PLK1 regulates spindle formation kinetics and APC/C activation in mouse zygote

    Czech Academy of Sciences Publication Activity Database

    Baran, V.; Brzáková, Adéla; Rehák, P.; Kovaříková, V.; Šolc, Petr

    2016-01-01

    Roč. 24, č. 3 (2016), s. 338-345 ISSN 0967-1994 R&D Projects: GA MŠk ED2.1.00/03.0124; GA MŠk LH12057 Institutional support: RVO:67985904 Keywords : APC/C * BI2536 * live cell imaging * mouse zygote * PLK1 * securin * spindle assembly Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.053, year: 2016

  15. INTERVIEW: Quick, Social and Collaborative - wiki-based user documentation at APC by Schneider Electric

    DEFF Research Database (Denmark)

    Møller, Margrethe H.; Pernille Bagger Nielsen, Pernille; Kalianov, Stanislav

    2013-01-01

    In the software documentation department at APC by Schneider Electric in Kolding, Denmark, Technical Writer Pernille Bagger Nielsen writes user documentation for the software developed by the company. In cooperation with Localization Manager Stanislav Kalianov she reorganised the user documentation...... for publication as wiki-based documentation on the internet. The new platform supports their strategy of using agile and iterative, topic-based, collaborative writing when developing user documentation. Their experience will interest readers who consider introducing a similar new strategy....

  16. Antihelminth compound niclosamide downregulates Wnt signaling and elicits antitumor responses in tumors with activating APC mutations.

    Science.gov (United States)

    Osada, Takuya; Chen, Minyong; Yang, Xiao Yi; Spasojevic, Ivan; Vandeusen, Jeffrey B; Hsu, David; Clary, Bryan M; Clay, Timothy M; Chen, Wei; Morse, Michael A; Lyerly, H Kim

    2011-06-15

    Wnt/β-catenin pathway activation caused by adenomatous polyposis coli (APC) mutations occurs in approximately 80% of sporadic colorectal cancers (CRC). The antihelminth compound niclosamide downregulates components of the Wnt pathway, specifically Dishevelled-2 (Dvl2) expression, resulting in diminished downstream β-catenin signaling. In this study, we determined whether niclosamide could inhibit the Wnt/β-catenin pathway in human CRCs and whether its inhibition might elicit antitumor effects in the presence of APC mutations. We found that niclosamide inhibited Wnt/β-catenin pathway activation, downregulated Dvl2, decreased downstream β-catenin signaling, and exerted antiproliferative effects in human colon cancer cell lines and CRC cells isolated by surgical resection of metastatic disease, regardless of mutations in APC. In contrast, inhibition of NF-κB or mTOR did not exert similar antiproliferative effects in these CRC model systems. In mice implanted with human CRC xenografts, orally administered niclosamide was well tolerated, achieved plasma and tumor levels associated with biologic activity, and led to tumor control. Our findings support clinical explorations to reposition niclosamide for the treatment of CRC.

  17. Cdh1-APC/C, cyclin B-Cdc2, and Alzheimer's disease pathology

    International Nuclear Information System (INIS)

    Aulia, Selina; Tang, Bor Luen

    2006-01-01

    The anaphase-promoting complex/cyclosome (APC/C) is a key E3 ubiquitin ligase complex that functions in regulating cell cycle transitions in proliferating cells and has, as revealed recently, novel roles in postmitotic neurons. Regulated by its activator Cdh1 (or Hct1), whose level is high in postmitotic neurons, APC/C seems to have multiple functions at different cellular locations, modulating diverse processes such as synaptic development and axonal growth. These processes do not, however, appear to be directly connected to cell cycle regulation. It is now shown that Cdh1-APC/C activity may also have a basic role in suppressing cyclin B levels, thus preventing terminally differentiated neurons from aberrantly re-entering the cell cycle. The result of an aberrant cyclin B-induced S-phase entry, at least for some of these neurons, would be death via apoptosis. Cdh1 thus play an active role in maintaining the terminally differentiated, non-cycling state of postmitotic neurons-a function that could become impaired in Alzheimer's and other neurodegenerative diseases

  18. Dual RING E3 Architectures Regulate Multiubiquitination and Ubiquitin Chain Elongation by APC/C.

    Science.gov (United States)

    Brown, Nicholas G; VanderLinden, Ryan; Watson, Edmond R; Weissmann, Florian; Ordureau, Alban; Wu, Kuen-Phon; Zhang, Wei; Yu, Shanshan; Mercredi, Peter Y; Harrison, Joseph S; Davidson, Iain F; Qiao, Renping; Lu, Ying; Dube, Prakash; Brunner, Michael R; Grace, Christy R R; Miller, Darcie J; Haselbach, David; Jarvis, Marc A; Yamaguchi, Masaya; Yanishevski, David; Petzold, Georg; Sidhu, Sachdev S; Kuhlman, Brian; Kirschner, Marc W; Harper, J Wade; Peters, Jan-Michael; Stark, Holger; Schulman, Brenda A

    2016-06-02

    Protein ubiquitination involves E1, E2, and E3 trienzyme cascades. E2 and RING E3 enzymes often collaborate to first prime a substrate with a single ubiquitin (UB) and then achieve different forms of polyubiquitination: multiubiquitination of several sites and elongation of linkage-specific UB chains. Here, cryo-EM and biochemistry show that the human E3 anaphase-promoting complex/cyclosome (APC/C) and its two partner E2s, UBE2C (aka UBCH10) and UBE2S, adopt specialized catalytic architectures for these two distinct forms of polyubiquitination. The APC/C RING constrains UBE2C proximal to a substrate and simultaneously binds a substrate-linked UB to drive processive multiubiquitination. Alternatively, during UB chain elongation, the RING does not bind UBE2S but rather lures an evolving substrate-linked UB to UBE2S positioned through a cullin interaction to generate a Lys11-linked chain. Our findings define mechanisms of APC/C regulation, and establish principles by which specialized E3-E2-substrate-UB architectures control different forms of polyubiquitination. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. A novel approach to assess the spontaneous gastrointestinal bleeding risk of antithrombotic agents using Apc(min/+) mice.

    Science.gov (United States)

    Wei, Huijun; Shang, Jin; Keohane, CarolAnn; Wang, Min; Li, Qiu; Ni, Weihua; O'Neill, Kim; Chintala, Madhu

    2014-06-01

    Assessment of the bleeding risk of antithrombotic agents is usually performed in healthy animals with some form of vascular injury to peripheral organs to induce bleeding. However, bleeding observed in patients with currently marketed antithrombotic drugs is typically spontaneous in nature such as intracranial haemorrhage (ICH) and gastrointestinal (GI) bleeding, which happens most frequently on top of preexisting pathologies such as GI ulcerations and polyps. Apc(min/+) mice are reported to develop multiple adenomas through the entire intestinal tract and display progressive anaemia.In this study, we evaluated the potential utility of Apc(min/+) mice as a model for assessing spontaneous GI bleeding with antithrombotic agents. Apc(min/+) mice exhibited progressive blood loss starting at the age of nine weeks. Despite the increase in bleeding, Apc(min/+) mice were in a hypercoagulable state and displayed an age-dependent increase in thrombin generation and circulating fibrinogen as well as a significant decrease in clotting times. We evaluated the effect of warfarin, dabigatran etexilate, apixaban and clopidogrel in this model by administering them in diet or in the drinking water to mice for 1-4 weeks. All of these marketed drugs significantly increased GI bleeding in Apc(min/+) mice, but not in wild-type mice. Although different exposure profiles of these antithrombotic agents make it challenging to compare the bleeding risk of compounds, our results indicate that the Apc(min/+) mouse may be a sensitive preclinical model for assessing the spontaneous GI bleeding risk of novel antithrombotic agents.

  20. Association between aberrant APC promoter methylation and breast cancer pathogenesis: a meta-analysis of 35 observational studies.

    Science.gov (United States)

    Zhou, Dan; Tang, Weiwei; Wang, Wenyi; Pan, Xiaoyan; An, Han-Xiang; Zhang, Yun

    2016-01-01

    Background. Adenomatous polyposis coli (APC) is widely known as an antagonist of the Wnt signaling pathway via the inactivation of β-catenin. An increasing number of studies have reported that APC methylation contributes to the predisposition to breast cancer (BC). However, recent studies have yielded conflicting results. Methods. Herein, we systematically carried out a meta-analysis to assess the correlation between APC methylation and BC risk. Based on searches of the Cochrane Library, PubMed, Web of Science and Embase databases, the odds ratio (OR) with 95% confidence interval (CI) values were pooled and summarized. Results. A total of 31 articles involving 35 observational studies with 2,483 cases and 1,218 controls met the inclusion criteria. The results demonstrated that the frequency of APC methylation was significantly higher in BC cases than controls under a random effect model (OR = 8.92, 95% CI [5.12-15.52]). Subgroup analysis further confirmed the reliable results, regardless of the sample types detected, methylation detection methods applied and different regions included. Interestingly, our results also showed that the frequency of APC methylation was significantly lower in early-stage BC patients than late-stage ones (OR = 0.62, 95% CI [0.42-0.93]). Conclusion. APC methylation might play an indispensable role in the pathogenesis of BC and could be regarded as a potential biomarker for the diagnosis of BC.

  1. The APC/C Coordinates Retinal Differentiation with G1 Arrest through the Nek2-Dependent Modulation of Wingless Signaling.

    Science.gov (United States)

    Martins, Torcato; Meghini, Francesco; Florio, Francesca; Kimata, Yuu

    2017-01-09

    The cell cycle is coordinated with differentiation during animal development. Here we report a cell-cycle-independent developmental role for a master cell-cycle regulator, the anaphase-promoting complex or cyclosome (APC/C), in the regulation of cell fate through modulation of Wingless (Wg) signaling. The APC/C controls both cell-cycle progression and postmitotic processes through ubiquitin-dependent proteolysis. Through an RNAi screen in the developing Drosophila eye, we found that partial APC/C inactivation severely inhibits retinal differentiation independently of cell-cycle defects. The differentiation inhibition coincides with hyperactivation of Wg signaling caused by the accumulation of a Wg modulator, Drosophila Nek2 (dNek2). The APC/C degrades dNek2 upon synchronous G1 arrest prior to differentiation, which allows retinal differentiation through local suppression of Wg signaling. We also provide evidence that decapentaplegic signaling may posttranslationally regulate this APC/C function. Thus, the APC/C coordinates cell-fate determination with the cell cycle through the modulation of developmental signaling pathways. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  2. Interphase APC/C-Cdc20 inhibition by cyclin A2-Cdk2 ensures efficient mitotic entry

    DEFF Research Database (Denmark)

    Hein, Jamin B; Nilsson, Jakob

    2016-01-01

    Proper cell-cycle progression requires tight temporal control of the Anaphase Promoting Complex/Cyclosome (APC/C), a large ubiquitin ligase that is activated by one of two co-activators, Cdh1 or Cdc20. APC/C and Cdc20 are already present during interphase but APC/C-Cdc20 regulation during...... this window of the cell cycle, if any, is unknown. Here we show that cyclin A2-Cdk2 binds and phosphorylates Cdc20 in interphase and this inhibits APC/C-Cdc20 activity. Preventing Cdc20 phosphorylation results in pre-mature activation of the APC/C-Cdc20 and several substrates, including cyclin B1 and A2......, are destabilized which lengthens G2 and slows mitotic entry. Expressing non-degradable cyclin A2 but not cyclin B1 restores mitotic entry in these cells. We have thus uncovered a novel positive feedback loop centred on cyclin A2-Cdk2 inhibition of interphase APC/C-Cdc20 to allow further cyclin A2 accumulation...

  3. APC and Smad7 link TGFβ type I receptors to the microtubule system to promote cell migration

    Science.gov (United States)

    Ekman, Maria; Mu, Yabing; Lee, So Young; Edlund, Sofia; Kozakai, Takaharu; Thakur, Noopur; Tran, Hoanh; Qian, Jiang; Groeden, Joanna; Heldin, Carl-Henrik; Landström, Maréne

    2012-01-01

    Cell migration occurs by activation of complex regulatory pathways that are spatially and temporally integrated in response to extracellular cues. Binding of adenomatous polyposis coli (APC) to the microtubule plus ends in polarized cells is regulated by glycogen synthase kinase 3β (GSK-3β). This event is crucial for establishment of cell polarity during directional migration. However, the role of APC for cellular extension in response to extracellular signals is less clear. Smad7 is a direct target gene for transforming growth factor-β (TGFβ) and is known to inhibit various TGFβ-induced responses. Here we report a new function for Smad7. We show that Smad7 and p38 mitogen–activated protein kinase together regulate the expression of APC and cell migration in prostate cancer cells in response to TGFβ stimulation. In addition, Smad7 forms a complex with APC and acts as an adaptor protein for p38 and GSK-3β kinases to facilitate local TGFβ/p38–dependent inactivation of GSK-3β, accumulation of β-catenin, and recruitment of APC to the microtubule plus end in the leading edge of migrating prostate cancer cells. Moreover, the Smad7–APC complex links the TGFβ type I receptor to the microtubule system to regulate directed cellular extension and migratory responses evoked by TGFβ. PMID:22496417

  4. MHC class II expression through a hitherto unknown pathway supports T helper cell-dependent immune responses: implications for MHC class II deficiency

    NARCIS (Netherlands)

    Buch, Thorsten; Polic, Bojan; Clausen, Björn E.; Weiss, Susanne; Akilli-Ozturk, Ozlem; Chang, Cheong-Hee; Flavell, Richard; Schulz, Ansgar; Jonjic, Stipan; Waisman, Ari; Förster, Irmgard

    2006-01-01

    MHC class II (MHCII) deficiency or bare lymphocyte syndrome (BLS) is a severe immunodeficiency characterized by deficient T helper (Th)-cell-dependent immunity. The disease is caused by defects of the MHCII promoter complex resulting in low or absent MHCII expression. We demonstrate in a murine

  5. Comparative genomic analysis of the MHC: the evolution of class I duplication blocks, diversity and complexity from shark to man.

    Science.gov (United States)

    Kulski, Jerzy K; Shiina, Takashi; Anzai, Tatsuya; Kohara, Sakae; Inoko, Hidetoshi

    2002-12-01

    The major histocompatibility complex (MHC) genomic region is composed of a group of linked genes involved functionally with the adaptive and innate immune systems. The class I and class II genes are intrinsic features of the MHC and have been found in all the jawed vertebrates studied so far. The MHC genomic regions of the human and the chicken (B locus) have been fully sequenced and mapped, and the mouse MHC sequence is almost finished. Information on the MHC genomic structures (size, complexity, genic and intergenic composition and organization, gene order and number) of other vertebrates is largely limited or nonexistent. Therefore, we are mapping, sequencing and analyzing the MHC genomic regions of different human haplotypes and at least eight nonhuman species. Here, we review our progress with these sequences and compare the human MHC structure with that of the nonhuman primates (chimpanzee and rhesus macaque), other mammals (pigs, mice and rats) and nonmammalian vertebrates such as birds (chicken and quail), bony fish (medaka, pufferfish and zebrafish) and cartilaginous fish (nurse shark). This comparison reveals a complex MHC structure for mammals and a relatively simpler design for nonmammalian animals with a hypothetical prototypic structure for the shark. In the mammalian MHC, there are two to five different class I duplication blocks embedded within a framework of conserved nonclass I and/or nonclass II genes. With a few exceptions, the class I framework genes are absent from the MHC of birds, bony fish and sharks. Comparative genomics of the MHC reveal a highly plastic region with major structural differences between the mammalian and nonmammalian vertebrates. Additional genomic data are needed on animals of the reptilia, crocodilia and marsupial classes to find the origins of the class I framework genes and examples of structures that may be intermediate between the simple and complex MHC organizations of birds and mammals, respectively.

  6. Peripheral nerve injury causes transient expression of MHC class I antigens in rat motor neurons and skeletal muscles

    DEFF Research Database (Denmark)

    Maehlen, J; Nennesmo, I; Olsson, A B

    1989-01-01

    After a peripheral nerve lesion (rat facial and sciatic) an induction of major histocompatibility complex (MHC) antigens class I was detected immunohistochemically in skeletal muscle fibers and motor neurons. This MHC expression was transient after a nerve crush, when regeneration occurred......, but persisted after a nerve cut, when regeneration was prevented. Since the time course of MHC class I expression correlates to that of regeneration a role for this cell surface molecule in regeneration may be considered....

  7. Prediction of the binding affinities of peptides to class II MHC using a regularized thermodynamic model

    Directory of Open Access Journals (Sweden)

    Mittelmann Hans D

    2010-01-01

    Full Text Available Abstract Background The binding of peptide fragments of extracellular peptides to class II MHC is a crucial event in the adaptive immune response. Each MHC allotype generally binds a distinct subset of peptides and the enormous number of possible peptide epitopes prevents their complete experimental characterization. Computational methods can utilize the limited experimental data to predict the binding affinities of peptides to class II MHC. Results We have developed the Regularized Thermodynamic Average, or RTA, method for predicting the affinities of peptides binding to class II MHC. RTA accounts for all possible peptide binding conformations using a thermodynamic average and includes a parameter constraint for regularization to improve accuracy on novel data. RTA was shown to achieve higher accuracy, as measured by AUC, than SMM-align on the same data for all 17 MHC allotypes examined. RTA also gave the highest accuracy on all but three allotypes when compared with results from 9 different prediction methods applied to the same data. In addition, the method correctly predicted the peptide binding register of 17 out of 18 peptide-MHC complexes. Finally, we found that suboptimal peptide binding registers, which are often ignored in other prediction methods, made significant contributions of at least 50% of the total binding energy for approximately 20% of the peptides. Conclusions The RTA method accurately predicts peptide binding affinities to class II MHC and accounts for multiple peptide binding registers while reducing overfitting through regularization. The method has potential applications in vaccine design and in understanding autoimmune disorders. A web server implementing the RTA prediction method is available at http://bordnerlab.org/RTA/.

  8. Low MHC variation in the endangered Galápagos penguin (Spheniscus mendiculus).

    Science.gov (United States)

    Bollmer, Jennifer L; Vargas, F Hernán; Parker, Patricia G

    2007-07-01

    The major histocompatibility complex (MHC) is one of the most polymorphic regions of the genome, likely due to balancing selection acting to maintain alleles over time. Lack of MHC variability has been attributed to factors such as genetic drift in small populations and relaxed selection pressure. The Galápagos penguin (Spheniscus mendiculus), endemic to the Galápagos Islands, is the only penguin that occurs on the equator. It relies upon cold, nutrient-rich upwellings and experiences severe population declines when ocean temperatures rise during El Niño events. These bottlenecks, occurring in an already small population, have likely resulted in reduced genetic diversity in this species. In this study, we used MHC class II exon 2 sequence data from a DRB1-like gene to characterize the amount of genetic variation at the MHC in 30 Galápagos penguins, as well as one Magellanic penguin (S. magellanicus) and two king penguins (Aptenodytes patagonicus), and compared it to that in five other penguin species for which published data exist. We found that the Galápagos penguin had the lowest MHC diversity (as measured by number of polymorphic sites and average divergence among alleles) of the eight penguin species studied. A phylogenetic analysis showed that Galápagos penguin MHC sequences are most closely related to Humboldt penguin (Spheniscus humboldti) sequences, its putative sister species based on other loci. An excess of non-synonymous mutations and a pattern of trans-specific evolution in the neighbor-joining tree suggest that selection is acting on the penguin MHC.

  9. Stepwise threshold clustering: a new method for genotyping MHC loci using next-generation sequencing technology.

    Directory of Open Access Journals (Sweden)

    William E Stutz

    Full Text Available Genes of the vertebrate major histocompatibility complex (MHC are of great interest to biologists because of their important role in immunity and disease, and their extremely high levels of genetic diversity. Next generation sequencing (NGS technologies are quickly becoming the method of choice for high-throughput genotyping of multi-locus templates like MHC in non-model organisms. Previous approaches to genotyping MHC genes using NGS technologies suffer from two problems:1 a "gray zone" where low frequency alleles and high frequency artifacts can be difficult to disentangle and 2 a similar sequence problem, where very similar alleles can be difficult to distinguish as two distinct alleles. Here were present a new method for genotyping MHC loci--Stepwise Threshold Clustering (STC--that addresses these problems by taking full advantage of the increase in sequence data provided by NGS technologies. Unlike previous approaches for genotyping MHC with NGS data that attempt to classify individual sequences as alleles or artifacts, STC uses a quasi-Dirichlet clustering algorithm to cluster similar sequences at increasing levels of sequence similarity. By applying frequency and similarity based criteria to clusters rather than individual sequences, STC is able to successfully identify clusters of sequences that correspond to individual or similar alleles present in the genomes of individual samples. Furthermore, STC does not require duplicate runs of all samples, increasing the number of samples that can be genotyped in a given project. We show how the STC method works using a single sample library. We then apply STC to 295 threespine stickleback (Gasterosteus aculeatus samples from four populations and show that neighboring populations differ significantly in MHC allele pools. We show that STC is a reliable, accurate, efficient, and flexible method for genotyping MHC that will be of use to biologists interested in a variety of downstream applications.

  10. New design of MHC class II tetramers to accommodate fundamental principles of antigen presentation.

    Science.gov (United States)

    Landais, Elise; Romagnoli, Pablo A; Corper, Adam L; Shires, John; Altman, John D; Wilson, Ian A; Garcia, K Christopher; Teyton, Luc

    2009-12-15

    Direct identification and isolation of Ag-specific T cells became possible with the development of MHC tetramers, based on fluorescent avidins displaying biotinylated peptide-MHC complexes. This approach, extensively used for MHC class I-restricted T cells, has met very limited success with class II peptide-MHC complex tetramers (pMHCT-2) for the detection of CD4(+)-specific T cells. In addition, a very large number of these reagents, although capable of specifically activating T cells after being coated on solid support, is still unable to stain. To try to understand this puzzle and design usable tetramers, we examined each parameter critical for the production of pMHCT-2 using the I-A(d)-OVA system as a model. Through this process, the geometry of peptide-MHC display by avidin tetramers was examined, as well as the stability of rMHC molecules. However, we discovered that the most important factor limiting the reactivity of pMHCT-2 was the display of peptides. Indeed, long peptides, as presented by MHC class II molecules, can be bound to I-A/HLA-DQ molecules in more than one register, as suggested by structural studies. This mode of anchorless peptide binding allows the selection of a broader repertoire on single peptides and should favor anti-infectious immune responses. Thus, beyond the technical improvements that we propose, the redesign of pMHCT-2 will give us the tools to evaluate the real size of the CD4 T cell repertoire and help us in the production and testing of new vaccines.

  11. Extensive shared polymorphism at non-MHC immune genes in recently diverged North American prairie grouse

    Science.gov (United States)

    Minias, Piotr; Bateson, Zachary W.; Whittingham, Linda A.; Johnson, Jeff A.; Oyler-McCance, Sara J.; Dunn, Peter O.

    2018-01-01

    Gene polymorphisms shared between recently diverged species are thought to be widespread and most commonly reflect introgression from hybridization or retention of ancestral polymorphism through incomplete lineage sorting. Shared genetic diversity resulting from incomplete lineage sorting is usually maintained for a relatively short period of time, but under strong balancing selection it may persist for millions of years beyond species divergence (balanced trans-species polymorphism), as in the case of the major histocompatibility complex (MHC) genes. However, balancing selection is much less likely to act on non-MHC immune genes. The aim of this study was to investigate the patterns of shared polymorphism and selection at non-MHC immune genes in five grouse species from Centrocercus and Tympanuchus genera. For this purpose, we genotyped five non-MHC immune genes that do not interact directly with pathogens, but are involved in signaling and regulate immune cell growth. In contrast to previous studies with MHC, we found no evidence for balancing selection or balanced trans-species polymorphism among the non-MHC immune genes. No haplotypes were shared between genera and in most cases more similar allelic variants sorted by genus. Between species within genera, however, we found extensive shared polymorphism, which was most likely attributable to introgression or incomplete lineage sorting following recent divergence and large ancestral effective population size (i.e., weak genetic drift). Our study suggests that North American prairie grouse may have attained relatively low degree of reciprocal monophyly at nuclear loci and reinforces the rarity of balancing selection in non-MHC immune genes.

  12. A new polymorphic and multicopy MHC gene family related to nonmammalian class I

    Energy Technology Data Exchange (ETDEWEB)

    Leelayuwat, C.; Degli-Esposti, M.A.; Abraham, L.J. [Univ. of Western Australia, Perth (Australia); Townend, D.C. [Sir Charles Gairdner Hospital, Perth (Australia); Dawkins, R.L. [Royal Perth Hospital, Perth (Australia)]|[Univ. of Western Australia, Perth (Australia)]|[Sir Charles Gairdner Hospital, Perth (Australia)

    1994-12-31

    The authors have used genomic analysis to characterize a region of the central major histocompatibility complex (MHC) spanning {approximately} 300 kilobases (kb) between TNF and HLA-B. This region has been suggested to carry genetic factors relevant to the development of autoimmune diseases such as myasthenia gravis (MG) and insulin dependent diabetes mellitus (IDDM). Genomic sequence was analyzed for coding potential, using two neural network programs, GRAIL and GeneParser. A genomic probe, JAB, containing putative coding sequences (PERB11) located 60 kb centromeric of HLA-B, was used for northern analysis of human tissues. Multiple transcripts were detected. Southern analysis of genomic DNA and overlapping YAC clones, covering the region from BAT1 to HLA-F, indicated that there are at least five copies of PERB11, four of which are located within this region of the MHC. The partial cDNA sequence of PERB11 was obtained from poly-A RNA derived from skeletal muscle. The putative amino acid sequence of PERB11 shares {approximately} 30% identity to MHC class I molecules from various species, including reptiles, chickens, and frogs, as well as to other MHC class I-like molecules, such as the IgG FcR of the mouse and rat and the human Zn-{alpha}2-glycoprotein. From direct comparison of amino acid sequences, it is concluded that PERB11 is a distinct molecule more closely related to nonmammalian than known mammalian MHC class I molecules. Genomic sequence analysis of PERB11 from five MHC ancestral haplotypes (AH) indicated that the gene is polymorphic at both DNA and protein level. The results suggest that the authors have identified a novel polymorphic gene family with multiple copies within the MHC. 48 refs., 10 figs., 2 tabs.

  13. The importance of immune gene variability (MHC in evolutionary ecology and conservation

    Directory of Open Access Journals (Sweden)

    Sommer Simone

    2005-10-01

    Full Text Available Abstract Genetic studies have typically inferred the effects of human impact by documenting patterns of genetic differentiation and levels of genetic diversity among potentially isolated populations using selective neutral markers such as mitochondrial control region sequences, microsatellites or single nucleotide polymorphism (SNPs. However, evolutionary relevant and adaptive processes within and between populations can only be reflected by coding genes. In vertebrates, growing evidence suggests that genetic diversity is particularly important at the level of the major histocompatibility complex (MHC. MHC variants influence many important biological traits, including immune recognition, susceptibility to infectious and autoimmune diseases, individual odours, mating preferences, kin recognition, cooperation and pregnancy outcome. These diverse functions and characteristics place genes of the MHC among the best candidates for studies of mechanisms and significance of molecular adaptation in vertebrates. MHC variability is believed to be maintained by pathogen-driven selection, mediated either through heterozygote advantage or frequency-dependent selection. Up to now, most of our knowledge has derived from studies in humans or from model organisms under experimental, laboratory conditions. Empirical support for selective mechanisms in free-ranging animal populations in their natural environment is rare. In this review, I first introduce general information about the structure and function of MHC genes, as well as current hypotheses and concepts concerning the role of selection in the maintenance of MHC polymorphism. The evolutionary forces acting on the genetic diversity in coding and non-coding markers are compared. Then, I summarise empirical support for the functional importance of MHC variability in parasite resistance with emphasis on the evidence derived from free-ranging animal populations investigated in their natural habitat. Finally, I

  14. Novel APC mutations in Czech and Slovak FAP families: clinical and genetic aspects

    Directory of Open Access Journals (Sweden)

    Vesela Kamila

    2007-04-01

    Full Text Available Abstract Background Germline mutations in the adenomatous polyposis gene (APC result in familial adenomatous polyposis (FAP. FAP is an autosomal dominantly inherited disorder predisposing to colorectal cancer. Typical FAP is characterized by hundreds to thousands of colorectal adenomatous polyps and by several extracolonic manifestations. An attenuated form of polyposis (AFAP is characterized by less than 100 adenomas and later onset of the disease. Methods Here, we analyzed the APC gene for germline mutations in 59 Czech and 15 Slovak FAP patients. In addition, 50 apparently APC mutation negative Czech probands and 3 probands of Slovak origin were screened for large deletions encompassing the APC gene. Mutation screening was performed using denaturing gradient gel electrophoresis and/or protein truncation test. DNA fragments showing an aberrant electrophoretic banding pattern were sequenced. Screening for large deletions was performed by multiplex ligation dependent probe amplification. The extent of deletions was analyzed using following microsatellite markers: D5S299, D5S82, D5S134 and D5S346. Results In the set of Czech and Slovak patients, we identified 46 germline mutations among 74 unrelated probands. Total mutation capture is 62,2% including large deletions. Thirty seven mutations were detected in 49 patients presenting a classical FAP phenotype (75,5% and 9 mutations in 25 patients with attenuated FAP (36%. We report 20 novel germline APC mutations and 3 large deletions (6% encompassing the whole-gene deletions and/or exon 14 deletion. In the patients with novel mutations, correlations of the mutation localization are discussed in context of the classical and/or attenuated phenotype of the disease. Conclusion The results of the molecular genetic testing are used both in the establishment of the predictive diagnosis and in the clinical management of patients. In some cases this study has also shown the difficulty to classify clinically

  15. Direct binding of autoimmune disease related T cell epitopes to purified Lewis rat MHC class II molecules

    DEFF Research Database (Denmark)

    Joosten, I; Wauben, M H; Holewijn, M C

    1994-01-01

    New strategies applied in the treatment of experimental autoimmune disease models involve blocking or modulation of MHC-peptide-TCR interactions either at the level of peptide-MHC interaction or, alternatively, at the level of T cell recognition. In order to identify useful competitor peptides one...... characteristics of the Lewis rat MHC class II RT1.B1 molecule. We have now developed a biochemical binding assay which enables competition studies in which the relative MHC binding affinity of a set of non-labelled peptides can be assessed while employing detection of biotinylated marker peptides...

  16. Epigenetic mechanisms regulate MHC and antigen processing molecules in human embryonic and induced pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Beatriz Suárez-Alvarez

    2010-04-01

    Full Text Available Human embryonic stem cells (hESCs are an attractive resource for new therapeutic approaches that involve tissue regeneration. hESCs have exhibited low immunogenicity due to low levels of Mayor Histocompatibility Complex (MHC class-I and absence of MHC class-II expression. Nevertheless, the mechanisms regulating MHC expression in hESCs had not been explored.We analyzed the expression levels of classical and non-classical MHC class-I, MHC class-II molecules, antigen-processing machinery (APM components and NKG2D ligands (NKG2D-L in hESCs, induced pluripotent stem cells (iPSCs and NTera2 (NT2 teratocarcinoma cell line. Epigenetic mechanisms involved in the regulation of these genes were investigated by bisulfite sequencing and chromatin immunoprecipitation (ChIP assays. We showed that low levels of MHC class-I molecules were associated with absent or reduced expression of the transporter associated with antigen processing 1 (TAP-1 and tapasin (TPN components in hESCs and iPSCs, which are involved in the transport and load of peptides. Furthermore, lack of beta2-microglobulin (beta2m light chain in these cells limited the expression of MHC class I trimeric molecule on the cell surface. NKG2D ligands (MICA, MICB were observed in all pluripotent stem cells lines. Epigenetic analysis showed that H3K9me3 repressed the TPN gene in undifferentiated cells whilst HLA-B and beta2m acquired the H3K4me3 modification during the differentiation to embryoid bodies (EBs. Absence of HLA-DR and HLA-G expression was regulated by DNA methylation.Our data provide fundamental evidence for the epigenetic control of MHC in hESCs and iPSCs. Reduced MHC class I and class II expression in hESCs and iPSCs can limit their recognition by the immune response against these cells. The knowledge of these mechanisms will further allow the development of strategies to induce tolerance and improve stem cell allograft acceptance.

  17. Epigenetic Mechanisms Regulate MHC and Antigen Processing Molecules in Human Embryonic and Induced Pluripotent Stem Cells

    Science.gov (United States)

    Suárez-Álvarez, Beatriz; Rodriguez, Ramón M.; Calvanese, Vincenzo; Blanco-Gelaz, Miguel A.; Suhr, Steve T.; Ortega, Francisco; Otero, Jesus; Cibelli, Jose B.; Moore, Harry; Fraga, Mario F.; López-Larrea, Carlos

    2010-01-01

    Background Human embryonic stem cells (hESCs) are an attractive resource for new therapeutic approaches that involve tissue regeneration. hESCs have exhibited low immunogenicity due to low levels of Mayor Histocompatibility Complex (MHC) class-I and absence of MHC class-II expression. Nevertheless, the mechanisms regulating MHC expression in hESCs had not been explored. Methodology/Principal Findings We analyzed the expression levels of classical and non-classical MHC class-I, MHC class-II molecules, antigen-processing machinery (APM) components and NKG2D ligands (NKG2D-L) in hESCs, induced pluripotent stem cells (iPSCs) and NTera2 (NT2) teratocarcinoma cell line. Epigenetic mechanisms involved in the regulation of these genes were investigated by bisulfite sequencing and chromatin immunoprecipitation (ChIP) assays. We showed that low levels of MHC class-I molecules were associated with absent or reduced expression of the transporter associated with antigen processing 1 (TAP-1) and tapasin (TPN) components in hESCs and iPSCs, which are involved in the transport and load of peptides. Furthermore, lack of β2-microglobulin (β2m) light chain in these cells limited the expression of MHC class I trimeric molecule on the cell surface. NKG2D ligands (MICA, MICB) were observed in all pluripotent stem cells lines. Epigenetic analysis showed that H3K9me3 repressed the TPN gene in undifferentiated cells whilst HLA-B and β2m acquired the H3K4me3 modification during the differentiation to embryoid bodies (EBs). Absence of HLA-DR and HLA-G expression was regulated by DNA methylation. Conclusions/Significance Our data provide fundamental evidence for the epigenetic control of MHC in hESCs and iPSCs. Reduced MHC class I and class II expression in hESCs and iPSCs can limit their recognition by the immune response against these cells. The knowledge of these mechanisms will further allow the development of strategies to induce tolerance and improve stem cell allograft acceptance

  18. Features of target cell lysis by class I and class II MHC restricted cytolytic T lymphocytes

    International Nuclear Information System (INIS)

    Maimone, M.M.; Morrison, L.A.; Braciale, V.L.; Braciale, T.J.

    1986-01-01

    The lytic activity of influenza virus-specific muvine cytolytic T lymphocyte (CTL) clones that are restricted by either H-2K/D (class I) or H-2I (class II) major histocompatibility (MHC) locus products was compared on an influenza virus-infected target cell expressing both K/D and I locus products. With the use of two in vitro measurements of cytotoxicity, conventional 51 Cr release, and detergent-releasable radiolabeled DNA (as a measure of nuclear disintegration in the early post-lethal hit period), the authors found no difference between class I and class II MHC-restricted CTL in the kinetics of target cell destruction. In addition, class II MHC-restricted antiviral CTL failed to show any lysis of radiolabeled bystander cells. Killing of labeled specific targets by these class II MHC-restricted CTL was also efficiently inhibited by unlabeled specific competitor cells in a cold target inhibition assay. In sum, these data suggest that class I and class II MHC-restricted CTL mediate target cell destruction by an essentially similar direct mechanism

  19. The peptide-receptive transition state of MHC-1 molecules: Insight from structure and molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Robinson H.; Mage, M.; Dolan, M.; Wang, R.; Boyd, L.; Revilleza, M.; Natarajan, K.; Myers, N.; Hansen, T.; Margulies, D.

    2012-05-01

    MHC class I (MHC-I) proteins of the adaptive immune system require antigenic peptides for maintenance of mature conformation and immune function via specific recognition by MHC-I-restricted CD8(+) T lymphocytes. New MHC-I molecules in the endoplasmic reticulum are held by chaperones in a peptide-receptive (PR) transition state pending release by tightly binding peptides. In this study, we show, by crystallographic, docking, and molecular dynamics methods, dramatic movement of a hinged unit containing a conserved 3(10) helix that flips from an exposed 'open' position in the PR transition state to a 'closed' position with buried hydrophobic side chains in the peptide-loaded mature molecule. Crystallography of hinged unit residues 46-53 of murine H-2L(d) MHC-I H chain, complexed with mAb 64-3-7, demonstrates solvent exposure of these residues in the PR conformation. Docking and molecular dynamics predict how this segment moves to help form the A and B pockets crucial for the tight peptide binding needed for stability of the mature peptide-loaded conformation, chaperone dissociation, and Ag presentation.

  20. Identification, inheritance, and linkage of B-G-like and MHC class I genes in cranes.

    Science.gov (United States)

    Jarvi, S I; Goto, R M; Gee, G F; Briles, W E; Miller, M M

    1999-01-01

    We identified B-G-like genes in the whooping and Florida sandhill cranes and linked them to the major histocompatibility complex (MHC). We evaluated the inheritance of B-G-like genes in families of whooping and Florida sandhill cranes using restriction fragment patterns (RFPs). Two B-G-like genes, designated wcbg1 and wcbg2, were located within 8 kb of one another. The fully sequenced wcbg2 gene encodes a B-G IgV-like domain, an additional Ig-like domain, a transmembrane domain, and a single heptad domain typical of alpha-helical coiled coils. Patterns of restriction fragments in DNA from the whooping crane and from a number of other species indicate that the B-G-like gene families of cranes are large with diverse sequences. Segregation of RFPs in families of Florida sandhill cranes provide evidence for genetic polymorphism in the B-G-like genes. The restriction fragments generally segregated in concert with MHC haplotypes assigned by serological typing and by single stranded conformational polymorphism (SSCP) assays based in the second exon of the crane MHC class I genes. This study supports the concept of a long-term association of polymorphic B-G-like genes with the MHC. It also establishes SSCP as a means for evaluating MHC genetic variability in cranes.

  1. Identification, inheritance, and linkage of B-G-like and MHC class I genes in cranes

    Science.gov (United States)

    Jarvi, S.I.; Goto, R.M.; Gee, G.F.; Briles, W.E.; Miller, M.M.

    1999-01-01

    We identified B-G-like genes in the whooping and Florida sandhill cranes and linked them to the major histocompatibility complex (MHC). We evaluated the inheritance of B-G-like genes in families of whooping and Florida sandhill cranes using restriction fragment patterns (RFPs). Two B-G-like genes, designated wcbgl and wcbg2, were located within 8 kb of one another. The fully sequenced wcbg2 gene encodes a B-G IgV-like domain, an additional Ig-like domain, a transmembrane domain, and a single heptad domain typical of '-helical coiled coils. Patterns of restriction fragments in DNA from the whooping crane and from a number of other species indicate that the B-G-like gene families of cranes are large with diverse sequences. Segregation of RFPs in families of Florida sandhill cranes provide evidence for genetic polymorphism in the B-G-like genes. The restriction fragments generally segregated in concert with MHC haplotypes assigned by serological typing and by single stranded conformational polymorphism (SSCP) assays based in the second exon of the crane MHC class I genes. This study supports the concept of a long-term association of polymorphic B-G-like genes with the MHC. It also establishes SSCP as a means for evaluating MHC genetic variability in cranes.

  2. Molecular characterization of classical and nonclassical MHC class I genes from the golden pheasant (Chrysolophus pictus).

    Science.gov (United States)

    Zeng, Q-Q; Zhong, G-H; He, K; Sun, D-D; Wan, Q-H

    2016-02-01

    Classical major histocompatibility complex (MHC) class I allelic polymorphism is essential for competent antigen presentation. To improve the genotyping efforts in the golden pheasant, it is necessary to differentiate more accurately between classical and nonclassical class I molecules. In our study, all MHC class I genes were isolated from one golden pheasant based on two overlapping PCR amplifications. In total, six full-length class I nucleotide sequences (A-F) were identified, and four were novel. Two (A and C) belonged to the IA1 gene, two (B and D) were alleles derived from the IA2 gene through transgene amplification, and two (E and F) comprised a third novel locus, IA3 that was excluded from the core region of the golden pheasant MHC-B. IA1 and IA2 exhibited the broad expression profiles characteristic of classical loci, while IA3 showed no expression in multiple tissues and was therefore defined as a nonclassical gene. Phylogenetic analysis indicated that the three IA genes in the golden pheasant share a much closer evolutionary relationship than the corresponding sequences in other galliform species. This observation was consistent with high sequence similarity among them, which likely arises from the homogenizing effect of recombination. Our careful distinction between the classical and nonclassical MHC class I genes in the golden pheasant lays the foundation for developing locus-specific genotyping and establishing a good molecular marker system of classical MHC I loci. © 2015 John Wiley & Sons Ltd.

  3. Cell surface appearance of unexpected host MHC determinants on thymocytes from radiation bone marrow chimeras

    International Nuclear Information System (INIS)

    Sharrow, S.O.; Mathieson, B.J.; Singer, A.

    1981-01-01

    The phenotypic appearance of cell surface antigens on murine thymocytes from long-term radiation bone marrow chimeras was analyzed using indirect immunofluorescence and flow microfluorometry. Cells maturing in the thymi of these mice were typed for MHC (Kk, I-Ak, H-2b, Kb, and Ib) and non-MHC (Lty 1, Ly 9, and TL) determinants. All cells were of donor origin as determined by non-MHC (Ly) phenotype in P1 leads to P2, P1 x P2 leads to P1, and P1 leads to P2 radiation chimeras. In contrast, the MHC phenotypes of these thymocytes were markedly affected by the host environment. Specifically, H-2 and I-A determinants of both parental phenotypes were detected on thymocytes from P1 leads to P1 x P2 chimeras; I-A determinants of host phenotype were present, whereas I-A determinants of donor phenotype were reduced on thymocytes from P1 x P2 leads to P1 chimeras; and thymocytes from P1 leads to P2 chimeras possessed H-2 and I-A determinants of host phenotype but showed reduction of donor I-A phenotype determinants. The appearance of host cell surface H-2 and I-A determinants on thymocytes from chimeras closely parallels the functional recognition of MHC determinants by T cells from chimeric mice and thus may be significantly related to the development of the self-recognition repertoire by maturing T cells

  4. Characterization of 47 MHC class I sequences in Filipino cynomolgus macaques

    Science.gov (United States)

    Campbell, Kevin J.; Detmer, Ann M.; Karl, Julie A.; Wiseman, Roger W.; Blasky, Alex J.; Hughes, Austin L.; Bimber, Benjamin N.; O’Connor, Shelby L.; O’Connor, David H.

    2009-01-01

    Cynomolgus macaques (Macaca fascicularis) provide increasingly common models for infectious disease research. Several geographically distinct populations of these macaques from Southeast Asia and the Indian Ocean island of Mauritius are available for pathogenesis studies. Though host genetics may profoundly impact results of such studies, similarities and differences between populations are often overlooked. In this study we identified 47 full-length MHC class I nucleotide sequences in 16 cynomolgus macaques of Filipino origin. The majority of MHC class I sequences characterized (39 of 47) were unique to this regional population. However, we discovered eight sequences with perfect identity and six sequences with close similarity to previously defined MHC class I sequences from other macaque populations. We identified two ancestral MHC haplotypes that appear to be shared between Filipino and Mauritian cynomolgus macaques, notably a Mafa-B haplotype that has previously been shown to protect Mauritian cynomolgus macaques against challenge with a simian/human immunodeficiency virus, SHIV89.6P. We also identified a Filipino cynomolgus macaque MHC class I sequence for which the predicted protein sequence differs from Mamu-B*17 by a single amino acid. This is important because Mamu-B*17 is strongly associated with protection against simian immunodeficiency virus (SIV) challenge in Indian rhesus macaques. These findings have implications for the evolutionary history of Filipino cynomolgus macaques as well as for the use of this model in SIV/SHIV research protocols. PMID:19107381

  5. Induction of endoplasmic reticulum stress by deletion of Grp78 depletes Apc mutant intestinal epithelial stem cells.

    Science.gov (United States)

    van Lidth de Jeude, J F; Meijer, B J; Wielenga, M C B; Spaan, C N; Baan, B; Rosekrans, S L; Meisner, S; Shen, Y H; Lee, A S; Paton, J C; Paton, A W; Muncan, V; van den Brink, G R; Heijmans, J

    2017-06-15

    Intestinal epithelial stem cells are highly sensitive to differentiation induced by endoplasmic reticulum (ER) stress. Colorectal cancer develops from mutated intestinal epithelial stem cells. The most frequent initiating mutation occurs in Apc, which results in hyperactivated Wnt signalling. This causes hyperproliferation and reduced sensitivity to chemotherapy, but whether these mutated stem cells are sensitive to ER stress induced differentiation remains unknown. Here we examined this by generating mice in which both Apc and ER stress repressor chaperone Grp78 can be conditionally deleted from the intestinal epithelium. For molecular studies, we used intestinal organoids derived from these mice. Homozygous loss of Apc alone resulted in crypt elongation, activation of the Wnt signature and accumulation of intestinal epithelial stem cells, as expected. This phenotype was however completely rescued on activation of ER stress by additional deletion of Grp78. In these Apc-Grp78 double mutant animals, stem cells were rapidly lost and repopulation occurred by non-mutant cells that had escaped recombination, suggesting that Apc-Grp78 double mutant stem cells had lost self-renewal capacity. Although in Apc-Grp78 double mutant mice the Wnt signature was lost, these intestines exhibited ubiquitous epithelial presence of nuclear β-catenin. This suggests that ER stress interferes with Wnt signalling downstream of nuclear β-catenin. In conclusion, our findings indicate that ER stress signalling results in loss of Apc mutated intestinal epithelial stem cells by interference with the Wnt signature. In contrast to many known inhibitors of Wnt signalling, ER stress acts downstream of β-catenin. Therefore, ER stress poses a promising target in colorectal cancers, which develop as a result of Wnt activating mutations.

  6. Identification of the APC/C co-factor FZR1 as a novel therapeutic target for multiple myeloma.

    Science.gov (United States)

    Crawford, Lisa J; Anderson, Gordon; Johnston, Cliona K; Irvine, Alexandra E

    2016-10-25

    Multiple Myeloma (MM) is a haematological neoplasm characterised by the clonal proliferation of malignant plasma cells in the bone marrow. The success of proteasome inhibitors in the treatment of MM has highlighted the importance of the ubiquitin proteasome system (UPS) in the pathogenesis of this disease. In this study, we analysed gene expression of UPS components to identify novel therapeutic targets within this pathway in MM. Here we demonstrate how this approach identified previously validated and novel therapeutic targets. In addition we show that FZR1 (Fzr), a cofactor of the multi-subunit E3 ligase complex anaphase-promoting complex/cyclosome (APC/C), represents a novel therapeutic target in myeloma. The APC/C associates independently with two cofactors, Fzr and Cdc20, to control cell cycle progression. We found high levels of FZR1 in MM primary cells and cell lines and demonstrate that expression is further increased on adhesion to bone marrow stromal cells (BMSCs). Specific knockdown of either FZR1 or CDC20 reduced viability and induced growth arrest of MM cell lines, and resulted in accumulation of APC/CFzr substrate Topoisomerase IIα (TOPIIα) or APC/CCdc20 substrate Cyclin B. Similar effects were observed following treatment with proTAME, an inhibitor of both APC/CFzr and APC/CCdc20. Combinations of proTAME with topoisomerase inhibitors, etoposide and doxorubicin, significantly increased cell death in MM cell lines and primary cells, particularly if TOPIIα levels were first increased through pre-treatment with proTAME. Similarly, combinations of proTAME with the microtubule inhibitor vincristine resulted in enhanced cell death. This study demonstrates the potential of targeting the APC/C and its cofactors as a therapeutic approach in MM.

  7. A limited role for p53 in modulating the immediate phenotype of Apc loss in the intestine

    International Nuclear Information System (INIS)

    Reed, Karen R; Meniel, Valerie S; Marsh, Victoria; Cole, Alicia; Sansom, Owen J; Clarke, Alan R

    2008-01-01

    p53 is an important tumour suppressor with a known role in the later stages of colorectal cancer, but its relevance to the early stages of neoplastic initiation remains somewhat unclear. Although p53-dependent regulation of Wnt signalling activity is known to occur, the importance of these regulatory mechanisms during the early stages of intestinal neoplasia has not been demonstrated. We have conditionally deleted the Adenomatous Polyposis coli gene (Apc) from the adult murine intestine in wild type and p53 deficient environments and subsequently compared the phenotype and transcriptome profiles in both genotypes. Expression of p53 was shown to be elevated following the conditional deletion of Apc in the adult small intestine. Furthermore, p53 status was shown to impact on the transcription profile observed following Apc loss. A number of key Wnt pathway components and targets were altered in the p53 deficient environment. However, the aberrant phenotype observed following loss of Apc (rapid nuclear localisation of β-catenin, increased levels of DNA damage, nuclear atypia, perturbed cell death, proliferation, differentiation and migration) was not significantly altered by the absence of p53. p53 related feedback mechanisms regulating Wnt signalling activity are present in the intestine, and become activated following loss of Apc. However, the physiological Wnt pathway regulation by p53 appears to be overwhelmed by Apc loss and consequently the activity of these regulatory mechanisms is not sufficient to modulate the immediate phenotypes seen following Apc loss. Thus we are able to provide an explanation to the apparent contradiction that, despite having a Wnt regulatory capacity, p53 loss is not associated with early lesion development

  8. Promoter methylation of APC and RAR-β genes as prognostic markers in non-small cell lung cancer (NSCLC).

    Science.gov (United States)

    Feng, Hongxiang; Zhang, Zhenrong; Qing, Xin; Wang, Xiaowei; Liang, Chaoyang; Liu, Deruo

    2016-02-01

    Aberrant promoter hypermethylations of tumor suppressor genes are promising markers for lung cancer diagnosis and prognosis. The purpose of this study was to determine methylation status at APC and RAR-β promoters in primary NSCLC, and whether they have any relationship with survival. APC and RAR-β promoter methylation status were determined in 41 NSCLC patients using methylation specific PCR. APC promoter methylation was detectable in 9 (22.0%) tumor samples and 6 (14.6%) corresponding non-tumor samples (P=0.391). RAR-β promoter methylation was detectable in 13 (31.7%) tumor samples and 4 (9.8%) corresponding non-tumor samples (P=0.049) in the NSCLC patients. APC promoter methylation was found to be associated with T stage (P=0.046) and nodal status (P=0.019) in non-tumor samples, and with smoking (P=0.004) in tumor samples. RAR-β promoter methylation was found associated with age (P=0.031) in non-tumor samples and with primary tumor site in tumor samples. Patients with APC promoter methylation in tumor samples showed significantly longer survival than patients without it (Log-rank P=0.014). In a multivariate analysis of prognostic factors, APC methylation in tumor samples was an independent prognostic factor (P=0.012), as were N1 positive lymph node number (P=0.025) and N2 positive lymph node number (P=0.06). Our study shows that RAR-β methylation detected in lung tissue may be used as a predictive marker for NSCLC diagnosis and that APC methylation in tumor sample may be a useful marker for superior survival in NSCLC patients. Copyright © 2015. Published by Elsevier Inc.

  9. MHC-Dependent Mate Selection within 872 Spousal Pairs of European Ancestry from the Health and Retirement Study

    Directory of Open Access Journals (Sweden)

    Zhen Qiao

    2018-01-01

    Full Text Available Disassortative mating refers to the phenomenon in which individuals with dissimilar genotypes and/or phenotypes mate with one another more frequently than would be expected by chance. Although the existence of disassortative mating is well established in plant and animal species, the only documented example of negative assortment in humans involves dissimilarity at the major histocompatibility complex (MHC locus. Previous studies investigating mating patterns at the MHC have been hampered by limited sample size and contradictory findings. Inspired by the sparse and conflicting evidence, we investigated the role that the MHC region played in human mate selection using genome-wide association data from 872 European American spouses from the Health and Retirement Study (HRS. First, we treated the MHC region as a whole, and investigated genomic similarity between spouses using three levels of genomic variation: single-nucleotide polymorphisms (SNPs, classical human leukocyte antigen (HLA alleles (both four-digit and two-digit classifications, and amino acid polymorphisms. The extent of MHC dissimilarity between spouses was assessed using a permutation approach. Second, we investigated fine scale mating patterns by testing for deviations from random mating at individual SNPs, HLA genes, and amino acids in HLA molecules. Third, we assessed how extreme the spousal relatedness at the MHC region was compared to the rest of the genome, to distinguish the MHC-specific effects from genome-wide effects. We show that neither the MHC region, nor any single SNPs, classic HLA alleles, or amino acid polymorphisms within the MHC region, were significantly dissimilar between spouses relative to non-spouse pairs. However, dissimilarity in the MHC region was extreme relative to the rest of genome for both spousal and non-spouse pairs. Despite the long-standing controversy, our analyses did not support a significant role of MHC dissimilarity in human mate choice.

  10. Vaccination against lymphocytic choriomeningitis virus infection in MHC class II-deficient mice

    DEFF Research Database (Denmark)

    Holst, Peter Johannes; Christensen, Jan Pravsgaard; Thomsen, Allan Randrup

    2011-01-01

    response could be elicited in MHC class II-deficient mice by vaccination with adenovirus encoding lymphocytic choriomeningitis virus (LCMV) glycoprotein tethered to MHC class II-associated invariant chain. Moreover, the response induced conferred significant cytolytic CD8(+) T cell-mediated protection...... against challenge with a high dose of the invasive clone 13 strain of LCMV. In contrast, vaccination with adenovirus encoding unlinked LCMV glycoprotein induced weak virus control in the absence of CD4(+) T cells, and mice may die of increased immunopathology associated with incomplete protection. Acute...... mortality was not observed in any vaccinated mice following infection with the less-invasive Traub strain. However, LCMV Traub infection caused accelerated late mortality in unvaccinated MHC class II-deficient mice; in this case, we observed a strong trend toward delayed mortality in vaccinated mice...

  11. Inhibition of MHC class I is a virulence factor in herpes simplex virus infection of mice.

    Directory of Open Access Journals (Sweden)

    Mark T Orr

    2005-09-01

    Full Text Available Herpes simplex virus (HSV has a number of genes devoted to immune evasion. One such gene, ICP47, binds to the transporter associated with antigen presentation (TAP 1/2 thereby preventing transport of viral peptides into the endoplasmic reticulum, loading of peptides onto nascent major histocompatibility complex (MHC class I molecules, and presentation of peptides to CD8 T cells. However, ICP47 binds poorly to murine TAP1/2 and so inhibits antigen presentation by MHC class I in mice much less efficiently than in humans, limiting the utility of murine models to address the importance of MHC class I inhibition in HSV immunopathogenesis. To address this limitation, we generated recombinant HSVs that efficiently inhibit antigen presentation by murine MHC class I. These recombinant viruses prevented cytotoxic T lymphocyte killing of infected cells in vitro, replicated to higher titers in the central nervous system, and induced paralysis more frequently than control HSV. This increase in virulence was due to inhibition of antigen presentation to CD8 T cells, since these differences were not evident in MHC class I-deficient mice or in mice in which CD8 T cells were depleted. Inhibition of MHC class I by the recombinant viruses did not impair the induction of the HSV-specific CD8 T-cell response, indicating that cross-presentation is the principal mechanism by which HSV-specific CD8 T cells are induced. This inhibition in turn facilitates greater viral entry, replication, and/or survival in the central nervous system, leading to an increased incidence of paralysis.

  12. Genetic variation and selection of MHC class I loci differ in two congeneric frogs.

    Science.gov (United States)

    Kiemnec-Tyburczy, Karen M; Tracy, Karen E; Lips, Karen R; Zamudio, Kelly R

    2018-04-01

    Major histocompatibility complex (MHC) genes encode proteins in the acquired immune response pathway that often show distinctive selection-driven patterns in wild vertebrate populations. We examined genetic variation and signatures of selection in the MHC class I alpha 1 (A1)- and alpha 2 (A2)-domain encoding exons of two frog congeners [Agalychnis callidryas (n = 20) and A. lemur (n = 20)] from a single locality in Panama. We also investigated how historical demographic processes may have impacted MHC genetic diversity by analyzing a neutral mitochondrial marker. We found that both MHC domains were highly variable in both species, with both species likely expressing three loci. Our analyses revealed different signatures of selection between the two species, most notably that the A. callidryas A2 domain had experienced positive selection while the A2 domain of A. lemur had not. Diversifying selection acted on the same number of A1 and A2 allelic lineages, but on a higher percentage of A1 sites compared to A2 sites. Neutrality tests of mitochondrial haplotypes predominately indicated that the two species were at genetic equilibrium when the samples were collected. In addition, two historical tests of demography indicated both species have had relatively stable population sizes over the past 100,000 years; thus large population size changes are unlikely to have greatly influenced MHC diversity in either species during this time period. In conclusion, our results suggest that the impact of selection on MHC diversity varied between these two closely related species, likely due to a combination of distinct ecological conditions and past pathogenic pressures.

  13. Thermodynamics of T cell receptor – peptide/MHC interactions: progress and opportunities

    Science.gov (United States)

    Armstrong, Kathryn M.; Insaidoo, Francis K.; Baker, Brian M.

    2013-01-01

    αβ T cell receptors (TCR) recognize peptide antigens presented by class I or class II major histocompatibility complex molecules (pMHC). Here we review the use of thermodynamic measurements in the study of TCR-pMHC interactions, with attention to the diversity in binding thermodynamics and how this is related to the variation in TCR-pMHC interfaces. We show that there is no enthalpic or entropic signature for TCR binding; rather, enthalpy and entropy changes vary in a compensatory manner that reflects a narrow free energy window for the interactions that have been characterized. Binding enthalpy and entropy changes do not correlate with structural features such as buried surface area or the number of hydrogen bonds within TCR-pMHC interfaces, possibly reflecting the myriad of contributors to binding thermodynamics, but likely also reflecting a reliance on van’t Hoff over calorimetric measurements and the unaccounted influence of equilibria linked to binding. TCR-pMHC binding heat capacity changes likewise vary considerably. In some cases the heat capacity changes are consistent with conformational differences between bound and free receptors, but there is little data indicating these conformational differences represent the need to organize commonly disordered CDR loops. In this regard, we discuss how thermodynamics may provide additional insight into conformational changes occurring upon TCR binding. Finally, we highlight opportunities for the further use of thermodynamic measurements in the study of TCR-pMHC interactions, not only for understanding TCR binding in general, but for understanding specifics of individual interactions and the engineering of T cell receptors with desired molecular recognition properties. PMID:18496839

  14. T cell reactivity with allergoids: influence of the type of APC.

    Science.gov (United States)

    Kahlert, H; Grage-Griebenow, E; Stüwe, H T; Cromwell, O; Fiebig, H

    2000-08-15

    The use of allergoids for allergen-specific immunotherapy has been established for many years. The characteristic features of these chemically modified allergens are their strongly reduced IgE binding activity compared with the native form and the retained immunogenicity. T cell reactivity of chemically modified allergens is documented in animals, but in humans indirect evidence of reactivity has been concluded from the induction of allergen-specific IgG during immunotherapy. Direct evidence of T cell reactivity was obtained recently using isolated human T cells. To obtain further insight into the mechanism of action of allergoids, we compared the Ag-presenting capacity of different APC types, including DC and macrophages, generated from CD14+ precursor cells from the blood of grass pollen allergic subjects, autologous PBMC, and B cells. These APC were used in experiments together with Phl p 5-specific T cell clones under stimulation with grass pollen allergen extract, rPhl p 5b, and the respective allergoids. Using DC and macrophages, allergoids exhibited a pronounced and reproducible T cell-stimulating capacity. Responses were superior to those with PBMC, and isolated B cells failed to present allergoids. Considerable IL-12 production was observed only when using the DC for Ag presentation of both allergens and allergoids. The amount of IL-10 in supernatants was dependent on the phenotype of the respective T cell clone. High IL-10 production was associated with suppressed IL-12 production from the DC in most cases. In conclusion, the reactivity of Th cells with allergoids is dependent on the type of the APC.

  15. Different modes of APC/C activation control growth and neuron-glia interaction in the developing Drosophila eye.

    Science.gov (United States)

    Neuert, Helen; Yuva-Aydemir, Yeliz; Silies, Marion; Klämbt, Christian

    2017-12-15

    The development of the nervous system requires tight control of cell division, fate specification and migration. The anaphase-promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase that affects different steps of cell cycle progression, as well as having postmitotic functions in nervous system development. It can therefore link different developmental stages in one tissue. The two adaptor proteins, Fizzy/Cdc20 and Fizzy-related/Cdh1, confer APC/C substrate specificity. Here, we show that two distinct modes of APC/C function act during Drosophila eye development. Fizzy/Cdc20 controls the early growth of the eye disc anlage and the concomitant entry of glial cells onto the disc. In contrast, fzr/cdh1 acts during neuronal patterning and photoreceptor axon growth, and subsequently affects neuron-glia interaction. To further address the postmitotic role of Fzr/Cdh1 in controlling neuron-glia interaction, we identified a series of novel APC/C candidate substrates. Four of our candidate genes are required for fzr/cdh1 -dependent neuron-glia interaction, including the dynein light chain Dlc90F Taken together, our data show how different modes of APC/C activation can couple early growth and neuron-glia interaction during eye disc development. © 2017. Published by The Company of Biologists Ltd.

  16. Intestinal APCs of the endogenous nanomineral pathway fail to express PD-L1 in Crohn’s disease

    Science.gov (United States)

    Robertson, Jack; Haas, Carolin T.; Pele, Laetitia C.; Monie, Tom P.; Charalambos, Charles; Parkes, Miles; Hewitt, Rachel E.; Powell, Jonathan J.

    2016-01-01

    Crohn’s disease is a chronic inflammatory condition most commonly affecting the ileum and colon. The aetiology of Crohn’s disease is complex and may include defects in peptidoglycan recognition, and/or failures in the establishment of intestinal tolerance. We have recently described a novel constitutive endogenous delivery system for the translocation of nanomineral-antigen-peptidoglycan (NAP) conjugates to antigen presenting cells (APCs) in intestinal lymphoid patches. In mice NAP conjugate delivery to APCs results in high surface expression of the immuno-modulatory molecule programmed death receptor ligand 1 (PD-L1). Here we report that NAP conjugate positive APCs in human ileal tissues from individuals with ulcerative colitis and intestinal carcinomas, also have high expression of PD-L1. However, NAP-conjugate positive APCs in intestinal tissue from patients with Crohn’s disease show selective failure in PD-L1 expression. Therefore, in Crohn’s disease intestinal antigen taken up by lymphoid patch APCs will be presented without PD-L1 induced tolerogenic signalling, perhaps initiating disease. PMID:27226337

  17. Intestinal APCs of the endogenous nanomineral pathway fail to express PD-L1 in Crohn's disease.

    Science.gov (United States)

    Robertson, Jack; Haas, Carolin T; Pele, Laetitia C; Monie, Tom P; Charalambos, Charles; Parkes, Miles; Hewitt, Rachel E; Powell, Jonathan J

    2016-05-26

    Crohn's disease is a chronic inflammatory condition most commonly affecting the ileum and colon. The aetiology of Crohn's disease is complex and may include defects in peptidoglycan recognition, and/or failures in the establishment of intestinal tolerance. We have recently described a novel constitutive endogenous delivery system for the translocation of nanomineral-antigen-peptidoglycan (NAP) conjugates to antigen presenting cells (APCs) in intestinal lymphoid patches. In mice NAP conjugate delivery to APCs results in high surface expression of the immuno-modulatory molecule programmed death receptor ligand 1 (PD-L1). Here we report that NAP conjugate positive APCs in human ileal tissues from individuals with ulcerative colitis and intestinal carcinomas, also have high expression of PD-L1. However, NAP-conjugate positive APCs in intestinal tissue from patients with Crohn's disease show selective failure in PD-L1 expression. Therefore, in Crohn's disease intestinal antigen taken up by lymphoid patch APCs will be presented without PD-L1 induced tolerogenic signalling, perhaps initiating disease.

  18. The Pleiotropic Phenotype of Apc Mutations in the Mouse: Allele Specificity and Effects of the Genetic Background

    Science.gov (United States)

    Halberg, Richard B.; Chen, Xiaodi; Amos-Landgraf, James M.; White, Alanna; Rasmussen, Kristin; Clipson, Linda; Pasch, Cheri; Sullivan, Ruth; Pitot, Henry C.; Dove, William F.

    2008-01-01

    Familial adenomatous polyposis (FAP) is a human cancer syndrome characterized by the development of hundreds to thousands of colonic polyps and extracolonic lesions including desmoid fibromas, osteomas, epidermoid cysts, and congenital hypertrophy of the pigmented retinal epithelium. Afflicted individuals are heterozygous for mutations in the APC gene. Detailed investigations of mice heterozygous for mutations in the ortholog Apc have shown that other genetic factors strongly influence the phenotype. Here we report qualitative and quantitative modifications of the phenotype of Apc mutants as a function of three genetic variables: Apc allele, p53 allele, and genetic background. We have found major differences between the Apc alleles Min and 1638N in multiplicity and regionality of intestinal tumors, as well as in incidence of extracolonic lesions. By contrast, Min mice homozygous for either of two different knockout alleles of p53 show similar phenotypic effects. These studies illustrate the classic principle that functional genetics is enriched by assessing penetrance and expressivity with allelic series. The mouse permits study of an allelic gene series on multiple genetic backgrounds, thereby leading to a better understanding of gene action in a range of biological processes. PMID:18723878

  19. Aggregate material formulated with MSWI bottom ash and APC fly ash for use as secondary building material

    International Nuclear Information System (INIS)

    Valle-Zermeño, R. del; Formosa, J.; Chimenos, J.M.; Martínez, M.; Fernández, A.I.

    2013-01-01

    Highlights: ► A concrete formulation was optimized using Bottom Ash and APC ash. ► 10% of APC ash achieves good compromise between economic and performance aspects. ► The crushed concrete was evaluated as secondary building granular material. ► The environmental behavior allows its use as secondary material. ► The abrasion resistance is not good enough for its use as a road sub-base material. - Abstract: The main goal of this paper is to obtain a granular material formulated with Municipal Solid Waste Incineration (MSWI) bottom ash (BA) and air pollution control (APC) fly ash to be used as secondary building material. Previously, an optimum concrete mixture using both MSWI residues as aggregates was formulated. A compromise between the environmental behavior whilst maximizing the reuse of APC fly ash was considered and assessed. Unconfined compressive strength and abrasion resistance values were measured in order to evaluate the mechanical properties. From these results, the granular mixture was not suited for certain applications owing to the high BA/APC fly ash content and low cement percentages used to reduce the costs of the final product. Nevertheless, the leaching test performed showed that the concentrations of all heavy metals were below the limits established by the current Catalan legislation for their reutilization. Therefore, the material studied might be mainly used in embankments, where high mechanical properties are not needed and environmental safety is assured

  20. MHC-I Ligand Discovery Using Targeted Database Searches of Mass Spectrometry Data: Implications for T-Cell Immunotherapies

    DEFF Research Database (Denmark)

    Murphy, J. Patrick; Konda, Prathyusha; Kowalewski, Daniel J.

    2017-01-01

    Class I major histocompatibility complex (MHC-I)-bound peptide ligands dictate the activation and specificity of CD8+ T cells and thus are important for devising T-cell immunotherapies. In recent times, advances in mass spectrometry (MS) have enabled the precise identification of these MHC-I pept...

  1. NN-align. An artificial neural network-based alignment algorithm for MHC class II peptide binding prediction

    Directory of Open Access Journals (Sweden)

    Lund Ole

    2009-09-01

    Full Text Available Abstract Background The major histocompatibility complex (MHC molecule plays a central role in controlling the adaptive immune response to infections. MHC class I molecules present peptides derived from intracellular proteins to cytotoxic T cells, whereas MHC class II molecules stimulate cellular and humoral immunity through presentation of extracellularly derived peptides to helper T cells. Identification of which peptides will bind a given MHC molecule is thus of great importance for the understanding of host-pathogen interactions, and large efforts have been placed in developing algorithms capable of predicting this binding event. Results Here, we present a novel artificial neural network-based method, NN-align that allows for simultaneous identification of the MHC class II binding core and binding affinity. NN-align is trained using a novel training algorithm that allows for correction of bias in the training data due to redundant binding core representation. Incorporation of information about the residues flanking the peptide-binding core is shown to significantly improve the prediction accuracy. The method is evaluated on a large-scale benchmark consisting of six independent data sets covering 14 human MHC class II alleles, and is demonstrated to outperform other state-of-the-art MHC class II prediction methods. Conclusion The NN-align method is competitive with the state-of-the-art MHC class II peptide binding prediction algorithms. The method is publicly available at http://www.cbs.dtu.dk/services/NetMHCII-2.0.

  2. Generation of a genomic tiling array of the human Major Histocompatibility Complex (MHC and its application for DNA methylation analysis

    Directory of Open Access Journals (Sweden)

    Ottaviani Diego

    2008-05-01

    Full Text Available Abstract Background The major histocompatibility complex (MHC is essential for human immunity and is highly associated with common diseases, including cancer. While the genetics of the MHC has been studied intensively for many decades, very little is known about the epigenetics of this most polymorphic and disease-associated region of the genome. Methods To facilitate comprehensive epigenetic analyses of this region, we have generated a genomic tiling array of 2 Kb resolution covering the entire 4 Mb MHC region. The array has been designed to be compatible with chromatin immunoprecipitation (ChIP, methylated DNA immunoprecipitation (MeDIP, array comparative genomic hybridization (aCGH and expression profiling, including of non-coding RNAs. The array comprises 7832 features, consisting of two replicates of both forward and reverse strands of MHC amplicons and appropriate controls. Results Using MeDIP, we demonstrate the application of the MHC array for DNA methylation profiling and the identification of tissue-specific differentially methylated regions (tDMRs. Based on the analysis of two tissues and two cell types, we identified 90 tDMRs within the MHC and describe their characterisation. Conclusion A tiling array covering the MHC region was developed and validated. Its successful application for DNA methylation profiling indicates that this array represents a useful tool for molecular analyses of the MHC in the context of medical genomics.

  3. High-throughput discovery of T cell epitopes in type 1 diabetes using DNA barcode labelledpeptide-MHC multimers

    DEFF Research Database (Denmark)

    Lyngaa, Rikke Birgitte; Bentzen, Amalie Kai; Overgaard, A. Julie

    2016-01-01

    applying a novel technology where the selection of MHC-multimer binding T cells is followed by amplification and sequencing of MHC multimer-associated DNA barcodes revealing their recognition. This technique enables simultaneous detection of >1000 specificities. Identifying post translational modifications...

  4. Deleterious impact of feto-maternal MHC compatibility on the success of pregnancy in a macaque model.

    Science.gov (United States)

    Aarnink, Alice; Mee, Edward T; Savy, Nicolas; Congy-Jolivet, Nicolas; Rose, Nicola J; Blancher, Antoine

    2014-02-01

    The impact of feto-maternal histocompatibility on reproduction has inspired long-lasting debates. However, after the review of numerous articles, the impact of HLA allele sharing within couples on fecundity remains questionable. We decided to explore the impact of major histocompatibility complex (MHC) feto-maternal compatibility on reproduction in a cynomolgus macaque facility composed of animals of Mauritian descent. The Mauritian-derived macaque population presents a very restricted MHC polymorphism (only seven founding haplotypes) due to a strong founding bottleneck effect. The MHC polymorphism was investigated in 237 trios (male, female and offspring) using 17 microsatellite markers distributed across the MHC. Haplotypes were confirmed by segregation analysis. We evaluated the relative frequencies of MHC-compatible and MHC-semi-compatible offspring with the mothers. Among the 237 trios, we selected 42 trios for which the identity of the father is certain and for which the theoretical probabilities of fully compatible and semi-compatible offspring were equal. We found 11 offspring fully compatible and 31 offspring semi-compatible with their respective mother. The observed proportions were clearly outside the interval of confidence of 99 % and therefore most probably resulted from a selection of the semi-compatible offspring during pregnancy. We concluded that MHC fully compatible cynomolgus macaque offspring have a selective survival disadvantage in comparison with offspring inheriting a paternal MHC haplotype differing from maternal haplotypes.

  5. MHC class IIB Exon 2 Polymorphism in the Grey Partridge (Perdix perdix) is shaped by selection, recombination and gene conversion

    Czech Academy of Sciences Publication Activity Database

    Promerová, Marta; Králová, Tereza; Bryjová, Anna; Albrecht, Tomáš; Bryja, Josef

    2013-01-01

    Roč. 8, č. 7 (2013), e69135 E-ISSN 1932-6203 R&D Projects: GA ČR GA206/08/1281 Institutional support: RVO:68081766 Keywords : major histocompatibility complex (MHC) * snipe Gallinago-media * Class-I genes * minimal-essential-MHC Subject RIV: EG - Zoology Impact factor: 3.534, year: 2013

  6. Liver Inflammation and Metabolic Signaling in ApcMin/+ Mice: The Role of Cachexia Progression

    Science.gov (United States)

    Narsale, Aditi A.; Enos, Reilly T.; Puppa, Melissa J.; Chatterjee, Saurabh; Murphy, E. Angela; Fayad, Raja; Pena, Majorette O’; Durstine, J. Larry; Carson, James A.

    2015-01-01

    The ApcMin/+ mouse exhibits an intestinal tumor associated loss of muscle and fat that is accompanied by chronic inflammation, insulin resistance and hyperlipidemia. Since the liver governs systemic energy demands through regulation of glucose and lipid metabolism, it is likely that the liver is a pathological target of cachexia progression in the ApcMin/+ mouse. The purpose of this study was to determine if cancer and the progression of cachexia affected liver endoplasmic reticulum (ER)-stress, inflammation, metabolism, and protein synthesis signaling. The effect of cancer (without cachexia) was examined in wild-type and weight-stable ApcMin/+ mice. Cachexia progression was examined in weight-stable, pre-cachectic, and severely-cachectic ApcMin/+ mice. Livers were analyzed for morphology, glycogen content, ER-stress, inflammation, and metabolic changes. Cancer induced hepatic expression of ER-stress markers BiP (binding immunoglobulin protein), IRE-1α (endoplasmic reticulum to nucleus signaling 1), and inflammatory intermediate STAT-3 (signal transducer and activator of transcription 3). While gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PEPCK) mRNA expression was suppressed by cancer, glycogen content or protein synthesis signaling remained unaffected. Cachexia progression depleted liver glycogen content and increased mRNA expression of glycolytic enzyme PFK (phosphofrucktokinase) and gluconeogenic enzyme PEPCK. Cachexia progression further increased pSTAT-3 but suppressed p-65 and JNK (c-Jun NH2-terminal kinase) activation. Interestingly, progression of cachexia suppressed upstream ER-stress markers BiP and IRE-1α, while inducing its downstream target CHOP (DNA-damage inducible transcript 3). Cachectic mice exhibited a dysregulation of protein synthesis signaling, with an induction of p-mTOR (mechanistic target of rapamycin), despite a suppression of Akt (thymoma viral proto-oncogene 1) and S6 (ribosomal protein S6) phosphorylation. Thus, cancer

  7. Electrodialytic upgrading of MSWI APC residue from hazardous waste to secondary resource

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Kirkelund, Gunvor Marie; Parés Viader, Raimon

    .g. for substitution of cement or fillers in concrete. In general leaching could not be reduced by optimizing current density and treatment time in the pilot scale stack treatment unit, as hypothesized, even though there was evidence of dependency on current density for e.g. zinc, this was not true for most elements......The aim of this project was to contribute to the development of electrodialytic treatment technology of air pollution control residues (APC) from municipal solid waste incineration (MSWI) to obtain maximal leaching reduction by optimization of treatment time and current density for different types...

  8. Sistem Monitoring Pendeteksi Kebocoran LPG berbasis Mikrokontroller ATmega16 menggunakan RF APC220

    Directory of Open Access Journals (Sweden)

    RATNA SUSANA

    2016-02-01

    Full Text Available Abstrak Penggunaan LPG sebagai bahan bakar alternatif pengganti bahan bakar minyak dirasakan lebih efektif dan praktis. Namun kandungan senyawa di dalamnya memiliki efek yang negatif jika menguap di udara bebas. Sistem detektor gas LPG dapat menjadi salah satu solusi untuk mengetahui lebih dini terjadinya kebocoran gas. Implementasi sistem detektor gas LPG pada penelitian ini berupa sistem monitoring nirkabel yang dilengkapi alarm sebagai indikasi jika terjadi kebocoran gas. Sistem terdiri dari bagian Remote Controller dan Master Controller. Remote Controller menggunakan mikrokontroler ATMega16 yang terintegrasi dengan sensor MQ5, LCD dan transceiver RF APC220. Sedangkan Master Controller berupa komputer (PC yang dapat menampilkan kondisi ruangan yang dideteksi oleh bagian Remote Controller. Sistem berhasil mendeteksi gas LPG dan menampilkan kadar konsentrasinya dalam rentang 200 sampai dengan 1000 ppm. Ketika kadar konsentrasi gas mencapai 5000 ppm, alarm aktif secara otomatis dan memberikan status waspada. Pengiriman data secara nirkabel dengan adanya sejumlah penghalang berhasil dilakukan sampai jarak 200 m. Kata kunci: Sistem Monitoring, Remote Controller, Master Controller, LPG, RF APC220   Abstract The use of LPG as a fuel alternative to fossil fuels may be more effective and practical. Neverfluless its compound has a negative effect if it evaporates to the air. LPG gas detector system may be one solution to determine the early occurrence of gas leak. The detector system implementation in this study was a wireless monitoring system that had alarm to indicate if there was the gas leak. The system consisted of the Remote Controller and the Master Controller. Remote Controller used ATmega16 microcontroller integrated with MQ5 sensor, LCD and RF transceiver APC220. While the Master Controller in the form of a computer (PC that could display a room condition was detected by the Remote Controller section. LPG gas system successfully detected

  9. Liver inflammation and metabolic signaling in ApcMin/+ mice: the role of cachexia progression.

    Directory of Open Access Journals (Sweden)

    Aditi A Narsale

    Full Text Available The ApcMin/+ mouse exhibits an intestinal tumor associated loss of muscle and fat that is accompanied by chronic inflammation, insulin resistance and hyperlipidemia. Since the liver governs systemic energy demands through regulation of glucose and lipid metabolism, it is likely that the liver is a pathological target of cachexia progression in the ApcMin/+ mouse. The purpose of this study was to determine if cancer and the progression of cachexia affected liver endoplasmic reticulum (ER-stress, inflammation, metabolism, and protein synthesis signaling. The effect of cancer (without cachexia was examined in wild-type and weight-stable ApcMin/+ mice. Cachexia progression was examined in weight-stable, pre-cachectic, and severely-cachectic ApcMin/+ mice. Livers were analyzed for morphology, glycogen content, ER-stress, inflammation, and metabolic changes. Cancer induced hepatic expression of ER-stress markers BiP (binding immunoglobulin protein, IRE-1α (endoplasmic reticulum to nucleus signaling 1, and inflammatory intermediate STAT-3 (signal transducer and activator of transcription 3. While gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PEPCK mRNA expression was suppressed by cancer, glycogen content or protein synthesis signaling remained unaffected. Cachexia progression depleted liver glycogen content and increased mRNA expression of glycolytic enzyme PFK (phosphofrucktokinase and gluconeogenic enzyme PEPCK. Cachexia progression further increased pSTAT-3 but suppressed p-65 and JNK (c-Jun NH2-terminal kinase activation. Interestingly, progression of cachexia suppressed upstream ER-stress markers BiP and IRE-1α, while inducing its downstream target CHOP (DNA-damage inducible transcript 3. Cachectic mice exhibited a dysregulation of protein synthesis signaling, with an induction of p-mTOR (mechanistic target of rapamycin, despite a suppression of Akt (thymoma viral proto-oncogene 1 and S6 (ribosomal protein S6 phosphorylation. Thus

  10. Signal peptide-dependent inhibition of MHC class I heavy chain translation by rhesus cytomegalovirus.

    Directory of Open Access Journals (Sweden)

    Colin J Powers

    2008-10-01

    Full Text Available The US2-11 region of human and rhesus cytomegalovirus encodes a conserved family of glycoproteins that inhibit MHC-I assembly with viral peptides, thus preventing cytotoxic T cell recognition. Since HCMV lacking US2-11 is no longer able to block assembly and transport of MHC-I, we examined whether this is also observed for RhCMV lacking the corresponding region. Unexpectedly, recombinant RhCMV lacking US2-11 was still able to inhibit MHC-I expression in infected fibroblasts, suggesting the presence of an additional MHC-I evasion mechanism. Progressive deletion analysis of RhCMV-specific genomic regions revealed that MHC-I expression is fully restored upon additional deletion of rh178. The protein encoded by this RhCMV-specific open reading frame is anchored in the endoplasmic reticulum membrane. In the presence of rh178, RhCMV prevented MHC-I heavy chain (HC expression, but did not inhibit mRNA transcription or association of HC mRNA with translating ribosomes. Proteasome inhibitors stabilized a HC degradation intermediate in the absence of rh178, but not in its presence, suggesting that rh178 prevents completion of HC translation. This interference was signal sequence-dependent since replacing the signal peptide with that of CD4 or murine HC rendered human HCs resistant to rh178. We have identified an inhibitor of antigen presentation encoded by rhesus cytomegalovirus unique in both its lack of homology to any other known protein and in its mechanism of action. By preventing signal sequence-dependent HC translocation, rh178 acts prior to US2, US3 and US11 which attack MHC-I proteins after protein synthesis is completed. Rh178 is the first viral protein known to interfere at this step of the MHC-I pathway, thus taking advantage of the conserved nature of HC leader peptides, and represents a new mechanism of translational interference.

  11. Predicting peptides binding to MHC class II molecules using multi-objective evolutionary algorithms

    Directory of Open Access Journals (Sweden)

    Feng Lin

    2007-11-01

    Full Text Available Abstract Background Peptides binding to Major Histocompatibility Complex (MHC class II molecules are crucial for initiation and regulation of immune responses. Predicting peptides that bind to a specific MHC molecule plays an important role in determining potential candidates for vaccines. The binding groove in class II MHC is open at both ends, allowing peptides longer than 9-mer to bind. Finding the consensus motif facilitating the binding of peptides to a MHC class II molecule is difficult because of different lengths of binding peptides and varying location of 9-mer binding core. The level of difficulty increases when the molecule is promiscuous and binds to a large number of low affinity peptides. In this paper, we propose two approaches using multi-objective evolutionary algorithms (MOEA for predicting peptides binding to MHC class II molecules. One uses the information from both binders and non-binders for self-discovery of motifs. The other, in addition, uses information from experimentally determined motifs for guided-discovery of motifs. Results The proposed methods are intended for finding peptides binding to MHC class II I-Ag7 molecule – a promiscuous binder to a large number of low affinity peptides. Cross-validation results across experiments on two motifs derived for I-Ag7 datasets demonstrate better generalization abilities and accuracies of the present method over earlier approaches. Further, the proposed method was validated and compared on two publicly available benchmark datasets: (1 an ensemble of qualitative HLA-DRB1*0401 peptide data obtained from five different sources, and (2 quantitative peptide data obtained for sixteen different alleles comprising of three mouse alleles and thirteen HLA alleles. The proposed method outperformed earlier methods on most datasets, indicating that it is well suited for finding peptides binding to MHC class II molecules. Conclusion We present two MOEA-based algorithms for finding motifs

  12. Axotomy induces MHC class I antigen expression on rat nerve cells

    DEFF Research Database (Denmark)

    Maehlen, J; Schröder, H D; Klareskog, L

    1988-01-01

    Immunomorphological staining demonstrates that class I major histocompatibility complex (MHC)-coded antigen expression can be selectively induced on otherwise class I-negative rat nerve cells by peripheral axotomy. Induction of class I as well as class II antigen expression was simultaneously seen...... on non-neural cells in the immediate vicinity of the injured nerve cells. As nerve regeneration after axotomy includes growth of new nerve cell processes and formation of new nerve cell contacts, the present findings raise the question of a role for MHC-coded molecules in cell-cell interactions during...... nerve cell growth....

  13. Horse cDNA clones encoding two MHC class I genes

    Energy Technology Data Exchange (ETDEWEB)

    Barbis, D.P.; Maher, J.K.; Stanek, J.; Klaunberg, B.A.; Antczak, D.F.

    1994-12-31

    Two full-length clones encoding MHC class I genes were isolated by screening a horse cDNA library, using a probe encoding in human HLA-A2.2Y allele. The library was made in the pcDNA1 vector (Invitrogen, San Diego, CA), using mRNA from peripheral blood lymphocytes obtained from a Thoroughbred stallion (No. 0834) homozygous for a common horse MHC haplotype (ELA-A2, -B2, -D2; Antczak et al. 1984; Donaldson et al. 1988). The clones were sequenced, using SP6 and T7 universal primers and horse-specific oligonucleotides designed to extend previously determined sequences.

  14. A Novel Therapeutic Vaccine for Metastatic Mammary Carcinoma: Focusing MHC/Peptide Complexes to Lipid Rafts

    Science.gov (United States)

    2006-11-01

    reportable outcomes). Briefly, the T cell lymphoma EL4 and the immortalized fibroblast cell line DAP (both expressing ova) were used to measure...and Use Committee. Cells , transfections, and antibodies B16.BL6 8.2, A20, EL4 and EL4 /ova were cultured as described (20-22). NIH3T3 cells were...types can donate MHC class I molecules to DC. To determine if the levels of MHC class I on the donor cell affected the efficiency of transfer, EL4 /ova

  15. The C-terminal amino acid of the MHC-I heavy chain is critical for binding to Derlin-1 in human cytomegalovirus US11-induced MHC-I degradation.

    Science.gov (United States)

    Cho, Sunglim; Kim, Bo Young; Ahn, Kwangseog; Jun, Youngsoo

    2013-01-01

    Derlin-1 plays a critical role in endoplasmic reticulum-associated protein degradation (ERAD) of a particular subset of proteins. Although it is generally accepted that Derlin-1 mediates the export of ERAD substrates from the ER to the cytosol, little is known about how Derlin-1 interacts with these substrates. Human cytomegalovirus (HCMV) US11 exploits Derlin-1-dependent ERAD to degrade major histocompatibility complex class I (MHC-I) molecules and evade immune surveillance. US11 requires the cytosolic tail of the MHC-I heavy chain to divert MHC-I molecules into the ERAD pathway for degradation; however, the underlying mechanisms remain unknown. Here, we show that the cytosolic tail of the MHC-I heavy chain, although not required for interaction with US11, is required for tight binding to Derlin-1 and thus for US11-induced dislocation of the MHC-I heavy chain to the cytosol for proteasomal degradation. Surprisingly, deletion of a single C-terminal amino acid from the cytosolic tail disrupted the interaction between MHC-I molecules and Derlin-1, rendering mutant MHC-I molecules resistant to US11-induced degradation. Consistently, deleting the C-terminal cytosolic region of Derlin-1 prevented it from binding to MHC-I molecules. Taken together, these results suggest that the cytosolic region of Derlin-1 is involved in ERAD substrate binding and that this interaction is critical for the Derlin-1-mediated dislocation of the MHC-I heavy chain to the cytosol during US11-induced MHC-I degradation.

  16. Additional file 4: of MHC class II expression and potential antigen-presenting cells in the retina during experimental autoimmune uveitis

    OpenAIRE

    Lipski, Deborah; Dewispelaere, RÊmi; Foucart, Vincent; Caspers, Laure; Defrance, Matthieu; Bruyns, Catherine; Willermain, François

    2017-01-01

    Figure S4. MHC class II expression in the retina during classical EAU. Three weeks after immunization, eye cryosections were prepared and stained for MHC class II (green) and IBA1 (red) or endoglin (magenta) detection. Cell nuclei were stained with Hoechst (blue). Each picture was chosen as representative of an experiment conducted on six or more animals. A. MHC class II and IBA1 expression. B. MHC class II and endoglin expression. (PPTX 7276 kb)

  17. Real-time, high-throughput measurements of peptide-MHC-I dissociation using a scintillation proximity assay

    DEFF Research Database (Denmark)

    Harndahl, Mikkel; Rasmussen, Michael; Røder, Gustav Andreas

    2011-01-01

    and it is well suited for high-throughput screening. To exemplify this, we screened a panel of 384 high-affinity peptides binding to the MHC class I molecule, HLA-A*02:01, and observed the rates of dissociation that ranged from 0.1h to 46h depending on the peptide used.......Efficient presentation of peptide-MHC class I complexes to immune T cells depends upon stable peptide-MHC class I interactions. Theoretically, determining the rate of dissociation of a peptide-MHC class I complexes is straightforward; in practical terms, however, generating the accurate and closely...... timed data needed to determine the rate of dissociation is not simple. Ideally, one should use a homogenous assay involving an inexhaustible and label-free assay principle. Here, we present a homogenous, high-throughput peptide-MHC class I dissociation assay, which by and large fulfill these ideal...

  18. Constitutive MHC class I molecules negatively regulate TLR-triggered inflammatory responses via the Fps-SHP-2 pathway.

    Science.gov (United States)

    Xu, Sheng; Liu, Xingguang; Bao, Yan; Zhu, Xuhui; Han, Chaofeng; Zhang, Peng; Zhang, Xuemin; Li, Weihua; Cao, Xuetao

    2012-04-22

    The molecular mechanisms that fine-tune Toll-like receptor (TLR)-triggered innate inflammatory responses remain to be fully elucidated. Major histocompatibility complex (MHC) molecules can mediate reverse signaling and have nonclassical functions. Here we found that constitutively expressed membrane MHC class I molecules attenuated TLR-triggered innate inflammatory responses via reverse signaling, which protected mice from sepsis. The intracellular domain of MHC class I molecules was phosphorylated by the kinase Src after TLR activation, then the tyrosine kinase Fps was recruited via its Src homology 2 domain to phosphorylated MHC class I molecules. This led to enhanced Fps activity and recruitment of the phosphatase SHP-2, which interfered with TLR signaling mediated by the signaling molecule TRAF6. Thus, constitutive MHC class I molecules engage in crosstalk with TLR signaling via the Fps-SHP-2 pathway and control TLR-triggered innate inflammatory responses.

  19. Leukemia prevention and long-term survival of AKR mice transplanted with MHC-matched or MHC-mismatched bone marrow

    International Nuclear Information System (INIS)

    Longley, R.E.; Good, R.A.

    1986-01-01

    The current studies were designed to evaluate the effectiveness of marrow transplantation within and outside the major histocompatibility complex (MHC) on the long-term survival and occurrence of spontaneous leukemia in AKR mice. AKR mice, which were lethally irradiated and received MHC-matched marrow from CBA/J mice (CBA----AKR), never developed leukemia and were alive and remained healthy for up to 280 days post-transplant. These long-term surviving chimeras possessed substantial immune vigor when both cell-mediated and humoral responses were tested. Lethally irradiated AKR mice, which had received MHC-mismatched marrow (anti-Thy-1.2 treated or nontreated) from C57BL/6J mice (B6----AKR), never developed leukemia and survived up to 170 days post-transplant. However, both groups of these chimeras began dying 180 to 270 days post-transplant due to a disease process which could not be readily identified. Histological analysis of B6----AKR chimeras revealed severe lymphoid cell depletion in thymus and spleen; however, none of these chimeras exhibited classical features of acute graft versus host disease. Concanavalin A mitogenesis, primary antibody responses to sheep red blood cells and the production of interleukin 2 (IL-2) were suppressed in B6----AKR chimeras. IL-2 treatment of B6----AKR chimeras was shown to partially correct these deficiencies without stimulating mixed lymphocyte responsiveness to donor or host lymphocytes. These studies indicate that the use of MHC-mismatched marrow for the prevention of spontaneous AKR leukemia may rely on augmentative IL-2 therapy for complete immune reconstitution of leukemia-free chimeras

  20. Immunization with MHC class I-negative but not -positive HPV16-associated tumour cells inhibits growth of MHC class I-negative tumours

    Czech Academy of Sciences Publication Activity Database

    Reiniš, Milan; Šímová, Jana; Indrová, Marie; Bieblová, Jana; Přibylová, Hana; Moravcová, Simona; Jandlová, Táňa; Bubeník, Jan

    2007-01-01

    Roč. 30, č. 4 (2007), s. 1011-1017 ISSN 1019-6439 R&D Projects: GA MZd NR7807 EU Projects: European Commission(XE) 18933 - CLINIGENE Grant - others:Liga proti rakovině, Praha(CZ) XX Institutional research plan: CEZ:AV0Z50520514 Keywords : HPV16 * MHC class I-deficient tumours * immunologic crossreaction Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.295, year: 2007

  1. Peptide motifs of the single dominantly expressed class I molecule explain the striking MHC-determined response to Rous sarcoma virus in chickens

    DEFF Research Database (Denmark)

    Wallny, Hans-Joachim; Avila, David; Hunt, Lawrence G.

    2006-01-01

    Compared with the MHC of typical mammals, the chicken MHC is smaller and simpler, with only two class I genes found in the B12 haplotype. We make five points to show that there is a single-dominantly expressed class I molecule that can have a strong effect on MHC function. First, we find only one...

  2. ATP depletion during mitotic arrest induces mitotic slippage and APC/CCdh1-dependent cyclin B1 degradation.

    Science.gov (United States)

    Park, Yun Yeon; Ahn, Ju-Hyun; Cho, Min-Guk; Lee, Jae-Ho

    2018-04-27

    ATP depletion inhibits cell cycle progression, especially during the G1 phase and the G2 to M transition. However, the effect of ATP depletion on mitotic progression remains unclear. We observed that the reduction of ATP after prometaphase by simultaneous treatment with 2-deoxyglucose and NaN 3 did not arrest mitotic progression. Interestingly, ATP depletion during nocodazole-induced prometaphase arrest resulted in mitotic slippage, as indicated by a reduction in mitotic cells, APC/C-dependent degradation of cyclin B1, increased cell attachment, and increased nuclear membrane reassembly. Additionally, cells successfully progressed through the cell cycle after mitotic slippage, as indicated by EdU incorporation and time-lapse imaging. Although degradation of cyclin B during normal mitotic progression is primarily regulated by APC/C Cdc20 , we observed an unexpected decrease in Cdc20 prior to degradation of cyclin B during mitotic slippage. This decrease in Cdc20 was followed by a change in the binding partner preference of APC/C from Cdc20 to Cdh1; consequently, APC/C Cdh1 , but not APC/C Cdc20 , facilitated cyclin B degradation following ATP depletion. Pulse-chase analysis revealed that ATP depletion significantly abrogated global translation, including the translation of Cdc20 and Cdh1. Additionally, the half-life of Cdh1 was much longer than that of Cdc20. These data suggest that ATP depletion during mitotic arrest induces mitotic slippage facilitated by APC/C Cdh1 -dependent cyclin B degradation, which follows a decrease in Cdc20 resulting from reduced global translation and the differences in the half-lives of the Cdc20 and Cdh1 proteins.

  3. Hsa-miR-11181 regulates Wnt signaling pathway through targeting of APC2 transcripts in SW480 cell line.

    Science.gov (United States)

    Dokanehiifard, Sadat; Soltani, Bahram M

    2018-01-30

    Wnt signaling plays important roles in differentiation, morphogenesis and development. This signaling pathway is highly regulated at all levels and microRNAs are small noncoding RNAs regulating Wnt signaling. Here, we intended to investigate hsa-miR-11181 (a novel miRNA located in TrkC gene) effect on Wnt signaling pathway in SW480 cell line. TOP/FOP flash assay indicated up-regulation of Wnt signaling, following the overexpression of hsa-miR-11181, verified through RT-qPCR. Bioinformatics analysis predicted APC1, APC2 and Axin1 might be targeted by hsa-miR-11181. Then, RT-qPCR analysis indicated that APC2 and Axin1 have been significantly down-regulated following the hsa-miR-11181 overexpression. However dual luciferase assay analysis supported only APC2 3'-UTR is directly targeted by this miRNA. Then, treatment of SW480 cells with Wnt-inhibitory small molecules supported the effect of hsa-miR-11181 at the inhibitory complex level containing APC2 protein. Consistently, viability of SW480 cells overexpressing hsa-miR-11181 was significantly elevated, measured through MTT assay. Overall, these results suggest that hsa-miR-11181 may play a crucial role in Wnt signaling regulation and confirmed that APC2 3'-UTR is targeted by hsa-miR-11181 and propose the presence of its recognition sites in the promoter or coding regions of Axin1 gene. Copyright © 2017. Published by Elsevier B.V.

  4. The effect of EBV on WIF1, NLK, and APC gene methylation and expression in gastric carcinoma and nasopharyngeal cancer.

    Science.gov (United States)

    Zhao, Zhenzhen; Liu, Wen; Liu, Jincheng; Wang, Jiayi; Luo, Bing

    2017-10-01

    Epstein-Barr virus (EBV) is an important DNA tumor virus that is associated with approximately 10% of gastric carcinomas and 99% of nasopharyngeal cancers (NPC). DNA methylation and microRNAs (miRNAs) are the most studied epigenetic mechanisms that can prompt disease susceptibility. This study aimed to detect the effect of EBV on Wnt inhibitory factor 1 (WIF1), Nemo-like kinase (NLK), and adenomatous polyposis coli (APC) gene methylation, and expression in gastric carcinoma and NPC. The WIF1, NLK, and APC gene mRNA expression levels were measured by real-time quantitative RT-PCR in four EBV-positive cell lines and four EBV-negative cell lines. Bisulfite genomic sequencing or methylation-specific PCR was used to detect the methylation status of the WIF1, NLK, and APC promoters. All cell lines were treated with 5-azacytidine (5-aza-dC), miR-BART19-3p mimics or an inhibitor, and analyzed by flow cytometry and MTT cell proliferation assays. The WIF1, NLK, and APC promoters were hypermethylated in all eight cell lines. 5-Aza-dC displayed a growth inhibitory effect on cells . After transfection with miR-BART19-3p mimics, the expression of WIF1, and APC decreased, and the cellular proliferation rate increased. After transfection with the miR-BART19-3p inhibitor, the expression levels were higher, and the cell growth was inhibited. In the NPC and GC cell lines, the promoters of WIF1, NLK, and APC are highly methylated, and the expression of these three genes is regulated by miR-BART19-3p. The activity of the Wnt pathway in EBV-associated tumors may be enhanced by miR-BART19-3p. © 2017 Wiley Periodicals, Inc.

  5. Intestinal microbiota: a potential diet-responsive prevention target in ApcMin mice.

    Science.gov (United States)

    Mai, Volker; Colbert, Lisa H; Perkins, Susan N; Schatzkin, Arthur; Hursting, Stephen D

    2007-01-01

    We previously reported that two dietary regimens, calorie restriction (CR) and a high olive oil-containing diet supplemented with a freeze-dried fruit and vegetable extract (OFV), reduced the development of intestinal adenomas in Apc(Min) mice by 57% and 33%, respectively, compared to control mice fed a defined diet ad libitum. The OFV diet was designed to have a strong effect on the composition of the intestinal microbiota through its high content of fiber, which represents a major source of fermentable substrate for the gut bacteria. We hypothesized that some of the observed effects of diet on intestinal carcinogenesis might be mediated by diet-related changes in the bacterial species that thrive in the gut. Therefore, we determined by fluorescent in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE) how the dietary interventions affected the composition of the intestinal microbiota, and we characterized specific microbiota changes that were associated with diet and reduced intestinal carcinogenesis. The OFV diet changed the overall composition of the intestinal microbiota, smaller changes were observed for the CR diet. Furthermore, we detected a 16S rDNA fragment associated with mice that did not develop polyps. Sequence analysis suggested that hitherto unidentified bacteria belonging to the family Lachnospiraceae (order Clostridiales) were its source. Thus, these bacteria may be an indicator of intestinal conditions associated with reduced intestinal carcinogenesis in Apc(Min) mice. Copyright 2006 Wiley-Liss, Inc.

  6. Evaluation of APC NbTi superconductor in a model dipole magnet

    International Nuclear Information System (INIS)

    Scanlan, R.M.; Lietzke, A.; Royet, J.; Wandesforde, A.; Taylor, C.E.; Wong, J.; Rudziak, M.K.

    1993-01-01

    The artificial pinning center (APC) approach to NbTi superconductor fabrication offers the potential benefits of higher current density and lower cost than the conventional process for NbTi. We have been evaluating several approaches for fabricating NbTi via the APC approach to determine whether these advantages can be realized in a practical conductor. The study began with the fabrication by several vendors of 10kg size samples which were evaluated as short samples. This was followed by the scale-up of one process to 150mm diameter billets. This material was evaluated first in a solenoid configuration and recently in a one-meter long dipole. We will report here on the results of these coil tests and other characterization results for this new material. We will also describe the plans to continue the scale-up to full size billets and we will discuss the potential cost savings of this approach compared with conventional NbTi fabrication

  7. Tetraspan microdomains distinct from lipid rafts enrich select peptide-MHC class II complexes

    Czech Academy of Sciences Publication Activity Database

    Kropshofer, H.; Spindeldreher, S.; Rohn, T. A.; Platania, N.; Grygar, C.; Daniel, N.; Wolpl, A.; Langen, H.; Hořejší, Václav; Vogt, A. B.

    2002-01-01

    Roč. 3, č. 1 (2002), s. 61-68 ISSN 1529-2908 Institutional research plan: CEZ:AV0Z5052915 Keywords : MHC II * tetraspan microdomains * peptide presentation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 27.868, year: 2002

  8. MHC class II B diversity in blue tits: a preliminary study.

    Science.gov (United States)

    Aguilar, Juan Rivero-de; Schut, Elske; Merino, Santiago; Martínez, Javier; Komdeur, Jan; Westerdahl, Helena

    2013-07-01

    In this study, we partly characterize major histocompatibility complex (MHC) class II B in the blue tit (Cyanistes caeruleus). A total of 22 individuals from three different European locations: Spain, The Netherlands, and Sweden were screened for MHC allelic diversity. The MHC genes were investigated using both PCR-based methods and unamplified genomic DNA with restriction fragment length polymorphism (RFLP) and southern blots. A total of 13 different exon 2 sequences were obtained independently from DNA and/or RNA, thus confirming gene transcription and likely functionality of the genes. Nine out of 13 alleles were found in more than one country, and two alleles appeared in all countries. Positive selection was detected in the region coding for the peptide binding region (PBR). A maximum of three alleles per individual was detected by sequencing and the RFLP pattern consisted of 4-7 fragments, indicating a minimum number of 2-4 loci per individual. A phylogenetic analysis, demonstrated that the blue tit sequences are divergent compared to sequences from other passerines resembling a different MHC lineage than those possessed by most passerines studied to date.

  9. Species-specific evolution of class I MHC genes in iguanas (order: Squamata; subfamily: Iguaninae).

    Science.gov (United States)

    Glaberman, Scott; Caccone, Adalgisa

    2008-07-01

    Over the last few decades, the major histocompatibility complex (MHC) has emerged as a model for understanding the influence of natural selection on genetic diversity in populations as well as for investigating the genetic basis of host resistance to pathogens. However, many vertebrate taxa remain underrepresented in the field of MHC research, preventing its application to studies of disease, evolution, and conservation genetics in these groups. This is particularly true for squamates, which are by far the most diversified order of non-avian reptiles but have not been the subject of any recent MHC studies. In this paper, we present MHC class I complementary DNA data from three squamate species in the subfamily Iguaninae (iguanas): the Galápagos marine iguana (Amblyrhynchus cristatus), the Galápagos land iguana (Conolophus subcristatus), and the green iguana (Iguana iguana). All sequences obtained are related to the few published class I genes from other squamates. There is evidence for multiple loci in each species, and the conserved alpha-3 domain appears to be evolving in a species-specific manner. Conversely, there is some indication of shared polymorphism between species in the peptide-binding alpha-1 and alpha-2 domains, suggesting that these two regions have different phylogenetic histories. The great similarity between alpha-3 sequences in marine iguanas in particular suggests that concerted evolution is acting to homogenize class I loci within species. However, while less likely, the data are also compatible with a birth and death model of evolution.

  10. AN MHC class I immune evasion gene of Marek's disease virus

    Science.gov (United States)

    Marek's disease virus (MDV) is a widespread a-herpesvirus of chickens that causes T cell tumors. Acute, but not latent, MDV infection has previously been shown to lead to downregulation of cell-surface MHC class I (Virology 282:198–205 (2001)), but the gene(s) involved have not been identified. Here...

  11. 75 FR 28685 - Colonial Bankshares, MHC, Vineland, NJ; Approval of Conversion Application

    Science.gov (United States)

    2010-05-21

    ... DEPARTMENT OF THE TREASURY Office of Thrift Supervision [AC-41: OTS Nos. 04983, H-3879, and H-4714... May 14, 2010, the Office of Thrift Supervision approved the application of Colonial Bankshares, MHC, and Colonial Bank, Vineland, New Jersey, to convert to the stock form of organization. Copies of the...

  12. 75 FR 28685 - Oritani Financial Corp., MHC, Township of Washington, NJ; Approval of Conversion Application

    Science.gov (United States)

    2010-05-21

    ... DEPARTMENT OF THE TREASURY Office of Thrift Supervision [AC-39: OTS Nos. H-2944 and H-4701... hereby given that on May 10, 2010, the Office of Thrift Supervision approved the application of Oritani Financial Corp., MHC, and Oritani Bank, Township of Washington, New Jersey, to convert to the stock form of...

  13. Evolution of MHC-based technologies used for detection of antigen-responsive T cells

    DEFF Research Database (Denmark)

    Bentzen, Amalie Kai; Hadrup, Sine Reker

    2017-01-01

    T cell-mediated recognition of peptide-major histocompatibility complex (pMHC) class I and II molecules is crucial for the control of intracellular pathogens and cancer, as well as for stimulation and maintenance of efficient cytotoxic responses. Such interactions may also play a role in the deve...

  14. MHC class I epitope binding prediction trained on small data sets

    DEFF Research Database (Denmark)

    Lundegaard, Claus; Nielsen, Morten; Lamberth, K.

    2004-01-01

    The identification of potential T-cell epitopes is important for development of new human or vetenary vaccines, both considering single protein/subunit vaccines, and for epitope/peptide vaccines as such. The highly diverse MHC class I alleles bind very different peptides, and accurate binding pre...... in situations where only very limited data are available for training....

  15. MHC class II-assortative mate choice in European badgers (Meles meles)

    NARCIS (Netherlands)

    Sin, Yung Wa; Annavi, Geetha; Newman, Chris; Buesching, Christina D.; Burke, Terry; Macdonald, David W.; Dugdale, Hannah

    The major histocompatibility complex (MHC) plays a crucial role in the immune system, and in some species, it is a target by which individuals choose mates to optimize the fitness of their offspring, potentially mediated by olfactory cues. Under the genetic compatibility hypothesis, individuals are

  16. MHC class I dowregulation, tumour escape from immune surveillance and design of therapeutic strategies

    Czech Academy of Sciences Publication Activity Database

    Bubeník, Jan

    2005-01-01

    Roč. 51, č. 1 (2005), s. 1-2 ISSN 0015-5500 R&D Projects: GA ČR GA301/04/0492; GA MZd NR7807 Institutional research plan: CEZ:AV0Z50520514 Keywords : MHC class I * immune surveillance * immunotherapy Subject RIV: EC - Immunology Impact factor: 0.719, year: 2005

  17. Variation in MHC class II B genes in marbled murrelets: implications for delineating conservation units

    Science.gov (United States)

    C. Vásquez-Carrillo; V. Friesen; L. Hall; M.Z. Peery

    2013-01-01

    Conserving genetic variation is critical for maintaining the evolutionary potential and viability of a species. Genetic studies seeking to delineate conservation units, however, typically focus on characterizing neutral genetic variation and may not identify populations harboring local adaptations. Here, variation at two major histocompatibility complex (MHC) class II...

  18. Mechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell Membrane

    KAUST Repository

    La Rocca, Rosanna; Tallerico, Rossana; Talib Hassan, Almosawy; Das, Gobind; Tadepally, Lakshmikanth; Matteucci, Marco; Liberale, Carlo; Mesuraca, Maria; Scumaci, Domenica; Gentile, Francesco; Cojoc, Gheorghe; Perozziello, Gerardo; Ammendolia, Antonio; Gallo, Adriana; Kä rre, Klas; Cuda, Giovanni; Candeloro, Patrizio; Di Fabrizio, Enzo M.; Carbone, Ennio

    2014-01-01

    bar (1 bar = 100.000 Pascal), depending on the devices used. Moreover, Raman spectroscopy analysis, after mechanical treatment, in the range between 700–1800 cm−1, indicated a relative concentration variation of MHC class I. PCA analysis was also

  19. Limitations of Ab Initio Predictions of Peptide Binding to MHC Class II Molecules

    DEFF Research Database (Denmark)

    Zhang, Hao; Lund, Ole; Nielsen, Morten

    2010-01-01

    potentials derived from the analysis of known protein structures; energetic evaluation of different peptide snapshots in a molecular dynamics simulation; and direct analysis of contacts made in known 3D structures of peptide:MHC complexes. These methods are ab initio in that they require structural data...

  20. Peptide-MHC class I stability is a stronger predictor of CTL immunogenicity than peptide affinity

    DEFF Research Database (Denmark)

    Harndahl, Mikkel Nors; Rasmussen, Michael; Nielsen, Morten

    2012-01-01

    Peptide-MHC class I stability is a stronger predictor of CTL immunogenicity than peptide affinity Mikkel Harndahla, Michael Rasmussena, Morten Nielsenb, Soren Buusa,∗ a Laboratory of Experimental Immunology, Faculty of Health Sciences, University of Copenhagen, Denmark b Center for Biological Seq...... al., 2007. J. Immunol. 178, 7890–7901. doi:10.1016/j.molimm.2012.02.025...

  1. Red Queen Processes Drive Positive Selection on Major Histocompatibility Complex (MHC Genes.

    Directory of Open Access Journals (Sweden)

    Maciej Jan Ejsmond

    2015-11-01

    Full Text Available Major Histocompatibility Complex (MHC genes code for proteins involved in the incitation of the adaptive immune response in vertebrates, which is achieved through binding oligopeptides (antigens of pathogenic origin. Across vertebrate species, substitutions of amino acids at sites responsible for the specificity of antigen binding (ABS are positively selected. This is attributed to pathogen-driven balancing selection, which is also thought to maintain the high polymorphism of MHC genes, and to cause the sharing of allelic lineages between species. However, the nature of this selection remains controversial. We used individual-based computer simulations to investigate the roles of two phenomena capable of maintaining MHC polymorphism: heterozygote advantage and host-pathogen arms race (Red Queen process. Our simulations revealed that levels of MHC polymorphism were high and driven mostly by the Red Queen process at a high pathogen mutation rate, but were low and driven mostly by heterozygote advantage when the pathogen mutation rate was low. We found that novel mutations at ABSs are strongly favored by the Red Queen process, but not by heterozygote advantage, regardless of the pathogen mutation rate. However, while the strong advantage of novel alleles increased the allele turnover rate, under a high pathogen mutation rate, allelic lineages persisted for a comparable length of time under Red Queen and under heterozygote advantage. Thus, when pathogens evolve quickly, the Red Queen is capable of explaining both positive selection and long coalescence times, but the tension between the novel allele advantage and persistence of alleles deserves further investigation.

  2. Improved methods for predicting peptide binding affinity to MHC class II molecules.

    Science.gov (United States)

    Jensen, Kamilla Kjaergaard; Andreatta, Massimo; Marcatili, Paolo; Buus, Søren; Greenbaum, Jason A; Yan, Zhen; Sette, Alessandro; Peters, Bjoern; Nielsen, Morten

    2018-01-06

    Major histocompatibility complex class II (MHC-II) molecules are expressed on the surface of professional antigen-presenting cells where they display peptides to T helper cells, which orchestrate the onset and outcome of many host immune responses. Understanding which peptides will be presented by the MHC-II molecule is therefore important for understanding the activation of T helper cells and can be used to identify T-cell epitopes. We here present updated versions of two MHC-II-peptide binding affinity prediction methods, NetMHCII and NetMHCIIpan. These were constructed using an extended data set of quantitative MHC-peptide binding affinity data obtained from the Immune Epitope Database covering HLA-DR, HLA-DQ, HLA-DP and H-2 mouse molecules. We show that training with this extended data set improved the performance for peptide binding predictions for both methods. Both methods are publicly available at www.cbs.dtu.dk/services/NetMHCII-2.3 and www.cbs.dtu.dk/services/NetMHCIIpan-3.2. © 2018 John Wiley & Sons Ltd.

  3. Tolerance to MHC class II disparate allografts through genetic modification of bone marrow

    Science.gov (United States)

    Jindra, Peter T.; Tripathi, Sudipta; Tian, Chaorui; Iacomini, John; Bagley, Jessamyn

    2012-01-01

    Induction of molecular chimerism through genetic modification of bone marrow is a powerful tool for the induction of tolerance. Here we demonstrate for the first time that expression of an allogeneic MHC class II gene in autologous bone marrow cells, resulting in a state of molecular chimerism, induces tolerance to MHC class II mismatched skin grafts, a stringent test of transplant tolerance. Reconstitution of recipients with syngeneic bone marrow transduced with retrovirus encoding H-2I-Ab (I-Ab) resulted the long-term expression of the retroviral gene product on the surface of MHC class II-expressing bone marrow derived cell types. Mechanistically, tolerance was maintained by the presence of regulatory T cells, which prevented proliferation and cytokine production by alloreactive host T cells. Thus, the introduction of MHC class II genes into bone marrow derived cells through genetic engineering results in tolerance. These results have the potential to extend the clinical applicability of molecular chimerism for tolerance induction. PMID:22833118

  4. Establishment of a quantitative ELISA capable of determining peptide - MHC class I interaction

    DEFF Research Database (Denmark)

    Sylvester-Hvid, C; Kristensen, N; Blicher, T

    2002-01-01

    dependent manner. Here, we exploit the availability of these molecules to generate a quantitative ELISA-based assay capable of measuring the affinity of the interaction between peptide and MHC-I. This assay is simple and sensitive, and one can easily envisage that the necessary reagents, standards...

  5. Thymic repopulation following intrathymic injection of mouse bone marrow cells in MHC matched and mismatched recipients

    International Nuclear Information System (INIS)

    Chervenak, R.

    1986-01-01

    T cell precursors (pre-T cells) have traditionally been detected by their ability to repopulate the thymus of heavily irradiated mice following intravenous injection. Recently, Goldschneider et. al. developed an assay system which involves the direct injection of pre-T cells into the thymus. The authors used this technique to evaluate the ability of bone marrow cells to repopulate thymuses in various donor-host strain combinations. Sub-lethally irradiated (600R) mice were injected intrathymically with 2 x 10 6 bone marrow cells which differed from the recipient with respect to their Thy 1 allotype. The percentage of thymus cells expressing either the donor or recipient type Thy 1 marker was determined 14 to 21 days after injection. These experiments showed that in MHC matched donor-host combinations (AKR/cum → AKR/J and CBA/J → AKR/J), cells derived from the donor inoculum accounted for 40% to 75% of the total thymus population. MHC mismatched donor-host combinations (C57BL/6J → AKR/J and Balb/c → AKR/J) resulted in significantly less donor-type repopulation of the thymus. In these cases, donor repopulation typically ranged from 0% to 4%. The ability of the pre-T cells detected by intrathymic injection to proliferate in the thymic environment, therefore, appears to be influenced by the MHC. This may reflect commitment of pre-T cells to MHC haplotype recognition prior to their migration to the thymus

  6. The MHC locus and genetic susceptibility to autoimmune and infectious diseases

    NARCIS (Netherlands)

    Matzaraki, Vasiliki; Kumar, Vinod; Wijmenga, Cisca; Zhernakova, Alexandra

    2017-01-01

    In the past 50 years, variants in the major histocompatibility complex (MHC) locus, also known as the human leukocyte antigen (HLA), have been reported as major risk factors for complex diseases. Recent advances, including large genetic screens, imputation, and analyses of non-additive and epistatic

  7. NetMHCpan, a method for MHC class I binding prediction beyond humans

    DEFF Research Database (Denmark)

    Hoof, Ilka; Peters, B; Sidney, J

    2009-01-01

    molecules. We show that the NetMHCpan-2.0 method can accurately predict binding to uncharacterized HLA molecules, including HLA-C and HLA-G. Moreover, NetMHCpan-2.0 is demonstrated to accurately predict peptide binding to chimpanzee and macaque MHC class I molecules. The power of NetMHCpan-2.0 to guide...

  8. High-resolution melting (HRM) re-analysis of a polyposis patients cohort reveals previously undetected heterozygous and mosaic APC gene mutations.

    Science.gov (United States)

    Out, Astrid A; van Minderhout, Ivonne J H M; van der Stoep, Nienke; van Bommel, Lysette S R; Kluijt, Irma; Aalfs, Cora; Voorendt, Marsha; Vossen, Rolf H A M; Nielsen, Maartje; Vasen, Hans F A; Morreau, Hans; Devilee, Peter; Tops, Carli M J; Hes, Frederik J

    2015-06-01

    Familial adenomatous polyposis is most frequently caused by pathogenic variants in either the APC gene or the MUTYH gene. The detection rate of pathogenic variants depends on the severity of the phenotype and sensitivity of the screening method, including sensitivity for mosaic variants. For 171 patients with multiple colorectal polyps without previously detectable pathogenic variant, APC was reanalyzed in leukocyte DNA by one uniform technique: high-resolution melting (HRM) analysis. Serial dilution of heterozygous DNA resulted in a lowest detectable allelic fraction of 6% for the majority of variants. HRM analysis and subsequent sequencing detected pathogenic fully heterozygous APC variants in 10 (6%) of the patients and pathogenic mosaic variants in 2 (1%). All these variants were previously missed by various conventional scanning methods. In parallel, HRM APC scanning was applied to DNA isolated from polyp tissue of two additional patients with apparently sporadic polyposis and without detectable pathogenic APC variant in leukocyte DNA. In both patients a pathogenic mosaic APC variant was present in multiple polyps. The detection of pathogenic APC variants in 7% of the patients, including mosaics, illustrates the usefulness of a complete APC gene reanalysis of previously tested patients, by a supplementary scanning method. HRM is a sensitive and fast pre-screening method for reliable detection of heterozygous and mosaic variants, which can be applied to leukocyte and polyp derived DNA.

  9. The World's Approach toward Publishing in Springer and Elsevier's APC-Funded Open Access Journals

    Science.gov (United States)

    Sotudeh, Hajar; Ghasempour, Zahra

    2018-01-01

    Purpose: The present study explored tendencies of the world's countries--at individual and scientific development levels--toward publishing in APC-funded open access journals. Design/Methodology/Approach: Using a bibliometric method, it studied OA and NOA articles issued in Springer and Elsevier's APC journals? during 2007-2011. The data were…

  10. IL-6 Production by TLR-Activated APC Broadly Enhances Aged Cognate CD4 Helper and B Cell Antibody Responses In Vivo.

    Science.gov (United States)

    Brahmakshatriya, Vinayak; Kuang, Yi; Devarajan, Priyadharshini; Xia, Jingya; Zhang, Wenliang; Vong, Allen Minh; Swain, Susan L

    2017-04-01

    Naive CD4 T cell responses, especially their ability to help B cell responses, become compromised with aging. We find that using APC pretreated ex vivo with TLR agonists, polyinosinic-polycytidylic acid and CpG, to prime naive CD4 T cells in vivo, restores their ability to expand and become germinal center T follicular helpers and enhances B cell IgG Ab production. Enhanced helper responses are dependent on IL-6 production by the activated APC. Aged naive CD4 T cells respond suboptimally to IL-6 compared with young cells, such that higher doses are required to induce comparable signaling. Preactivating APC overcomes this deficiency. Responses of young CD4 T cells are also enhanced by preactivating APC with similar effects but with only partial IL-6 dependency. Strikingly, introducing just the activated APC into aged mice significantly enhances otherwise compromised Ab production to inactivated influenza vaccine. These findings reveal a central role for the production of IL-6 by APC during initial cognate interactions in the generation of effective CD4 T cell help, which becomes greater with age. Without APC activation, aging CD4 T cell responses shift toward IL-6-independent Th1 and CD4 cytotoxic Th cell responses. Thus, strategies that specifically activate and provide Ag to APC could potentially enhance Ab-mediated protection in vaccine responses. Copyright © 2017 by The American Association of Immunologists, Inc.

  11. Novel mutations and phenotypic associations identified through APC, MUTYH, NTHL1, POLD1, POLE gene analysis in Indian Familial Adenomatous Polyposis cohort.

    Science.gov (United States)

    Khan, Nikhat; Lipsa, Anuja; Arunachal, Gautham; Ramadwar, Mukta; Sarin, Rajiv

    2017-05-22

    Colo-Rectal Cancer is a common cancer worldwide with 5-10% cases being hereditary. Familial Adenomatous Polyposis (FAP) syndrome is due to germline mutations in the APC or rarely MUTYH gene. NTHL1, POLD1, POLE have been recently reported in previously unexplained FAP cases. Unlike the Caucasian population, FAP phenotype and its genotypic associations have not been widely studied in several geoethnic groups. We report the first FAP cohort from South Asia and the only non-Caucasian cohort with comprehensive analysis of APC, MUTYH, NTHL1, POLD1, POLE genes. In this cohort of 112 individuals from 53 FAP families, we detected germline APC mutations in 60 individuals (45 families) and biallelic MUTYH mutations in 4 individuals (2 families). No NTHL1, POLD1, POLE mutations were identified. Fifteen novel APC mutations and a new Indian APC mutational hotspot at codon 935 were identified. Eight very rare FAP phenotype or phenotypes rarely associated with mutations outside specific APC regions were observed. APC genotype-phenotype association studies in different geo-ethnic groups can enrich the existing knowledge about phenotypic consequences of distinct APC mutations and guide counseling and risk management in different populations. A stepwise cost-effective mutation screening approach is proposed for genetic testing of south Asian FAP patients.

  12. MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus.

    Science.gov (United States)

    Yasukochi, Yoshiki; Kurosaki, Toshifumi; Yoneda, Masaaki; Koike, Hiroko; Satta, Yoko

    2012-11-29

    The major histocompatibility complex (MHC) genes are one of the most important genetic systems in the vertebrate immune response. The diversity of MHC genes may directly influence the survival of individuals against infectious disease. However, there has been no investigation of MHC diversity in the Asiatic black bear (Ursus thibetanus). Here, we analyzed 270-bp nucleotide sequences of the entire exon 2 region of the MHC DQB gene by using 188 samples from the Japanese black bear (Ursus thibetanus japonicus) from 12 local populations. Among 185 of 188 samples, we identified 44 MHC variants that encoded 31 different amino acid sequences (allotypes) and one putative pseudogene. The phylogenetic analysis suggests that MHC variants detected from the Japanese black bear are derived from the DQB locus. One of the 31 DQB allotypes, Urth-DQB*01, was found to be common to all local populations. Moreover, this allotype was shared between the black bear on the Asian continent and the Japanese black bear, suggesting that Urth-DQB*01 might have been maintained in the ancestral black bear population for at least 300,000 years. Our findings, from calculating the ratio of non-synonymous to synonymous substitutions, indicate that balancing selection has maintained genetic variation of peptide-binding residues at the DQB locus of the Japanese black bear. From examination of genotype frequencies among local populations, we observed a considerably lower level of observed heterozygosity than expected. The low level of observed heterozygosity suggests that genetic drift reduced DQB diversity in the Japanese black bear due to a bottleneck event at the population or species level. The decline of DQB diversity might have been accelerated by the loss of rare variants that have been maintained by negative frequency-dependent selection. Nevertheless, DQB diversity of the black bear appears to be relatively high compared with some other endangered mammalian species. This result suggests that

  13. MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus

    Science.gov (United States)

    2012-01-01

    Background The major histocompatibility complex (MHC) genes are one of the most important genetic systems in the vertebrate immune response. The diversity of MHC genes may directly influence the survival of individuals against infectious disease. However, there has been no investigation of MHC diversity in the Asiatic black bear (Ursus thibetanus). Here, we analyzed 270-bp nucleotide sequences of the entire exon 2 region of the MHC DQB gene by using 188 samples from the Japanese black bear (Ursus thibetanus japonicus) from 12 local populations. Results Among 185 of 188 samples, we identified 44 MHC variants that encoded 31 different amino acid sequences (allotypes) and one putative pseudogene. The phylogenetic analysis suggests that MHC variants detected from the Japanese black bear are derived from the DQB locus. One of the 31 DQB allotypes, Urth-DQB*01, was found to be common to all local populations. Moreover, this allotype was shared between the black bear on the Asian continent and the Japanese black bear, suggesting that Urth-DQB*01 might have been maintained in the ancestral black bear population for at least 300,000 years. Our findings, from calculating the ratio of non-synonymous to synonymous substitutions, indicate that balancing selection has maintained genetic variation of peptide-binding residues at the DQB locus of the Japanese black bear. From examination of genotype frequencies among local populations, we observed a considerably lower level of observed heterozygosity than expected. Conclusions The low level of observed heterozygosity suggests that genetic drift reduced DQB diversity in the Japanese black bear due to a bottleneck event at the population or species level. The decline of DQB diversity might have been accelerated by the loss of rare variants that have been maintained by negative frequency-dependent selection. Nevertheless, DQB diversity of the black bear appears to be relatively high compared with some other endangered mammalian

  14. MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus

    Directory of Open Access Journals (Sweden)

    Yasukochi Yoshiki

    2012-11-01

    Full Text Available Abstract Background The major histocompatibility complex (MHC genes are one of the most important genetic systems in the vertebrate immune response. The diversity of MHC genes may directly influence the survival of individuals against infectious disease. However, there has been no investigation of MHC diversity in the Asiatic black bear (Ursus thibetanus. Here, we analyzed 270-bp nucleotide sequences of the entire exon 2 region of the MHC DQB gene by using 188 samples from the Japanese black bear (Ursus thibetanus japonicus from 12 local populations. Results Among 185 of 188 samples, we identified 44 MHC variants that encoded 31 different amino acid sequences (allotypes and one putative pseudogene. The phylogenetic analysis suggests that MHC variants detected from the Japanese black bear are derived from the DQB locus. One of the 31 DQB allotypes, Urth-DQB*01, was found to be common to all local populations. Moreover, this allotype was shared between the black bear on the Asian continent and the Japanese black bear, suggesting that Urth-DQB*01 might have been maintained in the ancestral black bear population for at least 300,000 years. Our findings, from calculating the ratio of non-synonymous to synonymous substitutions, indicate that balancing selection has maintained genetic variation of peptide-binding residues at the DQB locus of the Japanese black bear. From examination of genotype frequencies among local populations, we observed a considerably lower level of observed heterozygosity than expected. Conclusions The low level of observed heterozygosity suggests that genetic drift reduced DQB diversity in the Japanese black bear due to a bottleneck event at the population or species level. The decline of DQB diversity might have been accelerated by the loss of rare variants that have been maintained by negative frequency-dependent selection. Nevertheless, DQB diversity of the black bear appears to be relatively high compared with some other

  15. Patterns of evolution of MHC class II genes of crows (Corvus suggest trans-species polymorphism

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    John A. Eimes

    2015-03-01

    Full Text Available A distinguishing characteristic of genes that code for the major histocompatibility complex (MHC is that alleles often share more similarity between, rather than within species. There are two likely mechanisms that can explain this pattern: convergent evolution and trans-species polymorphism (TSP, in which ancient allelic lineages are maintained by balancing selection and retained by descendant species. Distinguishing between these two mechanisms has major implications in how we view adaptation of immune genes. In this study we analyzed exon 2 of the MHC class IIB in three passerine bird species in the genus Corvus: jungle crows (Corvus macrorhynchos japonensis American crows (C. brachyrhynchos and carrion crows (C. corone orientalis. Carrion crows and American crows are recently diverged, but allopatric, sister species, whereas carrion crows and jungle crows are more distantly related but sympatric species, and possibly share pathogens linked to MHC IIB polymorphisms. These patterns of evolutionary divergence and current geographic ranges enabled us to test for trans-species polymorphism and convergent evolution of the MHC IIB in crows. Phylogenetic reconstructions of MHC IIB sequences revealed several well supported interspecific clusters containing all three species, and there was no biased clustering of variants among the sympatric carrion crows and jungle crows. The topologies of phylogenetic trees constructed from putatively selected sites were remarkably different than those constructed from putatively neutral sites. In addition, trees constructed using non-synonymous substitutions from a continuous fragment of exon 2 had more, and generally more inclusive, supported interspecific MHC IIB variant clusters than those constructed from the same fragment using synonymous substitutions. These phylogenetic patterns suggest that recombination, especially gene conversion, has partially erased the signal of allelic ancestry in these species. While

  16. Deep convolutional neural networks for pan-specific peptide-MHC class I binding prediction.

    Science.gov (United States)

    Han, Youngmahn; Kim, Dongsup

    2017-12-28

    Computational scanning of peptide candidates that bind to a specific major histocompatibility complex (MHC) can speed up the peptide-based vaccine development process and therefore various methods are being actively developed. Recently, machine-learning-based methods have generated successful results by training large amounts of experimental data. However, many machine learning-based methods are generally less sensitive in recognizing locally-clustered interactions, which can synergistically stabilize peptide binding. Deep convolutional neural network (DCNN) is a deep learning method inspired by visual recognition process of animal brain and it is known to be able to capture meaningful local patterns from 2D images. Once the peptide-MHC interactions can be encoded into image-like array(ILA) data, DCNN can be employed to build a predictive model for peptide-MHC binding prediction. In this study, we demonstrated that DCNN is able to not only reliably predict peptide-MHC binding, but also sensitively detect locally-clustered interactions. Nonapeptide-HLA-A and -B binding data were encoded into ILA data. A DCNN, as a pan-specific prediction model, was trained on the ILA data. The DCNN showed higher performance than other prediction tools for the latest benchmark datasets, which consist of 43 datasets for 15 HLA-A alleles and 25 datasets for 10 HLA-B alleles. In particular, the DCNN outperformed other tools for alleles belonging to the HLA-A3 supertype. The F1 scores of the DCNN were 0.86, 0.94, and 0.67 for HLA-A*31:01, HLA-A*03:01, and HLA-A*68:01 alleles, respectively, which were significantly higher than those of other tools. We found that the DCNN was able to recognize locally-clustered interactions that could synergistically stabilize peptide binding. We developed ConvMHC, a web server to provide user-friendly web interfaces for peptide-MHC class I binding predictions using the DCNN. ConvMHC web server can be accessible via http://jumong.kaist.ac.kr:8080/convmhc

  17. TLR4-HMGB1 signaling pathway affects the inflammatory reaction of autoimmune myositis by regulating MHC-I.

    Science.gov (United States)

    Wan, Zemin; Zhang, Xiujuan; Peng, Anping; He, Min; Lei, Zhenhua; Wang, Yunxiu

    2016-12-01

    To analyze the effects of TLR4 on the expression of the HMGB1, MHC-I and downstream cytokines IL-6 and TNF-α, and to investigate the biological role of the TLR4-HMGB1 signaling pathway in the development of the autoimmune myositis. We built mice models with experimental autoimmune myositis (EAM) and used the inverted screen experiment to measure their muscle endurance; we also examined inflammatory infiltration of muscle tissues after HE staining; and we assessed the expression of MHC-I using immunohistochemistry. In addition, peripheral blood mononuclear cells (PBMC) were extracted and flow cytometry was utilized to detect the effect of IFN-γ on the expression of MHC-I. Furthermore, PBMCs were treated with IFN-γ, anti-TLR4, anti-HMGB1 and anti-MHC-I. Real-time PCR and western blotting were employed to examine the expressions of TLR4, HMGB1 and MHC-I in different groups. The ELISA method was also utilized to detect the expression of the downstream cytokines TNF-α and IL-6. The expressions of TLR4, HMGB1 and MHC-I in muscle tissues from mice with EAM were significantly higher than those in the control group (all Pmyositis inflammation by regulating the expression of MHC-I and other pro-inflammatory cytokines. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Detection of new MHC mutations in mice by skin grafting, tumor transplantation and monoclonal antibodies: a comparison

    International Nuclear Information System (INIS)

    Egorov, I.K.; Egorov, O.S.

    1988-01-01

    Two mechanisms of major histocompatibility complex (MHC) mutations have been described in mice: gene conversion and homologous but unequal recombination. However, the knowledge of mutations in MHC is incomplete because studies have been limited almost exclusively to two haplotypes, H-2/sup b/ and H-2/sup d/, while hundreds of haplotypes exist in nature; it has been biased by the use of only one procedure of screening for mutation, skin grafting. The authors used three procedures to screen for MHC mutations: (1) conventional techniques of skin grafting, (2) syngeneic tumor transplantation and (3) typing with monoclonal anti-MHC antibodies (mAbs) and complement. The faster technique of tumor transplantation detected mutants similar to those discovered by skin grafting technique. Screening with mAbs allowed us to detect both mutants that are capable of rejecting standard skin grafts and those that are silent in skin grafting tests, and which therefore resulted in a higher apparent mutation frequency. Two mutants of the H-2/sup a/ haplotype were found that carry concomitant class I and class II antigenic alterations. Both MHC mutants silent in skin grafting tests and mutants carrying concomitant class I and class II alterations have never been studied before and are expected to reveal new mechanisms of generating MHC mutations. 1-Ethyl-1-nitrosourea (ENU) failed to induce de novo MHC mutations in our skin grafting series

  19. HUBUNGAN ANTARA PERTUMBUHAN DENGAN KEBERADAAN GEN TAHAN PENYAKIT MAJOR HISTOCOMPATIBILITY COMPLEX (MHC PADA IKAN MAS (Cyprinus carpio

    Directory of Open Access Journals (Sweden)

    Erma Primanita Hayuningtyas

    2016-04-01

    Full Text Available Wabah penyakit koi herpes virus (KHV di Indonesia yang terjadi sejak tahun 2002 merupakan salah satu faktor yang memicu kemerosotan produksi ikan mas budidaya. Pembentukan strain unggul ikan mas tahan KHV dapat menjadi solusi bagi permasalahan tersebut. Pemilihan genotip ikan mas tahan KHV dengan marka molekuler gen major histocompatibility complex class II (MHC-II, khususnya pada alel Cyca DAB 1*05 akan membantu dalam kegiatan seleksi. Penelitian ini bertujuan untuk mengetahui keberadaan gen MHC-II pada populasi dasar G0 ikan mas strain Rajadanu dan hubungannya dengan pertumbuhan (bobot. Metode deteksi keberadaan gen MHC-II pada dua kelompok ikan dengan ukuran berbeda dilakukan dengan teknik PCR. Hubungan antara pertumbuhan ikan mas dengan persentase kemunculan gen MHC-II dianalisis dengan menggunakan program SPSS (Statistical Package for the Social Sciences, sehingga diperoleh korelasi di antara keduanya. Hasil penelitian menunjukkan bahwa hubungan antara pertumbuhan dengan persentase keberadaan gen MHC-II berkorelasi negatif dengan nilai R = -0,742. Hal ini mengindikasikan bahwa semakin cepat pertumbuhan populasi ikan mas maka semakin sedikit persentase individu yang mempunyai gen MHC-II pada setiap populasi ikan mas. Sehingga populasi ikan mas yang pertumbuhannya lambat memiliki tingkat persentase positif MHC-II lebih tinggi (85,71%-100% dibandingkan populasi ikan mas yang pertumbuhannya cepat (42,86%-85,71%.

  20. Selection, diversity and evolutionary patterns of the MHC class II DAB in free-ranging Neotropical marsupials

    Directory of Open Access Journals (Sweden)

    Otten Celine

    2008-06-01

    Full Text Available Abstract Background Research on the genetic architecture and diversity of the MHC has focused mainly on eutherian mammals, birds and fish. So far, studies on model marsupials used in laboratory investigations indicated very little or even no variation in MHC class II genes. However, natural levels of diversity and selection are unknown in marsupials as studies on wild populations are virtually absent. We used two endemic South American mouse opossums, Gracilinanus microtarsus and Marmosops incanus, to investigate characteristic features of MHC selection. This study is the first investigation of MHC selection in free-ranging Neotropical marsupials. In addition, the evolutionary history of MHC lineages within the group of marsupials was examined. Results G. microtarsus showed extensive levels of MHC diversity within and among individuals as 47 MHC-DAB alleles and high levels of sequence divergence were detected at a minimum of four loci. Positively selected codon sites were identified, of which most were congruent with human antigen binding sites. The diversity in M. incanus was rather low with only eight observed alleles at presumably two loci. However, these alleles also revealed high sequence divergence. Again, positive selection was identified on specific codon sites, all congruent with human ABS and with positively selected sites observed in G. microtarsus. In a phylogenetic comparison alleles of M. incanus interspersed widely within alleles of G. microtarsus with four alleles being present in both species. Conclusion Our investigations revealed extensive MHC class II polymorphism in a natural marsupial population, contrary to previous assumptions. Furthermore, our study confirms for the first time in marsupials the presence of three characteristic features common at MHC loci of eutherian mammals, birds and fish: large allelic sequence divergence, positive selection on specific sites and trans-specific polymorphism.

  1. DETERMINATION OF PHASE COMPOSITION OF SEALING COATING BASED ON APC (ALUMINOPHOSPHATE COMPOUNDS

    Directory of Open Access Journals (Sweden)

    BOLSHAKOV V. I.

    2017-02-01

    Full Text Available Summary. Goal. To investigate the phase composition of the obtained sealing coatings based on aluminophosphate compound (APC and the impact of temperature rise on it. Methods. Qualitative X-ray phase analysis (XRPA and differential thermal analysis (DTA are used as the methods of research. Roentgenograms for structural analysis were obtained on a DRON-4-07 using filtered copper radiation in the secondary beam. Registration and initial processing of diffraction patterns was performed using the software package PDOS with the output of the diffraction patterns on the screen. Using the "loupe" option allowed to identify weak interference lines, which increased the accuracy of the method of qualitative XRPA. The thermograms for DTA received on the device type Termoskan-2. The results. It is revealed that base of coating is X-ray amorphous phase. There are following crystalline phases: Al, AlPO4, Al (PO3 3, BN found in the coating. It is revealed that annealing doesn’t make a significant influence on the phase composition of the crystalline phases and the coating doesn’t lose properties after annealing during repeated thermal stress. Scientific novelty. The phase composition of the proposed sealing coatings based on APC and produced by plasma spraying, and the effect of annealing on the phase composition of the coating are investigated. The reaction of synthesis of primary material forming on the basis of APC for coating is offered. Practical significance. The results can be used in aviation technology in the development of gas turbine engines (GTE and the design of the compressors. The sealing coating may be used to improve the reliability of the compressor and to increase the efficiency ratio of turbine engine. During the operation the compressor’s blades touch the sealing coating of compressor’s stator and grooves it without causing locking and destruction of the rotor. Therefore, the development of new sealing coating compositions that

  2. Specific blockade by CD54 and MHC II of CD40-mediated signaling for B cell proliferation and survival

    DEFF Research Database (Denmark)

    Doyle, I S; Hollmann, C A; Crispe, I N

    2001-01-01

    Regulation of B lymphocyte proliferation is critical to maintenance of self-tolerance, and intercellular interactions are likely to signal such regulation. Here, we show that coligation of either the adhesion molecule ICAM-1/CD54 or MHC II with CD40 inhibited cell cycle progression and promoted...... these effects. Addition of BCR or IL-4 signals did not overcome the effect of ICAM-1 or MHC II on CD40-induced proliferation. FasL expression was not detected in B cell populations. These results show that MHC II and ICAM-1 specifically modulate CD40-mediated signaling, so inhibiting proliferation...

  3. Casein Kinase 1δ Is an APC/CCdh1 Substrate that Regulates Cerebellar Granule Cell Neurogenesis

    Directory of Open Access Journals (Sweden)

    Clara Penas

    2015-04-01

    Full Text Available Although casein kinase 1δ (CK1δ is at the center of multiple signaling pathways, its role in the expansion of CNS progenitor cells is unknown. Using mouse cerebellar granule cell progenitors (GCPs as a model for brain neurogenesis, we demonstrate that the loss of CK1δ or treatment of GCPs with a highly selective small molecule inhibits GCP expansion. In contrast, CK1δ overexpression increases GCP proliferation. Thus, CK1δ appears to regulate GCP neurogenesis. CK1δ is targeted for proteolysis via the anaphase-promoting complex/cyclosome (APC/CCdh1 ubiquitin ligase, and conditional deletion of the APC/CCdh1 activator Cdh1 in cerebellar GCPs results in higher levels of CK1δ. APC/CCdh1 also downregulates CK1δ during cell-cycle exit. Therefore, we conclude that APC/CCdh1 controls CK1δ levels to balance proliferation and cell-cycle exit in the developing CNS. Similar studies in medulloblastoma cells showed that CK1δ holds promise as a therapeutic target.

  4. Regulation of APC and AXIN2 expression by intestinal tumor suppressor CDX2 in colon cancer cells

    DEFF Research Database (Denmark)

    Olsen, Anders Krüger; Coskun, Mehmet; Bzorek, Michael

    2013-01-01

    was associated with endogenous downregulation of APC and AXIN2 expression in Caco-2 cells but did not affect GSK3β expression. Furthermore, elevated levels of nuclear β-catenin and reduced levels of cytoplasmic APC were correlated to a low CDX2 expression in migrating colon cancer cells in vivo. These results......Wnt signaling is often constitutively active in colorectal cancer cells. The expression of the intestinal specific transcription factor CDX2 is found to be transiently decreased in invasive cells at the tumor/stroma interface. A recent ChIP-Seq study has indicated that several Wnt signaling......-related genes are regulated by CDX2. The aim was to investigate the role of decreased CDX2 level on the expression of APC, AXIN2 and GSK3β in migrating colon cancer cells at the invasive front. CDX2-bound promoter and enhancer regions from APC, AXIN2 and GSK3β were analyzed for gene regulatory activity...

  5. Dietary fat and risk of colon and rectal cancer with aberrant MLH1 expression, APC or KRAS genes.

    NARCIS (Netherlands)

    Weijenberg, M.P.; Luchtenborg, M.; Goeij, A.F. de; Brink, M.; Muijen, G.N.P. van; Bruine, A.P. de; Goldbohm, R.A.; Brandt, P.A. van den

    2007-01-01

    OBJECTIVE: To investigate baseline fat intake and the risk of colon and rectal tumors lacking MLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2) repair gene expression and harboring mutations in the APC (adenomatous polyposis coli) tumor suppressor gene and in the KRAS (v-Ki-ras2 Kirsten rat

  6. Molecular dissection of the APC/C inhibitor Rca1 shows a novel F-box-dependent function.

    Science.gov (United States)

    Zielke, Norman; Querings, Silvia; Grosskortenhaus, Ruth; Reis, Tânia; Sprenger, Frank

    2006-12-01

    Rca1 (regulator of Cyclin A)/Emi (early mitotic inhibitor) proteins are essential inhibitors of the anaphase-promoting complex/cyclosome (APC/C). In Drosophila, Rca1 is required during G2 to prevent premature cyclin degradation by the Fizzy-related (Fzr)-dependent APC/C activity. Here, we present a structure and function analysis of Rca1 showing that a carboxy-terminal fragment is sufficient for APC/C inhibition. Rca1/Emi proteins contain a conserved F-box and interact with components of the Skp-Cullin-F-box (SCF) complex. So far, no function has been ascribed to this domain. We find that the F-box of Rca1 is dispensable for APC/C-Fzr inhibition during G2. Nevertheless, we show that Rca1 has an additional function at the G1-S transition, which requires the F-box. Overexpression of Rca1 accelerates the G1-S transition in an F-box-dependent manner. Conversely, S-phase entry is delayed in cells in which endogenous Rca1 is replaced by a transgene lacking the F-box. We propose that Rca1 acts as an F-box protein in an as yet uncharacterized SCF complex, which promotes S-phase entry.

  7. Application of the microbiological method DEFT/APC to detect minimally processed vegetables treated with gamma radiation

    Science.gov (United States)

    Araújo, M. M.; Duarte, R. C.; Silva, P. V.; Marchioni, E.; Villavicencio, A. L. C. H.

    2009-07-01

    Marketing of minimally processed vegetables (MPV) are gaining impetus due to its convenience, freshness and apparent health effect. However, minimal processing does not reduce pathogenic microorganisms to safe levels. Food irradiation is used to extend the shelf life and to inactivate food-borne pathogens. In combination with minimal processing it could improve safety and quality of MPV. A microbiological screening method based on the use of direct epifluorescent filter technique (DEFT) and aerobic plate count (APC) has been established for the detection of irradiated foodstuffs. The aim of this study was to evaluate the applicability of this technique in detecting MPV irradiation. Samples from retail markets were irradiated with 0.5 and 1.0 kGy using a 60Co facility. In general, with a dose increment, DEFT counts remained similar independent of the irradiation while APC counts decreased gradually. The difference of the two counts gradually increased with dose increment in all samples. It could be suggested that a DEFT/APC difference over 2.0 log would be a criteria to judge if a MPV was treated by irradiation. The DEFT/APC method could be used satisfactorily as a screening method for indicating irradiation processing.

  8. Application of the microbiological method DEFT/APC to detect minimally processed vegetables treated with gamma radiation

    International Nuclear Information System (INIS)

    Araujo, M.M.; Duarte, R.C.; Silva, P.V.; Marchioni, E.; Villavicencio, A.L.C.H.

    2009-01-01

    Marketing of minimally processed vegetables (MPV) are gaining impetus due to its convenience, freshness and apparent health effect. However, minimal processing does not reduce pathogenic microorganisms to safe levels. Food irradiation is used to extend the shelf life and to inactivate food-borne pathogens. In combination with minimal processing it could improve safety and quality of MPV. A microbiological screening method based on the use of direct epifluorescent filter technique (DEFT) and aerobic plate count (APC) has been established for the detection of irradiated foodstuffs. The aim of this study was to evaluate the applicability of this technique in detecting MPV irradiation. Samples from retail markets were irradiated with 0.5 and 1.0 kGy using a 60 Co facility. In general, with a dose increment, DEFT counts remained similar independent of the irradiation while APC counts decreased gradually. The difference of the two counts gradually increased with dose increment in all samples. It could be suggested that a DEFT/APC difference over 2.0 log would be a criteria to judge if a MPV was treated by irradiation. The DEFT/APC method could be used satisfactorily as a screening method for indicating irradiation processing.

  9. Application of the microbiological method DEFT/APC to detect minimally processed vegetables treated with gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, M.M.; Duarte, R.C.; Silva, P.V. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Centro de Tecnologia das Radiacoes, Laboratorio de Deteccao de Alimentos Irradiados, Cidade Universitaria, Av. Prof. Lineu Prestes 2242, Butanta Zip Code 05508-000 Sao Paulo (Brazil); Marchioni, E. [Laboratoire de Chimie Analytique et Sciences de l' Aliment (UMR 7512), Faculte de Pharmacie, Universite Louis Pasteur, 74, route du Rhin, F-67400 Illkirch (France); Villavicencio, A.L.C.H. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Centro de Tecnologia das Radiacoes, Laboratorio de Deteccao de Alimentos Irradiados, Cidade Universitaria, Av. Prof. Lineu Prestes 2242, Butanta Zip Code 05508-000 Sao Paulo (Brazil)], E-mail: villavic@ipen.br

    2009-07-15

    Marketing of minimally processed vegetables (MPV) are gaining impetus due to its convenience, freshness and apparent health effect. However, minimal processing does not reduce pathogenic microorganisms to safe levels. Food irradiation is used to extend the shelf life and to inactivate food-borne pathogens. In combination with minimal processing it could improve safety and quality of MPV. A microbiological screening method based on the use of direct epifluorescent filter technique (DEFT) and aerobic plate count (APC) has been established for the detection of irradiated foodstuffs. The aim of this study was to evaluate the applicability of this technique in detecting MPV irradiation. Samples from retail markets were irradiated with 0.5 and 1.0 kGy using a {sup 60}Co facility. In general, with a dose increment, DEFT counts remained similar independent of the irradiation while APC counts decreased gradually. The difference of the two counts gradually increased with dose increment in all samples. It could be suggested that a DEFT/APC difference over 2.0 log would be a criteria to judge if a MPV was treated by irradiation. The DEFT/APC method could be used satisfactorily as a screening method for indicating irradiation processing.

  10. Thermal Treatment of Iron Oxide Stabilized APC Residues from Waste Incineration and the Effect on Heavy Metal Binding

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Stackpoole, M.; Bender-Koch, C.

    2000-01-01

    Iron oxide stabilized APC residues from MSWI were heat treated at 600°C and 900°C. The thermal treatments resulted in a change in product stability by forcing a transformation in the mineralogical structures of the products. The treatments, moreover, simulated somewhat the natural aging processes...

  11. Dietary fat and risk of colon and rectal cancer with aberrant MLH1 expression, APC or KRAS genes.

    Science.gov (United States)

    Weijenberg, Matty P; Lüchtenborg, Margreet; de Goeij, Anton F P M; Brink, Mirian; van Muijen, Goos N P; de Bruïne, Adriaan P; Goldbohm, R Alexandra; van den Brandt, Piet A

    2007-10-01

    To investigate baseline fat intake and the risk of colon and rectal tumors lacking MLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2) repair gene expression and harboring mutations in the APC (adenomatous polyposis coli) tumor suppressor gene and in the KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) oncogene. After 7.3 years of follow-up of the Netherlands Cohort Study (n = 120,852), adjusted incidence rate ratios (RR) and 95% confidence intervals (CI) were computed, based on 401 colon and 130 rectal cancer patients. Total, saturated and monounsaturated fat were not associated with the risk of colon or rectal cancer, or different molecular subgroups. There was also no association between polyunsaturated fat and the risk of overall or subgroups of rectal cancer. Linoleic acid, the most abundant polyunsaturated fatty acid in the diet, was associated with increased risk of colon tumors with only a KRAS mutation and no additional truncating APC mutation or lack of MLH1 expression (RR = 1.41, 95% CI 1.18-1.69 for one standard deviation (i.e., 7.5 g/day) increase in intake, p-trend over the quartiles of intake colon tumors without any of the gene defects, or with tumors harboring aberrations in either MLH1 or APC. Linoleic acid intake is associated with colon tumors with an aberrant KRAS gene, but an intact APC gene and MLH1 expression, suggesting a unique etiology of tumors with specific genetic aberrations.

  12. Selenium and sulindac are synergistic to inhibit intestinal tumorigenesis in Apc/p21 mice

    Directory of Open Access Journals (Sweden)

    Bi Xiuli

    2013-01-01

    Full Text Available Abstract Background Both selenium and non-steroidal anti-inflammatory drug (NSAID sulindac are effective in cancer prevention, but their effects are affected by several factors including epigenetic alterations and gene expression. The current study was designed to determine the effects of the combination of selenium and sulindac on tumor inhibition and the underlying mechanisms. Results We fed the intestinal tumor model Apc/p21 mice with selenium- and sulindac-supplemented diet for 24 weeks, and found that the combination of selenium and sulindac significantly inhibited intestinal tumorigenesis, in terms of reducing tumor incidence by 52% and tumor multiplicities by 80% (p Conclusions The selenium is synergistic with sulindac to exert maximal effects on tumor inhibition. This finding provides an important chemopreventive strategy using combination of anti-cancer agents, which has a great impact on cancer prevention and has a promising translational potential.

  13. The effect of soy isoflavones on the development of intestinal neoplasia in Apc(Min) mouse

    DEFF Research Database (Denmark)

    Sørensen, Ilona Kryspin; Kristiansen, Eva; Mortensen, Alicja

    1998-01-01

    Data from epidemiological studies suggest that isoflavones in soy may have a protective effect on the development of colon cancer in humans. Therefore, we have investigated whether soy isoflavones will inhibit intestinal tumour development in Apc(Min) mice. The mice were fed a Western-type high...... risk diet (high fat, low fibre and calcium) containing two different isolates of soy protein as a protein source. For the control and test groups this resulted in the administration of about 16 and 475 mg of total isoflavones per kg diet, respectively. As a positive control, a third group of mice...... was administered a low isoflavone diet supplemented with 300 ppm sulindac. No significant differences in the incidence, multiplicity, size and distribution of intestinal tumours were observed between Min mice fed low and high isoflavone-containing diets. However, a clear reduction in the number of small intestinal...

  14. Chemopreventive Effects of RXR-Selective Rexinoid Bexarotene on Intestinal Neoplasia of ApcMin/+ Mice

    Directory of Open Access Journals (Sweden)

    Naveena B. Janakiram

    2012-02-01

    Full Text Available Retinoid X receptor (RXR has been implicated in several neoplastic diseases. Previously, we have shown that RXR-α is downregulated in human and rodent colonic tumors, suggesting a potential target for colon cancer prevention (http://www.cancer.org/Cancer/ColonandRectumCancer/DetailedGuide/colorectal-cancer-key-statistics. Experiments were designed to assess the chemopreventive efficacy of the selective RXR agonist bexarotene for the suppression of intestinal tumorigenesis in ApcMin/+ mice. Before the efficacy studies, we determined that the maximal tolerated dose in C57BL/6J mice was less than 400 ppm. For the efficacy study, 6-week-old male and female C57BL/6J-ApcMin/+ mice (nine mice per group were fed diets containing 0, 30, and 60 ppm of bexarotene or 200 ppm of bexarotene for 80 days before intestinal tumors were evaluated. Dietary administration of 30 and 60 ppm of bexarotene suppressed the intestinal polyp formation by 38% (P < .015 and 60% (P < .0001 in males, respectively, and by 8.5% and 37% (P < .007 in females, respectively. Also, significant inhibition (50%–100% of colonic tumor formation was observed in both male and female mice with bexarotene treatment. Administration of 200 ppm of bexarotene showed significant suppression of tumor formation (66%, P < .0001; however, it had significant toxicity. Intestinal tumors of bexarotene-fed mice showed significantly reduced expression of proliferating cell nuclear antigen (60%, P < .0001, cyclin D1, and cyclooxygenase 2 and increased RXR-α messenger RNA and uptake of oleate (34%, P < .01. Also, bexarotene-fed mice showed dose-dependent suppression of serum triglycerides (25%–72%, P < .0001 and inflammatory cytokines.

  15. Voluntary exercise inhibits intestinal tumorigenesis in ApcMin/+ mice and azoxymethane/dextran sulfate sodium-treated mice

    International Nuclear Information System (INIS)

    Ju, Jihyeung; Nolan, Bonnie; Cheh, Michelle; Bose, Mousumi; Lin, Yong; Wagner, George C; Yang, Chung S

    2008-01-01

    Epidemiological studies suggest that physical activity reduces the risk of colon cancer in humans. Results from animal studies, however, are inconclusive. The present study investigated the effects of voluntary exercise on intestinal tumor formation in two different animal models, Apc Min/+ mice and azoxymethane (AOM)/dextran sulfate sodium (DSS)-treated mice. In Experiments 1 and 2, five-week old female Apc Min/+ mice were either housed in regular cages or cages equipped with a running wheel for 6 weeks (for mice maintained on the AIN93G diet; Experiment 1) or 9 weeks (for mice on a high-fat diet; Experiment 2). In Experiment 3, male CF-1 mice at 6 weeks of age were given a dose of AOM (10 mg/kg body weight, i.p.) and, 12 days later, 1.5% DSS in drinking fluid for 1 week. The mice were then maintained on a high-fat diet and housed in regular cages or cages equipped with a running wheel for 16 weeks. In the Apc Min/+ mice maintained on either the AIN93G or the high-fat diet, voluntary exercise decreased the number of small intestinal tumors. In the AOM/DSS-treated mice maintained on a high-fat diet, voluntary exercise also decreased the number of colon tumors. In Apc Min/+ mice, voluntary exercise decreased the ratio of serum insulin like growth factor (IGF)-1 to IGF binding protein (BP)-3 levels. It also decreased prostaglandin E 2 and nuclear β-catenin levels, but increased E-cadherin levels in the tumors. These results indicate hat voluntary exercise inhibited intestinal tumorigenesis in Apc Min/+ mice and AOM/DSS-treated mice, and the inhibitory effect is associated with decreased IGF-1/IGFBP-3 ratio, aberrant β-catenin signaling, and arachidonic acid metabolism

  16. Apc inactivation, but not obesity, synergizes with Pten deficiency to drive intestinal stem cell-derived tumorigenesis.

    Science.gov (United States)

    Tabrizian, Tahmineh; Wang, Donghai; Guan, Fangxia; Hu, Zunju; Beck, Amanda P; Delahaye, Fabien; Huffman, Derek M

    2017-06-01

    Obesity is a major risk factor for colorectal cancer and can accelerate Lgr5+ intestinal stem cell (ISC)-derived tumorigenesis after the inactivation of Apc However, whether non-canonical pathways involving PI3K-Akt signaling in ISCs can lead to tumor formation, and if this can be further exacerbated by obesity is unknown. Despite the synergy between Pten and Apc inactivation in epithelial cells on intestinal tumor formation, their combined role in Lgr5+-ISCs, which are the most rapidly dividing ISC population in the intestine, is unknown. Lgr5+-GFP mice were provided low-fat diet (LFD) or high-fat diet (HFD) for 8 months, and the transcriptome was evaluated in Lgr5+-ISCs. For tumor studies, Lgr5+-GFP and Lgr5+-GFP- Pten flox/flox mice were tamoxifen treated to inactivate Pten in ISCs and provided LFD or HFD until 14-15 months of age. Finally, various combinations of Lgr5+-ISC-specific, Apc- and Pten -deleted mice were generated and evaluated for histopathology and survival. HFD did not overtly alter Akt signaling in ISCs, but did increase other metabolic pathways. Pten deficiency, but not HFD, increased BrdU-positive cells in the small intestine ( P  Apc deficiency synergistically increased proliferative markers, tumor pathology and mortality, in a dose-dependent fashion ( P  Apc deficiency in ISCs synergistically increases proliferation, tumor formation and mortality. Thus, aberrant Wnt/β-catenin, rather than PI3K-Akt signaling, is requisite for obesity to drive Lgr5+ ISC-derived tumorigenesis. © 2017 Society for Endocrinology.

  17. Regulation of nuclear envelope dynamics via APC/C is necessary for the progression of semi-open mitosis in Schizosaccharomyces japonicus.

    Science.gov (United States)

    Aoki, Keita; Shiwa, Yuh; Takada, Hiraku; Yoshikawa, Hirofumi; Niki, Hironori

    2013-09-01

    Three types of mitosis, which are open, closed or semi-open mitosis, function in eukaryotic cells, respectively. The open mitosis involves breakage of the nuclear envelope before nuclear division, whereas the closed mitosis proceeds with an intact nuclear envelope. To understand the mechanism and significance of three types of mitotic division in eukaryotes, we investigated the process of semi-open mitosis, in which the nuclear envelope is only partially broken, in the fission yeast Schizosaccharomyces japonicus. In anaphase-promoting complex/cyclosome (APC/C) mutants of Sz. japonicus, the nuclear envelope remained relatively intact during anaphase, resulting in impaired semi-open mitosis. As a suppressor of apc2 mutant, a mutation of Oar2, which was a 3-oxoacyl-[acyl carrier protein] reductase, was obtained. The level of the Oar2, which had two destruction-box motifs recognized by APC/C, was increased in APC/C mutants. Furthermore, the defective semi-open mitosis observed in an apc2 mutant was restored by mutated oar2+. Based on these findings, we propose that APC/C regulates the dynamics of the nuclear envelope through degradation of Oar2 dependent on APC/C during the metaphase-to-anaphase transition of semi-open mitosis in Sz. japonicus. © 2013 The Authors Genes to Cells © 2013 by the Molecular Biology Society of Japan and Wiley Publishing Asia Pty Ltd.

  18. Definition of APC presentation of phosphoantigen (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate to Vgamma2Vdelta 2 TCR.

    Science.gov (United States)

    Wei, Huiyong; Huang, Dan; Lai, Xiaomin; Chen, Meiling; Zhong, Weihua; Wang, Richard; Chen, Zheng W

    2008-10-01

    Although microbial (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP) can activate primate Vgamma2Vdelta2 T cells, molecular mechanisms by which HMBPP interacts with Vgamma2Vdelta2 T cells remain poorly characterized. Here, we developed soluble, tetrameric Vgamma2Vdelta2 TCR of rhesus macaques to define HMBPP/APC interaction with Vgamma2Vdelta2 TCR. While exogenous HMBPP was associated with APC membrane in an appreciable affinity, the membrane-associated HMBPP readily bound to the Vgamma2Vdelta2 TCR tetramer. The Vgamma2Vdelta2 TCR tetramer was shown to bind stably to HMBPP presented on membrane by various APC cell lines from humans and nonhuman primates but not those from mouse, rat, or pig. The Vgamma2Vdelta2 TCR tetramer also bound to the membrane-associated HMBPP on primary monocytes, B cells and T cells. Consistently, endogenous phosphoantigen produced in Mycobacterium-infected dendritic cells was transported and presented on membrane, and bound stably to the Vgamma2Vdelta2 TCR tetramer. The capability of APC to present HMBPP for recognition by Vgamma2Vdelta2 TCR was diminished after protease treatment of APC. Thus, our studies elucidated an affinity HMBPP-APC association conferring stable binding to the Vgamma2Vdelta2 TCR tetramer and the protease-sensitive nature of phosphoantigen presentation. The findings defined APC presentation of phosphoantigen HMBPP to Vgamma2Vdelta2 TCR.

  19. Nek2A destruction marks APC/C activation at the prophase-to-prometaphase transition by spindle-checkpoint-restricted Cdc20.

    Science.gov (United States)

    Boekhout, Michiel; Wolthuis, Rob

    2015-04-15

    Nek2 isoform A (Nek2A) is a presumed substrate of the anaphase-promoting complex/cyclosome containing Cdc20 (APC/C(Cdc20)). Nek2A, like cyclin A, is degraded in mitosis while the spindle checkpoint is active. Cyclin A prevents spindle checkpoint proteins from binding to Cdc20 and is recruited to the APC/C in prometaphase. We found that Nek2A and cyclin A avoid being stabilized by the spindle checkpoint in different ways. First, enhancing mitotic checkpoint complex (MCC) formation by nocodazole treatment inhibited the degradation of geminin and cyclin A, whereas Nek2A disappeared at a normal rate. Second, depleting Cdc20 effectively stabilized cyclin A but not Nek2A. Nevertheless, Nek2A destruction crucially depended on Cdc20 binding to the APC/C. Third, in contrast to cyclin A, Nek2A was recruited to the APC/C before the start of mitosis. Interestingly, the spindle checkpoint very effectively stabilized an APC/C-binding mutant of Nek2A, which required the Nek2A KEN box. Apparently, in cells, the spindle checkpoint primarily prevents Cdc20 from binding destruction motifs. Nek2A disappearance marks the prophase-to-prometaphase transition, when Cdc20, regardless of the spindle checkpoint, activates the APC/C. However, Mad2 depletion accelerated Nek2A destruction, showing that spindle checkpoint release further increases APC/C(Cdc20) catalytic activity. © 2015. Published by The Company of Biologists Ltd.

  20. Mechanisms controlling the temporal degradation of Nek2A and Kif18A by the APC/C-Cdc20 complex

    DEFF Research Database (Denmark)

    Sedgwick, G.G.; Hayward, D.G.; Nilsson, J.

    2013-01-01

    The Anaphase Promoting Complex/Cyclosome (APC/C) in complex with its co-activator Cdc20 is responsible for targeting proteins for ubiquitin-mediated degradation during mitosis. The activity of APC/C-Cdc20 is inhibited during prometaphase by the Spindle Assembly Checkpoint (SAC) yet certain...... substrates escape this inhibition. Nek2A degradation during prometaphase depends on direct binding of Nek2A to the APC/C via a C-terminal MR dipeptide but whether this motif alone is sufficient is not clear. Here, we identify Kif18A as a novel APC/C-Cdc20 substrate and show that Kif18A degradation depends...... by the APC/C. Nek2A and the mitotic checkpoint complex (MCC) have an overlap in APC/C subunit requirements for binding and we propose that Nek2A binds with high affinity to apo-APC/C and is degraded by the pool of Cdc20 that avoids inhibition by the SAC....

  1. Prediction of MHC class II binding affinity using SMM-align, a novel stabilization matrix alignment method

    DEFF Research Database (Denmark)

    Nielsen, Morten; Lundegaard, Claus; Lund, Ole

    2007-01-01

    the correct alignment of a peptide in the binding groove a crucial part of identifying the core of an MHC class II binding motif. Here, we present a novel stabilization matrix alignment method, SMM-align, that allows for direct prediction of peptide:MHC binding affinities. The predictive performance...... of the method is validated on a large MHC class II benchmark data set covering 14 HLA-DR (human MHC) and three mouse H2-IA alleles. RESULTS: The predictive performance of the SMM-align method was demonstrated to be superior to that of the Gibbs sampler, TEPITOPE, SVRMHC, and MHCpred methods. Cross validation...... between peptide data set obtained from different sources demonstrated that direct incorporation of peptide length potentially results in over-fitting of the binding prediction method. Focusing on amino terminal peptide flanking residues (PFR), we demonstrate a consistent gain in predictive performance...

  2. The mRNA expression profile of metabolic genes relative to MHC isoform pattern in human skeletal muscles

    DEFF Research Database (Denmark)

    Plomgaard, Peter; Penkowa, Milena; Leick, Lotte

    2006-01-01

    The metabolic profile of rodent muscle is generally reflected in the myosin heavy chain (MHC) fiber-type composition. The present study was conducted to test the hypothesis that metabolic gene expression is not tightly coupled with MHC fiber-type composition for all genes in human skeletal muscle....... Triceps brachii, vastus lateralis quadriceps, and soleus muscle biopsies were obtained from normally physically active, healthy, young male volunteers, because these muscles are characterized by different fiber-type compositions. As expected, citrate synthase and 3-hydroxyacyl dehydrogenase activity...... of a broad range of metabolic genes. The triceps muscle had two- to fivefold higher MHC IIa, phosphofructokinase, and LDH A mRNA content and two- to fourfold lower MHC I, lipoprotein lipase, CD36, hormone-sensitive lipase, and LDH B and hexokinase II mRNA than vastus lateralis or soleus. Interestingly...

  3. Reversible epigenetic down-regulation of MHC molecules by devil facial tumour disease illustrates immune escape by a contagious cancer

    DEFF Research Database (Denmark)

    Siddle, Hannah V; Kreiss, Alexandre; Tovar, Cesar

    2013-01-01

    Contagious cancers that pass between individuals as an infectious cell line are highly unusual pathogens. Devil facial tumor disease (DFTD) is one such contagious cancer that emerged 16 y ago and is driving the Tasmanian devil to extinction. As both a pathogen and an allograft, DFTD cells should...... be rejected by the host-immune response, yet DFTD causes 100% mortality among infected devils with no apparent rejection of tumor cells. Why DFTD cells are not rejected has been a question of considerable confusion. Here, we show that DFTD cells do not express cell surface MHC molecules in vitro or in vivo......, MHC class I molecules can be restored to the surface of DFTD cells in vitro by using recombinant devil IFN-γ, which is associated with up-regulation of the MHC class II transactivator, a key transcription factor with deacetylase activity. Further, expression of MHC class I molecules by DFTD cells can...

  4. MHC class II tetramers made from isolated recombinant α and β chains refolded with affinity-tagged peptides

    DEFF Research Database (Denmark)

    Braendstrup, Peter; Justesen, Sune Frederik Lamdahl; Osterbye, Thomas

    2013-01-01

    Targeting CD4+ T cells through their unique antigen-specific, MHC class II-restricted T cell receptor makes MHC class II tetramers an attractive strategy to identify, validate and manipulate these cells at the single cell level. Currently, generating class II tetramers is a specialized undertaking...... effectively limiting their use and emphasizing the need for improved methods of production. Using class II chains expressed individually in E. coli as versatile recombinant reagents, we have previously generated peptide-MHC class II monomers, but failed to generate functional class II tetramers. Adding...... a monomer purification principle based upon affinity-tagged peptides, we here provide a robust method to produce class II tetramers and demonstrate staining of antigen-specific CD4+ T cells. We also provide evidence that both MHC class II and T cell receptor molecules largely accept affinity-tagged peptides...

  5. Generation of murine tumor cell lines deficient in MHC molecule surface expression using the CRISPR/Cas9 system.

    Directory of Open Access Journals (Sweden)

    Krishna Das

    Full Text Available In this study, the CRISPR/Cas9 technology was used to establish murine tumor cell lines, devoid of MHC I or MHC II surface expression, respectively. The melanoma cell line B16F10 and the murine breast cancer cell line EO-771, the latter stably expressing the tumor antigen NY-BR-1 (EO-NY, were transfected with an expression plasmid encoding a β2m-specific single guide (sgRNA and Cas9. The resulting MHC I negative cells were sorted by flow cytometry to obtain single cell clones, and loss of susceptibility of peptide pulsed MHC I negative clones to peptide-specific CTL recognition was determined by IFNγ ELISpot assay. The β2m knockout (KO clones did not give rise to tumors in syngeneic mice (C57BL/6N, unless NK cells were depleted, suggesting that outgrowth of the β2m KO cell lines was controlled by NK cells. Using sgRNAs targeting the β-chain encoding locus of the IAb molecule we also generated several B16F10 MHC II KO clones. Peptide loaded B16F10 MHC II KO cells were insusceptible to recognition by OT-II cells and tumor growth was unaltered compared to parental B16F10 cells. Thus, in our hands the CRISPR/Cas9 system has proven to be an efficient straight forward strategy for the generation of MHC knockout cell lines. Such cell lines could serve as parental cells for co-transfection of compatible HLA alleles together with human tumor antigens of interest, thereby facilitating the generation of HLA matched transplantable tumor models, e.g. in HLAtg mouse strains of the newer generation, lacking cell surface expression of endogenous H2 molecules. In addition, our tumor cell lines established might offer a useful tool to investigate tumor reactive T cell responses that function independently from MHC molecule surface expression by the tumor.

  6. Probing natural killer cell education by Ly49 receptor expression analysis and computational modelling in single MHC class I mice.

    Directory of Open Access Journals (Sweden)

    Sofia Johansson

    Full Text Available Murine natural killer (NK cells express inhibitory Ly49 receptors for MHC class I molecules, which allows for "missing self" recognition of cells that downregulate MHC class I expression. During murine NK cell development, host MHC class I molecules impose an "educating impact" on the NK cell pool. As a result, mice with different MHC class I expression display different frequency distributions of Ly49 receptor combinations on NK cells. Two models have been put forward to explain this impact. The two-step selection model proposes a stochastic Ly49 receptor expression followed by selection for NK cells expressing appropriate receptor combinations. The sequential model, on the other hand, proposes that each NK cell sequentially expresses Ly49 receptors until an interaction of sufficient magnitude with self-class I MHC is reached for the NK cell to mature. With the aim to clarify which one of these models is most likely to reflect the actual biological process, we simulated the two educational schemes by mathematical modelling, and fitted the results to Ly49 expression patterns, which were analyzed in mice expressing single MHC class I molecules. Our results favour the two-step selection model over the sequential model. Furthermore, the MHC class I environment favoured maturation of NK cells expressing one or a few self receptors, suggesting a possible step of positive selection in NK cell education. Based on the predicted Ly49 binding preferences revealed by the model, we also propose, that Ly49 receptors are more promiscuous than previously thought in their interactions with MHC class I molecules, which was supported by functional studies of NK cell subsets expressing individual Ly49 receptors.

  7. De novo transcriptome assembly facilitates characterisation of fast-evolving gene families, MHC class I in the bank vole (Myodes glareolus).

    Science.gov (United States)

    Migalska, M; Sebastian, A; Konczal, M; Kotlík, P; Radwan, J

    2017-04-01

    The major histocompatibility complex (MHC) plays a central role in the adaptive immune response and is the most polymorphic gene family in vertebrates. Although high-throughput sequencing has increasingly been used for genotyping families of co-amplifying MHC genes, its potential to facilitate early steps in the characterisation of MHC variation in nonmodel organism has not been fully explored. In this study we evaluated the usefulness of de novo transcriptome assembly in characterisation of MHC sequence diversity. We found that although de novo transcriptome assembly of MHC I genes does not reconstruct sequences of individual alleles, it does allow the identification of conserved regions for PCR primer design. Using the newly designed primers, we characterised MHC I sequences in the bank vole. Phylogenetic analysis of the partial MHC I coding sequence (2-4 exons) of the bank vole revealed a lack of orthology to MHC I of other Cricetidae, consistent with the high gene turnover of this region. The diversity of expressed alleles was characterised using ultra-deep sequencing of the third exon that codes for the peptide-binding region of the MHC molecule. High allelic diversity was demonstrated, with 72 alleles found in 29 individuals. Interindividual variation in the number of expressed loci was found, with the number of alleles per individual ranging from 5 to 14. Strong signatures of positive selection were found for 8 amino acid sites, most of which are inferred to bind antigens in human MHC, indicating conservation of structure despite rapid sequence evolution.

  8. NetH2pan: A Computational Tool to Guide MHC peptide prediction on Murine Tumors

    DEFF Research Database (Denmark)

    DeVette, Christa I; Andreatta, Massimo; Bardet, Wilfried

    2018-01-01

    With the advancement of personalized cancer immunotherapies, new tools are needed to identify tumor antigens and evaluate T-cell responses in model systems, specifically those that exhibit clinically relevant tumor progression. Key transgenic mouse models of breast cancer are generated and mainta......With the advancement of personalized cancer immunotherapies, new tools are needed to identify tumor antigens and evaluate T-cell responses in model systems, specifically those that exhibit clinically relevant tumor progression. Key transgenic mouse models of breast cancer are generated...... for evaluating antigen specificity in the murine FVB strain. Our study provides the first detailed molecular and immunoproteomic characterization of the FVB H-2q MHC Class I alleles, including >8500 unique peptide ligands, a multi-allele murine MHC peptide prediction tool, and in vivo validation of these data...

  9. Mechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell Membrane

    DEFF Research Database (Denmark)

    La Rocca, Rosanna; Tallerico, Rossana; Hassan, Almosawy Talib

    2014-01-01

    In our body, cells are continuously exposed to physical forces that can regulate different cell functions such as cell proliferation, differentiation and death. In this work, we employed two different strategies to mechanically stress cancer cells. The cancer and healthy cell populations were...... treated either with mechanical stress delivered by a micropump (fabricated by deep X-ray nanolithography) or by ultrasound wave stimuli. A specific down-regulation of Major Histocompatibility Complex (MHC) class I molecules expression on cancer cell membrane compared to different kinds of healthy cells...... between 700–1800 cm-1, indicated a relative concentration variation of MHC class I. PCA analysis was also performed to distinguish control and stressed cells within different cell lines. These mechanical induced phenotypic changes increase the tumor immunogenicity, as revealed by the related increased...

  10. Oriented coupling of major histocompatibility complex (MHC) to sensor surfaces using light assisted immobilisation technology

    DEFF Research Database (Denmark)

    Snabe, Torben; Røder, Gustav Andreas; Neves-Petersen, Maria Teresa

    2005-01-01

    Controlled and oriented immobilisation of proteins for biosensor purposes is of extreme interest since this provides more efficient sensors with a larger density of active binding sites per area compared to sensors produced by conventional immobilisation. In this paper oriented coupling of a major...... histocompatibility complex (MHC class I) to a sensor surface is presented. The coupling was performed using light assisted immobilisation--a novel immobilisation technology which allows specific opening of particular disulphide bridges in proteins which then is used for covalent bonding to thiol-derivatised surfaces...... via a new disulphide bond. Light assisted immobilisation specifically targets the disulphide bridge in the MHC-I molecule alpha(3)-domain which ensures oriented linking of the complex with the peptide binding site exposed away from the sensor surface. Structural analysis reveals that a similar...

  11. New recombinants within the MHC (B-complex) of the chicken

    DEFF Research Database (Denmark)

    Koch, C; Skjødt, K; Toivanen, A

    1983-01-01

    In a search for genetic recombinations within the major histocompatibility complex (MHC) of the chicken, the B-complex, the offspring from matings between heterozygous B15/B21 and B4/B6 animals were analysed by red cell agglutination. Among the progeny, 8,912 informative typings were performed...... followed B-F/B-L. The mapping distance between the two loci B-F and B-G is in the range of 0.04 centimorgan. The lack of recombinants separating individual B-F loci in this study and in the studies of others might indicate that chicken MHC is less complex than those of mammalian species, but alternative...

  12. The roles of MHC class II genes and post-translational modification in celiac disease.

    Science.gov (United States)

    Sollid, Ludvig M

    2017-08-01

    Our increasing understanding of the etiology of celiac disease, previously considered a simple food hypersensitivity disorder caused by an immune response to cereal gluten proteins, challenges established concepts of autoimmunity. HLA is a chief genetic determinant, and certain HLA-DQ allotypes predispose to the disease by presenting posttranslationally modified (deamidated) gluten peptides to CD4 + T cells. The deamidation of gluten peptides is mediated by transglutaminase 2. Strikingly, celiac disease patients generate highly disease-specific autoantibodies to the transglutaminase 2 enzyme. The dual role of transglutaminase 2 in celiac disease is hardly coincidental. This paper reviews the genetic mapping and involvement of MHC class II genes in disease pathogenesis, and discusses the evidence that MHC class II genes, via the involvement of transglutaminase 2, influence the generation of celiac disease-specific autoantibodies.

  13. Sequence Variation of MHC Class II DQB Gene in Bottlenose Dolphin (Tursiops truncatus from Taiwanese Waters

    Directory of Open Access Journals (Sweden)

    Wei-Cheng Yang

    2008-03-01

    Full Text Available The major histocompatibility complex (MHC is a large multigene coding for glycoproteins that play a key role in the initiation of immune responses in vertebrates. For a better understanding of the immunologic diversity in thriving marine mammal species, the sequence variation of the exon 2 region of MHC DQB locus was analyzed in 42 bottlenose dolphins (Tursiops truncatus collected from strandings and fishery bycatch in Taiwanese waters. The 172 bp sequences amplified showed no more than two alleles in each individual. The high proportion of non-synonymous nucleotide substitutions and the moderate amount of variation suggest positive selection pressure on this locus, arguing against a reduction in the marine environment selection pressure. The phylogenetic relationship among DQB exon 2 sequences of T. truncatus and other cetaceans did not coincide with taxonomic relationship, indicating a trans-species evolutionary pattern.

  14. Extreme MHC class I diversity in the sedge warbler (Acrocephalus schoenobaenus); selection patterns and allelic divergence suggest that different genes have different functions.

    Science.gov (United States)

    Biedrzycka, Aleksandra; O'Connor, Emily; Sebastian, Alvaro; Migalska, Magdalena; Radwan, Jacek; Zając, Tadeusz; Bielański, Wojciech; Solarz, Wojciech; Ćmiel, Adam; Westerdahl, Helena

    2017-07-05

    Recent work suggests that gene duplications may play an important role in the evolution of immunity genes. Passerine birds, and in particular Sylvioidea warblers, have highly duplicated major histocompatibility complex (MHC) genes, which are key in immunity, compared to other vertebrates. However, reasons for this high MHC gene copy number are yet unclear. High-throughput sequencing (HTS) allows MHC genotyping even in individuals with extremely duplicated genes. This HTS data can reveal evidence of selection, which may help to unravel the putative functions of different gene copies, i.e. neofunctionalization. We performed exhaustive genotyping of MHC class I in a Sylvioidea warbler, the sedge warbler, Acrocephalus schoenobaenus, using the Illumina MiSeq technique on individuals from a wild study population. The MHC diversity in 863 genotyped individuals by far exceeds that of any other bird species described to date. A single individual could carry up to 65 different alleles, a large proportion of which are expressed (transcribed). The MHC alleles were of three different lengths differing in evidence of selection, diversity and divergence within our study population. Alleles without any deletions and alleles containing a 6 bp deletion showed characteristics of classical MHC genes, with evidence of multiple sites subject to positive selection and high sequence divergence. In contrast, alleles containing a 3 bp deletion had no sites subject to positive selection and had low divergence. Our results suggest that sedge warbler MHC alleles that either have no deletion, or contain a 6 bp deletion, encode classical antigen presenting MHC molecules. In contrast, MHC alleles containing a 3 bp deletion may encode molecules with a different function. This study demonstrates that highly duplicated MHC genes can be characterised with HTS and that selection patterns can be useful for revealing neofunctionalization. Importantly, our results highlight the need to consider the

  15. ATR-Chk1-APC/C-dependent stabilization of Cdc7-ASK (Dbf4) kinase is required for DNA lesion bypass under replication stress

    DEFF Research Database (Denmark)

    Yamada, M.; Watanabe, K.; Mistrik, M.

    2013-01-01

    replication. Stalled DNA replication evoked stabilization of the Cdc7-ASK (Dbf4) complex in a manner dependent on ATR-Chk1-mediated checkpoint signaling and its interplay with the anaphase-promoting complex/cyclosomeCdh1 (APC/C) ubiquitin ligase. Mechanistically, Chk1 kinase inactivates APC/C through...... degradation of Cdh1 upon replication block, thereby stabilizing APC/C substrates, including Cdc7-ASK (Dbf4). Furthermore, motif C of ASK (Dbf4) interacts with the N-terminal region of RAD18 ubiquitin ligase, and this interaction is required for chromatin binding of RAD18. Impaired interaction of ASK (Dbf4...

  16. MHC Expression on Spleen Lymphocyte Subsets in Genetically Resistant and Susceptible Chickens Infected with Marek's Disease Virus

    DEFF Research Database (Denmark)

    Dalgaard, Tina; Bøving, Mette K.; Handberg, Kurt

    2009-01-01

    cytometry for MHC surface expression. In the spleen, constitutive MHC class I surface expression was found to be highest in homozygous B19, lowest in homozygous B21, and intermediate in heterozygous B19/B21 animals. This was observed on CD4(+), CD8(+), and Bu-1(+) splenic lymphocytes. Chickens of all three...... genotypes were subjected to infection with MD virus (GA strain) and spleen samples from infected as well as MHC-matched negative controls were analyzed at 1, 4, and 8 wk post-infection (p.i.). It was observed that MDV induced an increase in MHC class I expression late in the infection. Thus, MHC class I...... was increased on the surface of CD4(+) cells from infected chickens of all genotypes at 4 and 8 wk p.i. compared with negative controls. Also, MHC class I expression was increased on CD8(+) cells from infected chickens of all genotypes at 4 and 8 wk p.i., except for the homozygous B19 animals, that showed...

  17. Immunohistochemical detection and correlation between MHC antigen and cell-mediated immune system in recurrent glioma by APAAP method.

    Science.gov (United States)

    Miyagi, K; Ingram, M; Techy, G B; Jacques, D B; Freshwater, D B; Sheldon, H

    1990-09-01

    As part of an on-going clinical trial of immunotherapy for recurrent malignant gliomas, using alkaline phosphatase-anti-alkaline phosphatase method with monoclonal antibodies, we investigated the correlation between expression of the major histocompatibility complex (MHC) and the subpopulation of tumor-infiltrating lymphocytes (TILs) in 38 glioma specimens (20 grade IV, 11 grade III, and 7 grade II) from 33 patients. Thirty specimens (78.9%) were positive to class I MHC antigen and 20 (52.6%) were positive to class II MHC antigen. The correlations between class I MHC antigen expression and the number of infiltrating T8 (p less than 0.01), and also between class II MHC antigen expression and the number of infiltrating T4 (p less than 0.05) were significant. We conclude that TILs are the result of immunoreaction (host-defense mechanism). 31.6% of specimens had perivascular infiltration of T cells. The main infiltrating lymphocyte subset in moderate to marked perivascular cuffing was T4. Our results may indicate that lack of MHC antigen on the glioma cell surface has a share in the poor immunogenicity in glioma-bearing patients. In addition, considering the effector/target ratio, the number of infiltrating lymphocytes against glioma cells was too small, so the immunological intervention seems to be essential in glioma therapy. Previous radiation therapy and chemotherapy, including steroid therapy, did not influence lymphocyte and macrophage infiltration.

  18. Expression and characterization of recombinant single-chain salmon class I MHC fused with beta2-microglobulin with biological activity

    DEFF Research Database (Denmark)

    Zhao, Heng; Stet, René J M; Skjødt, Karsten

    2008-01-01

    Heterodimeric class I major histocompatibility complex (MHC) molecules consist of a putative 45-kDa heavy chain and a 12-kDa beta2-microglobulin (beta2m) light chain. The knowledge about MHC genes in Atlantic salmon accumulated during the last decade has allowed us to generate soluble and stable ...... MHC class I molecules with biological activity. We report here the use of a bacterial expression system to produce the recombinant single-chain MHC molecules based on a specific allele Sasa-UBA*0301. This particular allele was selected because previous work has shown its association...... antibodies were successfully produced against both the MHC class I heavy chain and beta(2)m, and showed binding to the recombinant molecule. The recombinant complex Sasabeta2mUBA*0301 was expressed and isolated; the production was scaled up by adjusting to its optimal conditions. Subsequently......, the recombinant proteins were purified by affinity chromatography using mAb against beta2m and alpha3. Eluates were analyzed by Western blot and refolded by the removal of denaturant. The correct folding was confirmed by measuring its binding capacity against mAb produced to recognize the native form of MHC...

  19. Improved methods for predicting peptide binding affinity to MHC class II molecules

    DEFF Research Database (Denmark)

    Jensen, Kamilla Kjærgaard; Andreatta, Massimo; Marcatili, Paolo

    2018-01-01

    Major histocompatibility complex class II (MHC-II) molecules are expressed on the surface of professional antigen presenting cells where they display peptides to T helper cells, which orchestrate the onset and outcome of many host immune responses. Understanding which peptides will be presented b...... are publicly available at www.cbs.dtu.dk/services/NetMHCII-2.3 and www.cbs.dtu.dk/services/NetMHCIIpan-3.2. This article is protected by copyright. All rights reserved....

  20. MHC class I down-regulation: Tumour escape from immune surveillance? (Review)

    Czech Academy of Sciences Publication Activity Database

    Bubeník, Jan

    2004-01-01

    Roč. 25, č. 2 (2004), s. 487-491 ISSN 1019-6439 R&D Projects: GA MZd NC7148; GA ČR GA301/04/0492; GA AV ČR IAA5052203 Institutional research plan: CEZ:AV0Z5052915 Keywords