Selenium Potentiates Chemotherapeutic Selectivity: Improving Efficacy and Reducing Toxicity

DTIC Science & Technology

2007-04-01

regulates the rate-limiting step in global genomic repair through transcriptional control of the DNA damage recognition proteins xeroderma pigmentosum ...31). Xeroderma pigmentosum XPA cells defective in DNA repair served as a negative control for some experiments, as previously described (28). Cell...simian virus 40-transformed human cells. Mol Carcinog 2000;29:17–24. 14. Hwang BJ, Ford JM, Hanawalt PC, Chu G. Expression of the p48 xeroderma pigmentosum

Phagocyte-myocyte interactions and consequences during hypoxic wound healing.

PubMed

Zhang, Shuang; Dehn, Shirley; DeBerge, Matthew; Rhee, Ki-Jong; Hudson, Barry; Thorp, Edward B

2014-01-01

Myocardial infarction (MI), secondary to atherosclerotic plaque rupture and occlusive thrombi, triggers acute margination of inflammatory neutrophils and monocyte phagocyte subsets to the damaged heart, the latter of which may give rise briefly to differentiated macrophage-like or dendritic-like cells. Within the injured myocardium, a primary function of these phagocytic cells is to remove damaged extracellular matrix, necrotic and apoptotic cardiac cells, as well as immune cells that turn over. Recognition of dying cellular targets by phagocytes triggers intracellular signaling, particularly in macrophages, wherein cytokines and lipid mediators are generated to promote inflammation resolution, fibrotic scarring, angiogenesis, and compensatory organ remodeling. These actions cooperate in an effort to preserve myocardial contractility and prevent heart failure. Immune cell function is modulated by local tissue factors that include secreted protease activity, oxidative stress during clinical reperfusion, and hypoxia. Importantly, experimental evidence suggests that monocyte function and phagocytosis efficiency is compromised in the setting of MI risk factors, including hyperlipidemia and ageing, however underlying mechanisms remain unclear. Herein we review seminal phagocyte and cardiac molecular factors that lead to, and culminate in, the recognition and removal of dying injured myocardium, the effects of hypoxia, and their relationship to cardiac infarct size and heart healing. Copyright © 2014 Elsevier Inc. All rights reserved.

DDB2 promotes chromatin decondensation at UV-induced DNA damage

PubMed Central

Lindh, Michael; Acs, Klara; Vrouwe, Mischa G.; Pines, Alex; van Attikum, Haico; Mullenders, Leon H.

2012-01-01

Nucleotide excision repair (NER) is the principal pathway that removes helix-distorting deoxyribonucleic acid (DNA) damage from the mammalian genome. Recognition of DNA lesions by xeroderma pigmentosum group C (XPC) protein in chromatin is stimulated by the damaged DNA-binding protein 2 (DDB2), which is part of a CUL4A–RING ubiquitin ligase (CRL4) complex. In this paper, we report a new function of DDB2 in modulating chromatin structure at DNA lesions. We show that DDB2 elicits unfolding of large-scale chromatin structure independently of the CRL4 ubiquitin ligase complex. Our data reveal a marked adenosine triphosphate (ATP)–dependent reduction in the density of core histones in chromatin containing UV-induced DNA lesions, which strictly required functional DDB2 and involved the activity of poly(adenosine diphosphate [ADP]–ribose) polymerase 1. Finally, we show that lesion recognition by XPC, but not DDB2, was strongly reduced in ATP-depleted cells and was regulated by the steady-state levels of poly(ADP-ribose) chains. PMID:22492724

Autophagic control of RLR signaling

PubMed Central

Tal, Michal Caspi; Iwasaki, Akiko

2013-01-01

Innate immunity to viral infection is initiated within the infected cells through the recognition of unique viral signatures by pattern recognition receptors (PRRs) that mediate the induction of potent antiviral factor, type I interferons (IFNs). Infection with RNA viruses is recognized by the members of the retinoic acid inducible gene I (RIG-I)-like receptor (RLR) family in the cytosol. Our recent study demonstrates that IFN production in response to RNA viral ligands is increased in the absence of autophagy. The process of autophagy functions as an internal clean-up crew within the cell, shuttling damaged cellular organelles and long-lived proteins to the lysosomes for degradation. Our data show that the absence of autophagy leads to the amplification of RLR signaling in two ways. First, in the absence of autophagy, mitochondria accumulate within the cell leading to the build up of mitochondrial associated protein, IPS-1, a key signaling protein for RLRs. Second, damaged mitochondria that are not degraded in the absence of autophagy provide a source of reactive oxygen species (ROS), which amplify RLR signaling in Atg5 knockout cells. Our study provides the first link between ROS and cytosolic signaling mediated by the RLRs, and suggests the importance of autophagy in the regulation of signaling emanating from mitochondria. PMID:19571662

THE ROLE OF THE RETINOBLASTOMA/E2F1 TUMOR SUPPRESSOR PATHWAY IN THE LESION RECOGNITION STEP OF NUCLEOTIDE EXCISION REPAIR

PubMed Central

Lin, Patrick S.; McPherson, Lisa A.; Chen, Aubrey Y.; Sage, Julien; Ford, James M.

2009-01-01

The retinoblastoma Rb/E2F tumor suppressor pathway plays a major role in the regulation of mammalian cell cycle progression. The pRb protein, along with closely related proteins p107 and p130, exerts its anti-proliferative effects by binding to the E2F family of transcription factors known to regulate essential genes throughout the cell cycle. We sought to investigate the role of the Rb/E2F1 pathway in the lesion recognition step of nucleotide excision repair (NER) in mouse embryonic fibroblasts (MEFs). Rb−/−;p107−/−;p130−/− MEFs repaired both cyclobutane pyrimidine dimers (CPD) and 6-4 photoproducts (6-4PPs) at higher efficiency than did wildtype cells following UV-C irradiation. The expression of damaged DNA binding gene DDB2 involved in the DNA lesion recognition step was elevated in the Rb family-deficient MEFs. To determine if the enhanced DNA repair in the absence of the Rb gene family is due to the derepression of E2F1, we assayed the ability of E2F1-deficient cells to repair damaged DNA and demonstrated that E2F1−/− MEFs are impaired for the removal of both CPDs and 6-4PPs. Furthermore, wildtype cells induced a higher expression of DDB2 and xeroderma pigmentosum gene XPC transcript levels than did E2F1−/− cells following UV-C irradiation. Using an E2F SiteScan algorithm, we uncovered a putative E2F-responsive element in the XPC promoter upstream of the transcription start site. We showed with chromatin immunoprecipitation assays the binding of E2F1 to the XPC promoter in a UV-dependent manner, suggesting that E2F1 is a transcriptional regulator of XPC. Our study identifies a novel E2F1 gene target and further supports the growing body of evidence that the Rb/E2F1 tumor suppressor pathway is involved in the regulation of the DNA lesion recognition step of nucleotide excision repair. PMID:19376752

Damage signals in the insect immune response

PubMed Central

Krautz, Robert; Arefin, Badrul; Theopold, Ulrich

2014-01-01

Insects and mammals share an ancient innate immune system comprising both humoral and cellular responses. The insect immune system consists of the fat body, which secretes effector molecules into the hemolymph and several classes of hemocytes, which reside in the hemolymph and of protective border epithelia. Key features of wound- and immune responses are shared between insect and mammalian immune systems including the mode of activation by commonly shared microbial (non-self) patterns and the recognition of these patterns by dedicated receptors. It is unclear how metazoan parasites in insects, which lack these shared motifs, are recognized. Research in recent years has demonstrated that during entry into the insect host, many eukaryotic pathogens leave traces that alert potential hosts of the damage they have afflicted. In accordance with terminology used in the mammalian immune systems, these signals have been dubbed danger- or damage-associated signals. Damage signals are necessary byproducts generated during entering hosts either by mechanical or proteolytic damage. Here, we briefly review the current stage of knowledge on how wound closure and wound healing during mechanical damage is regulated and how damage-related signals contribute to these processes. We also discuss how sensors of proteolytic activity induce insect innate immune responses. Strikingly damage-associated signals are also released from cells that have aberrant growth, including tumor cells. These signals may induce apoptosis in the damaged cells, the recruitment of immune cells to the aberrant tissue and even activate humoral responses. Thus, this ensures the removal of aberrant cells and compensatory proliferation to replace lost tissue. Several of these pathways may have been co-opted from wound healing and developmental processes. PMID:25071815

Lipopolysaccharide Clearance, Bacterial Clearance, and Systemic Inflammatory Responses Are Regulated by Cell Type–Specific Functions of TLR4 during Sepsis

PubMed Central

Deng, Meihong; Loughran, Patricia; Gibson, Gregory; Sodhi, Chhinder; Watkins, Simon; Hackam, David

2013-01-01

The morbidity associated with bacterial sepsis is the result of host immune responses to pathogens, which are dependent on pathogen recognition by pattern recognition receptors, such as TLR4. TLR4 is expressed on a range of cell types, yet the mechanisms by which cell-specific functions of TLR4 lead to an integrated sepsis response are poorly understood. To address this, we generated mice in which TLR4 was specifically deleted from myeloid cells (LysMTLR4KO) or hepatocytes (HCTLR4KO) and then determined survival, bacterial counts, host inflammatory responses, and organ injury in a model of cecal ligation and puncture (CLP), with or without antibiotics. LysM-TLR4 was required for phagocytosis and efficient bacterial clearance in the absence of antibiotics. Survival, the magnitude of the systemic and local inflammatory responses, and liver damage were associated with bacterial levels. HCTLR4 was required for efficient LPS clearance from the circulation, and deletion of HCTLR4 was associated with enhanced macrophage phagocytosis, lower bacterial levels, and improved survival in CLP without antibiotics. Antibiotic administration during CLP revealed an important role for hepatocyte LPS clearance in limiting sepsis-induced inflammation and organ injury. Our work defines cell type–selective roles for TLR4 in coordinating complex immune responses to bacterial sepsis and suggests that future strategies for modulating microbial molecule recognition should account for varying roles of pattern recognition receptors in multiple cell populations. PMID:23562812

Cell Death and DAMPs in Acute Pancreatitis

PubMed Central

Kang, Rui; Lotze, Michael T; Zeh, Herbert J; Billiar, Timothy R; Tang, Daolin

2014-01-01

Cell death and inflammation are key pathologic responses of acute pancreatitis (AP), the leading cause of hospital admissions for gastrointestinal disorders. It is becoming increasingly clear that damage-associated molecular pattern molecules (DAMPs) play an important role in the pathogenesis of AP by linking local tissue damage to systemic inflammation syndrome. Endogenous DAMPs released from dead, dying or injured cells initiate and extend sterile inflammation via specific pattern recognition receptors. Inhibition of the release and activity of DAMPs (for example, high mobility group box 1, DNA, histones and adenosine triphosphate) provides significant protection against experimental AP. Moreover, increased serum levels of DAMPs in patients with AP correlate with disease severity. These findings provide novel insight into the mechanism, diagnosis and management of AP. DAMPs might be an attractive therapeutic target in AP. PMID:25105302

What Combined Measurements From Structures and Imaging Tell Us About DNA Damage Responses

PubMed Central

Brosey, Chris A.; Ahmed, Zamal; Lees-Miller, Susan P.; Tainer, John A.

2017-01-01

DNA damage outcomes depend upon the efficiency and fidelity of DNA damage responses (DDRs) for different cells and damage. As such, DDRs represent tightly regulated prototypical systems for linking nanoscale biomolecular structure and assembly to the biology of genomic regulation and cell signaling. However, the dynamic and multifunctional nature of DDR assemblies can render elusive the correlation between the structures of DDR factors and specific biological disruptions to the DDR when these structures are altered. In this chapter, we discuss concepts and strategies for combining structural, biophysical, and imaging techniques to investigate DDR recognition and regulation, and thus bridge sequence-level structural biochemistry to quantitative biological outcomes visualized in cells. We focus on representative DDR responses from PARP/PARG/AIF damage signaling in DNA single-strand break repair and nonhomologous end joining complexes in double-strand break repair. Methods with exemplary experimental results are considered with a focus on strategies for probing flexibility, conformational changes, and assembly processes that shape a predictive understanding of DDR mechanisms in a cellular context. Integration of structural and imaging measurements promises to provide foundational knowledge to rationally control and optimize DNA damage outcomes for synthetic lethality and for immune activation with resulting insights for biology and cancer interventions. PMID:28668129

Helminth Infections: Recognition and Modulation of the Immune Response by Innate Immune Cells

PubMed Central

Motran, Claudia Cristina; Silvane, Leonardo; Chiapello, Laura Silvina; Theumer, Martin Gustavo; Ambrosio, Laura Fernanda; Volpini, Ximena; Celias, Daiana Pamela; Cervi, Laura

2018-01-01

The survival of helminths in the host over long periods of time is the result of a process of adaptation or dynamic co-evolution between the host and the parasite. However, infection with helminth parasites causes damage to the host tissues producing the release of danger signals that induce the recruitment of various cells, including innate immune cells such as macrophages (Mo), dendritic cells (DCs), eosinophils, basophils, and mast cells. In this scenario, these cells are able to secrete soluble factors, which orchestrate immune effector mechanisms that depend on the different niches these parasites inhabit. Here, we focus on recent advances in the knowledge of excretory-secretory products (ESP), resulting from helminth recognition by DCs and Mo. Phagocytes and other cells types such as innate lymphocyte T cells 2 (ILC2), when activated by ESP, participate in an intricate cytokine network to generate innate and adaptive Th2 responses. In this review, we also discuss the mechanisms of innate immune cell-induced parasite killing and the tissue repair necessary to assure helminth survival over long periods of time. PMID:29670630

Under what conditions is recognition spared relative to recall after selective hippocampal damage in humans?

PubMed

Holdstock, J S; Mayes, A R; Roberts, N; Cezayirli, E; Isaac, C L; O'Reilly, R C; Norman, K A

2002-01-01

The claim that recognition memory is spared relative to recall after focal hippocampal damage has been disputed in the literature. We examined this claim by investigating object and object-location recall and recognition memory in a patient, YR, who has adult-onset selective hippocampal damage. Our aim was to identify the conditions under which recognition was spared relative to recall in this patient. She showed unimpaired forced-choice object recognition but clearly impaired recall, even when her control subjects found the object recognition task to be numerically harder than the object recall task. However, on two other recognition tests, YR's performance was not relatively spared. First, she was clearly impaired at an equivalently difficult yes/no object recognition task, but only when targets and foils were very similar. Second, YR was clearly impaired at forced-choice recognition of object-location associations. This impairment was also unrelated to difficulty because this task was no more difficult than the forced-choice object recognition task for control subjects. The clear impairment of yes/no, but not of forced-choice, object recognition after focal hippocampal damage, when targets and foils are very similar, is predicted by the neural network-based Complementary Learning Systems model of recognition. This model postulates that recognition is mediated by hippocampally dependent recollection and cortically dependent familiarity; thus hippocampal damage should not impair item familiarity. The model postulates that familiarity is ineffective when very similar targets and foils are shown one at a time and subjects have to identify which items are old (yes/no recognition). In contrast, familiarity is effective in discriminating which of similar targets and foils, seen together, is old (forced-choice recognition). Independent evidence from the remember/know procedure also indicates that YR's familiarity is normal. The Complementary Learning Systems model can also accommodate the clear impairment of forced-choice object-location recognition memory if it incorporates the view that the most complete convergence of spatial and object information, represented in different cortical regions, occurs in the hippocampus.

Nucleotide Excision Repair Proteins Rapidly Accumulate but Fail to Persist in Human XP-E (DDB2 Mutant) Cells

PubMed Central

Oh, Kyu-Seon; Imoto, Kyoko; Emmert, Steffen; Tamura, Deborah; DiGiovanna, John J.; Kraemer, Kenneth. H.

2011-01-01

The XP-E DNA damage binding protein (DDB2) is involved in early recognition of global genome DNA damage during DNA nucleotide excision repair (NER). We found that skin fibroblasts from 4 newly reported XP-E patients with numerous skin cancers and DDB2 mutations had slow repair of 6-4 photoproducts (6-4PP) and markedly reduced repair of cyclobutane pyrimidine dimers (CPD). NER proteins (XPC, XPB, XPG, XPA, and XPF) co-localized to CPD and 6-4PP positive regions immediately (< 0.1h) after localized UV irradiation in cells from the XP-E patients and normal controls. While these proteins persist in normal cells, surprisingly, within 0.5h these repair proteins were no longer detectable at the sites of DNA damage in XP-E cells. Our results indicate that DDB2 is not required for the rapid recruitment of NER proteins to sites of UV photoproducts or for partial repair of 6-4PP but is essential for normal persistence of these proteins for CPD photoproduct removal. PMID:21388382

Association of a Platinum Complex to a G-Quadruplex Ligand Enhances Telomere Disruption.

PubMed

Charif, Razan; Granotier-Beckers, Christine; Bertrand, Hélène Charlotte; Poupon, Joël; Ségal-Bendirdjian, Evelyne; Teulade-Fichou, Marie-Paule; Boussin, François D; Bombard, Sophie

2017-08-21

Telomeres protect the ends of chromosomes against illegitimate recombination and repair. They can be targets for G-quadruplex ligands and platinum complexes due to their repeated G-rich sequences. Protection of telomeres is ensured by a complex of six proteins, including TRF2, which inhibits the DNA damage response pathway. We analyzed telomere modifications induced in cancer cells by the experimental hybrid platinum complex, Pt-MPQ, comprising both an ethylene diamine monofunctional platinum complex and a G-quadruplex recognition moiety (MPQ). Pt-MPQ promotes the displacement of two telomeric proteins (TRF2 and TRF1) from telomeres, as well as the formation of telomere damage and telomere sister losses, whereas the control compound MPQ does not. This suggests that the platinum moiety potentiates the targeting of the G-quadruplex ligand to telomeres, opening a new perspective for telomere biology and anticancer therapy. Interestingly, the chemotherapy drug cisplatin, which has no specific affinity for G-quadruplex structures, partially induces the TRF2 delocalization from telomeres but produces less telomeric DNA damage, suggesting that this TRF2 displacement could be independent of G-quadruplex recognition.

Regulation of the Prostate Cancer Tumor Microenvironment

DTIC Science & Technology

2015-04-01

growth can be altered through modulating the composition of TILs through innate immunity . Body Pathogens or cancerous cells alike can produce danger... innate immunity , including Toll-like receptors (TLRs). Thirteen mammalian TLRs have been identified to date with ligands ranging from...damage-associated molecular patterns (DAMPs) released by the tumor stimulate the innate immune pathways through pattern recognition receptors (PRRs

Recognition of emotion with temporal lobe epilepsy and asymmetrical amygdala damage.

PubMed

Fowler, Helen L; Baker, Gus A; Tipples, Jason; Hare, Dougal J; Keller, Simon; Chadwick, David W; Young, Andrew W

2006-08-01

Impairments in emotion recognition occur when there is bilateral damage to the amygdala. In this study, ability to recognize auditory and visual expressions of emotion was investigated in people with asymmetrical amygdala damage (AAD) and temporal lobe epilepsy (TLE). Recognition of five emotions was tested across three participant groups: those with right AAD and TLE, those with left AAD and TLE, and a comparison group. Four tasks were administered: recognition of emotion from facial expressions, sentences describing emotion-laden situations, nonverbal sounds, and prosody. Accuracy scores for each task and emotion were analysed, and no consistent overall effect of AAD on emotion recognition was found. However, some individual participants with AAD were significantly impaired at recognizing emotions, in both auditory and visual domains. The findings indicate that a minority of individuals with AAD have impairments in emotion recognition, but no evidence of specific impairments (e.g., visual or auditory) was found.

Immunology of Cryptococcal Infections: Developing a Rational Approach to Patient Therapy

PubMed Central

Elsegeiny, Waleed; Marr, Kieren A.; Williamson, Peter R.

2018-01-01

Cryptococcal meningoencephalitis is responsible for upwards of 15% of HIV-related deaths worldwide and is currently the most common cause of non-viral meningitis in the US, affecting both previously healthy and people with immune suppression caused by cancer chemotherapy, transplantation, and biologic therapies. Despite a continued 30–50% attributable mortality, recommended therapeutic strategies have remained largely unchanged since the 1950s. Recent murine models and human studies examining the role of the immune system in both susceptibility to the infection as well as host damage have begun to influence patient care decisions. The Damage Framework Response, originally proposed in 1999, was recently used to discuss dichotomous etiologies of host damage in cryptococcal disease. These include patients suffering microbiological damage with low host immunity (especially those immunosuppressed with HIV) and those having low (live) microbiological burden but high immune-mediated damage (HIV-related immune reconstitution syndrome and non-HIV-related postinfectious inflammatory response syndrome). Cryptococcal disease in previously healthy hosts, albeit rare, has been known for a long time. Immunophenotyping and dendritic cell-T cell signaling studies on cerebral spinal fluid of these rare patients reveal immune capacity for recognition and T-cell activation pathways including increased levels of HLA-DR and CD56. However, despite effective T-cell signals, brain biopsy and autopsy specimens demonstrated an M2 alternative macrophage polarization and poor phagocytosis of fungal cells. These studies expand the paradigm for cryptococcal disease susceptibility to include a prominent role for immune-mediated damage and suggest a need for careful individual consideration of immune activation during therapy of cryptococcal disease in diverse hosts. PMID:29670625

Immunology of Cryptococcal Infections: Developing a Rational Approach to Patient Therapy.

PubMed

Elsegeiny, Waleed; Marr, Kieren A; Williamson, Peter R

2018-01-01

Cryptococcal meningoencephalitis is responsible for upwards of 15% of HIV-related deaths worldwide and is currently the most common cause of non-viral meningitis in the US, affecting both previously healthy and people with immune suppression caused by cancer chemotherapy, transplantation, and biologic therapies. Despite a continued 30-50% attributable mortality, recommended therapeutic strategies have remained largely unchanged since the 1950s. Recent murine models and human studies examining the role of the immune system in both susceptibility to the infection as well as host damage have begun to influence patient care decisions. The Damage Framework Response, originally proposed in 1999, was recently used to discuss dichotomous etiologies of host damage in cryptococcal disease. These include patients suffering microbiological damage with low host immunity (especially those immunosuppressed with HIV) and those having low (live) microbiological burden but high immune-mediated damage (HIV-related immune reconstitution syndrome and non-HIV-related postinfectious inflammatory response syndrome). Cryptococcal disease in previously healthy hosts, albeit rare, has been known for a long time. Immunophenotyping and dendritic cell-T cell signaling studies on cerebral spinal fluid of these rare patients reveal immune capacity for recognition and T-cell activation pathways including increased levels of HLA-DR and CD56. However, despite effective T-cell signals, brain biopsy and autopsy specimens demonstrated an M2 alternative macrophage polarization and poor phagocytosis of fungal cells. These studies expand the paradigm for cryptococcal disease susceptibility to include a prominent role for immune-mediated damage and suggest a need for careful individual consideration of immune activation during therapy of cryptococcal disease in diverse hosts.

Intestinal inflammation induces genotoxicity to extraintestinal tissues and cell types in mice

PubMed Central

Westbrook, Aya M.; Wei, Bo; Braun, Jonathan; Schiestl, Robert H.

2011-01-01

Chronic intestinal inflammation leads to increased risk of colorectal and small intestinal cancers, and is also associated with extraintestinal manifestations such as lymphomas, other solid cancers, and autoimmune disorders. We have previously found that acute and chronic intestinal inflammation causes DNA damage to circulating peripheral leukocytes, manifesting a systemic effect in genetic and chemically-induced models of intestinal inflammation. This study addresses the scope of tissue targets and genotoxic damage induced by inflammation-associated genotoxicity. Using several experimental models of intestinal inflammation, we analyzed various types of DNA damage in leukocyte subpopulations of the blood, spleen, mesenteric and peripheral lymph nodes; and, in intestinal epithelial cells, hepatocytes, and the brain. Genotoxicity in the form of DNA single and double stranded breaks accompanied by oxidative base damage was found in leukocyte subpopulations of the blood, diverse lymphoid organs, intestinal epithelial cells, and hepatocytes. The brain did not demonstrate significant levels of DNA double strand breaks as measured by γ-H2AX immunostaining. CD4+ and CD8+ T-cells were most sensitive to DNA damage versus other cell types in the peripheral blood. In vivo measurements and in vitro modeling suggested that genotoxicity was induced by increased levels of systemically circulating proinflammatory cytokines. Moreover, genotoxicity involved increased damage rather than reduced repair, since it not associated with decreased expression of the DNA double-strand break recognition and repair protein, ataxia telangiectasia mutated (ATM). These findings suggest that levels of intestinal inflammation contribute to the remote tissue burden of genotoxicity, with potential effects on non-intestinal diseases and cancer. PMID:21520038

Determination of the accuracy for targeted irradiations of cellular substructures at SNAKE

NASA Astrophysics Data System (ADS)

Siebenwirth, C.; Greubel, C.; Drexler, S. E.; Girst, S.; Reindl, J.; Walsh, D. W. M.; Dollinger, G.; Friedl, A. A.; Schmid, T. E.; Drexler, G. A.

2015-04-01

In the last 10 years the ion microbeam SNAKE, installed at the Munich 14 MV tandem accelerator, has been successfully used for radiobiological experiments by utilizing pattern irradiation without targeting single cells. Now for targeted irradiation of cellular substructures a precise irradiation device was added to the live cell irradiation setup at SNAKE. It combines a sub-micrometer single ion irradiation facility with a high resolution optical fluorescence microscope. Most systematic errors can be reduced or avoided by using the same light path in the microscope for beam spot verification as well as for and target recognition. In addition online observation of the induced cellular responses is possible. The optical microscope and the beam delivering system are controlled by an in-house developed software which integrates the open-source image analysis software, CellProfiler, for semi-automatic target recognition. In this work the targeting accuracy was determined by irradiation of a cross pattern with 55 MeV carbon ions on nucleoli in U2OS and HeLa cells stably expressing a GFP-tagged repair protein MDC1. For target recognition, nuclei were stained with Draq5 and nucleoli were stained with Syto80 or Syto83. The damage response was determined by live-cell imaging of MDC1-GFP accumulation directly after irradiation. No systematic displacement and a random distribution of about 0.7 μm (SD) in x-direction and 0.8 μm (SD) in y-direction were observed. An independent analysis after immunofluorescence staining of the DNA damage marker yH2AX yielded similar results. With this performance a target with a size similar to that of nucleoli (i.e. a diameter of about 3 μm) is hit with a probability of more than 80%, which enables the investigation of the radiation response of cellular subcompartments after targeted ion irradiation in the future.

Complexity of Danger: The Diverse Nature of Damage-associated Molecular Patterns*

PubMed Central

Schaefer, Liliana

2014-01-01

In reply to internal or external danger stimuli, the body orchestrates an inflammatory response. The endogenous triggers of this process are the damage-associated molecular patterns (DAMPs). DAMPs represent a heterogeneous group of molecules that draw their origin either from inside the various compartments of the cell or from the extracellular space. Following interaction with pattern recognition receptors in cross-talk with various non-immune receptors, DAMPs determine the downstream signaling outcome of septic and aseptic inflammatory responses. In this review, the diverse nature, structural characteristics, and signaling pathways elicited by DAMPs will be critically evaluated. PMID:25391648

Attenuation of the DNA Damage Response by Transforming Growth Factor-Beta Inhibitors Enhances Radiation Sensitivity of Non–Small-Cell Lung Cancer Cells In Vitro and In Vivo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Shisuo; Bouquet, Sophie; Lo, Chen-Hao

2015-01-01

Purpose: To determine whether transforming growth factor (TGF)-β inhibition increases the response to radiation therapy in human and mouse non–small-cell lung carcinoma (NSCLC) cells in vitro and in vivo. Methods and Materials: TGF-β–mediated growth response and pathway activation were examined in human NSCLC NCI-H1299, NCI-H292, and A549 cell lines and murine Lewis lung cancer (LLC) cells. Cells were treated in vitro with LY364947, a small-molecule inhibitor of the TGF-β type 1 receptor kinase, or with the pan-isoform TGF-β neutralizing monoclonal antibody 1D11 before radiation exposure. The DNA damage response was assessed by ataxia telangiectasia mutated (ATM) or Trp53 protein phosphorylation, γH2AX foci formation,more » or comet assay in irradiated cells. Radiation sensitivity was determined by clonogenic assay. Mice bearing syngeneic subcutaneous LLC tumors were treated with 5 fractions of 6 Gy and/or neutralizing or control antibody. Results: The NCI-H1299, A549, and LLC NSCLC cell lines pretreated with LY364947 before radiation exposure exhibited compromised DNA damage response, indicated by decreased ATM and p53 phosphorylation, reduced γH2AX foci, and increased radiosensitivity. The NCI-H292 cells were unresponsive. Transforming growth factor-β signaling inhibition in irradiated LLC cells resulted in unresolved DNA damage. Subcutaneous LLC tumors in mice treated with TGF-β neutralizing antibody exhibited fewer γH2AX foci after irradiation and significantly greater tumor growth delay in combination with fractionated radiation. Conclusions: Inhibition of TGF-β before radiation attenuated DNA damage recognition and increased radiosensitivity in most NSCLC cells in vitro and promoted radiation-induced tumor control in vivo. These data support the rationale for concurrent TGF-β inhibition and RT to provide therapeutic benefit in NSCLC.« less

Targeting Cytosolic Nucleic Acid-Sensing Pathways for Cancer Immunotherapies.

PubMed

Iurescia, Sandra; Fioretti, Daniela; Rinaldi, Monica

2018-01-01

The innate immune system provides the first line of defense against pathogen infection though also influences pathways involved in cancer immunosurveillance. The innate immune system relies on a limited set of germ line-encoded sensors termed pattern recognition receptors (PRRs), signaling proteins and immune response factors. Cytosolic receptors mediate recognition of danger damage-associated molecular patterns (DAMPs) signals. Once activated, these sensors trigger multiple signaling cascades, converging on the production of type I interferons and proinflammatory cytokines. Recent studies revealed that PRRs respond to nucleic acids (NA) released by dying, damaged, cancer cells, as danger DAMPs signals, and presence of signaling proteins across cancer types suggests that these signaling mechanisms may be involved in cancer biology. DAMPs play important roles in shaping adaptive immune responses through the activation of innate immune cells and immunological response to danger DAMPs signals is crucial for the host response to cancer and tumor rejection. Furthermore, PRRs mediate the response to NA in several vaccination strategies, including DNA immunization. As route of double-strand DNA intracellular entry, DNA immunization leads to expression of key components of cytosolic NA-sensing pathways. The involvement of NA-sensing mechanisms in the antitumor response makes these pathways attractive drug targets. Natural and synthetic agonists of NA-sensing pathways can trigger cell death in malignant cells, recruit immune cells, such as DCs, CD8 + T cells, and NK cells, into the tumor microenvironment and are being explored as promising adjuvants in cancer immunotherapies. In this minireview, we discuss how cGAS-STING and RIG-I-MAVS pathways have been targeted for cancer treatment in preclinical translational researches. In addition, we present a targeted selection of recent clinical trials employing agonists of cytosolic NA-sensing pathways showing how these pathways are currently being targeted for clinical application in oncology.

Hijacking of the mismatch repair system to cause CAG expansion and cell death in neurodegenerative disease.

PubMed

McMurray, Cynthia T

2008-07-01

Mammalian cells have evolved sophisticated DNA repair systems to correct mispaired or damaged bases and extrahelical loops. Emerging evidence suggests that, in some cases, the normal DNA repair machinery is "hijacked" to become a causative factor in mutation and disease, rather than act as a safeguard of genomic integrity. In this review, we consider two cases in which active MMR leads to mutation or to cell death. There may be similar mechanisms by which uncoupling of normal MMR recognition from downstream repair allows triplet expansions underlying human neurodegenerative disease, or cell death in response to chemical lesion.

The role of airway macrophages in apoptotic cell clearance following acute and chronic lung inflammation.

PubMed

Grabiec, Aleksander M; Hussell, Tracy

2016-07-01

Acute and chronic inflammatory responses in the lung are associated with the accumulation of large quantities of immune and structural cells undergoing apoptosis, which need to be engulfed by phagocytes in a process called 'efferocytosis'. Apoptotic cell recognition and removal from the lung is mediated predominantly by airway macrophages, though immature dendritic cells and non-professional phagocytes, such as epithelial cells and mesenchymal cells, can also display this function. Efficient clearance of apoptotic cells from the airways is essential for successful resolution of inflammation and the return to lung homeostasis. Disruption of this process leads to secondary necrosis of accumulating apoptotic cells, release of necrotic cell debris and subsequent uncontrolled inflammatory activation of the innate immune system by the released 'damage associated molecular patterns' (DAMPS). To control the duration of the immune response and prevent autoimmune reactions, anti-inflammatory signalling cascades are initiated in the phagocyte upon apoptotic cell uptake, mediated by a range of receptors that recognise specific phospholipids or proteins externalised on, or secreted by, the apoptotic cell. However, prolonged activation of apoptotic cell recognition receptors, such as the family of receptor tyrosine kinases Tyro3, Axl and MerTK (TAM), may delay or prevent inflammatory responses to subsequent infections. In this review, we will discuss recent advances in our understanding of the mechanism controlling apoptotic cell recognition and removal from the lung in homeostasis and during inflammation, the contribution of defective efferocytosis to chronic inflammatory lung diseases, such as chronic obstructive pulmonary disease, asthma and cystic fibrosis, and implications of the signals triggered by apoptotic cells in the susceptibility to pulmonary microbial infections.

Oxidation modifies the structure and function of the extracellular matrix generated by human coronary artery endothelial cells.

PubMed

Chuang, Christine Y; Degendorfer, Georg; Hammer, Astrid; Whitelock, John M; Malle, Ernst; Davies, Michael J

2014-04-15

ECM (extracellular matrix) materials, such as laminin, perlecan, type IV collagen and fibronectin, play a key role in determining the structure of the arterial wall and the properties of cells that interact with the ECM. The aim of the present study was to investigate the effect of peroxynitrous acid, an oxidant generated by activated macrophages, on the structure and function of the ECM laid down by HCAECs (human coronary artery endothelial cells) in vitro and in vivo. We show that exposure of HCAEC-derived native matrix components to peroxynitrous acid (but not decomposed oxidant) at concentrations >1 μM results in a loss of antibody recognition of perlecan, collagen IV, and cell-binding sites on laminin and fibronectin. Loss of recognition was accompanied by decreased HCAEC adhesion. Real-time PCR showed up-regulation of inflammation-associated genes, including MMP7 (matrix metalloproteinase 7) and MMP13, as well as down-regulation of the laminin α2 chain, in HCAECs cultured on peroxynitrous acid-treated matrix compared with native matrix. Immunohistochemical studies provided evidence of co-localization of laminin with 3-nitrotyrosine, a biomarker of peroxynitrous acid damage, in type II-III/IV human atherosclerotic lesions, consistent with matrix damage occurring during disease development in vivo. The results of the present study suggest a mechanism through which peroxynitrous acid modifies endothelial cell-derived native ECM proteins of the arterial basement membrane in atherosclerotic lesions. These changes to ECM and particularly perlecan and laminin may be important in inducing cellular dysfunction and contribute to atherogenesis.

Activation of WIP1 Phosphatase by HTLV-1 Tax Mitigates the Cellular Response to DNA Damage

PubMed Central

Dayaram, Tajhal; Lemoine, Francene J.; Donehower, Lawrence A.; Marriott, Susan J.

2013-01-01

Genomic instability stemming from dysregulation of cell cycle checkpoints and DNA damage response (DDR) is a common feature of many cancers. The cancer adult T cell leukemia (ATL) can occur in individuals infected with human T cell leukemia virus type 1 (HTLV-1), and ATL cells contain extensive chromosomal abnormalities, suggesting that they have defects in the recognition or repair of DNA damage. Since Tax is the transforming protein encoded by HTLV-1, we asked whether Tax can affect cell cycle checkpoints and the DDR. Using a combination of flow cytometry and DNA repair assays we showed that Tax-expressing cells exit G1 phase and initiate DNA replication prematurely following damage. Reduced phosphorylation of H2AX (γH2AX) and RPA2, phosphoproteins that are essential to properly initiate the DDR, was also observed in Tax-expressing cells. To determine the cause of decreased DDR protein phosphorylation in Tax-expressing cells, we examined the cellular phosphatase, WIP1, which is known to dephosphorylate γH2AX. We found that Tax can interact with Wip1 in vivo and in vitro, and that Tax-expressing cells display elevated levels of Wip1 mRNA. In vitro phosphatase assays showed that Tax can enhance Wip1 activity on a γH2AX peptide target by 2-fold. Thus, loss of γH2AX in vivo could be due, in part, to increased expression and activity of WIP1 in the presence of Tax. siRNA knockdown of WIP1 in Tax-expressing cells rescued γH2AX in response to damage, confirming the role of WIP1 in the DDR. These studies demonstrate that Tax can disengage the G1/S checkpoint by enhancing WIP1 activity, resulting in reduced DDR. Premature G1 exit of Tax-expressing cells in the presence of DNA lesions creates an environment that tolerates incorporation of random mutations into the host genome. PMID:23405243

Addressing the issue of insufficient information in data-based bridge health monitoring : final report.

DOT National Transportation Integrated Search

2015-11-01

One of the most efficient ways to solve the damage detection problem using the statistical pattern recognition : approach is that of exploiting the methods of outlier analysis. Cast within the pattern recognition framework, : damage detection assesse...

Oral candidosis in relation to oral immunity.

PubMed

Feller, L; Khammissa, R A G; Chandran, R; Altini, M; Lemmer, J

2014-09-01

Symptomatic oral infection with Candida albicans is characterized by invasion of the oral epithelium by virulent hyphae that cause tissue damage releasing the inflammatory mediators that initiate and sustain local inflammation. Candida albicans triggers pattern-recognition receptors of keratinocytes, macrophages, monocytes and dendritic cells, stimulating the production of IL-1β, IL-6 and IL-23. These cytokines induce the differentiation of Th17 cells and the generation of IL-17- and/or IL-22-mediated antifungal protective immuno-inflammatory responses in infected mucosa. Some immune cells including NKT cells, γδ T cells and lymphoid cells that are innate to the oral mucosa have the capacity to produce large quantities of IL-17 in response to C. albicans, sufficient to mediate effective protective immunity against C. albicans. On the other hand, molecular structures of commensal C. albicans blastoconidia, although detected by pattern-recognition receptors, are avirulent, do not invade the oral epithelium, do not elicit inflammatory responses in a healthy host, but induce regulatory immune responses that maintain tissue tolerance to the commensal fungi. The type, specificity and sensitivity of the protective immune response towards C. albicans is determined by the outcome of the integrated interactions between the intracellular signalling pathways of specific combinations of activated pattern-recognition receptors (TLR2, TLR4, Dectin-1 and Dectin-2). IL-17-mediated protective immune response is essential for oral mucosal immunity to C. albicans infection. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Autoregressive statistical pattern recognition algorithms for damage detection in civil structures

NASA Astrophysics Data System (ADS)

Yao, Ruigen; Pakzad, Shamim N.

2012-08-01

Statistical pattern recognition has recently emerged as a promising set of complementary methods to system identification for automatic structural damage assessment. Its essence is to use well-known concepts in statistics for boundary definition of different pattern classes, such as those for damaged and undamaged structures. In this paper, several statistical pattern recognition algorithms using autoregressive models, including statistical control charts and hypothesis testing, are reviewed as potentially competitive damage detection techniques. To enhance the performance of statistical methods, new feature extraction techniques using model spectra and residual autocorrelation, together with resampling-based threshold construction methods, are proposed. Subsequently, simulated acceleration data from a multi degree-of-freedom system is generated to test and compare the efficiency of the existing and proposed algorithms. Data from laboratory experiments conducted on a truss and a large-scale bridge slab model are then used to further validate the damage detection methods and demonstrate the superior performance of proposed algorithms.

Faster DNA Repair of Ultraviolet-Induced Cyclobutane Pyrimidine Dimers and Lower Sensitivity to Apoptosis in Human Corneal Epithelial Cells than in Epidermal Keratinocytes

PubMed Central

Mallet, Justin D.; Bastien, Nathalie; Gendron, Sébastien P.; Rochette, Patrick J.

2016-01-01

Absorption of UV rays by DNA generates the formation of mutagenic cyclobutane pyrimidine dimers (CPD) and pyrimidine (6–4) pyrimidone photoproducts (6-4PP). These damages are the major cause of skin cancer because in turn, they can lead to signature UV mutations. The eye is exposed to UV light, but the cornea is orders of magnitude less prone to UV-induced cancer. In an attempt to shed light on this paradox, we compared cells of the corneal epithelium and the epidermis for UVB-induced DNA damage frequency, repair and cell death sensitivity. We found similar CPD levels but a 4-time faster UVB-induced CPD, but not 6-4PP, repair and lower UV-induced apoptosis sensitivity in corneal epithelial cells than epidermal. We then investigated levels of DDB2, a UV-induced DNA damage recognition protein mostly impacting CPD repair, XPC, essential for the repair of both CPD and 6-4PP and p53 a protein upstream of the genotoxic stress response. We found more DDB2, XPC and p53 in corneal epithelial cells than in epidermal cells. According to our results analyzing the protein stability of DDB2 and XPC, the higher level of DDB2 and XPC in corneal epithelial cells is most likely due to an increased stability of the protein. Taken together, our results show that corneal epithelial cells have a better efficiency to repair UV-induced mutagenic CPD. On the other hand, they are less prone to UV-induced apoptosis, which could be related to the fact that since the repair is more efficient in the HCEC, the need to eliminate highly damaged cells by apoptosis is reduced. PMID:27611318

Facial recognition in children after perinatal stroke.

PubMed

Ballantyne, A O; Trauner, D A

1999-04-01

To examine the effects of prenatal or perinatal stroke on the facial recognition skills of children and young adults. It was hypothesized that the nature and extent of facial recognition deficits seen in patients with early-onset lesions would be different from that seen in adults with later-onset neurologic impairment. Numerous studies with normal and neurologically impaired adults have found a right-hemisphere superiority for facial recognition. In contrast, little is known about facial recognition in children after early focal brain damage. Forty subjects had single, unilateral brain lesions from pre- or perinatal strokes (20 had left-hemisphere damage, and 20 had right-hemisphere damage), and 40 subjects were controls who were individually matched to the lesion subjects on the basis of age, sex, and socioeconomic status. Each subject was given the Short-Form of Benton's Test of Facial Recognition. Data were analyzed using the Wilcoxon matched-pairs signed-rank test and multiple regression. The lesion subjects performed significantly more poorly than did matched controls. There was no clear-cut lateralization effect, with the left-hemisphere group performing significantly more poorly than matched controls and the right-hemisphere group showing a trend toward poorer performance. Parietal lobe involvement, regardless of lesion side, adversely affected facial recognition performance in the lesion group. Results could not be accounted for by IQ differences between lesion and control groups, nor was lesion severity systematically related to facial recognition performance. Pre- or perinatal unilateral brain damage results in a subtle disturbance in facial recognition ability, independent of the side of the lesion. Parietal lobe involvement, in particular, has an adverse effect on facial recognition skills. These findings suggest that the parietal lobes may be involved in the acquisition of facial recognition ability from a very early point in brain development, but that there is sufficient potential to reorganize or compensate such that the residual deficits, though significant, are subtle.

Inhibition of P2X Receptors Protects Human Monocytes against Damage by Leukotoxin from Aggregatibacter actinomycetemcomitans and α-Hemolysin from Escherichia coli

PubMed Central

Skals, Marianne

2016-01-01

α-Hemolysin (HlyA) from Escherichia coli and leukotoxin A (LtxA) from Aggregatibacter actinomycetemcomitans are important virulence factors in ascending urinary tract infections and aggressive periodontitis, respectively. The extracellular signaling molecule ATP is released immediately after insertion of the toxins into plasma membranes and, via P2X receptors, is essential for the erythrocyte damage inflicted by these toxins. Moreover, ATP signaling is required for the ensuing recognition and phagocytosis of damaged erythrocytes by the monocytic cell line THP-1. Here, we investigate how these toxins affect THP-1 monocyte function. We demonstrate that both toxins trigger early ATP release and a following increase in the intracellular Ca2+ concentration ([Ca2+]i) in THP-1 monocytes. The HlyA- and LtxA-induced [Ca2+]i response is diminished by the P2 receptor antagonist in a pattern that fits the functional P2 receptor expression in these cells. Both toxins are capable of lysing THP-1 cells, with LtxA being more aggressive. Either desensitization or blockage of P2X1, P2X4, or P2X7 receptors markedly reduces toxin-induced cytolysis. This pattern is paralleled in freshly isolated human monocytes from healthy volunteers. Interestingly, only a minor fraction of the toxin-damaged THP-1 monocytes eventually lyse. P2X7 receptor inhibition generally prevents cell damage, except from a distinct cell shrinkage that prevails in response to the toxins. Moreover, we find that preexposure to HlyA preserves the capacity of THP-1 monocytes to phagocytose damaged erythrocytes and may induce readiness to discriminate between damaged and healthy erythrocytes. These findings suggest a new pharmacological target for protecting monocytes during exposure to pore-forming cytolysins during infection or injury. PMID:27528275

An in vitro metabolomics approach to identify hepatotoxicity biomarkers in human L02 liver cells treated with pekinenal, a natural compound.

PubMed

Shi, Jiexia; Zhou, Jing; Ma, Hongyue; Guo, Hongbo; Ni, Zuyao; Duan, Jin'ao; Tao, Weiwei; Qian, Dawei

2016-02-01

An in vitro cell metabolomics study was performed on human L02 liver cells to investigate the toxic biomarkers of pekinenal from the herb Euphorbia pekinensis Rupr. Pekinenal significantly induced L02 cell damage, which was characterised by necrosis and apoptosis. Metabolomics combined with data pattern recognition showed that pekinenal significantly altered the profiles of more than 1299 endogenous metabolites with variable importance in the projection (VIP) > 1. Further, screening correlation coefficients between the intensities of all metabolites and the extent of L02 cell damage (MTT) identified 12 biomarker hits: ten were downregulated and two were upregulated. Among these hits, LysoPC(18:1(9Z)/(11Z)), PC(22:0/15:0) and PC(20:1(11Z)/14:1(9Z)) were disordered, implying the initiation of inflammation and cell damage. Several fatty acids (FAs) (3-hydroxytetradecanedioic acid, pivaloylcarnitine and eicosapentaenoyl ethanolamide) decreased due to fatty acid oxidation. Dihydroceramide and Cer(d18:0/14:0) were also altered and are associated with apoptosis. Additional examination of the levels of intracellular reactive oxygen species (ROS) and two eicosanoids (PGE2, PGF2α) in the cell supernatant confirmed the fatty acid oxidation and arachidonic acid metabolism pathways, respectively. In summary, cell metabolomics is a highly efficient approach for identifying toxic biomarkers and helping understand toxicity mechanisms and predict herb-induced liver injury.

Detection of insect damage in almonds

NASA Astrophysics Data System (ADS)

Kim, Soowon; Schatzki, Thomas F.

1999-01-01

Pinhole insect damage in natural almonds is very difficult to detect on-line. Further, evidence exists relating insect damage to aflatoxin contamination. Hence, for quality and health reasons, methods to detect and remove such damaged nuts are of great importance in this study, we explored the possibility of using x-ray imaging to detect pinhole damage in almonds by insects. X-ray film images of about 2000 almonds and x-ray linescan images of only 522 pinhole damaged almonds were obtained. The pinhole damaged region appeared slightly darker than non-damaged region in x-ray negative images. A machine recognition algorithm was developed to detect these darker regions. The algorithm used the first order and the second order information to identify the damaged region. To reduce the possibility of false positive results due to germ region in high resolution images, germ detection and removal routines were also included. With film images, the algorithm showed approximately an 81 percent correct recognition ratio with only 1 percent false positives whereas line scan images correctly recognized 65 percent of pinholes with about 9 percent false positives. The algorithms was very fast and efficient requiring only minimal computation time. If implemented on line, theoretical throughput of this recognition system would be 66 nuts/second.

The Molecular Origin of the MMR-dependent Apoptosis Pathway from Dynamics Analysis of MutSα-DNA Complexes

PubMed Central

Negureanu, Lacramioara; Salsbury, Freddie R.

2012-01-01

The cellular response to DNA damage signaling by MMR proteins is incompletely understood. It is generally accepted that MMR-dependent apoptosis pathway in response to DNA damage detection is independent of MMR's DNA repair function. In this study we investigate correlated motions in response to the binding of mismatched and PCL DNA fragments by MutSα, as derived from 50 ns molecular dynamics simulations. The protein dynamics in response to the mismatched and damaged DNA recognition suggests that MutSα signals their recognition through independent pathways providing evidence for the molecular origin of the MMR-dependent apoptosis. MSH2 subunit is indicated to play a key role in signaling both mismatched and damaged DNA recognition; localized and collective motions within the protein allow identifying sites on the MSH2 surface possible involved in recruiting proteins responsible for downstream events. Unlike in the mismatch complex, predicted key communication sites specific for the damage recognition are on the list of known cancer causing mutations or deletions. This confirms MSH2's role in signaling DNA-damage induced apoptosis and suggests that defects in MMR alone is sufficient to trigger tumorigenesis, supporting the experimental evidence that MMR-damage response function could protect from the early occurrence of tumors. Identifying these particular communication sites may have implications for the treatment of cancers that are not defective for MMR, but are unable to function optimally for MMR-dependent responses following DNA damage such as the case of resistance to cisplatin. PMID:22712459

Strand-specific Recognition of DNA Damages by XPD Provides Insights into Nucleotide Excision Repair Substrate Versatility*

PubMed Central

Buechner, Claudia N.; Heil, Korbinian; Michels, Gudrun; Carell, Thomas; Kisker, Caroline; Tessmer, Ingrid

2014-01-01

Recognition and removal of DNA damages is essential for cellular and organismal viability. Nucleotide excision repair (NER) is the sole mechanism in humans for the repair of carcinogenic UV irradiation-induced photoproducts in the DNA, such as cyclobutane pyrimidine dimers. The broad substrate versatility of NER further includes, among others, various bulky DNA adducts. It has been proposed that the 5′-3′ helicase XPD (xeroderma pigmentosum group D) protein plays a decisive role in damage verification. However, despite recent advances such as the identification of a DNA-binding channel and central pore in the protein, through which the DNA is threaded, as well as a dedicated lesion recognition pocket near the pore, the exact process of target site recognition and verification in eukaryotic NER still remained elusive. Our single molecule analysis by atomic force microscopy reveals for the first time that XPD utilizes different recognition strategies to verify structurally diverse lesions. Bulky fluorescein damage is preferentially detected on the translocated strand, whereas the opposite strand preference is observed for a cyclobutane pyrimidine dimer lesion. Both states, however, lead to similar conformational changes in the resulting specific complexes, indicating a merge to a “final” verification state, which may then trigger the recruitment of further NER proteins. PMID:24338567

The nucleosome: orchestrating DNA damage signaling and repair within chromatin.

PubMed

Agarwal, Poonam; Miller, Kyle M

2016-10-01

DNA damage occurs within the chromatin environment, which ultimately participates in regulating DNA damage response (DDR) pathways and repair of the lesion. DNA damage activates a cascade of signaling events that extensively modulates chromatin structure and organization to coordinate DDR factor recruitment to the break and repair, whilst also promoting the maintenance of normal chromatin functions within the damaged region. For example, DDR pathways must avoid conflicts between other DNA-based processes that function within the context of chromatin, including transcription and replication. The molecular mechanisms governing the recognition, target specificity, and recruitment of DDR factors and enzymes to the fundamental repeating unit of chromatin, i.e., the nucleosome, are poorly understood. Here we present our current view of how chromatin recognition by DDR factors is achieved at the level of the nucleosome. Emerging evidence suggests that the nucleosome surface, including the nucleosome acidic patch, promotes the binding and activity of several DNA damage factors on chromatin. Thus, in addition to interactions with damaged DNA and histone modifications, nucleosome recognition by DDR factors plays a key role in orchestrating the requisite chromatin response to maintain both genome and epigenome integrity.

Enzymatic recognition of DNA damage induced by UVB-photosensitized titanium dioxide and biological consequences in Saccharomyces cerevisiae: evidence for oxidatively DNA damage generation.

PubMed

Pinto, A Viviana; Deodato, Elder L; Cardoso, Janine S; Oliveira, Eliza F; Machado, Sérgio L; Toma, Helena K; Leitão, Alvaro C; de Pádula, Marcelo

2010-06-01

Although titanium dioxide (TiO(2)) has been considered to be biologically inert, finding use in cosmetics, paints and food colorants, recent reports have demonstrated that when TiO(2) is attained by UVA radiation oxidative genotoxic and cytotoxic effects are observed in living cells. However, data concerning TiO(2)-UVB association is poor, even if UVB radiation represents a major environmental carcinogen. Herein, we investigated DNA damage, repair and mutagenesis induced by TiO(2) associated with UVB irradiation in vitro and in vivo using Saccharomyces cerevisiae model. It was found that TiO(2) plus UVB treatment in plasmid pUC18 generated, in addition to cyclobutane pyrimidine dimers (CPDs), specific damage to guanine residues, such as 8-oxo-7,8-dihydroguanine (8-oxoG) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG), which are characteristic oxidatively generated lesions. In vivo experiments showed that, although the presence of TiO(2) protects yeast cells from UVB cytotoxicity, high mutation frequencies are observed in the wild-type (WT) and in an ogg1 strain (deficient in 8-oxoG and FapyG repair). Indeed, after TiO(2) plus UVB treatment, induced mutagenesis was drastically enhanced in ogg1 cells, indicating that mutagenic DNA lesions are repaired by the Ogg1 protein. This effect could be attenuated by the presence of metallic ion chelators: neocuproine or dipyridyl, which partially block oxidatively generated damage occurring via Fenton reactions. Altogether, the results indicate that TiO(2) plus UVB potentates UVB oxidatively generated damage to DNA, possibly via Fenton reactions involving the production of DNA base damage, such as 8-oxo-7,8-dihydroguanine. Copyright 2010 Elsevier B.V. All rights reserved.

Personalizing Stem Cell Research and Therapy: The Arduous Road Ahead or Missed Opportunity?

PubMed Central

Patel, S.A.; King, C.C.; Lim, P.K.; Habiba, U.; Dave, M.; Porecha, R.; Rameshwar, P.

2010-01-01

The euphoria of stem cell therapy has diminished, allowing scientists, clinicians and the general public to seriously re-examine how and what types of stem cells would effectively repair damaged tissue, prevent further tissue damage and/or replace lost cells. Importantly, there is a growing recognition that there are substantial person-to-person differences in the outcome of stem cell therapy. Even though the small molecule pharmaceuticals have long remained a primary focus of the personalized medicine research, individualized or targeted use of stem cells to suit a particular individual could help forecast potential failures of the therapy or identify, early on, the individuals who might benefit from stem cell interventions. This would however demand collaboration among several specialties such as pharmacology, immunology, genomics and transplantation medicine. Such transdisciplinary work could also inform how best to achieve efficient and predictable stem cell migration to sites of tissue damage, thereby facilitating tissue repair. This paper discusses the possibility of polarizing immune responses to rationalize and individualize therapy with stem cell interventions, since generalized “one-size-fits-all” therapy is difficult to achieve in the face of the diverse complexities posed by stem cell biology. We also present the challenges to stem cell delivery in the context of the host related factors. Although we focus on the mesenchymal stem cells in this paper, the overarching rationale can be extrapolated to other types of stem cells as well. Hence, the broader purpose of this paper is to initiate a dialogue within the personalized medicine community by expanding the scope of inquiry in the field from pharmaceuticals to stem cells and related cell-based health interventions. PMID:20563265

Image recognition on raw and processed potato detection: a review

NASA Astrophysics Data System (ADS)

Qi, Yan-nan; Lü, Cheng-xu; Zhang, Jun-ning; Li, Ya-shuo; Zeng, Zhen; Mao, Wen-hua; Jiang, Han-lu; Yang, Bing-nan

2018-02-01

Objective: Chinese potato staple food strategy clearly pointed out the need to improve potato processing, while the bottleneck of this strategy is technology and equipment of selection of appropriate raw and processed potato. The purpose of this paper is to summarize the advanced raw and processed potato detection methods. Method: According to consult research literatures in the field of image recognition based potato quality detection, including the shape, weight, mechanical damage, germination, greening, black heart, scab potato etc., the development and direction of this field were summarized in this paper. Result: In order to obtain whole potato surface information, the hardware was built by the synchronous of image sensor and conveyor belt to achieve multi-angle images of a single potato. Researches on image recognition of potato shape are popular and mature, including qualitative discrimination on abnormal and sound potato, and even round and oval potato, with the recognition accuracy of more than 83%. Weight is an important indicator for potato grading, and the image classification accuracy presents more than 93%. The image recognition of potato mechanical damage focuses on qualitative identification, with the main affecting factors of damage shape and damage time. The image recognition of potato germination usually uses potato surface image and edge germination point. Both of the qualitative and quantitative detection of green potato have been researched, currently scab and blackheart image recognition need to be operated using the stable detection environment or specific device. The image recognition of processed potato mainly focuses on potato chips, slices and fries, etc. Conclusion: image recognition as a food rapid detection tool have been widely researched on the area of raw and processed potato quality analyses, its technique and equipment have the potential for commercialization in short term, to meet to the strategy demand of development potato as staple food in China.

Does Infection-Induced Immune Activation Contribute to Dementia?

PubMed Central

Barichello, Tatiana; Generoso, Jaqueline S; Goularte, Jessica A; Collodel, Allan; Pitcher, Meagan R; Simões, Lutiana R; Quevedo, João; Dal-Pizzol, Felipe

2015-01-01

The central nervous system (CNS) is protected by a complex blood-brain barrier system; however, a broad diversity of virus, bacteria, fungi, and protozoa can gain access and cause illness. As pathogens replicate, they release molecules that can be recognized by innate immune cells. These molecules are pathogen-associated molecular patterns (PAMP) and they are identified by pattern-recognition receptors (PRR) expressed on antigen-presenting cells. Examples of PRR include toll-like receptors (TLR), receptors for advanced glycation endproducts (RAGE), nucleotide binding oligomerisation domain (NOD)-like receptors (NLR), c-type lectin receptors (CLR), RIG-I-like receptors (RLR), and intra-cytosolic DNA sensors. The reciprocal action between PAMP and PRR triggers the release of inflammatory mediators that regulate the elimination of invasive pathogens. Damage-associated molecular patterns (DAMP) are endogenous constituents released from damaged cells that also have the ability to activate the innate immune response. An increase of RAGE expression levels on neurons, astrocytes, microglia, and endothelial cells could be responsible for the accumulation of αβ-amyloid in dementia and related to the chronic inflammatory state that is found in neurodegenerative disorders. PMID:26425389

Dissociable Contributions of Thalamic Nuclei to Recognition Memory: Novel Evidence from a Case of Medial Dorsal Thalamic Damage

ERIC Educational Resources Information Center

Newsome, Rachel N.; Trelle, Alexandra N.; Fidalgo, Celia; Hong, Bryan; Smith, Victoria M.; Jacob, Alexander; Ryan, Jennifer D.; Rosenbaum, R. Shayna; Cowell, Rosemary A.; Barense, Morgan D.

2018-01-01

The thalamic nuclei are thought to play a critical role in recognition memory. Specifically, the anterior thalamic nuclei and medial dorsal nuclei may serve as critical output structures in distinct hippocampal and perirhinal cortex systems, respectively. Existing evidence indicates that damage to the anterior thalamic nuclei leads to impairments…

Regulation of Nucleotide Excision Repair by UV-DDB: Prioritization of Damage Recognition to Internucleosomal DNA

PubMed Central

Luch, Andreas; Glas, Andreas; Carell, Thomas; Naegeli, Hanspeter

2011-01-01

How tightly packed chromatin is thoroughly inspected for DNA damage is one of the fundamental unanswered questions in biology. In particular, the effective excision of carcinogenic lesions caused by the ultraviolet (UV) radiation of sunlight depends on UV-damaged DNA-binding protein (UV-DDB), but the mechanism by which this DDB1-DDB2 heterodimer stimulates DNA repair remained enigmatic. We hypothesized that a distinctive function of this unique sensor is to coordinate damage recognition in the nucleosome repeat landscape of chromatin. Therefore, the nucleosomes of human cells have been dissected by micrococcal nuclease, thus revealing, to our knowledge for the first time, that UV-DDB associates preferentially with lesions in hypersensitive, hence, highly accessible internucleosomal sites joining the core particles. Surprisingly, the accompanying CUL4A ubiquitin ligase activity is necessary to retain the xeroderma pigmentosum group C (XPC) partner at such internucleosomal repair hotspots that undergo very fast excision kinetics. This CUL4A complex thereby counteracts an unexpected affinity of XPC for core particles that are less permissive than hypersensitive sites to downstream repair subunits. That UV-DDB also adopts a ubiquitin-independent function is evidenced by domain mapping and in situ protein dynamics studies, revealing direct but transient interactions that promote a thermodynamically unfavorable β-hairpin insertion of XPC into substrate DNA. We conclude that the evolutionary advent of UV-DDB correlates with the need for a spatiotemporal organizer of XPC positioning in higher eukaryotic chromatin. PMID:22039351

Human T-cell leukemia virus-I tax oncoprotein functionally targets a subnuclear complex involved in cellular DNA damage-response.

PubMed

Haoudi, Abdelali; Daniels, Rodney C; Wong, Eric; Kupfer, Gary; Semmes, O John

2003-09-26

The virally encoded oncoprotein Tax has been implicated in HTLV-1-mediated cellular transformation. The exact mechanism by which this protein contributes to the oncogenic process is not known. However, it has been hypothesized that Tax induces genomic instability via repression of cellular DNA repair. We examined the effect of de novo Tax expression upon the cell cycle, because appropriate activation of cell cycle checkpoints is essential to a robust damage-repair response. Upon induction of tax expression, Jurkat T-cells displayed a pronounced accumulation in G2/M that was reversible by caffeine. We examined the G2-specific checkpoint signaling response in these cells and found activation of the ATM/chk2-mediated pathway, whereas the ATR/chk1-mediated response was unaffected. Immunoprecipitation with anti-chk2 antibody results in co-precipitation of Tax demonstrating a direct interaction of Tax with a chk2-containing complex. We also show that Tax targets a discrete nuclear site and co-localizes with chk2 and not chk1. This nuclear site, previously identified as Tax Speckled Structures (TSS), also contains the early damage response factor 53BP1. The recruitment of 53BP1 to TSS is dependent upon ATM signaling and requires expression of Tax. Specifically, Tax expression induces redistribution of diffuse nuclear 53BP1 to the TSS foci. Taken together these data suggest that the TSS describe a unique nuclear site involved in DNA damage recognition, repair response, and cell cycle checkpoint activation. We suggest that association of Tax with this multifunctional subnuclear site results in disruption of a subset of the site-specific activities and contributes to cellular genomic instability.

Rapid DNA double-strand breaks resulting from processing of Cr-DNA cross-links by both MutS dimers.

PubMed

Reynolds, Mindy F; Peterson-Roth, Elizabeth C; Bespalov, Ivan A; Johnston, Tatiana; Gurel, Volkan M; Menard, Haley L; Zhitkovich, Anatoly

2009-02-01

Mismatch repair (MMR) strongly enhances cyto- and genotoxicity of several chemotherapeutic agents and environmental carcinogens. DNA double-strand breaks (DSB) formed after two replication cycles play a major role in MMR-dependent cell death by DNA alkylating drugs. Here, we examined DNA damage detection and the mechanisms of the unusually rapid induction of DSB by MMR proteins in response to carcinogenic chromium(VI). We found that MSH2-MSH6 (MutSalpha) dimer effectively bound DNA probes containing ascorbate-Cr-DNA and cysteine-Cr-DNA cross-links. Binary Cr-DNA adducts, the most abundant form of Cr-DNA damage, were poor substrates for MSH2-MSH6, and their toxicity in cells was weak and MMR independent. Although not involved in the initial recognition of Cr-DNA damage, MSH2-MSH3 (MutSbeta) complex was essential for the induction of DSB, micronuclei, and apoptosis in human cells by chromate. In situ fractionation of Cr-treated cells revealed MSH6 and MSH3 chromatin foci that originated in late S phase and did not require replication of damaged DNA. Formation of MSH3 foci was MSH6 and MLH1 dependent, whereas MSH6 foci were unaffected by MSH3 status. DSB production was associated with progression of cells from S into G(2) phase and was completely blocked by the DNA synthesis inhibitor aphidicolin. Interestingly, chromosome 3 transfer into MSH3-null HCT116 cells activated an alternative, MSH3-like activity that restored dinucleotide repeat stability and sensitivity to chromate. Thus, sequential recruitment and unprecedented cooperation of MutSalpha and MutSbeta branches of MMR in processing of Cr-DNA cross-links is the main cause of DSB and chromosomal breakage at low and moderate Cr(VI) doses.

C/EBPα regulates CRL4Cdt2-mediated degradation of p21 in response to UVB-induced DNA damage to control the G1/S checkpoint

PubMed Central

Hall, Jonathan R; Bereman, Michael S; Nepomuceno, Angelito I; Thompson, Elizabeth A; Muddiman, David C; Smart, Robert C

2014-01-01

The bZIP transcription factor, C/EBPα is highly inducible by UVB and other DNA damaging agents in keratinocytes. C/EBPα-deficient keratinocytes fail to undergo cell cycle arrest in G1 in response to UVB-induced DNA damage and mice lacking epidermal C/EBPα are highly susceptible to UVB-induced skin cancer. The mechanism through which C/EBPα regulates the cell cycle checkpoint in response to DNA damage is unknown. Here we report untreated C/EBPα-deficient keratinocytes have normal levels of the cyclin-dependent kinase inhibitor, p21, however, UVB-treated C/EBPα-deficient keratinocytes fail to up-regulate nuclear p21 protein levels despite normal up-regulation of Cdkn1a mRNA levels. UVB-treated C/EBPα-deficient keratinocytes displayed a 4-fold decrease in nuclear p21 protein half-life due to the increased proteasomal degradation of p21 via the E3 ubiquitin ligase CRL4Cdt2. Cdt2 is the substrate recognition subunit of CRL4Cdt2 and Cdt2 mRNA and protein levels were up-regulated in UVB-treated C/EBPα-deficient keratinocytes. Knockdown of Cdt2 restored p21 protein levels in UVB-treated C/EBPα-deficient keratinocytes. Lastly, the failure to accumulate p21 in response to UVB in C/EBPα-deficient keratinocytes resulted in decreased p21 interactions with critical cell cycle regulatory proteins, increased CDK2 activity, and inappropriate entry into S-phase. These findings reveal C/EBPα regulates G1/S cell cycle arrest in response to DNA damage via the control of CRL4Cdt2 mediated degradation of p21. PMID:25483090

The posterior parietal cortex in recognition memory: a neuropsychological study.

PubMed

Haramati, Sharon; Soroker, Nachum; Dudai, Yadin; Levy, Daniel A

2008-01-01

Several recent functional neuroimaging studies have reported robust bilateral activation (L>R) in lateral posterior parietal cortex and precuneus during recognition memory retrieval tasks. It has not yet been determined what cognitive processes are represented by those activations. In order to examine whether parietal lobe-based processes are necessary for basic episodic recognition abilities, we tested a group of 17 first-incident CVA patients whose cortical damage included (but was not limited to) extensive unilateral posterior parietal lesions. These patients performed a series of tasks that yielded parietal activations in previous fMRI studies: yes/no recognition judgments on visual words and on colored object pictures and identifiable environmental sounds. We found that patients with left hemisphere lesions were not impaired compared to controls in any of the tasks. Patients with right hemisphere lesions were not significantly impaired in memory for visual words, but were impaired in recognition of object pictures and sounds. Two lesion--behavior analyses--area-based correlations and voxel-based lesion symptom mapping (VLSM)---indicate that these impairments resulted from extra-parietal damage, specifically to frontal and lateral temporal areas. These findings suggest that extensive parietal damage does not impair recognition performance. We suggest that parietal activations recorded during recognition memory tasks might reflect peri-retrieval processes, such as the storage of retrieved memoranda in a working memory buffer for further cognitive processing.

Evidence for conformational capture mechanism for damage recognition by NER protein XPC/Rad4.

NASA Astrophysics Data System (ADS)

Chakraborty, Sagnik; Steinbach, Peter J.; Paul, Debamita; Min, Jung-Hyun; Ansari, Anjum

Altered flexibility of damaged DNA sites is considered to play an important role in damage recognition by DNA repair proteins. Characterizing lesion-induced DNA dynamics has remained a challenge. We have combined ps-resolved fluorescence lifetime measurements with cytosine analog FRET pair uniquely sensitive to local unwinding/twisting to analyze DNA conformational distributions. This innovative approach maps out with unprecedented sensitivity the alternative conformations accessible to a series of DNA constructs containing 3-base-pair mismatch, suitable model lesions for the DNA repair protein xeroderma pigmentosum C (XPC) complex. XPC initiates eukaryotic nucleotide excision repair by recognizing various DNA lesions primarily through DNA deformability. Structural studies show that Rad4 (yeast ortholog of XPC) unwinds DNA at the lesion site and flips out two nucleotide pairs. Our results elucidate a broad range of conformations accessible to mismatched DNA even in the absence of the protein. Notably, the most severely distorted conformations share remarkable resemblance to the deformed conformation seen in the crystal structure of the Rad4-bound ``recognition'' complex supporting for the first time a possible ``conformational capture'' mechanism for damage recognition by XPC/Rad4. NSF Univ of Illinois-Chicago.

Small RNA-mediated repair of UV-induced DNA lesions by the DNA DAMAGE-BINDING PROTEIN 2 and ARGONAUTE 1

PubMed Central

Schalk, Catherine; Cognat, Valérie; Graindorge, Stéfanie; Vincent, Timothée; Voinnet, Olivier; Molinier, Jean

2017-01-01

As photosynthetic organisms, plants need to prevent irreversible UV-induced DNA lesions. Through an unbiased, genome-wide approach, we have uncovered a previously unrecognized interplay between Global Genome Repair and small interfering RNAs (siRNAs) in the recognition of DNA photoproducts, prevalently in intergenic regions. Genetic and biochemical approaches indicate that, upon UV irradiation, the DNA DAMAGE-BINDING PROTEIN 2 (DDB2) and ARGONAUTE 1 (AGO1) of Arabidopsis thaliana form a chromatin-bound complex together with 21-nt siRNAs, which likely facilitates recognition of DNA damages in an RNA/DNA complementary strand-specific manner. The biogenesis of photoproduct-associated siRNAs involves the noncanonical, concerted action of RNA POLYMERASE IV, RNA-DEPENDENT RNA POLYMERASE-2, and DICER-LIKE-4. Furthermore, the chromatin association/dissociation of the DDB2-AGO1 complex is under the control of siRNA abundance and DNA damage signaling. These findings reveal unexpected nuclear functions for DCL4 and AGO1, and shed light on the interplay between small RNAs and DNA repair recognition factors at damaged sites. PMID:28325872

Dissociation between recognition and recall in developmental amnesia

PubMed Central

Adlam, Anna-Lynne R.; Malloy, Megan; Mishkin, Mortimer; Vargha-Khadem, Faraneh

2009-01-01

Developmental amnesia (DA) is a memory disorder due to hypoxia/ischaemia-induced damage to the hippocampus early in life. To test the hypothesis that this disorder is associated with a disproportionate impairment in recall vis-à-vis recognition, we examined a group of 10 patients with DA on the Doors and People test, which affords a quantitative comparison between measures of the two memory processes. The results supported the hypothesis in that the patients showed a sharp, though not complete, recall-recognition dissociation, exhibiting impairment on both measures relative to their matched controls, but with a far greater loss in recall than in recognition. Whether their relatively spared recognition ability is due to restriction of their medial temporal lobe damage to the hippocampus or whether it is due instead to their early age at injury is still uncertain. PMID:19524088

The Medial Dorsal Thalamic Nucleus and the Medial Prefrontal Cortex of the Rat Function Together to Support Associative Recognition and Recency but Not Item Recognition

ERIC Educational Resources Information Center

Cross, Laura; Brown, Malcolm W.; Aggleton, John P.; Warburton, E. Clea

2013-01-01

In humans recognition memory deficits, a typical feature of diencephalic amnesia, have been tentatively linked to mediodorsal thalamic nucleus (MD) damage. Animal studies have occasionally investigated the role of the MD in single-item recognition, but have not systematically analyzed its involvement in other recognition memory processes. In…

Structural Basis for the Interaction of Mutasome Assembly Factor REV1 with Ubiquitin.

PubMed

Cui, Gaofeng; Botuyan, Maria Victoria; Mer, Georges

2018-05-18

REV1 is an evolutionarily conserved translesion synthesis (TLS) DNA polymerase and an assembly factor key for the recruitment of other TLS polymerases to DNA damage sites. REV1-mediated recognition of ubiquitin in the proliferative cell nuclear antigen is thought to be the trigger for TLS activation. Here we report the solution NMR structure of a 108-residue fragment of human REV1 encompassing the two putative ubiquitin-binding motifs UBM1 and UBM2 in complex with ubiquitin. While in mammals UBM1 and UBM2 are both required for optimal association of REV1 with replication factories after DNA damage, we show that only REV1 UBM2 binds ubiquitin. Structure-guided mutagenesis in Saccharomyces cerevisiae further highlights the importance of UBM2 for REV1-mediated mutagenesis and DNA damage tolerance. Copyright © 2018 Elsevier Ltd. All rights reserved.

Emotion Recognition in Stroke Patients with Left and Right Hemispheric Lesion: Results with a New Instrument-The Feel Test

ERIC Educational Resources Information Center

Braun, M.; Traue, H.C.; Frisch, S.; Deighton, R.M.; Kessler, H.

2005-01-01

The aim of this study was to investigate the effect of a stroke event on people's ability to recognize basic emotions. In particular, the hypothesis that right brain-damaged (RBD) patients would show less of emotion recognition ability compared with left brain-damaged (LBD) patients and healthy controls, was tested. To investigate this the FEEL…

Evolutionary Convergence and Divergence in NLR Function and Structure.

PubMed

Meunier, Etienne; Broz, Petr

2017-10-01

The recognition of cellular damage caused by either pathogens or abiotic stress is essential for host defense in all forms of life in the plant and animal kingdoms. The NOD-like receptors (NLRs) represent a large family of multidomain proteins that were initially discovered for their role in host defense in plants and vertebrates. Over recent years the wide distribution of NLRs among metazoans has become apparent and their origins have begun to emerge. Moreover, intense study of NLR function has shown that they play essential roles beyond pathogen recognition - in the regulation of antigen presentation, cell death, inflammation, and even in embryonic development. We summarize here the latest insights into NLR biology and discuss examples of converging and diverging evolution of NLR function and structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Autophagy and self-defense.

PubMed

Martínez-Borra, Jesús; López-Larrea, Carlos

2012-01-01

Autophagy is a highly conserved mechanism which is essential for the maintenance of cellular homeostasis in response to cellular stress. Autophagy has been conserved from yeast to humans as a quality control process that is involved in the recognition and turnover of damaged proteins and organelles. It is also a response mechanism to nutrient starvation. In mammals, autophagy is involved in antigen presentation, tolerance, inflammation and protection against neurodegenerative diseases. The decrease of autophagy during aging reduces the removal of damaged organelles and increases the accumulation of waste products in the cells. In this chapter, we review these aspects of autophagy along with their role in self-nonself distinction, their implication in innate and adaptive immune response, and its dysregulation in the pathology of certain inflammatory and autoimmune diseases.

Supreme EnLIGHTenment: Damage Recognition and Signaling in the Mammalian UV Response

PubMed Central

Herrlich, Peter; Karin, Michael; Weiss, Carsten

2009-01-01

Like their prokaryotic counterparts, mammalian cells can sense light, especially in the ultraviolet (UV) range of the spectrum. Following UV exposure cells mount an elaborate response – called the UV response, which mimics physiological signaling responses except that it targets multiple pathways thereby lacking the defined specificity of receptor-triggered signal transduction. Despite many years of research it is still not fully clear how UV radiation is sensed and converted into the „language of cells“ - signal reception and transduction. This review focuses on how photonic energy and its primary cellular products are sensed to elicit the UV response. PMID:18280234

Object memory effects on figure assignment: conscious object recognition is not necessary or sufficient.

PubMed

Peterson, M A; de Gelder, B; Rapcsak, S Z; Gerhardstein, P C; Bachoud-Lévi, A

2000-01-01

In three experiments we investigated whether conscious object recognition is necessary or sufficient for effects of object memories on figure assignment. In experiment 1, we examined a brain-damaged participant, AD, whose conscious object recognition is severely impaired. AD's responses about figure assignment do reveal effects from memories of object structure, indicating that conscious object recognition is not necessary for these effects, and identifying the figure-ground test employed here as a new implicit test of access to memories of object structure. In experiments 2 and 3, we tested a second brain-damaged participant, WG, for whom conscious object recognition was relatively spared. Nevertheless, effects from memories of object structure on figure assignment were not evident in WG's responses about figure assignment in experiment 2, indicating that conscious object recognition is not sufficient for effects of object memories on figure assignment. WG's performance sheds light on AD's performance, and has implications for the theoretical understanding of object memory effects on figure assignment.

The ibrutinib B-cell proliferation inhibition is potentiated in vitro by dexamethasone: Application to chronic lymphocytic leukemia.

PubMed

Manzoni, Delphine; Catallo, Régine; Chebel, Amel; Baseggio, Lucile; Michallet, Anne-Sophie; Roualdes, Olivier; Magaud, Jean-Pierre; Salles, Gilles; Ffrench, Martine

2016-08-01

New B-cell receptor-targeted therapies such as ibrutinib, a Bruton tyrosine kinase inhibitor, are now proposed for lymphoid pathologies. The putative benefits of its combination with glucocorticoids were evaluated here. We compared the effects of dexamethasone (DXM), ibrutinib and their in vitro combination on proliferation and metabolic stress markers in stimulated normal B-lymphocytes and in malignant lymphocytes from chronic lymphocytic leukemia (CLL) patients. In both cellular models, cell cycle progression was globally inhibited by DXM and/or ibrutinib. This inhibition was significantly amplified by DXM addition to ibrutinib and was related to a significant decrease in the expression of the cell cycle regulatory proteins CDK4 and cyclin E. Apoptosis increased especially with DXM/ibrutinib combination and was associated with a significant decrease in Mcl-1 expression. Treatment effects on metabolic stress were evaluated by DNA damage recognition after 53BP1 foci labeling. The percentage of cells with more than five 53BP1 foci decreased significantly with ibrutinib in normal and CLL lymphocytes. This decrease was strongly reinforced, in CLL, by DXM addition. Our data indicated that, in vitro, DXM potentiated antiproliferative effects of ibrutinib and decreased DNA damage in lymphoid B-cells. Thus their combination may be proposed for CLL treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neutrophil cell surface receptors and their intracellular signal transduction pathways☆

PubMed Central

Futosi, Krisztina; Fodor, Szabina; Mócsai, Attila

2013-01-01

Neutrophils play a critical role in the host defense against bacterial and fungal infections, but their inappropriate activation also contributes to tissue damage during autoimmune and inflammatory diseases. Neutrophils express a large number of cell surface receptors for the recognition of pathogen invasion and the inflammatory environment. Those include G-protein-coupled chemokine and chemoattractant receptors, Fc-receptors, adhesion receptors such as selectins/selectin ligands and integrins, various cytokine receptors, as well as innate immune receptors such as Toll-like receptors and C-type lectins. The various cell surface receptors trigger very diverse signal transduction pathways including activation of heterotrimeric and monomeric G-proteins, receptor-induced and store-operated Ca2 + signals, protein and lipid kinases, adapter proteins and cytoskeletal rearrangement. Here we provide an overview of the receptors involved in neutrophil activation and the intracellular signal transduction processes they trigger. This knowledge is crucial for understanding how neutrophils participate in antimicrobial host defense and inflammatory tissue damage and may also point to possible future targets of the pharmacological therapy of neutrophil-mediated autoimmune or inflammatory diseases. PMID:23994464

Comprehensive Profiling of Radiosensitive Human Cell Lines with DNA Damage Response Assays Identifies the Neutral Comet Assay as a Potential Surrogate for Clonogenic Survival

PubMed Central

Nahas, Shareef A.; Davies, Robert; Fike, Francesca; Nakamura, Kotoka; Du, Liutao; Kayali, Refik; Martin, Nathan T.; Concannon, Patrick; Gatti, Richard A.

2015-01-01

In an effort to explore the possible causes of human radiosensitivity and identify more rapid assays for cellular radiosensitivity, we interrogated a set of assays that evaluate cellular functions involved in recognition and repair of DNA double-strand breaks: (1) neutral comet assay, (2) radiation-induced γ-H2AX focus formation, (3) the temporal kinetics of structural maintenance of chromosomes 1 phosphorylation, (4) intra-S-phase checkpoint integrity, and (5) mitochondrial respiration. We characterized a unique panel of 19 “radiosensitive” human lymphoblastoid cell lines from individuals with undiagnosed diseases suggestive of a DNA repair disorder. Radiosensitivity was defined by reduced cellular survival using a clonogenic survival assay. Each assay identified cell lines with defects in DNA damage response functions. The highest concordance rate observed, 89% (17/19), was between an abnormal neutral comet assay and reduced survival by the colony survival assay. Our data also suggested that the neutral comet assay would be a more rapid surrogate for analyzing DNA repair/processing disorders. PMID:21962002

Expression of Pattern Recognition Receptors in Epithelial Cells Around Clinically Healthy Implants and Healthy Teeth.

PubMed

Calcaterra, Roberta; Di Girolamo, Michele; Mirisola, Concetta; Baggi, Luigi

2016-06-01

Gingival epithelial cells have a pivotal role in the recognition of microorganisms and damage-associated molecular pattern molecules and in the regulation of the immune response. The investigation of the behavior of Toll-like receptors (TLRs) and nucleotide oligomerization domain (NOD) like receptors (NLRs) around a healthy implant may help to address the first step of periimplantitis pathogenesis. To investigate by quantitative real-time polymerase chain reaction, the mRNA expressions of TLR2, TLR3, TLR4, TLR5, TLR6, TLR9, NOD1, NOD2, and NLRP3 from gingival epithelial cells of the sulcus around healthy implants and around healthy teeth. Two types of implant-abutment systems with tube-in-tube interface were tested. After 6 months of implant restoration, gingival epithelial cells were obtained from the gingival sulcus around the implants and around the adjacent teeth of 10 patients. Our results did not reach statistical significance among the mRNA expressions of TLR2, TLR3, TLR4, TLR5, TLR6, TLR9, NOD1, NOD2, and NLRP3 in epithelial cells around the implant versus around natural teeth. This study shows that the implant-abutment systems tested did not induce an immune response by the surrounding epithelial cells at 6 months since their positioning, as well as in the adjacent clincally healthy teeth.

Overexpression of xeroderma pigmentosum group C decreases the chemotherapeutic sensitivity of colorectal carcinoma cells to cisplatin.

PubMed

Zhang, Yi; Cao, Jia; Meng, Yanni; Qu, Chunying; Shen, Feng; Xu, Leiming

2018-05-01

Xeroderma pigmentosum group C (XPC) is a DNA-damage-recognition gene active at the early stage of DNA repair. XPC also participates in regulation of cell-cycle checkpoint and DNA-damage-induced apoptosis. In the present study, the expression levels of genes involved in nucleotide excision repair (NER) were assessed in human colorectal cancer (CRC) tissue. This analysis revealed that expression of XPC mRNA significantly increased in colorectal carcinoma tissues compared with matched normal controls. Expression of XPC gradually increased along with the degree of progression of CRC. In vitro , an XTT assay demonstrated that small interfering RNA (siRNA) targeting XPC significantly increased the sensitivity of CRC SW480 cells to cisplatin, whereas cells transfected with a XPC-overexpression plasmid became more resistant to cisplatin. Furthermore, flow cytometry revealed that the proportion of apoptotic cells significantly increased in XPC-knockdown cells upon cisplatin treatment. However, the overexpression XPC significantly increased the resistance of cells to cisplatin. In vivo , tumor growth was significantly reduced in tumor-bearing mice when the XPC gene was knocked down. Upregulation of the expression of pro-apoptotic Bcl-associated X and downregulation of the anti-apoptotic B-cell lymphoma 2 proteins was observed in the implanted tumor tissue. In conclusion, XPC serves a key role in chemotherapeutic sensitivity of CRC to cisplatin, meaning that it may be a potential target for chemotherapy of CRC.

Clinical implications of basic science discoveries: induced pluripotent stem cell therapy in transplantation--a potential role for immunologic tolerance.

PubMed

Wertheim, J A; Leventhal, J R

2015-04-01

Induced pluripotent stem cells (iPSCs) hold the potential for future development of genetically identical tissues from almost any mature cell lineage. For clinical applications in cell therapy and transplantation, it may provide a means to one-day restore dysfunctional or damaged tissue without the need for immunosuppression. A recent study by de Almeida et al published in the journal Nature Communications indicates that iPSCs may indeed elicit an immune response that evolves as cells differentiate toward maturity to induce a state of tolerance within a recipient animal. If these early findings hold true, it suggests a possible explanation for self-recognition of mature cells derived from iPSCs for use in future therapeutic interventions in transplantation such as cellular therapy or tissue engineering. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

Cancer treatment by photodynamic therapy combined with NK-cell-line-based adoptive immunotherapy

NASA Astrophysics Data System (ADS)

Korbelik, Mladen; Sun, Jinghai

1998-05-01

Treatment of solid cancers by photodynamic therapy (PDT) triggers a strong acute inflammatory reaction localized to the illuminated malignant tissue. This event is regulated by a massive release of various potent mediators which have a profound effect not only on local host cell populations, but also attract different types of immune cells to the treated tumor. Phagocytosis of PDT-damaged cancerous cells by antigen presenting cells, such as activated tumor associated macrophages, enables the recognition of even poorly immunogenic tumors by specific immune effector cells and the generation of immune memory populations. Because of its inflammatory/immune character, PDT is exceptionally responsive to adjuvant treatments with various types of immunotherapy. Combining PDT with immuneactivators, such as cytokines or other specific or non-specific immune agents, rendered marked improvements in tumor cures with various cancer models. Another clinically attractive strategy is adoptive immunotherapy, and the prospects of its use in conjunction with PDT are outlined.

The Differential Effects of Thalamus and Basal Ganglia on Facial Emotion Recognition

ERIC Educational Resources Information Center

Cheung, Crystal C. Y.; Lee, Tatia M. C.; Yip, James T. H.; King, Kristin E.; Li, Leonard S. W.

2006-01-01

This study examined if subcortical stroke was associated with impaired facial emotion recognition. Furthermore, the lateralization of the impairment and the differential profiles of facial emotion recognition deficits with localized thalamic or basal ganglia damage were also studied. Thirty-eight patients with subcortical strokes and 19 matched…

Toxicities of chimeric antigen receptor T cells: recognition and management

PubMed Central

Brudno, Jennifer N.

2016-01-01

Chimeric antigen receptor (CAR) T cells can produce durable remissions in hematologic malignancies that are not responsive to standard therapies. Yet the use of CAR T cells is limited by potentially severe toxicities. Early case reports of unexpected organ damage and deaths following CAR T-cell therapy first highlighted the possible dangers of this new treatment. CAR T cells can potentially damage normal tissues by specifically targeting a tumor-associated antigen that is also expressed on those tissues. Cytokine release syndrome (CRS), a systemic inflammatory response caused by cytokines released by infused CAR T cells can lead to widespread reversible organ dysfunction. CRS is the most common type of toxicity caused by CAR T cells. Neurologic toxicity due to CAR T cells might in some cases have a different pathophysiology than CRS and requires different management. Aggressive supportive care is necessary for all patients experiencing CAR T-cell toxicities, with early intervention for hypotension and treatment of concurrent infections being essential. Interleukin-6 receptor blockade with tocilizumab remains the mainstay pharmacologic therapy for CRS, though indications for administration vary among centers. Corticosteroids should be reserved for neurologic toxicities and CRS not responsive to tocilizumab. Pharmacologic management is complicated by the risk of immunosuppressive therapy abrogating the antimalignancy activity of the CAR T cells. This review describes the toxicities caused by CAR T cells and reviews the published approaches used to manage toxicities. We present guidelines for treating patients experiencing CRS and other adverse events following CAR T-cell therapy. PMID:27207799

The Yin and Yang of innate immunity in stroke.

PubMed

Xu, Xiaomeng; Jiang, Yongjun

2014-01-01

Immune system plays an elementary role in the pathophysiological progress of ischemic stroke. It consists of innate and adaptive immune system. Activated within minutes after ischemic onset, innate immunity is responsible for the elimination of necrotic cells and tissue repair, while it is critically involved in the initiation and amplification of poststroke inflammation that amplifies ischemic damage to the brain tissue. Innate immune response requires days to be fully developed, providing a considerable time window for therapeutic intervention, suggesting prospect of novel immunomodulatory therapies against poststroke inflammation-induced brain injury. However, obstacles still exist and a comprehensive understanding of ischemic stroke and innate immune reaction is essential. In this review, we highlighted the current experimental and clinical data depicting the innate immune response following ischemic stroke, mainly focusing on the recognition of damage-associated molecular patterns, activation and recruitment of innate immune cells, and involvement of various cytokines. In addition, clinical trials targeting innate immunity were also documented regardless of the outcome, stressing the requirements for further investigation.

Finite element model updating and damage detection for bridges using vibration measurement.

DOT National Transportation Integrated Search

2013-12-01

In this report, the results of a study on developing a damage detection methodology based on Statistical Pattern Recognition are : presented. This methodology uses a new damage sensitive feature developed in this study that relies entirely on modal :...

Amplification of unscheduled DNA synthesis signal enables fluorescence-based single cell quantification of transcription-coupled nucleotide excision repair

PubMed Central

Wienholz, Franziska; Vermeulen, Wim

2017-01-01

Abstract Nucleotide excision repair (NER) comprises two damage recognition pathways: global genome NER (GG-NER) and transcription-coupled NER (TC-NER), which remove a wide variety of helix-distorting lesions including UV-induced damage. During NER, a short stretch of single-stranded DNA containing damage is excised and the resulting gap is filled by DNA synthesis in a process called unscheduled DNA synthesis (UDS). UDS is measured by quantifying the incorporation of nucleotide analogues into repair patches to provide a measure of NER activity. However, this assay is unable to quantitatively determine TC-NER activity due to the low contribution of TC-NER to the overall NER activity. Therefore, we developed a user-friendly, fluorescence-based single-cell assay to measure TC-NER activity. We combined the UDS assay with tyramide-based signal amplification to greatly increase the UDS signal, thereby allowing UDS to be quantified at low UV doses, as well as DNA-repair synthesis of other excision-based repair mechanisms such as base excision repair and mismatch repair. Importantly, we demonstrated that the amplified UDS is sufficiently sensitive to quantify TC-NER-derived repair synthesis in GG-NER-deficient cells. This assay is important as a diagnostic tool for NER-related disorders and as a research tool for obtaining new insights into the mechanism and regulation of excision repair. PMID:28088761

Early effects of whole-body (56)Fe irradiation on hippocampal function in C57BL/6J mice.

PubMed

Haley, Gwendolen E; Yeiser, Lauren; Olsen, Reid H J; Davis, Matthew J; Johnson, Lance A; Raber, Jacob

2013-05-01

Relatively little is known about early irradiation effects on hippocampal function in wild-type mice. In this study, the effects of (56)Fe irradiation on hippocampal function were assessed starting 2 weeks after whole-body irradiation. Compared to sham irradiation, radiation impaired novel object recognition in female and male C57BL/6J wild-type mice. There were no effects of irradiation on contextual fear conditioning or spatial memory retention in the water maze. It is possible that oxidative damage might contribute to radiation-induced cognitive changes. Therefore, hippocampal and cortical levels of 3-nitrotyrosine (3NT) and lipid peroxidation, measures of oxidative damage were assessed. There were no effects of irradiation on these measures of oxidative damage. As (56)Fe irradiation can increase reactive oxygen species (ROS) levels, which may contribute to the impairments in novel object recognition, the effects of the antioxidant alpha-lipoic acid (ALA) on cognition following sham irradiation and irradiation were also assessed. ALA did not prevent radiation-induced impairments in novel object recognition and impaired spatial memory retention of sham-irradiated and irradiated mice in the probe trial after the first day of hidden platform training in the water maze. Thus, the novel object recognition test is particularly sensitive to detect early cognitive effects of (56)Fe irradiation through a mechanism unlikely involving ROS or oxidative damage.

Innate Immune Regulations and Liver Ischemia Reperfusion Injury

PubMed Central

Lu, Ling; Zhou, Haoming; Ni, Ming; Wang, Xuehao; Busuttil, Ronald; Kupiec-Weglinski, Jerzy; Zhai, Yuan

2016-01-01

Liver ischemia reperfusion activates innate immune system to drive the full development of inflammatory hepatocellular injury. Damage-associated molecular patterns (DAMPs) stimulate myeloid and dendritic cells via pattern recognition receptors (PRRs) to initiate the immune response. Complex intracellular signaling network transduces inflammatory signaling to regulate both innate immune cell activation and parenchymal cell death. Recent studies have revealed that DAMPs may trigger not only proinflammatory, but also immune regulatory responses by activating different PRRs or distinctive intracellular signaling pathways or in special cell populations. Additionally, tissue injury milieu activates PRR-independent receptors which also regulate inflammatory disease processes. Thus, the innate immune mechanism of liver IRI involves diverse molecular and cellular interactions, subjected to both endogenous and exogenous regulation in different cells. A better understanding of these complicated regulatory pathways/network is imperative for us in designing safe and effective therapeutic strategy to ameliorate liver IRI in patients. PMID:27861288

A new selective developmental deficit: Impaired object recognition with normal face recognition.

PubMed

Germine, Laura; Cashdollar, Nathan; Düzel, Emrah; Duchaine, Bradley

2011-05-01

Studies of developmental deficits in face recognition, or developmental prosopagnosia, have shown that individuals who have not suffered brain damage can show face recognition impairments coupled with normal object recognition (Duchaine and Nakayama, 2005; Duchaine et al., 2006; Nunn et al., 2001). However, no developmental cases with the opposite dissociation - normal face recognition with impaired object recognition - have been reported. The existence of a case of non-face developmental visual agnosia would indicate that the development of normal face recognition mechanisms does not rely on the development of normal object recognition mechanisms. To see whether a developmental variant of non-face visual object agnosia exists, we conducted a series of web-based object and face recognition tests to screen for individuals showing object recognition memory impairments but not face recognition impairments. Through this screening process, we identified AW, an otherwise normal 19-year-old female, who was then tested in the lab on face and object recognition tests. AW's performance was impaired in within-class visual recognition memory across six different visual categories (guns, horses, scenes, tools, doors, and cars). In contrast, she scored normally on seven tests of face recognition, tests of memory for two other object categories (houses and glasses), and tests of recall memory for visual shapes. Testing confirmed that her impairment was not related to a general deficit in lower-level perception, object perception, basic-level recognition, or memory. AW's results provide the first neuropsychological evidence that recognition memory for non-face visual object categories can be selectively impaired in individuals without brain damage or other memory impairment. These results indicate that the development of recognition memory for faces does not depend on intact object recognition memory and provide further evidence for category-specific dissociations in visual recognition. Copyright © 2010 Elsevier Srl. All rights reserved.

Cell-type specific role of the RNA-binding protein, NONO, in the DNA double-strand break response in the mouse testes.

PubMed

Li, Shuyi; Shu, Feng-Jue; Li, Zhentian; Jaafar, Lahcen; Zhao, Shourong; Dynan, William S

2017-03-01

The tandem RNA recognition motif protein, NONO, was previously identified as a candidate DNA double-strand break (DSB) repair factor in a biochemical screen for proteins with end-joining stimulatory activity. Subsequent work showed that NONO and its binding partner, SFPQ, have many of the properties expected for bona fide repair factors in cell-based assays. Their contribution to the DNA damage response in intact tissue in vivo has not, however, been demonstrated. Here we compare DNA damage sensitivity in the testes of wild-type mice versus mice bearing a null allele of the NONO homologue (Nono gt ). In wild-type mice, NONO protein was present in Sertoli, peritubular myoid, and interstitial cells, with an increase in expression following induction of DNA damage. As expected for the product of an X-linked gene, NONO was not detected in germ cells. The Nono gt/0 mice had at most a mild testis developmental phenotype in the absence of genotoxic stress. However, following irradiation at sublethal, 2-4 Gy doses, Nono gt/0 mice displayed a number of indicators of radiosensitivity as compared to their wild-type counterparts. These included higher levels of persistent DSB repair foci, increased numbers of apoptotic cells in the seminiferous tubules, and partial degeneration of the blood-testis barrier. There was also an almost complete loss of germ cells at later times following irradiation, evidently arising as an indirect effect reflecting loss of stromal support. Results demonstrate a role for NONO protein in protection against direct and indirect biological effects of ionizing radiation in the whole animal. Copyright © 2017 Elsevier B.V. All rights reserved.

Break-induced telomere synthesis underlies alternative telomere maintenance

PubMed Central

Dilley, Robert L.; Verma, Priyanka; Cho, Nam Woo; Winters, Harrison D.; Wondisford, Anne R.; Greenberg, Roger A.

2017-01-01

Homology-directed DNA repair is essential for genome maintenance through templated DNA synthesis. Alternative lengthening of telomeres (ALT) necessitates homology-directed DNA repair to maintain telomeres in about 10–15% of human cancers. How DNA damage induces assembly and execution of a DNA replication complex (break-induced replisome) at telomeres or elsewhere in the mammalian genome is poorly understood. Here we define break-induced telomere synthesis and demonstrate that it utilizes a specialized replisome, which underlies ALT telomere maintenance. DNA double-strand breaks enact nascent telomere synthesis by long-tract unidirectional replication. Proliferating cell nuclear antigen (PCNA) loading by replication factor C (RFC) acts as the initial sensor of telomere damage to establish predominance of DNA polymerase δ (Pol δ) through its POLD3 subunit. Break-induced telomere synthesis requires the RFC–PCNA–Pol δ axis, but is independent of other canonical replisome components, ATM and ATR, or the homologous recombination protein Rad51. Thus, the inception of telomere damage recognition by the break-induced replisome orchestrates homology-directed telomere maintenance. PMID:27760120

What happens to the motor theory of perception when the motor system is damaged?

PubMed

Stasenko, Alena; Garcea, Frank E; Mahon, Bradford Z

2013-09-01

Motor theories of perception posit that motor information is necessary for successful recognition of actions. Perhaps the most well known of this class of proposals is the motor theory of speech perception, which argues that speech recognition is fundamentally a process of identifying the articulatory gestures (i.e. motor representations) that were used to produce the speech signal. Here we review neuropsychological evidence from patients with damage to the motor system, in the context of motor theories of perception applied to both manual actions and speech. Motor theories of perception predict that patients with motor impairments will have impairments for action recognition. Contrary to that prediction, the available neuropsychological evidence indicates that recognition can be spared despite profound impairments to production. These data falsify strong forms of the motor theory of perception, and frame new questions about the dynamical interactions that govern how information is exchanged between input and output systems.

What happens to the motor theory of perception when the motor system is damaged?

PubMed Central

Stasenko, Alena; Garcea, Frank E.; Mahon, Bradford Z.

2016-01-01

Motor theories of perception posit that motor information is necessary for successful recognition of actions. Perhaps the most well known of this class of proposals is the motor theory of speech perception, which argues that speech recognition is fundamentally a process of identifying the articulatory gestures (i.e. motor representations) that were used to produce the speech signal. Here we review neuropsychological evidence from patients with damage to the motor system, in the context of motor theories of perception applied to both manual actions and speech. Motor theories of perception predict that patients with motor impairments will have impairments for action recognition. Contrary to that prediction, the available neuropsychological evidence indicates that recognition can be spared despite profound impairments to production. These data falsify strong forms of the motor theory of perception, and frame new questions about the dynamical interactions that govern how information is exchanged between input and output systems. PMID:26823687

Overexpression of xeroderma pigmentosum group C decreases the chemotherapeutic sensitivity of colorectal carcinoma cells to cisplatin

PubMed Central

Zhang, Yi; Cao, Jia; Meng, Yanni; Qu, Chunying; Shen, Feng; Xu, Leiming

2018-01-01

Xeroderma pigmentosum group C (XPC) is a DNA-damage-recognition gene active at the early stage of DNA repair. XPC also participates in regulation of cell-cycle checkpoint and DNA-damage-induced apoptosis. In the present study, the expression levels of genes involved in nucleotide excision repair (NER) were assessed in human colorectal cancer (CRC) tissue. This analysis revealed that expression of XPC mRNA significantly increased in colorectal carcinoma tissues compared with matched normal controls. Expression of XPC gradually increased along with the degree of progression of CRC. In vitro, an XTT assay demonstrated that small interfering RNA (siRNA) targeting XPC significantly increased the sensitivity of CRC SW480 cells to cisplatin, whereas cells transfected with a XPC-overexpression plasmid became more resistant to cisplatin. Furthermore, flow cytometry revealed that the proportion of apoptotic cells significantly increased in XPC-knockdown cells upon cisplatin treatment. However, the overexpression XPC significantly increased the resistance of cells to cisplatin. In vivo, tumor growth was significantly reduced in tumor-bearing mice when the XPC gene was knocked down. Upregulation of the expression of pro-apoptotic Bcl-associated X and downregulation of the anti-apoptotic B-cell lymphoma 2 proteins was observed in the implanted tumor tissue. In conclusion, XPC serves a key role in chemotherapeutic sensitivity of CRC to cisplatin, meaning that it may be a potential target for chemotherapy of CRC. PMID:29616110

Characterization of a DNA damage-recognition protein mammalian cells that binds specifically to intrastrand d(GpG) and d(ApG) DNA adducts of the anticancer drug cisplatin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donahue, B.A.; Augot, M.; Bellon, S.F.

1990-06-19

A factor has been identified in extracts from human HeLa and hamster V79 cells that retards the electrophoretic mobility of several DNA restriction fragments modified with the antitumor drug cis-diamminedichloroplatinum(II) (cisplatin). Binding of the factor to cisplatin-modified DNA was sensitive to pretreatment with proteinase K, establishing that the factor is a protein. Gel mobility shifts were observed with probes containing as few as seven Pt atoms per kilobase of duplex DNA. By competition experiments the dissociation constant, K{sub d}, of the protein from cisplatin-modified DNA was estimated to be (1-20) {times} 10{sup {minus}10} M. Protein binding is selective for DNAmore » modified with cisplatin, (Pt(en)Cl{sub 2}) (en, ethylenediamine), and (Pt(dach)Cl{sub 2}) (dach, 1,2-diaminocyclohexane) but not with chemotherapeutically inactive trans-diamminedichloroplatinum(II) or monofunctionally coordinating (Pt(dien)Cl)Cl (dien, diethylenetriamine) complexes. The protein binds specifically to 1,2-intrastrand d(GpG) and d(ApG) cross-links formed by cisplatin. The apparent molecular weight of the protein is 91,000, as determined by sucrose gradient centrifugation of a preparation partially purified by ammonium sulfate fractionation. Binding of the protein to platinum-modified DNA does not require cofactors but is sensitive to treatment with 5 mM MnCl{sub 2}, CdCl{sub 2}, CoCl{sub 2}, or ZnCl{sub 2} and with 1 mM HgCl{sub 2}. This protein, alone or in conjunction with other cellular constituents, could be of general importance in the initial stages of processing of mammalian DNA damaged by cisplatin or other genotoxic agents and may belong to a wider class of such cellular damage-recognition proteins (DRPs).« less

Decoding cell death signals in liver inflammation.

PubMed

Brenner, Catherine; Galluzzi, Lorenzo; Kepp, Oliver; Kroemer, Guido

2013-09-01

Inflammation can be either beneficial or detrimental to the liver, depending on multiple factors. Mild (i.e., limited in intensity and destined to resolve) inflammatory responses have indeed been shown to exert consistent hepatoprotective effects, contributing to tissue repair and promoting the re-establishment of homeostasis. Conversely, excessive (i.e., disproportionate in intensity and permanent) inflammation may induce a massive loss of hepatocytes and hence exacerbate the severity of various hepatic conditions, including ischemia-reperfusion injury, systemic metabolic alterations (e.g., obesity, diabetes, non-alcoholic fatty liver disorders), alcoholic hepatitis, intoxication by xenobiotics and infection, de facto being associated with irreversible liver damage, fibrosis, and carcinogenesis. Both liver-resident cells (e.g., Kupffer cells, hepatic stellate cells, sinusoidal endothelial cells) and cells that are recruited in response to injury (e.g., monocytes, macrophages, dendritic cells, natural killer cells) emit pro-inflammatory signals including - but not limited to - cytokines, chemokines, lipid messengers, and reactive oxygen species that contribute to the apoptotic or necrotic demise of hepatocytes. In turn, dying hepatocytes release damage-associated molecular patterns that-upon binding to evolutionary conserved pattern recognition receptors-activate cells of the innate immune system to further stimulate inflammatory responses, hence establishing a highly hepatotoxic feedforward cycle of inflammation and cell death. In this review, we discuss the cellular and molecular mechanisms that account for the most deleterious effect of hepatic inflammation at the cellular level, that is, the initiation of a massive cell death response among hepatocytes. Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Visual and Visuospatial Short-Term Memory in Mild Cognitive Impairment and Alzheimer Disease: Role of Attention

ERIC Educational Resources Information Center

Alescio-Lautier, B.; Michel, B. F.; Herrera, C.; Elahmadi, A.; Chambon, C.; Touzet, C.; Paban, V.

2007-01-01

It has been proposed that visual recognition memory and certain attentional mechanisms are impaired early in Alzheimer disease (AD). Little is known about visuospatial recognition memory in AD. The crucial role of the hippocampus on spatial memory and its damage in AD suggest that visuospatial recognition memory may also be impaired early. The aim…

Injury and immune response: applying the danger theory to mosquitoes

PubMed Central

Moreno-García, Miguel; Recio-Tótoro, Benito; Claudio-Piedras, Fabiola; Lanz-Mendoza, Humberto

2014-01-01

The insect immune response can be activated by the recognition of both non-self and molecular by-products of tissue damage. Since pathogens and tissue damage usually arise at the same time during infection, the specific mechanisms of the immune response to microorganisms, and to tissue damage have not been unraveled. Consequently, some aspects of damage caused by microorganisms in vector-borne arthropods have been neglected. We herein reassess the Anopheles–Plasmodium interaction, incorporating Matzinger’s danger/damage hypothesis and George Salt’s injury assumptions. The invasive forms of the parasite cross the peritrophic matrix and midgut epithelia to reach the basal lamina and differentiate into an oocyst. The sporozoites produced in the oocyst are released into the hemolymph, and from there enter the salivary gland. During parasite development, wounds to midgut tissue and the basement membrane are produced. We describe the response of the different compartments where the parasite interacts with the mosquito. In the midgut, the response includes the expression of antimicrobial peptides, production of reactive oxygen species, and possible activation of midgut regenerative cells. In the basal membrane, wound repair mainly involves the production of molecules and the recruitment of hemocytes. We discuss the susceptibility to damage in tissues, and how the place and degree of damage may influence the differential response and the expression of damage associated molecular patterns (DAMPs). Knowledge about damage caused by parasites may lead to a deeper understanding of the relevance of tissue damage and the immune response it generates, as well as the origins and progression of infection in this insect–parasite interaction. PMID:25250040

Nonhuman TRIM5 Variants Enhance Recognition of HIV-1-Infected Cells by CD8+ T Cells

PubMed Central

Jimenez-Moyano, Esther; Ruiz, Alba; Kløverpris, Henrik N.; Rodriguez-Plata, Maria T.; Peña, Ruth; Blondeau, Caroline; Selwood, David L.; Izquierdo-Useros, Nuria; Moris, Arnaud; Clotet, Bonaventura; Goulder, Philip; Towers, Greg J.

2016-01-01

ABSTRACT Tripartite motif-containing protein 5 (TRIM5) restricts human immunodeficiency virus type 1 (HIV-1) in a species-specific manner by uncoating viral particles while activating early innate responses. Although the contribution of TRIM5 proteins to cellular immunity has not yet been studied, their interactions with the incoming viral capsid and the cellular proteasome led us to hypothesize a role for them. Here, we investigate whether the expression of two nonhuman TRIM5 orthologs, rhesus TRIM5α (RhT5) and TRIM-cyclophilin A (TCyp), both of which are potent restrictors of HIV-1, could enhance immune recognition of infected cells by CD8+ T cells. We illustrate how TRIM5 restriction improves CD8+ T-cell-mediated HIV-1 inhibition. Moreover, when TRIM5 activity was blocked by the nonimmunosuppressive analog of cyclosporine (CsA), sarcosine-3(4-methylbenzoate)–CsA (SmBz-CsA), we found a significant reduction in CD107a/MIP-1β expression in HIV-1-specific CD8+ T cells. This finding underscores the direct link between TRIM5 restriction and activation of CD8+ T-cell responses. Interestingly, cells expressing RhT5 induced stronger CD8+ T-cell responses through the specific recognition of the HIV-1 capsid by the immune system. The underlying mechanism of this process may involve TRIM5-specific capsid recruitment to cellular proteasomes and increase peptide availability for loading and presentation of HLA class I antigens. In summary, we identified a novel function for nonhuman TRIM5 variants in cellular immunity. We hypothesize that TRIM5 can couple innate viral sensing and CD8+ T-cell activation to increase species barriers against retrovirus infection. IMPORTANCE New therapeutics to tackle HIV-1 infection should aim to combine rapid innate viral sensing and cellular immune recognition. Such strategies could prevent seeding of the viral reservoir and the immune damage that occurs during acute infection. The nonhuman TRIM5 variants, rhesus TRIM5α (RhT5) and TRIM-cyclophilin A (TCyp), are attractive candidates owing to their potency in sensing HIV-1 and blocking its activity. Here, we show that expression of RhT5 and TCyp in HIV-1-infected cells improves CD8+ T-cell-mediated inhibition through the direct activation of HIV-1-specific CD8+ T-cell responses. We found that the potency in CD8+ activation was stronger for RhT5 variants and capsid-specific CD8+ T cells in a mechanism that relies on TRIM5-dependent particle recruitment to cellular proteasomes. This novel mechanism couples innate viral sensing with cellular immunity in a single protein and could be exploited to develop innovative therapeutics for control of HIV-1 infection. PMID:27440884

Elevation of cAMP Levels Inhibits Doxorubicin-Induced Apoptosis in Pre- B ALL NALM- 6 Cells Through Induction of BAD Phosphorylation and Inhibition of P53 Accumulation.

PubMed

Fatemi, Ahmad; Kazemi, Ahmad; Kashiri, Meysam; Safa, Majid

2015-01-01

Recognition of the molecular mechanisms of cAMP action against DNA damage-induced apoptosis can be useful to improve the efficacy of DNA damaging therapeutic agents. Considering the critical role of bcl-2-associated death promoter (BAD) and p53 proteins in DNA damage -induced apoptosis, the aim of this study was to assess the effect of cAMP-elevating agents on these proteins in doxorubicin-treated pre-B acute lymphoblastic leukemia (pre-B ALL) NALM-6 cells.The pre-B ALL cell line NALM-6 was cultured and treated with doxorubicin in combination with or without cAMP-elevating agents forskolin and 3-isobutyl-1-methylxanthine (IBMX). Cell viability was measured by trypan blue staining and MTT assay. For evaluation of apoptosis, annexin-V staining by flow cytometry and caspase-3 activity assay were used. Protein expression of p53, BAD and phoshorylated BAD was detected by western blotting analysis.cAMP-increasing agents diminished the doxorubicin-mediated cytotoxicity in NALM-6 cells as indicated by the viability assays. Annexin-V apoptosis assay showed that the cAMP-elevating agents decreased doxorubicin-induced apoptosis. Moreover, doxorubicin-induced caspase-3 activity was attenuated in the presence of cAMP-increasing agents. Western blot results revealed the reduced expression of p53 protein in cells treated with combination of cAMP-elevating agents and doxorubicin in contrast to cells treated with doxorubicin alone. Expression of total BAD protein was not affected by doxorubicin and cAMP-elevating agents. However, phosphorylation of BAD protein was induced in the presence of cAMP-elevating agents. Our study suggests that elevated cAMP levels inhibit doxorubicin-induced apoptosis in pre-B ALL cells through induction of BAD phosphorylation and abrogation of p53 accumulation.

Damage-associated molecular pattern activated Toll-like receptor 4 signalling modulates blood pressure in L-NAME-induced hypertension.

PubMed

Sollinger, Daniel; Eißler, Ruth; Lorenz, Steffen; Strand, Susanne; Chmielewski, Stefan; Aoqui, Cristiane; Schmaderer, Christoph; Bluyssen, Hans; Zicha, Josef; Witzke, Oliver; Scherer, Elias; Lutz, Jens; Heemann, Uwe; Baumann, Marcus

2014-03-01

Recent publications have shed new light on the role of the adaptive and innate immune system in the pathogenesis of hypertension. However, there are limited data whether receptors of the innate immune system may influence blood pressure. Toll-like receptor 4 (TLR4), a pattern recognition receptor, is a key component of the innate immune system, which is activated by exogenous and endogenous ligands. Hypertension is associated with end-organ damage and thus might lead to the release of damage-associated molecular patterns (DAMPs), which are endogenous activators of TLR4 receptors. The present study aimed to elucidate whether TLR4 signalling is able to modulate vascular contractility in an experimental model of hypertension thus contributing to blood pressure regulation. NG-nitro-l-arginine methyl ester (l-NAME)-induced hypertension was blunted in TLR4(-/-) when compared with wild-type mice. Treatment with l-NAME was associated with a release of DAMPs, leading to reactive oxygen species production of smooth muscle cells in a TLR4-dependent manner. As oxidative stress leads to an impaired function of the NO-sGC-cyclic GMP (cGMP) pathway, we were able to demonstrate that TLR4(-/-) was protected from sGC inactivation. Consequently, arterial contractility was reduced in TLR4(-/-). Cell damage-associated TLR4 signalling might act as a direct mediator of vascular contractility providing a molecular link between inflammation and hypertension.

Engineering a Cell-surface Aptamer Circuit for Targeted and Amplified Photodynamic Cancer Therapy

PubMed Central

Han, Da; Zhu, Guizhi; Wu, Cuichen; Zhu, Zhi; Chen, Tao; Zhang, Xiaobing

2013-01-01

Photodynamic therapy (PDT) is one of the most promising and noninvasive methods for clinical treatment of different malignant diseases. Here, we present a novel strategy of designing an aptamer-based DNA nanocircuit capable of the selective recognition of cancer cells, controllable activation of photosensitizer and amplification of photodynamic therapeutic effect. The aptamers can selectively recognize target cancer cells and bind to the specific proteins on cell membranes. Then the overhanging catalyst sequence on aptamer can trigger a toehold-mediated catalytic strand displacement to activate photosensitizer and achieve amplified therapeutic effect. The specific binding-induced activation allows the DNA circuit to distinguish diseased cells from healthy cells, reducing damage to nearby healthy cells. Moreover, the catalytic amplification reaction will only take place close to the target cancer cells, resulting in a high local concentration of singlet oxygen to selectively kill the target cells. The principle employed in this study demonstrated the feasibility of assembling a DNA circuit on cell membranes and could further broaden the utility of DNA circuits for applications in biology, biotechnology, and biomedicine. PMID:23397942

Therapeutic Hypothermia and Hypoxia-Ischemia in the Term-equivalent Neonatal Rat: Characterization of a Translational Pre-clinical Model

PubMed Central

Patel, Shyama D.; Pierce, Leslie; Ciardiello, Amber; Hutton, Alexandra; Paskewitz, Samuel; Aronowitz, Eric; Voss, Henning U.; Moore, Holly; Vannucci, Susan J.

2015-01-01

Background Hypoxic-ischemic encephalopathy (HIE) is a major cause of morbidity in survivors. Therapeutic hypothermia (TH) is the only available intervention, but the protection is incomplete. Preclinical studies of HIE/TH in the rodent have relied on the postnatal day (P) 7 rat whose brain approximates a 32–36 week gestation infant, less relevant for these studies. We propose that HIE and TH in the term-equivalent P10 rat will be more translational. Methods P10–11 rat pups were subjected to unilateral hypoxia-ischemia (HI) and 4 hours recovery in normothermic (N) or hypothermic (TH) conditions. Brain damage was assessed longitudinally at 24 hours, 2 and 12 weeks. Motor function was assessed with the beam walk; recognition memory was measured by novel object recognition. Results Neuroprotection with TH was apparent at 2 and 12 weeks in both moderately and severely damaged animals. TH improved motor function in moderate, but not severe damage. Impaired object recognition occurred with severe damage with no evidence of protection of TH. Conclusion This adaptation of the immature rat model of HI provides a reproducible platform to further study HIE/TH in which individual animals are followed longitudinally to provide a useful translational preclinical model. PMID:25996893

Repair of DNA-polypeptide crosslinks by human excision nuclease

NASA Astrophysics Data System (ADS)

Reardon, Joyce T.; Sancar, Aziz

2006-03-01

DNA-protein crosslinks are relatively common DNA lesions that form during the physiological processing of DNA by replication and recombination proteins, by side reactions of base excision repair enzymes, and by cellular exposure to bifunctional DNA-damaging agents such as platinum compounds. The mechanism by which pathological DNA-protein crosslinks are repaired in humans is not known. In this study, we investigated the mechanism of recognition and repair of protein-DNA and oligopeptide-DNA crosslinks by the human excision nuclease. Under our assay conditions, the human nucleotide excision repair system did not remove a 16-kDa protein crosslinked to DNA at a detectable level. However, 4- and 12-aa-long oligopeptides crosslinked to the DNA backbone were recognized by some of the damage recognition factors of the human excision nuclease with moderate selectivity and were excised from DNA at relatively efficient rates. Our data suggest that, if coupled with proteolytic degradation of the crosslinked protein, the human excision nuclease may be the major enzyme system for eliminating protein-DNA crosslinks from the genome. damage recognition | nucleotide excision repair

Leukemia and Benzene

PubMed Central

Snyder, Robert

2012-01-01

Excessive exposure to benzene has been known for more than a century to damage the bone marrow resulting in decreases in the numbers of circulating blood cells, and ultimately, aplastic anemia. Of more recent vintage has been the appreciation that an alternative outcome of benzene exposure has been the development of one or more types of leukemia. While many investigators agree that the array of toxic metabolites, generated in the liver or in the bone marrow, can lead to traumatic bone marrow injury, the more subtle mechanisms leading to leukemia have yet to be critically dissected. This problem appears to have more general interest because of the recognition that so-called “second cancer” that results from prior treatment with alkylating agents to yield tumor remissions, often results in a type of leukemia reminiscent of benzene-induced leukemia. Furthermore, there is a growing literature attempting to characterize the fine structure of the marrow and the identification of so called “niches” that house a variety of stem cells and other types of cells. Some of these “niches” may harbor cells capable of initiating leukemias. The control of stem cell differentiation and proliferation via both inter- and intra-cellular signaling will ultimately determine the fate of these transformed stem cells. The ability of these cells to avoid checkpoints that would prevent them from contributing to the leukemogenic response is an additional area for study. Much of the study of benzene-induced bone marrow damage has concentrated on determining which of the benzene metabolites lead to leukemogenesis. The emphasis now should be directed to understanding how benzene metabolites alter bone marrow cell biology. PMID:23066403

Screening for modulators of cisplatin sensitivity: unbiased screens reveal common themes.

PubMed

Nijwening, Jeroen H; Kuiken, Hendrik J; Beijersbergen, Roderick L

2011-02-01

Cisplatin is a widely used chemotherapeutic agent to treat a variety of solid tumors. The cytotoxic mode of action of cisplatin is mediated by inducing conformational changes in DNA including intra- and inter-strand crosslink adducts. Recognition of these adducts results in the activation of the DNA damage response resulting in cell cycle arrest, repair, and potentially, apoptosis. Despite the clinical efficacy of cisplatin, many tumors are either intrinsically resistant or acquire resistance during treatment. The identification of cisplatin drug response modulators can help us understand these resistance mechanisms, provide biomarkers for treatment strategies, or provide drug targets for combination therapy. Here we discuss functional genetic screens, including one performed by us, set up to identify genes whose inhibition results in increased sensitivity to cisplatin. In summary, the validated genes identified in these screens mainly operate in DNA damage response including nucleotide excision repair, translesion synthesis, and homologous recombination.

Genomic amplification of the human DHFR/MSH3 locus remodels mismatch recognition and repair activities.

PubMed

Drummond, J T

1999-01-01

Mismatch recognition in human cells is mediated by two heterodimers, MutS alpha and MutS beta. MutS alpha appears to shoulder primary responsibility for mismatch correction during replication, based on its relative abundance and ability to recognize a broad spectrum of base-base and base-insertion mismatches. Because MutS alpha and MutS beta share a common component, MSH2, conditions that influence the expression or degradation of MSH3 or MSH6 can redistribute the profile of mismatch recognition and repair. MSH3 is linked by a shared promoter with DHFR, connecting two pathways with key roles in DNA metabolism. In a classic example of gene amplification, the DHFR (and MSH3) locus can become amplified to several hundred copies in the presence of methotrexate. Under these conditions, MutS beta forms at the expense of MutS alpha, and the mutation rate in these tumor cells rises more than 100-fold. The implications for cancer chemotherapy include a potential increase in mutability when tumors are treated with methotrexate, which could increase the frequency of subsequent mutations that influence the tumor's drug sensitivity or aggressiveness. Because processing certain types of DNA damage by the mismatch repair pathway has also been implicated in tumor sensitivity to agents such as cisplatin, changes in expression at the DHFR/MSH3 locus may have further relevance to the outcome of multi-drug treatment regimens.

Structural damage detection based on stochastic subspace identification and statistical pattern recognition: I. Theory

NASA Astrophysics Data System (ADS)

Ren, W. X.; Lin, Y. Q.; Fang, S. E.

2011-11-01

One of the key issues in vibration-based structural health monitoring is to extract the damage-sensitive but environment-insensitive features from sampled dynamic response measurements and to carry out the statistical analysis of these features for structural damage detection. A new damage feature is proposed in this paper by using the system matrices of the forward innovation model based on the covariance-driven stochastic subspace identification of a vibrating system. To overcome the variations of the system matrices, a non-singularity transposition matrix is introduced so that the system matrices are normalized to their standard forms. For reducing the effects of modeling errors, noise and environmental variations on measured structural responses, a statistical pattern recognition paradigm is incorporated into the proposed method. The Mahalanobis and Euclidean distance decision functions of the damage feature vector are adopted by defining a statistics-based damage index. The proposed structural damage detection method is verified against one numerical signal and two numerical beams. It is demonstrated that the proposed statistics-based damage index is sensitive to damage and shows some robustness to the noise and false estimation of the system ranks. The method is capable of locating damage of the beam structures under different types of excitations. The robustness of the proposed damage detection method to the variations in environmental temperature is further validated in a companion paper by a reinforced concrete beam tested in the laboratory and a full-scale arch bridge tested in the field.

Mitochondrial damage elicits a TCDD-inducible poly(ADP-ribose) polymerase-mediated antiviral response

PubMed Central

Kozaki, Tatsuya; Komano, Jun; Kanbayashi, Daiki; Takahama, Michihiro; Misawa, Takuma; Satoh, Takashi; Takeuchi, Osamu; Kawai, Taro; Shimizu, Shigeomi; Matsuura, Yoshiharu; Akira, Shizuo; Saitoh, Tatsuya

2017-01-01

The innate immune system senses RNA viruses by pattern recognition receptors (PRRs) and protects the host from virus infection. PRRs mediate the production of immune modulatory factors and direct the elimination of RNA viruses. Here, we show a unique PRR that mediates antiviral response. Tetrachlorodibenzo-p-dioxin (TCDD)-inducible poly(ADP ribose) polymerase (TIPARP), a Cysteine3 Histidine (CCCH)-type zinc finger-containing protein, binds to Sindbis virus (SINV) RNA via its zinc finger domain and recruits an exosome to induce viral RNA degradation. TIPARP typically localizes in the nucleus, but it accumulates in the cytoplasm after SINV infection, allowing targeting of cytoplasmic SINV RNA. Redistribution of TIPARP is induced by reactive oxygen species (ROS)-dependent oxidization of the nuclear pore that affects cytoplasmic-nuclear transport. BCL2-associated X protein (BAX) and BCL2 antagonist/killer 1 (BAK1), B-cell leukemia/lymphoma 2 (BCL2) family members, mediate mitochondrial damage to generate ROS after SINV infection. Thus, TIPARP is a viral RNA-sensing PRR that mediates antiviral responses triggered by BAX- and BAK1-dependent mitochondrial damage. PMID:28213497

Inflammation in acute and chronic pancreatitis.

PubMed

Habtezion, Aida

2015-09-01

This report reviews recent animal model and human studies associated with inflammatory responses in acute and chronic pancreatitis. Animal model and limited human acute and chronic pancreatitis studies unravel the dynamic nature of the inflammatory processes and the ability of the immune cells to sense danger and environmental signals. In acute pancreatitis, such molecules include pathogen-associated molecular pattern recognition receptors such as toll-like receptors, and the more recently appreciated damage-associated molecular pattern molecules or 'alarmin' high mobility group box 1 and IL-33. In chronic pancreatitis, a recent understanding of a critical role for macrophage-pancreatic stellate cell interaction offers a potential targetable pathway that can alter fibrogenesis. Microbiome research in pancreatitis is a new field gaining interest but will require further investigation. Immune cell contribution to the pathogenesis of acute and chronic pancreatitis is gaining more appreciation and further understanding in immune signaling presents potential therapeutic targets that can alter disease progression.

Senescence in chronic liver disease: Is the future in aging?

PubMed

Aravinthan, Aloysious D; Alexander, Graeme J M

2016-10-01

Cellular senescence is a fundamental, complex mechanism with an important protective role present from embryogenesis to late life across all species. It limits the proliferative potential of damaged cells thus protecting against malignant change, but at the expense of substantial alterations to the microenvironment and tissue homeostasis, driving inflammation, fibrosis and paradoxically, malignant disease if the process is sustained. Cellular senescence has attracted considerable recent interest with recognition of pathways linking aging, malignancy and insulin resistance and the current focus on therapeutic interventions to extend health-span. There are major implications for hepatology in the field of fibrosis and cancer, where cellular senescence of hepatocytes, cholangiocytes, stellate cells and immune cells has been implicated in chronic liver disease progression. This review focuses on cellular senescence in chronic liver disease and explores therapeutic opportunities. Copyright © 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Fanconi anemia and the cell cycle: new perspectives on aneuploidy

PubMed Central

2014-01-01

Fanconi anemia (FA) is a complex heterogenic disorder of genomic instability, bone marrow failure, cancer predisposition, and congenital malformations. The FA signaling network orchestrates the DNA damage recognition and repair in interphase as well as proper execution of mitosis. Loss of FA signaling causes chromosome instability by weakening the spindle assembly checkpoint, disrupting centrosome maintenance, disturbing resolution of ultrafine anaphase bridges, and dysregulating cytokinesis. Thus, the FA genes function as guardians of genome stability throughout the cell cycle. This review discusses recent advances in diagnosis and clinical management of Fanconi anemia and presents the new insights into the origins of genomic instability in FA. These new discoveries may facilitate the development of rational therapeutic strategies for FA and for FA-deficient malignancies in the general population. PMID:24765528

Long-term cannabidiol treatment prevents the development of social recognition memory deficits in Alzheimer's disease transgenic mice.

PubMed

Cheng, David; Spiro, Adena S; Jenner, Andrew M; Garner, Brett; Karl, Tim

2014-01-01

Impairments in cognitive ability and widespread pathophysiological changes caused by neurotoxicity, neuroinflammation, oxidative damage, and altered cholesterol homeostasis are associated with Alzheimer's disease (AD). Cannabidiol (CBD) has been shown to reverse cognitive deficits of AD transgenic mice and to exert neuroprotective, anti-oxidative, and anti-inflammatory properties in vitro and in vivo. Here we evaluate the preventative properties of long-term CBD treatment in male AβPPSwe/PS1ΔE9 (AβPP × PS1) mice, a transgenic model of AD. Control and AD transgenic mice were treated orally from 2.5 months of age with CBD (20 mg/kg) daily for 8 months. Mice were then assessed in the social preference test, elevated plus maze, and fear conditioning paradigms, before cortical and hippocampal tissues were analyzed for amyloid load, oxidative damage, cholesterol, phytosterols, and inflammation. We found that AβPP × PS1 mice developed a social recognition deficit, which was prevented by CBD treatment. CBD had no impact on anxiety or associative learning. The prevention of the social recognition deficit was not associated with any changes in amyloid load or oxidative damage. However, the study revealed a subtle impact of CBD on neuroinflammation, cholesterol, and dietary phytosterol retention, which deserves further investigation. This study is the first to demonstrate CBD's ability to prevent the development of a social recognition deficit in AD transgenic mice. Our findings provide the first evidence that CBD may have potential as a preventative treatment for AD with a particular relevance for symptoms of social withdrawal and facial recognition.

Distinct Functional Domains of Ubc9 Dictate Cell Survival and Resistance to Genotoxic Stress

PubMed Central

van Waardenburg, Robert C. A. M.; Duda, David M.; Lancaster, Cynthia S.; Schulman, Brenda A.; Bjornsti, Mary-Ann

2006-01-01

Covalent modification with SUMO alters protein function, intracellular localization, or protein-protein interactions. Target recognition is determined, in part, by the SUMO E2 enzyme, Ubc9, while Siz/Pias E3 ligases may facilitate select interactions by acting as substrate adaptors. A yeast conditional Ubc9P123L mutant was viable at 36°C yet exhibited enhanced sensitivity to DNA damage. To define functional domains in Ubc9 that dictate cellular responses to genotoxic stress versus those necessary for cell viability, a 1.75-Å structure of yeast Ubc9 that demonstrated considerable conservation of backbone architecture with human Ubc9 was solved. Nevertheless, differences in side chain geometry/charge guided the design of human/yeast chimeras, where swapping domains implicated in (i) binding residues within substrates that flank canonical SUMOylation sites, (ii) interactions with the RanBP2 E3 ligase, and (iii) binding of the heterodimeric E1 and SUMO had distinct effects on cell growth and resistance to DNA-damaging agents. Our findings establish a functional interaction between N-terminal and substrate-binding domains of Ubc9 and distinguish the activities of E3 ligases Siz1 and Siz2 in regulating cellular responses to genotoxic stress. PMID:16782883

Implications of Animal Object Memory Research for Human Amnesia

ERIC Educational Resources Information Center

Winters, Boyer D.; Saksida, Lisa M.; Bussey, Timothy J.

2010-01-01

Damage to structures in the human medial temporal lobe causes severe memory impairment. Animal object recognition tests gained prominence from attempts to model "global" human medial temporal lobe amnesia, such as that observed in patient HM. These tasks, such as delayed nonmatching-to-sample and spontaneous object recognition, for assessing…

An Inducible, Isogenic Cancer Cell Line System for Targeting the State of Mismatch Repair Deficiency

PubMed Central

Bailis, Julie M.; Gordon, Marcia L.; Gurgel, Jesse L.; Komor, Alexis C.; Barton, Jacqueline K.; Kirsch, Ilan R.

2013-01-01

The DNA mismatch repair system (MMR) maintains genome stability through recognition and repair of single-base mismatches and small insertion-deletion loops. Inactivation of the MMR pathway causes microsatellite instability and the accumulation of genomic mutations that can cause or contribute to cancer. In fact, 10-20% of certain solid and hematologic cancers are MMR-deficient. MMR-deficient cancers do not respond to some standard of care chemotherapeutics because of presumed increased tolerance of DNA damage, highlighting the need for novel therapeutic drugs. Toward this goal, we generated isogenic cancer cell lines for direct comparison of MMR-proficient and MMR-deficient cells. We engineered NCI-H23 lung adenocarcinoma cells to contain a doxycycline-inducible shRNA designed to suppress the expression of the mismatch repair gene MLH1, and compared single cell subclones that were uninduced (MLH1-proficient) versus induced for the MLH1 shRNA (MLH1-deficient). Here we present the characterization of these MMR-inducible cell lines and validate a novel class of rhodium metalloinsertor compounds that differentially inhibit the proliferation of MMR-deficient cancer cells. PMID:24205301

Defect Localization Capabilities of a Global Detection Scheme: Spatial Pattern Recognition Using Full-field Vibration Test Data in Plates

NASA Technical Reports Server (NTRS)

Saleeb, A. F.; Prabhu, M.; Arnold, S. M. (Technical Monitor)

2002-01-01

Recently, a conceptually simple approach, based on the notion of defect energy in material space has been developed and extensively studied (from the theoretical and computational standpoints). The present study focuses on its evaluation from the viewpoint of damage localization capabilities in case of two-dimensional plates; i.e., spatial pattern recognition on surfaces. To this end, two different experimental modal test results are utilized; i.e., (1) conventional modal testing using (white noise) excitation and accelerometer-type sensors and (2) pattern recognition using Electronic speckle pattern interferometry (ESPI), a full field method capable of analyzing the mechanical vibration of complex structures. Unlike the conventional modal testing technique (using contacting accelerometers), these emerging ESPI technologies operate in a non-contacting mode, can be used even under hazardous conditions with minimal or no presence of noise and can simultaneously provide measurements for both translations and rotations. Results obtained have clearly demonstrated the robustness and versatility of the global NDE scheme developed. The vectorial character of the indices used, which enabled the extraction of distinct patterns for localizing damages proved very useful. In the context of the targeted pattern recognition paradigm, two algorithms were developed for the interrogation of test measurements; i.e., intensity contour maps for the damaged index, and the associated defect energy vector field plots.

Immunotherapy against cancer-related viruses

PubMed Central

Tashiro, Haruko; Brenner, Malcolm K

2017-01-01

Approximately 12% of all cancers worldwide are associated with viral infections. To date, eight viruses have been shown to contribute to the development of human cancers, including Epstein-Barr virus (EBV), Hepatitis B and C viruses, and Human papilloma virus, among others. These DNA and RNA viruses produce oncogenic effects through distinct mechanisms. First, viruses may induce sustained disorders of host cell growth and survival through the genes they express, or may induce DNA damage response in host cells, which in turn increases host genome instability. Second, they may induce chronic inflammation and secondary tissue damage favoring the development of oncogenic processes in host cells. Viruses like HIV can create a more permissive environment for cancer development through immune inhibition, but we will focus on the previous two mechanisms in this review. Unlike traditional cancer therapies that cannot distinguish infected cells from non-infected cells, immunotherapies are uniquely equipped to target virus-associated malignancies. The targeting and functioning mechanisms associated with the immune response can be exploited to prevent viral infections by vaccination, and can also be used to treat infection before cancer establishment. Successes in using the immune system to eradicate established malignancy by selective recognition of virus-associated tumor cells are currently being reported. For example, numerous clinical trials of adoptive transfer of ex vivo generated virus-specific T cells have shown benefit even for established tumors in patients with EBV-associated malignancies. Additional studies in other virus-associated tumors have also been initiated and in this review we describe the current status of immunotherapy for virus-associated malignancies and discuss future prospects. PMID:28008927

Relationship of the Xeroderma Pigmentosum Group E DNA Repair Defect to the Chromatin and DNA Binding Proteins UV-DDB and Replication Protein A

PubMed Central

Rapić Otrin, Vesna; Kuraoka, Isao; Nardo, Tiziana; McLenigan, Mary; Eker, A. P. M.; Stefanini, Miria; Levine, Arthur S.; Wood, Richard D.

1998-01-01

Cells from complementation groups A through G of the heritable sun-sensitive disorder xeroderma pigmentosum (XP) show defects in nucleotide excision repair of damaged DNA. Proteins representing groups A, B, C, D, F, and G are subunits of the core recognition and incision machinery of repair. XP group E (XP-E) is the mildest form of the disorder, and cells generally show about 50% of the normal repair level. We investigated two protein factors previously implicated in the XP-E defect, UV-damaged DNA binding protein (UV-DDB) and replication protein A (RPA). Three newly identified XP-E cell lines (XP23PV, XP25PV, and a line formerly classified as an XP variant) were defective in UV-DDB binding activity but had levels of RPA in the normal range. The XP-E cell extracts did not display a significant nucleotide excision repair defect in vitro, with either UV-irradiated DNA or a uniquely placed cisplatin lesion used as a substrate. Purified UV-DDB protein did not stimulate repair of naked DNA by DDB− XP-E cell extracts, but microinjection of the protein into DDB− XP-E cells could partially correct the repair defect. RPA stimulated repair in normal, XP-E, or complemented extracts from other XP groups, and so the effect of RPA was not specific for XP-E cell extracts. These data strengthen the connection between XP-E and UV-DDB. Coupled with previous results, the findings suggest that UV-DDB has a role in the repair of DNA in chromatin. PMID:9584159

Bioengineering T cells to target carbohydrate to treat opportunistic fungal infection

PubMed Central

Kumaresan, Pappanaicken R.; Manuri, Pallavi R.; Albert, Nathaniel D.; Maiti, Sourindra; Singh, Harjeet; Mi, Tiejuan; Roszik, Jason; Rabinovich, Brian; Olivares, Simon; Krishnamurthy, Janani; Zhang, Ling; Najjar, Amer M.; Huls, M. Helen; Lee, Dean A.; Champlin, Richard E.; Kontoyiannis, Dimitrios P.; Cooper, Laurence J. N.

2014-01-01

Clinical-grade T cells are genetically modified ex vivo to express chimeric antigen receptors (CARs) to redirect their specificity to target tumor-associated antigens in vivo. We now have developed this molecular strategy to render cytotoxic T cells specific for fungi. We adapted the pattern-recognition receptor Dectin-1 to activate T cells via chimeric CD28 and CD3-ζ (designated “D-CAR”) upon binding with carbohydrate in the cell wall of Aspergillus germlings. T cells genetically modified with the Sleeping Beauty system to express D-CAR stably were propagated selectively on artificial activating and propagating cells using an approach similar to that approved by the Food and Drug Administration for manufacturing CD19-specific CAR+ T cells for clinical trials. The D-CAR+ T cells exhibited specificity for β-glucan which led to damage and inhibition of hyphal growth of Aspergillus in vitro and in vivo. Treatment of D-CAR+ T cells with steroids did not compromise antifungal activity significantly. These data support the targeting of carbohydrate antigens by CAR+ T cells and provide a clinically appealing strategy to enhance immunity for opportunistic fungal infections using T-cell gene therapy. PMID:25002471

Hemoglobin redox reactions and red blood cell aging.

PubMed

Rifkind, Joseph M; Nagababu, Enika

2013-06-10

The physiological mechanism(s) for recognition and removal of red blood cells (RBCs) from circulation after 120 days of its lifespan is not fully understood. Many of the processes thought to be associated with the removal of RBCs involve oxidative stress. We have focused on hemoglobin (Hb) redox reactions, which is the major source of RBC oxidative stress. The importance of Hb redox reactions have been shown to originate in large parts from the continuous slow autoxidation of Hb producing superoxide and its dramatic increase under hypoxic conditions. In addition, oxidative stress has been shown to be associated with redox reactions that originate from Hb reactions with nitrite and nitric oxide (NO) and the resultant formation of highly toxic peroxynitrite when NO reacts with superoxide released during Hb autoxidation. The interaction of Hb, particularly under hypoxic conditions with band 3 of the RBC membrane is critical for the generating the RBC membrane changes that trigger the removal of cells from circulation. These changes include exposure of antigenic sites, increased calcium leakage into the RBC, and the resultant leakage of potassium out of the RBC causing cell shrinkage and impaired deformability. The need to understand the oxidative damage to specific membrane proteins that result from redox reactions occurring when Hb is bound to the membrane. Proteomic studies that can pinpoint the specific proteins damaged under different conditions will help elucidate the cellular aging processes that result in cells being removed from circulation.

Differential Induction of Immunogenic Cell Death and Interferon Expression in Cancer Cells by Structured ssRNAs.

PubMed

Lee, Jaewoo; Lee, Youngju; Xu, Li; White, Rebekah; Sullenger, Bruce A

2017-06-07

Activation of the RNA-sensing pattern recognition receptor (PRR) in cancer cells leads to cell death and cytokine expression. This cancer cell death releases tumor antigens and damage-associated molecular patterns (DAMPs) that induce anti-tumor immunity. However, these cytokines and DAMPs also cause adverse inflammatory and thrombotic complications that can limit the overall therapeutic benefits of PRR-targeting anti-cancer therapies. To overcome this problem, we generated and evaluated two novel and distinct ssRNA molecules (immunogenic cell-killing RNA [ICR]2 and ICR4). ICR2 and ICR4 differentially stimulated cell death and PRR signaling pathways and induced different patterns of cytokine expression in cancer and innate immune cells. Interestingly, DAMPs released from ICR2- and ICR4-treated cancer cells had distinct patterns of stimulation of innate immune receptors and coagulation. Finally, ICR2 and ICR4 inhibited in vivo tumor growth as effectively as poly(I:C). ICR2 and ICR4 are potential therapeutic agents that differentially induce cell death, immune stimulation, and coagulation when introduced into tumors. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Membrane-derived second messenger regulates x-ray-mediated tumor necrosis factor alpha gene induction.

PubMed Central

Hallahan, D E; Virudachalam, S; Kuchibhotla, J; Kufe, D W; Weichselbaum, R R

1994-01-01

Cells adapt to adverse environmental conditions through a wide range of responses that are conserved throughout evolution. Physical agents such as ionizing radiation are known to initiate a stress response that is triggered by the recognition of DNA damage. We have identified a signaling pathway involving the activation of phospholipase A2 and protein kinase C in human cells that confers x-ray induction of the tumor necrosis factor alpha gene. Treatment of human cells with ionizing radiation or H2O2 was associated with the production of arachidonic acid. Inhibition of phospholipase A2 abolished radiation-mediated arachidonate production as well as the subsequent activation of protein kinase C and tumor necrosis factor alpha gene expression. These findings demonstrate that ionizing radiation-mediated gene expression in human cells is regulated in part by extranuclear signal transduction. One practical application of phospholipase A2 inhibitors is to ameliorate the adverse effects of radiotherapy associated with tumor necrosis factor alpha production. Images PMID:8197153

Current and historical perspectives on methodological flaws in processing umbilical cord blood.

PubMed

Mehrishi, J N

2013-11-01

Umbilical cord blood (UCB) hematopoietic stem cells (HSC-CD34+) are valuable for treating malignant or nonmalignant disease. Processing UCB by HESPAN-6% and anti-CD34-Miltenyi particles provides insufficient cells for treating adults. Physicochemical-electrokinetic studies on UCB-mononuclear cells (MNCs) under conditions of delayed processing, ice or very low temperatures, and some cell separation media identified artifacts introduced by procedures. Adsorption of biomaterials from cell damage by temperature, degradation products after using enzymes, harsh reagents, dithiothreitol, and HESPAN affect cell properties and distribution. Miltenyi particles internalized by cells could release iron that accumulating in liver or spleen would then risk toxicity. Summary topics included the effects of temperature, HESPAN (fast sedimenting agent), glycoproteases, DNase, and dithiothreitol risk affecting cell receptors in recognition, "homing," leading to possible unintended iatrogenic bioeffects should such cells be transfused into humans. The loss of undetectable and uncaptured low CD34 antigen-bearing cells by Miltenyi particles seems to occur when the current methods of isolation of CD34+ cells and other cells are critically assessed. The purpose here is to highlight and suggest avoiding the procedural flaws involved. Preventing ice temperatures avoids ice-damaged platelets releasing biomaterials that are adsorbed on cells altering UBC-MNCs/HSC properties and cell loss. Omitting the positive selection with antibody-linked Miltenyi particles obviates the use of harsh reagents to release the cells. Internalized Miltenyi particles are a toxicity hazard that needs investigations. Achieving approximately 5% yields of CD34+ cells (153 × 10(5) /110 mL cord-placenta blood) is a major advance holding great promise, for the first time increasing the prospect of stem cell therapy of 70-kg adults, using a single UCB donation (with dose of 1.5 × 10(5) cells/kg) and considerably cheaper cultured red blood cells manufacture (multiple packs/2 × 10(12) ). © 2013 American Association of Blood Banks.

Bihippocampal damage with emotional dysfunction: impaired auditory recognition of fear.

PubMed

Ghika-Schmid, F; Ghika, J; Vuilleumier, P; Assal, G; Vuadens, P; Scherer, K; Maeder, P; Uske, A; Bogousslavsky, J

1997-01-01

A right-handed man developed a sudden transient, amnestic syndrome associated with bilateral hemorrhage of the hippocampi, probably due to Urbach-Wiethe disease. In the 3rd month, despite significant hippocampal structural damage on imaging, only a milder degree of retrograde and anterograde amnesia persisted on detailed neuropsychological examination. On systematic testing of recognition of facial and vocal expression of emotion, we found an impairment of the vocal perception of fear, but not that of other emotions, such as joy, sadness and anger. Such selective impairment of fear perception was not present in the recognition of facial expression of emotion. Thus emotional perception varies according to the different aspects of emotions and the different modality of presentation (faces versus voices). This is consistent with the idea that there may be multiple emotion systems. The study of emotional perception in this unique case of bilateral involvement of hippocampus suggests that this structure may play a critical role in the recognition of fear in vocal expression, possibly dissociated from that of other emotions and from that of fear in facial expression. In regard of recent data suggesting that the amygdala is playing a role in the recognition of fear in the auditory as well as in the visual modality this could suggest that the hippocampus may be part of the auditory pathway of fear recognition.

Neutrophils come of age in chronic inflammation

PubMed Central

Caielli, Simone; Banchereau, Jacques; Pascual, Virginia

2013-01-01

Neutrophils have long been known to participate in acute inflammation, but a role in chronic inflammatory and autoimmune diseases is now emerging. These cells are key players in the recognition and elimination of pathogens, but they also sense self components, including nucleic acids and products of sterile tissue damage. While this normally contributes to tissue repair, it can also lead to the release of highly immunogenic products that can trigger and/or amplify autoimmune pathogenic loops. Understanding the mechanisms that underlie neutrophil activation, migration, survival and their various forms of death in health and disease might provide us with new approaches to treat chronic inflammatory conditions. PMID:23127555

Measuring Apoptosis by Microscopy and Flow Cytometry.

PubMed

Hollville, Emilie; Martin, Seamus J

2016-02-02

Apoptosis is a mode of programmed cell death that plays an important role during development and in the maintenance of tissue homeostasis. Numerous physiological as well as pathological stimuli trigger apoptosis such as engagement of Fas, TRAIL, or TNF receptors, growth factor deprivation, hypoxia, or exposure to cytotoxic drugs. Apoptosis is coordinated from within by members of the caspase family of cysteine proteases that, upon activation, trigger a series of morphological changes including cell shrinkage, extensive plasma membrane blebbing, chromatin condensation, DNA hydrolysis, and nuclear fragmentation. These dramatic structural and biochemical alterations result not only in the controlled dismantling of the cell, but also in the efficient recognition and removal of apoptotic cells by phagocytes. Necrosis, which is typically nonprogrammed or imposed upon the cell by overwhelming membrane or organelle damage, is characterized by rapid plasma membrane rupture followed by organelle and cell swelling. Necrosis is often provoked by infectious agents or a severe departure from physiological conditions. This unit describes protocols for the measurement of apoptosis and for distinguishing apoptosis from necrosis. Copyright © 2016 John Wiley & Sons, Inc.

Cepstrum based feature extraction method for fungus detection

NASA Astrophysics Data System (ADS)

Yorulmaz, Onur; Pearson, Tom C.; Çetin, A. Enis

2011-06-01

In this paper, a method for detection of popcorn kernels infected by a fungus is developed using image processing. The method is based on two dimensional (2D) mel and Mellin-cepstrum computation from popcorn kernel images. Cepstral features that were extracted from popcorn images are classified using Support Vector Machines (SVM). Experimental results show that high recognition rates of up to 93.93% can be achieved for both damaged and healthy popcorn kernels using 2D mel-cepstrum. The success rate for healthy popcorn kernels was found to be 97.41% and the recognition rate for damaged kernels was found to be 89.43%.

Recognition of DNA abasic site nanocavity by fluorophore-switched probe: Suitable for all sequence environments

NASA Astrophysics Data System (ADS)

Wang, Ying; Hu, Yuehua; Wu, Tao; Zhang, Lihua; Liu, Hua; Zhou, Xiaoshun; Shao, Yong

2016-01-01

Removal of a damaged base in DNA produces an abasic site (AP site) nanocavity. If left un-repaired in vivo by the specific enzyme, this nanocavity will result in nucleotide mutation in the following DNA replication. Therefore, selective recognition of AP site nanocavity by small molecules is important for identification of such DNA damage and development of genetic drugs. In this work, we investigate the fluorescence behavior of isoquinoline alkaloids including palmatine (PAL), berberine (BER), epiberberine (EPI), jatrorrhizine (JAT), coptisine (COP), coralyne (COR), worenine (WOR), berberrubine (BEU), sanguinarine (SAN), chelerythrine (CHE), and nitidine (NIT) upon binding with the AP nanocavity. PAL is screened out as the most efficient fluorophore-switched probe to recognize the AP nanocavity over the fully matched DNA. Its fluorescence enhancement occurs for all of the AP nanocavity sequence environments, which has not been achieved by the previously used probes. The bridged π conjugation effect should partially contribute to the AP nanocavity-specific fluorescence, as opposed to the solvent effect. Due to the strong binding with the AP nanocavity, PAL will find wide applications in the DNA damage recognition and sensor development.

Fractionation of memory in medial temporal lobe amnesia.

PubMed

Bird, Chris M; Shallice, Tim; Cipolotti, Lisa

2007-03-25

We report a comprehensive investigation of the anterograde memory functions of two patients with memory impairments (RH and JC). RH had neuroradiological evidence of apparently selective right-sided hippocampal damage and an intact cognitive profile apart from selective memory impairments. JC, had neuroradiological evidence of bilateral hippocampal damage following anoxia due to cardiac arrest. He had anomic and "executive" difficulties in addition to a global amnesia, suggesting atrophy extending beyond hippocampal regions. Their performance is compared with that of a previously reported hippocampal amnesic patient who showed preserved recollection and familiarity for faces in the context of severe verbal and topographical memory impairment [VC; Cipolotti, L., Bird, C., Good, T., Macmanus, D., Rudge, P., & Shallice, T. (2006). Recollection and familiarity in dense hippocampal amnesia: A case study. Neuropsychologia, 44, 489-506.] The patients were administered experimental tests using verbal (words) and two types of non-verbal materials (faces and buildings). Receiver operating characteristic analyses were used to estimate the contribution of recollection and familiarity to recognition performance on the experimental tests. RH had preserved verbal recognition memory. Interestingly, her face recognition memory was also spared, whilst topographical recognition memory was impaired. JC was impaired for all types of verbal and non-verbal materials. In both patients, deficits in recollection were invariably associated with deficits in familiarity. JC's data demonstrate the need for a comprehensive cognitive investigation in patients with apparently selective hippocampal damage following anoxia. The data from RH suggest that the right hippocampus is necessary for recollection and familiarity for topographical materials, whilst the left hippocampus is sufficient to underpin these processes for at least some types of verbal materials. Face recognition memory may be adequately subserved by areas outside of the hippocampus.

From The Cover: Induction of antiviral immunity requires Toll-like receptor signaling in both stromal and dendritic cell compartments

NASA Astrophysics Data System (ADS)

Sato, Ayuko; Iwasaki, Akiko

2004-11-01

Pattern recognition by Toll-like receptors (TLRs) is known to be important for the induction of dendritic cell (DC) maturation. DCs, in turn, are critically important in the initiation of T cell responses. However, most viruses do not infect DCs. This recognition system poses a biological problem in ensuring that most viral infections be detected by pattern recognition receptors. Furthermore, it is unknown what, if any, is the contribution of TLRs expressed by cells that are infected by a virus, versus TLRs expressed by DCs, in the initiation of antiviral adaptive immunity. Here we address these issues using a physiologically relevant model of mucosal infection with herpes simplex virus type 2. We demonstrate that innate immune recognition of viral infection occurs in two distinct stages, one at the level of the infected epithelial cells and the other at the level of the noninfected DCs. Importantly, both TLR-mediated recognition events are required for the induction of effector T cells. Our results demonstrate that virally infected tissues instruct DCs to initiate the appropriate class of effector T cell responses and reveal the critical importance of the stromal cells in detecting infectious agents through their own pattern recognition receptors. mucosal immunity | pattern recognition | viral infection

Zalypsis has in vitro activity in acute myeloid blasts and leukemic progenitor cells through the induction of a DNA damage response

PubMed Central

Colado, Enrique; Paíno, Teresa; Maiso, Patricia; Ocio, Enrique M.; Chen, Xi; Álvarez-Fernández, Stela; Gutiérrez, Norma C.; Martín-Sánchez, Jesús; Flores-Montero, Juan; San Segundo, Laura; Garayoa, Mercedes; Fernández-Lázaro, Diego; Vidriales, Maria-Belen; Galmarini, Carlos M.; Avilés, Pablo; Cuevas, Carmen; Pandiella, Atanasio; San-Miguel, Jesús F.

2011-01-01

Background Although the majority of patients with acute myeloid leukemia initially respond to conventional chemotherapy, relapse is still the leading cause of death, probably because of the presence of leukemic stem cells that are insensitive to current therapies. We investigated the antileukemic activity and mechanism of action of zalypsis, a novel alkaloid of marine origin. Design and Methods The activity of zalypsis was studied in four acute myeloid leukemia cell lines and in freshly isolated blasts taken from patients with acute myeloid leukemia before they started therapy. Zalypsis-induced apoptosis of both malignant and normal cells was measured using flow cytometry techniques. Gene expression profiling and western blot studies were performed to assess the mechanism of action of the alkaloid. Results Zalypsis showed a very potent antileukemic activity in all the cell lines tested and potentiated the effect of conventional antileukemic drugs such as cytarabine, fludarabine and daunorubicin. Interestingly, zalypsis showed remarkable ex vivo potency, including activity against the most immature blast cells (CD34+ CD38− Lin−) which include leukemic stem cells. Zalypsis-induced apoptosis was the result of an important deregulation of genes involved in the recognition of double-strand DNA breaks, such as Fanconi anemia genes and BRCA1, but also genes implicated in the repair of double-strand DNA breaks, such as RAD51 and RAD54. These gene findings were confirmed by an increase in several proteins involved in the pathway (pCHK1, pCHK2 and pH2AX). Conclusions The potent and selective antileukemic effect of zalypsis on DNA damage response mechanisms observed in acute myeloid leukemia cell lines and in patients’ samples provides the rationale for the investigation of this compound in clinical trials. PMID:21330323

Stem Cells in Skin Regeneration, Wound Healing, and Their Clinical Applications

PubMed Central

Ojeh, Nkemcho; Pastar, Irena; Tomic-Canic, Marjana; Stojadinovic, Olivera

2015-01-01

The skin is the largest organ of the body and has an array of functions. Skin compartments, epidermis, and hair follicles house stem cells that are indispensable for skin homeostasis and regeneration. These stem cells also contribute to wound repair, resulting in restoration of tissue integrity and function of damaged tissue. Unsuccessful wound healing processes often lead to non-healing wounds. Chronic wounds are caused by depletion of stem cells and a variety of other cellular and molecular mechanisms, many of which are still poorly understood. Current chronic wound therapies are limited, so the search to develop better therapeutic strategies is ongoing. Adult stem cells are gaining recognition as potential candidates for numerous skin pathologies. In this review, we will discuss epidermal and other stem cells present in the skin, and highlight some of the therapeutic applications of epidermal stem cells and other adult stem cells as tools for cell/scaffold-based therapies for non-healing wounds and other skin disorders. We will also discuss emerging concepts and offer some perspectives on how skin tissue-engineered products can be optimized to provide efficacious therapy in cutaneous repair and regeneration. PMID:26512657

Stem Cells in Skin Regeneration, Wound Healing, and Their Clinical Applications.

PubMed

Ojeh, Nkemcho; Pastar, Irena; Tomic-Canic, Marjana; Stojadinovic, Olivera

2015-10-23

The skin is the largest organ of the body and has an array of functions. Skin compartments, epidermis, and hair follicles house stem cells that are indispensable for skin homeostasis and regeneration. These stem cells also contribute to wound repair, resulting in restoration of tissue integrity and function of damaged tissue. Unsuccessful wound healing processes often lead to non-healing wounds. Chronic wounds are caused by depletion of stem cells and a variety of other cellular and molecular mechanisms, many of which are still poorly understood. Current chronic wound therapies are limited, so the search to develop better therapeutic strategies is ongoing. Adult stem cells are gaining recognition as potential candidates for numerous skin pathologies. In this review, we will discuss epidermal and other stem cells present in the skin, and highlight some of the therapeutic applications of epidermal stem cells and other adult stem cells as tools for cell/scaffold-based therapies for non-healing wounds and other skin disorders. We will also discuss emerging concepts and offer some perspectives on how skin tissue-engineered products can be optimized to provide efficacious therapy in cutaneous repair and regeneration.

Bioinspired Pollen-Like Hierarchical Surface for Efficient Recognition of Target Cancer Cells.

PubMed

Wang, Wenshuo; Yang, Gao; Cui, Haijun; Meng, Jingxin; Wang, Shutao; Jiang, Lei

2017-08-01

The efficient recognition and isolation of rare cancer cells holds great promise for cancer diagnosis and prognosis. In nature, pollens exploit spiky structures to realize recognition and adhesion to stigma. Herein, a bioinspired pollen-like hierarchical surface is developed by replicating the assembly of pollen grains, and efficient and specific recognition to target cancer cells is achieved. The pollen-like surface is fabricated by combining filtering-assisted assembly and soft lithography-based replication of pollen grains of wild chrysanthemum. After modification with a capture agent specific to cancer cells, the pollen-like surface enables the capture of target cancer cells with high efficiency and specificity. In addition, the pollen-like surface not only assures high viability of captured cells but also performs well in cell mixture system and at low cell density. This study represents a good example of constructing cell recognition biointerfaces inspired by pollen-stigma adhesion. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Current Management of Sickle Cell Anemia

PubMed Central

McGann, Patrick T.; Nero, Alecia C.; Ware, Russell E.

2013-01-01

Proper management of sickle cell anemia (SCA) begins with establishing the correct diagnosis early in life, ideally during the newborn period. The identification of affected infants by neonatal screening programs allows early initiation of prophylactic penicillin and pneumococcal immunizations, which help prevent overwhelming sepsis. Ongoing education of families promotes the early recognition of disease-released complications, which allows prompt and appropriate medical evaluation and therapeutic intervention. Periodic evaluation by trained specialists helps provide comprehensive care, including transcranial Doppler examinations to identify children at risk for primary stroke, plus assessments for other parenchymal organ damage as patients become teens and adults. Treatment approaches that previously highlighted acute vaso-occlusive events are now evolving to the concept of preventive therapy. Liberalized use of blood transfusions and early consideration of hydroxyurea treatment represent a new treatment paradigm for SCA management. PMID:23709685

The Enemy within: Innate Surveillance-Mediated Cell Death, the Common Mechanism of Neurodegenerative Disease

PubMed Central

Richards, Robert I.; Robertson, Sarah A.; O'Keefe, Louise V.; Fornarino, Dani; Scott, Andrew; Lardelli, Michael; Baune, Bernhard T.

2016-01-01

Neurodegenerative diseases comprise an array of progressive neurological disorders all characterized by the selective death of neurons in the central nervous system. Although, rare (familial) and common (sporadic) forms can occur for the same disease, it is unclear whether this reflects several distinct pathogenic pathways or the convergence of different causes into a common form of nerve cell death. Remarkably, neurodegenerative diseases are increasingly found to be accompanied by activation of the innate immune surveillance system normally associated with pathogen recognition and response. Innate surveillance is the cell's quality control system for the purpose of detecting such danger signals and responding in an appropriate manner. Innate surveillance is an “intelligent system,” in that the manner of response is relevant to the magnitude and duration of the threat. If possible, the threat is dealt with within the cell in which it is detected, by degrading the danger signal(s) and restoring homeostasis. If this is not successful then an inflammatory response is instigated that is aimed at restricting the spread of the threat by elevating degradative pathways, sensitizing neighboring cells, and recruiting specialized cell types to the site. If the danger signal persists, then the ultimate response can include not only the programmed cell death of the original cell, but the contents of this dead cell can also bring about the death of adjacent sensitized cells. These responses are clearly aimed at destroying the ability of the detected pathogen to propagate and spread. Innate surveillance comprises intracellular, extracellular, non-cell autonomous and systemic processes. Recent studies have revealed how multiple steps in these processes involve proteins that, through their mutation, have been linked to many familial forms of neurodegenerative disease. This suggests that individuals harboring these mutations may have an amplified response to innate-mediated damage in neural tissues, and renders innate surveillance mediated cell death a plausible common pathogenic pathway responsible for neurodegenerative diseases, in both familial and sporadic forms. Here we have assembled evidence in favor of the hypothesis that neurodegenerative disease is the cumulative result of chronic activation of the innate surveillance pathway, triggered by endogenous or environmental danger or damage associated molecular patterns in a progressively expanding cascade of inflammation, tissue damage and cell death. PMID:27242399

Histone deacetylases (HDACs) in XPC gene silencing and bladder cancer

PubMed Central

2011-01-01

Bladder cancer is one of the most common malignancies and causes hundreds of thousands of deaths worldwide each year. Bladder cancer is strongly associated with exposure to environmental carcinogens. It is believed that DNA damage generated by environmental carcinogens and their metabolites causes development of bladder cancer. Nucleotide excision repair (NER) is the major DNA repair pathway for repairing bulk DNA damage generated by most environmental carcinogens, and XPC is a DNA damage recognition protein required for initiation of the NER process. Recent studies demonstrate reduced levels of XPC protein in tumors for a majority of bladder cancer patients. In this work we investigated the role of histone deacetylases (HDACs) in XPC gene silencing and bladder cancer development. The results of our HDAC inhibition study revealed that the treatment of HTB4 and HTB9 bladder cancer cells with the HDAC inhibitor valproic acid (VPA) caused an increase in transcription of the XPC gene in these cells. The results of our chromatin immunoprecipitation (ChIP) studies indicated that the VPA treatment caused increased binding of both CREB1 and Sp1 transcription factors at the promoter region of the XPC gene for both HTB4 and HTB9 cells. The results of our immunohistochemistry (IHC) staining studies further revealed a strong correlation between the over-expression of HDAC4 and increased bladder cancer occurrence (p < 0.001) as well as a marginal significance of increasing incidence of HDAC4 positivity seen with an increase in severity of bladder cancer (p = 0.08). In addition, the results of our caspase 3 activation studies demonstrated that prior treatment with VPA increased the anticancer drug cisplatin-induced activation of caspase 3 in both HTB4 and HTB9 cells. All of these results suggest that the HDACs negatively regulate transcription of the XPC gene in bladder cancer cells and contribute to the severity of bladder tumors. PMID:21507255

TATA Binding Protein Discriminates between Different Lesions on DNA, Resulting in a Transcription Decrease

PubMed Central

Coin, Frédéric; Frit, Philippe; Viollet, Benoit; Salles, Bernard; Egly, Jean-Marc

1998-01-01

DNA damage recognition by basal transcription factors follows different mechanisms. Using transcription-competition, nitrocellulose filter binding, and DNase I footprinting assays, we show that, although the general transcription factor TFIIH is able to target any kind of lesion which can be repaired by the nucleotide excision repair pathway, TATA binding protein (TBP)-TFIID is more selective in damage recognition. Only genotoxic agents which are able to induce kinked DNA structures similar to the one for the TATA box in its TBP complex are recognized. Indeed, DNase I footprinting patterns reveal that TBP protects equally 4 nucleotides upstream and 6 nucleotides downstream from the A-T (at position −29 of the noncoding strand) of the adenovirus major late promoter and from the G-G of a cisplatin-induced 1,2-d(GpG) cross-link. Together, our results may partially explain differences in transcription inhibition rates following DNA damage. PMID:9632775

The Role of Candida albicans Transcription Factor RLM1 in Response to Carbon Adaptation.

PubMed

Oliveira-Pacheco, João; Alves, Rosana; Costa-Barbosa, Augusto; Cerqueira-Rodrigues, Bruno; Pereira-Silva, Patricia; Paiva, Sandra; Silva, Sónia; Henriques, Mariana; Pais, Célia; Sampaio, Paula

2018-01-01

Candida albicans is the main causative agent of candidiasis and one of the most frequent causes of nosocomial infections worldwide. In order to establish an infection, this pathogen supports effective stress responses to counter host defenses and adapts to changes in the availability of important nutrients, such as alternative carbon sources. These stress responses have clear implications on the composition and structure of Candida cell wall. Therefore, we studied the impact of lactate, a physiologically relevant carbon source, on the activity of C. albicans RLM1 transcriptional factor. RLM1 is involved in the cell wall integrity pathway and plays an important role in regulating the flow of carbohydrates into cell wall biosynthesis pathways. The role of C. albicans RLM1 in response to lactate adaptation was assessed in respect to several virulence factors, such as the ability to grow under cell wall damaging agents, filament, adhere or form biofilm, as well as to immune recognition. The data showed that growth of C. albicans cells in the presence of lactate induces the secretion of tartaric acid, which has the potential to modulate the TCA cycle on both the yeast and the host cells. In addition, we found that adaptation of C. albicans cells to lactate reduces their internalization by immune cells and consequent % of killing, which could be correlated with a lower exposure of the cell wall β-glucans. In addition, absence of RLM1 has a minor impact on internalization, compared with the wild-type and complemented strains, but it reduces the higher efficiency of lactate grown cells at damaging phagocytic cells and induces a high amount of IL-10, rendering these cells more tolerable to the immune system. The data suggests that RLM1 mediates cell wall remodeling during carbon adaptation, impacting their interaction with immune cells.

Magnetic Flux Leakage Sensing and Artificial Neural Network Pattern Recognition-Based Automated Damage Detection and Quantification for Wire Rope Non-Destructive Evaluation.

PubMed

Kim, Ju-Won; Park, Seunghee

2018-01-02

In this study, a magnetic flux leakage (MFL) method, known to be a suitable non-destructive evaluation (NDE) method for continuum ferromagnetic structures, was used to detect local damage when inspecting steel wire ropes. To demonstrate the proposed damage detection method through experiments, a multi-channel MFL sensor head was fabricated using a Hall sensor array and magnetic yokes to adapt to the wire rope. To prepare the damaged wire-rope specimens, several different amounts of artificial damages were inflicted on wire ropes. The MFL sensor head was used to scan the damaged specimens to measure the magnetic flux signals. After obtaining the signals, a series of signal processing steps, including the enveloping process based on the Hilbert transform (HT), was performed to better recognize the MFL signals by reducing the unexpected noise. The enveloped signals were then analyzed for objective damage detection by comparing them with a threshold that was established based on the generalized extreme value (GEV) distribution. The detected MFL signals that exceed the threshold were analyzed quantitatively by extracting the magnetic features from the MFL signals. To improve the quantitative analysis, damage indexes based on the relationship between the enveloped MFL signal and the threshold value were also utilized, along with a general damage index for the MFL method. The detected MFL signals for each damage type were quantified by using the proposed damage indexes and the general damage indexes for the MFL method. Finally, an artificial neural network (ANN) based multi-stage pattern recognition method using extracted multi-scale damage indexes was implemented to automatically estimate the severity of the damage. To analyze the reliability of the MFL-based automated wire rope NDE method, the accuracy and reliability were evaluated by comparing the repeatedly estimated damage size and the actual damage size.

Detection of sunn pest-damaged wheat samples using visible/near-infrared spectroscopy based on pattern recognition.

PubMed

Basati, Zahra; Jamshidi, Bahareh; Rasekh, Mansour; Abbaspour-Gilandeh, Yousef

2018-05-30

The presence of sunn pest-damaged grains in wheat mass reduces the quality of flour and bread produced from it. Therefore, it is essential to assess the quality of the samples in collecting and storage centers of wheat and flour mills. In this research, the capability of visible/near-infrared (Vis/NIR) spectroscopy combined with pattern recognition methods was investigated for discrimination of wheat samples with different percentages of sunn pest-damaged. To this end, various samples belonging to five classes (healthy and 5%, 10%, 15% and 20% unhealthy) were analyzed using Vis/NIR spectroscopy (wavelength range of 350-1000 nm) based on both supervised and unsupervised pattern recognition methods. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) as the unsupervised techniques and soft independent modeling of class analogies (SIMCA) and partial least squares-discriminant analysis (PLS-DA) as supervised methods were used. The results showed that Vis/NIR spectra of healthy samples were correctly clustered using both PCA and HCA. Due to the high overlapping between the four unhealthy classes (5%, 10%, 15% and 20%), it was not possible to discriminate all the unhealthy samples in individual classes. However, when considering only the two main categories of healthy and unhealthy, an acceptable degree of separation between the classes can be obtained after classification with supervised pattern recognition methods of SIMCA and PLS-DA. SIMCA based on PCA modeling correctly classified samples in two classes of healthy and unhealthy with classification accuracy of 100%. Moreover, the power of the wavelengths of 839 nm, 918 nm and 995 nm were more than other wavelengths to discriminate two classes of healthy and unhealthy. It was also concluded that PLS-DA provides excellent classification results of healthy and unhealthy samples (R 2  = 0.973 and RMSECV = 0.057). Therefore, Vis/NIR spectroscopy based on pattern recognition techniques can be useful for rapid distinguishing the healthy wheat samples from those damaged by sunn pest in the maintenance and processing centers. Copyright © 2018 Elsevier B.V. All rights reserved.

Voice Recognition in Face-Blind Patients

PubMed Central

Liu, Ran R.; Pancaroglu, Raika; Hills, Charlotte S.; Duchaine, Brad; Barton, Jason J. S.

2016-01-01

Right or bilateral anterior temporal damage can impair face recognition, but whether this is an associative variant of prosopagnosia or part of a multimodal disorder of person recognition is an unsettled question, with implications for cognitive and neuroanatomic models of person recognition. We assessed voice perception and short-term recognition of recently heard voices in 10 subjects with impaired face recognition acquired after cerebral lesions. All 4 subjects with apperceptive prosopagnosia due to lesions limited to fusiform cortex had intact voice discrimination and recognition. One subject with bilateral fusiform and anterior temporal lesions had a combined apperceptive prosopagnosia and apperceptive phonagnosia, the first such described case. Deficits indicating a multimodal syndrome of person recognition were found only in 2 subjects with bilateral anterior temporal lesions. All 3 subjects with right anterior temporal lesions had normal voice perception and recognition, 2 of whom performed normally on perceptual discrimination of faces. This confirms that such lesions can cause a modality-specific associative prosopagnosia. PMID:25349193

The role of pattern recognition receptors in lung sarcoidosis.

PubMed

Mortaz, Esmaeil; Adcock, Ian M; Abedini, Atefhe; Kiani, Arda; Kazempour-Dizaji, Mehdi; Movassaghi, Masoud; Garssen, Johan

2017-08-05

Sarcoidosis is a granulomatous disorder of unknown etiology. Infection, genetic factors, autoimmunity and an aberrant innate immune system have been explored as potential causes of sarcoidosis. The etiology of sarcoidosis remains unknown, and it is thought that it might be caused by an infectious agent in a genetically predisposed, susceptible host. Inflammation results from recognition of evolutionarily conserved structures of pathogens (Pathogen-associated molecular patterns, PAMPs) and/or from reaction to tissue damage associated patterns (DAMPs) through recognition by a limited number of germ line-encoded pattern recognition receptors (PRRs). Due to the similar clinical and histopathological picture of sarcoidosis and tuberculosis, Mycobacterium tuberculosis antigens such early secreted antigen (ESAT-6), heat shock proteins (Mtb-HSP), catalase-peroxidase (katG) enzyme and superoxide dismutase A peptide (sodA) have been often considered as factors in the etiopathogenesis of sarcoidosis. Potential non-TB-associated PAMPs include lipopolysaccharide (LPS) from the outer membrane of Gram-negative bacteria, peptidoglycan, lipoteichoic acid, bacterial DNA, viral DNA/RNA, chitin, flagellin, leucine-rich repeats (LRR), mannans in the yeast cell wall, and microbial HSPs. Furthermore, exogenous non-organic antigens such as metals, silica, pigments with/without aluminum in tattoos, pesticides, and pollen have been evoked as potential causes of sarcoidosis. Exposure of the airways to diverse infectious and non-infectious agents may be important in the pathogenesis of sarcoidosis. The current review provides and update on the role of PPRs and DAMPs in the pathogenesis of sarcoidsis. Copyright © 2017 Elsevier B.V. All rights reserved.

Plant cell wall-mediated immunity: cell wall changes trigger disease resistance responses.

PubMed

Bacete, Laura; Mélida, Hugo; Miedes, Eva; Molina, Antonio

2018-02-01

Plants have evolved a repertoire of monitoring systems to sense plant morphogenesis and to face environmental changes and threats caused by different attackers. These systems integrate different signals into overreaching triggering pathways which coordinate developmental and defence-associated responses. The plant cell wall, a dynamic and complex structure surrounding every plant cell, has emerged recently as an essential component of plant monitoring systems, thus expanding its function as a passive defensive barrier. Plants have a dedicated mechanism for maintaining cell wall integrity (CWI) which comprises a diverse set of plasma membrane-resident sensors and pattern recognition receptors (PRRs). The PRRs perceive plant-derived ligands, such as peptides or wall glycans, known as damage-associated molecular patterns (DAMPs). These DAMPs function as 'danger' alert signals activating DAMP-triggered immunity (DTI), which shares signalling components and responses with the immune pathways triggered by non-self microbe-associated molecular patterns that mediate disease resistance. Alteration of CWI by impairment of the expression or activity of proteins involved in cell wall biosynthesis and/or remodelling, as occurs in some plant cell wall mutants, or by wall damage due to colonization by pathogens/pests, activates specific defensive and growth responses. Our current understanding of how these alterations of CWI are perceived by the wall monitoring systems is scarce and few plant sensors/PRRs and DAMPs have been characterized. The identification of these CWI sensors and PRR-DAMP pairs will help us to understand the immune functions of the wall monitoring system, and might allow the breeding of crop varieties and the design of agricultural strategies that would enhance crop disease resistance. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Toll-like Receptor Signaling Activation by Entamoeba histolytica Induces Beta Defensin 2 in Human Colonic Epithelial Cells: Its Possible Role as an Element of the Innate Immune Response

PubMed Central

Ayala-Sumuano, Jorge-Tonatiuh; Téllez-López, Victor M.; Domínguez-Robles, M. del Carmen; Shibayama-Salas, Mineko; Meza, Isaura

2013-01-01

Background Entamoeba histolytica, a protozoan parasite of humans, produces dysenteric diarrhea, intestinal mucosa damage and extraintestinal infection. It has been proposed that the intestinal microbiota composition could be an important regulatory factor of amebic virulence and tissue invasion, particularly if pathogenic bacteria are present. Recent in vitro studies have shown that Entamoeba histolytica trophozoites induced human colonic CaCo2 cells to synthesize TLR-2 and TLR-4 and proinflammatory cytokines after binding to the amebic Gal/GalNac lectin carbohydrate recognition domain. The magnitude of the inflammatory response induced by trophozoites and the subsequent cell damage were synergized when cells had previously been exposed to pathogenic bacteria. Methodology/Principal Findings We show here that E. histolytica activation of the classic TLR pathway in CaCo2 cells is required to induce β defensin-2 (HBD2) mRNA expression and production of a 5-kDa cationic peptide with similar properties to the antimicrobial HBD2 expressed by CaCo2 cells exposed to enterotoxigenic Escherichia coli. The induced peptide showed capacity to permeabilize membranes of bacteria and live trophozoites. This activity was abrogated by inhibition of TLR2/4-NFκB pathway or by neutralization with an anti-HBD2 antibody. Conclusions/Significance Entamoeba histolytica trophozoites bind to human intestinal cells and induce expression of HBD2; an antimicrobial molecule with capacity to destroy pathogenic bacteria and trophozoites. HDB2's possible role as a modulator of the course of intestinal infections, particularly in mixed ameba/bacteria infections, is discussed. PMID:23469306

A human XPC protein interactome--a resource.

PubMed

Lubin, Abigail; Zhang, Ling; Chen, Hua; White, Victoria M; Gong, Feng

2013-12-23

Global genome nucleotide excision repair (GG-NER) is responsible for identifying and removing bulky adducts from non-transcribed DNA that result from damaging agents such as UV radiation and cisplatin. Xeroderma pigmentosum complementation group C (XPC) is one of the essential damage recognition proteins of the GG-NER pathway and its dysfunction results in xeroderma pigmentosum (XP), a disorder involving photosensitivity and a predisposition to cancer. To better understand the identification of DNA damage by XPC in the context of chromatin and the role of XPC in the pathogenesis of XP, we characterized the interactome of XPC using a high throughput yeast two-hybrid screening. Our screening showed 49 novel interactors of XPC involved in DNA repair and replication, proteolysis and post-translational modifications, transcription regulation, signal transduction, and metabolism. Importantly, we validated the XPC-OTUD4 interaction by co-IP and provided evidence that OTUD4 knockdown in human cells indeed affects the levels of ubiquitinated XPC, supporting a hypothesis that the OTUD4 deubiquitinase is involved in XPC recycling by cleaving the ubiquitin moiety. This high-throughput characterization of the XPC interactome provides a resource for future exploration and suggests that XPC may have many uncharacterized cellular functions.

Segregation of anterior temporal regions critical for retrieving names of unique and nonunique entities reflects underlying long-range connectivity

PubMed Central

Mehta, Sonya; Inoue, Kayo; Rudrauf, David; Damasio, Hanna; Tranel, Daniel; Grabowski, Thomas

2015-01-01

Lesion-deficit studies support the hypothesis that the left anterior temporal lobe (ATL) plays a critical role in retrieving names of concrete entities. They further suggest that different regions of the left ATL process different conceptual categories. Here we test the specificity of these relationships and whether the anatomical segregation is related to the underlying organization of white matter connections. We reanalyzed data from a previous lesion study of naming and recognition across five categories of concrete entities. In voxelwise logistic regressions of lesion-deficit associations, we formally incorporated measures of disconnection of long-range association fiber tracts (FTs) and covaried for recognition and non-category specific naming deficits. We also performed fiber tractwise analyses to assess whether damage to specific FTs was preferentially associated with category-selective naming deficits. Damage to the basolateral ATL was associated with naming deficits for both unique (famous faces) and non-unique entities, whereas the damage to the temporal pole was associated with naming deficits for unique entities only. This segregation pattern remained after accounting for comorbid recognition deficits or naming deficits in other categories. The tractwise analyses showed that damage to the uncinate fasciculus was associated with naming impairments for unique entities, while damage to the inferior longitudinal fasciculus was associated with naming impairments for non-unique entities. Covarying for FT transection in voxelwise analyses rendered the cortical association for unique entities more focal. These results are consistent with the partial segregation of brain system support for name retrieval of unique and non-unique entities at both the level of cortical components and underlying white matter fiber bundles. Our study reconciles theoretic accounts of the functional organization of the left ATL by revealing both category-related processing and semantic hub sectors. PMID:26707082

Human XPA and RPA DNA repair proteins participate in specific recognition of triplex-induced helical distortions

NASA Astrophysics Data System (ADS)

Vasquez, Karen M.; Christensen, Jesper; Li, Lei; Finch, Rick A.; Glazer, Peter M.

2002-04-01

Nucleotide excision repair (NER) plays a central role in maintaining genomic integrity by detecting and repairing a wide variety of DNA lesions. Xeroderma pigmentosum complementation group A protein (XPA) is an essential component of the repair machinery, and it is thought to be involved in the initial step as a DNA damage recognition and/or confirmation factor. Human replication protein A (RPA) and XPA have been reported to interact to form a DNA damage recognition complex with greater specificity for damaged DNA than XPA alone. The mechanism by which these two proteins recognize such a wide array of structures resulting from different types of DNA damage is not known. One possibility is that they recognize a common feature of the lesions, such as distortions of the helical backbone. We have tested this idea by determining whether human XPA and RPA proteins can recognize the helical distortions induced by a DNA triple helix, a noncanonical DNA structure that has been shown to induce DNA repair, mutagenesis, and recombination. We measured binding of XPA and RPA, together or separately, to substrates containing triplexes with three, two, or no strands covalently linked by psoralen conjugation and photoaddition. We found that RPA alone recognizes all covalent triplex structures, but also forms multivalent nonspecific DNA aggregates at higher concentrations. XPA by itself does not recognize the substrates, but it binds them in the presence of RPA. Addition of XPA decreases the nonspecific DNA aggregate formation. These results support the hypothesis that the NER machinery is targeted to helical distortions and demonstrate that RPA can recognize damaged DNA even without XPA.

Lower nucleotide excision repair capacity in newborns compared to their mothers: a pilot study.

PubMed

Vande Loock, Kim; Decordier, Ilse; Plas, Gina; Ciardelli, Roberta; Haumont, Dominique; Kirsch-Volders, Micheline

2014-01-01

Recognition of the potential vulnerability of children and newborns and protection of their health is essential, especially regarding to genotoxic compounds. Benzo(a)pyrene B(a)P a commonly found carcinogen, and its metabolite BPDE, are known to cross the placenta. To investigate how well newborns are able to cope with BPDE-induced DNA damage, a recent developed nucleotide excision repair cell phenotype assay was applied in a pilot study of 25 newborn daughters and their mothers, using the Alkaline Comet Assay and taking demographic data into account. Newborns seemed to be less able to repair BPDE-induced DNA damage since lower repair capacity levels were calculated compared to their mothers although statistical significance was not reached. Assessment of repair capacity in combination with genotypes will provide important information to support preventive strategies in neonatal care and to define science based exposure limits for pregnant women and children. Copyright © 2013 Elsevier Inc. All rights reserved.

Enemy at the gates: traffic at the plant cell pathogen interface.

PubMed

Hoefle, Caroline; Hückelhoven, Ralph

2008-12-01

The plant apoplast constitutes a space for early recognition of potentially harmful non-self. Basal pathogen recognition operates via dynamic sensing of conserved microbial patterns by pattern recognition receptors or of elicitor-active molecules released from plant cell walls during infection. Recognition elicits defence reactions depending on cellular export via SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex-mediated vesicle fusion or plasma membrane transporter activity. Lipid rafts appear also involved in focusing immunity-associated proteins to the site of pathogen contact. Simultaneously, pathogen effectors target recognition, apoplastic host proteins and transport for cell wall-associated defence. This microreview highlights most recent reports on the arms race for plant disease and immunity at the cell surface.

Dynamic nanoplatforms in biosensor and membrane constitutional systems.

PubMed

Mahon, Eugene; Aastrup, Teodor; Barboiu, Mihail

2012-01-01

Molecular recognition in biological systems occurs mainly at interfacial environments such as membrane surfaces, enzyme active sites, or the interior of the DNA double helix. At the cell membrane surface, carbohydrate-protein recognition principles apply to a range of specific non-covalent interactions including immune response, cell proliferation, adhesion and death, cell-cell interaction and communication. Protein-protein recognition meanwhile accounts for signalling processes and ion channel structure. In this chapter we aim to describe such constitutional dynamic interfaces for biosensing and membrane transport applications. Constitutionally adaptive interfaces may mimic the recognition capabilities intrinsic to natural recognition processes. We present some recent examples of 2D and 3D constructed sensors and membranes of this type and describe their sensing and transport capabilities.

Recognition mechanism of p63 by the E3 ligase Itch

PubMed Central

Bellomaria, Alessia; Barbato, Gaetano; Melino, Gerry; Paci, Maurizio; Melino, Sonia

2012-01-01

The HECT-containing E3 ubiquitin ligase Itch mediates the degradation of several proteins, including p63 and p73, involved in cell specification and fate. Itch contains four WW domains, which are essential for recognition on the target substrate, which contains a short proline-rich sequence. Several signaling complexes containing these domains have been associated with human diseases such as muscular dystrophy, Alzheimer’s or Huntington’s diseases. To gain further insight into the structural determinants of the Itch-WW2 domain, we investigated its interaction with p63. We assigned, by 3D heteronuclear NMR experiments, the backbone and side chains of the uniformly ¹³C-¹⁵N-labeled Itch-WW2. In vitro interaction of Itch-WW2 domain with p63 was studied using its interactive p63 peptide, pep63. Pep63 is an 18-mer peptide corresponding to the region from 534–551 residue of p63, encompassing the PPxY motif that interacts with the Itch-WW domains, and we identified the residues involved in this molecular recognition. Moreover, here, a strategy of stabilization of the conformation of the PPxY peptide has been adopted, increasing the WW-ligand binding. We demonstrated that cyclization of pep63 leads to an increase of both the biological stability of the peptide and of the WW-ligand complex. Stable metal-binding complexes of the pep63 have been also obtained, and localized oxidative damage on Itch-WW2 domain has been induced, demonstrating the possibility of use of metal-pep63 complexes as models for the design of metal drugs to inhibit the Itch-WW-p63 recognition in vivo. Thus, our data suggest a novel strategy to study and inhibit the recognition mechanism of Itch E3-ligase. PMID:22935697

A voxel-based lesion study on facial emotion recognition after penetrating brain injury

PubMed Central

Dal Monte, Olga; Solomon, Jeffrey M.; Schintu, Selene; Knutson, Kristine M.; Strenziok, Maren; Pardini, Matteo; Leopold, Anne; Raymont, Vanessa; Grafman, Jordan

2013-01-01

The ability to read emotions in the face of another person is an important social skill that can be impaired in subjects with traumatic brain injury (TBI). To determine the brain regions that modulate facial emotion recognition, we conducted a whole-brain analysis using a well-validated facial emotion recognition task and voxel-based lesion symptom mapping (VLSM) in a large sample of patients with focal penetrating TBIs (pTBIs). Our results revealed that individuals with pTBI performed significantly worse than normal controls in recognizing unpleasant emotions. VLSM mapping results showed that impairment in facial emotion recognition was due to damage in a bilateral fronto-temporo-limbic network, including medial prefrontal cortex (PFC), anterior cingulate cortex, left insula and temporal areas. Beside those common areas, damage to the bilateral and anterior regions of PFC led to impairment in recognizing unpleasant emotions, whereas bilateral posterior PFC and left temporal areas led to impairment in recognizing pleasant emotions. Our findings add empirical evidence that the ability to read pleasant and unpleasant emotions in other people's faces is a complex process involving not only a common network that includes bilateral fronto-temporo-limbic lobes, but also other regions depending on emotional valence. PMID:22496440

B-cell acquisition of antigen: Sensing the surface.

PubMed

Knight, Andrew M

2015-06-01

B-cell antigen receptor (BCR) recognition and acquisition of antigen by B cells is the essential first step in the generation of effective antibody responses. As B-cell-mediated antigen presentation is also believed to play a significant role in the activation of CD4(+) Th-cell responses, considerable effort has focused on clarifying the nature of antigen/BCR interactions. Following earlier descriptions of interactions of soluble antigens with the BCR, it is now clear that B cells also recognize, physically extract and present antigens that are tethered to, or integral components of, the surfaces or extracellular matrix of other cells. In this issue of the European Journal of Immunology, Zeng et al. [Eur. J. Immunol. 2015. 45: XXXX-XXXX] examine how the physical property or "stiffness" of the surface displaying antigens to B cells influences the B-cell response. This commentary reports that antigen tethered on "less stiff" surfaces induces increased B-cell activation and antibody responses. I then infer how "sensing the surface" by B cells may represent a new component of the immune system's ability to detect "damage," and how this understanding may influence approaches to clinical therapies where immune activity is either unwanted or desired. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The machinery of Nod-like receptors: refining the paths to immunity and cell death.

PubMed

Saleh, Maya

2011-09-01

One of the fundamental aspects of the innate immune system is its capacity to discriminate between self and non-self or altered self, and to quickly respond by eliciting effector mechanisms that act in concert to restore normalcy. This capacity is determined by a set of evolutionarily conserved pattern recognition receptors (PRRs) that sense the presence of microbial motifs or endogenous danger signals, including tissue damage, cellular transformation or metabolic perturbation, and orchestrate the nature, duration and intensity of the innate immune response. Nod-like receptors (NLRs), a group of intracellular PRRs, are particularly essential as evident by the high incidence of genetic variations in their genes in various diseases of homeostasis. Here, I overview the signaling mechanisms of NLRs and discuss the mounting evidence of evolutionary conservation between their pathways and the cell death machinery. I also describe their effector functions that link the sensing of danger to the induction of inflammation, autophagy or cell death. © 2011 John Wiley & Sons A/S.

Autoimmune neuropathies associated to rheumatic diseases.

PubMed

Martinez, Alberto R M; Faber, Ingrid; Nucci, Anamarli; Appenzeller, Simone; França, Marcondes C

2017-04-01

Systemic manifestations are frequent in autoimmune rheumatic diseases and include peripheral nervous system damage. Neuron cell body, axons and myelin sheath may all be affected in this context. This involvement results in severe and sometimes disabling symptoms. Sensory, motor and autonomic features may be present in different patterns that emerge as peculiar clinical pictures. Prompt recognition of these neuropathies is pivotal to guide treatment and reduce the risks of long term disability. In this review, we aim to describe the main immune-mediated neuropathies associated to rheumatic diseases: sensory neuronopathies, multiple mononeuropathies and chronic inflammatory demyelinating polyradiculoneuropathy, with an emphasis on clinical features and therapeutic options. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of transfused red blood cells for shock and coagulopathy within remote damage control resuscitation.

PubMed

Spinella, Philip C; Doctor, Allan

2014-05-01

The philosophy of damage control resuscitation (DCR) and remote damage control resuscitation (RDCR) can be summarized by stating that the goal is to prevent death from hemorrhagic shock by "staying out of trouble instead of getting out of trouble." In other words, it is preferred to arrest the progression of shock, rather than also having to reverse this condition after significant tissue damage and organ injury cascades are established. Moreover, to prevent death from exsanguination, a balanced approach to the treatment of both shock and coagulopathy is required. This was military doctrine during World War II, but seemed to be forgotten during the last half of the 20th century. Damage control resuscitation and RDCR have revitalized the approach, but there is still more to learn about the most effective and safe resuscitative strategies to simultaneously treat shock and hemorrhage. Current data suggest that our preconceived notions regarding the efficacy of standard issue red blood cells (RBCs) during the hours after transfusion may be false. Standard issue RBCs may not increase oxygen delivery and may in fact decrease it by disturbing control of regional blood flow distribution (impaired nitric oxide processing) and failing to release oxygen, even when perfusing hypoxic tissue (abnormal oxygen affinity). Standard issue RBCs may assist with hemostasis but appear to have competing effects on thrombin generation and platelet function. If standard issue or RBCs of increased storage age are not optimal, then are there alternatives that will allow for an efficacious and safe treatment of shock while also supporting hemostasis? Studies are required to determine if fresh RBCs less than 7 to 10 days provide an outcome advantage. A resurgence in the study of whole blood stored at 4°C for up to 10 days also holds promise. Two randomized controlled trials in humans have indicated that following transfusion with either whole blood stored at 4°C or platelets stored at 4°C there was less clinical bleeding than when blood was reconstituted with components or when platelets were stored at 22°C. Early reversal of shock is essential to prevent exacerbation of coagulopathy and progression of cell death cascades in patients with severe traumatic injuries. Red blood cell storage solutions have evolved to accommodate the needs of non-critically ill patients yet may not be optimal for patients in hemorrhagic shock. Continued focus on the recognition and treatment of shock is essential for continued improvement in outcomes for patients who require damage control resuscitation and RDCR.

Prenatal Exposure to DEHP Induces Neuronal Degeneration and Neurobehavioral Abnormalities in Adult Male Mice.

PubMed

Barakat, Radwa; Lin, Po-Ching; Park, Chan Jin; Best-Popescu, Catherine; Bakery, Hatem H; Abosalum, Mohamed E; Abdelaleem, Nabila M; Flaws, Jodi A; Ko, CheMyong

2018-04-23

Phthalates are a family of synthetic chemicals that are used in producing a variety of consumer products. Di-(2-ethylhexyl) phthalate (DEHP) is an widely used phthalate and poses a public health concern. Prenatal exposure to DEHP has been shown to induce premature reproductive senescence in animal studies. In this study, we tested the hypothesis that prenatal exposure to DEHP impairs neurobehavior and recognition memory in her male offspring and we investigated one possible mechanism-oxidative damage in the hippocampus. Pregnant CD-1 female mice were orally administered 200μg, 500mg, or 750mg/kg/day DEHP or vehicle from gestational day 11 until birth. The neurobehavioral impact of the prenatal DEHP exposure was assessed at the ages of 16 to 22 months. Elevated plus maze and open field tests were used to measure anxiety levels. Y-maze and novel object recognition tests were employed to measure memory function. The oxidative damage in the hippocampus was measured by the levels of oxidative DNA damage and by SLIM microscopic counting of hippocampal neurons. Adult male mice that were prenatally exposed to DEHP exhibited anxious behaviors and impaired spatial and short-term recognition memory. The number of hippocampal pyramidal neurons was significantly decreased in the DEHP mice. Furthermore, DEHP mice expressed remarkably high levels of cyclooxygenase-2, 8-hydroxyguanine, and thymidine glycol in their hippocampal neurons. DEHP mice also had lower circulating testosterone concentrations and displayed a weaker immunoreactivity than the control mice to androgen receptor expression in the brain. This study found that prenatal exposure to DEHP caused elevated anxiety behavior and impaired recognition memory. These behavioral changes may originate from neurodegeneration caused by oxidative damage and inflammation in the hippocampus. Decreased circulating testosterone concentrations and decreased expression of androgen receptor in the brain also may be factors contributing to the impaired neurobehavior in the DEHP mice.

Step-by-step mechanism of DNA damage recognition by human 8-oxoguanine DNA glycosylase.

PubMed

Kuznetsova, Alexandra A; Kuznetsov, Nikita A; Ishchenko, Alexander A; Saparbaev, Murat K; Fedorova, Olga S

2014-01-01

Extensive structural studies of human DNA glycosylase hOGG1 have revealed essential conformational changes of the enzyme. However, at present there is little information about the time scale of the rearrangements of the protein structure as well as the dynamic behavior of individual amino acids. Using pre-steady-state kinetic analysis with Trp and 2-aminopurine fluorescence detection the conformational dynamics of hOGG1 wild-type (WT) and mutants Y203W, Y203A, H270W, F45W, F319W and K249Q as well as DNA-substrates was examined. The roles of catalytically important amino acids F45, Y203, K249, H270, and F319 in the hOGG1 enzymatic pathway and their involvement in the step-by-step mechanism of oxidative DNA lesion recognition and catalysis were elucidated. The results show that Tyr-203 participates in the initial steps of the lesion site recognition. The interaction of the His-270 residue with the oxoG base plays a key role in the insertion of the damaged base into the active site. Lys-249 participates not only in the catalytic stages but also in the processes of local duplex distortion and flipping out of the oxoG residue. Non-damaged DNA does not form a stable complex with hOGG1, although a complex with a flipped out guanine base can be formed transiently. The kinetic data obtained in this study significantly improves our understanding of the molecular mechanism of lesion recognition by hOGG1. © 2013.

Enhanced spontaneous DNA twisting/bending fluctuations unveiled by fluorescence lifetime distributions promote mismatch recognition by the Rad4 nucleotide excision repair complex

PubMed Central

Chakraborty, Sagnik; Steinbach, Peter J; Paul, Debamita; Mu, Hong; Broyde, Suse

2018-01-01

Abstract Rad4/XPC recognizes diverse DNA lesions including ultraviolet-photolesions and carcinogen-DNA adducts, initiating nucleotide excision repair. Studies have suggested that Rad4/XPC senses lesion-induced helix-destabilization to flip out nucleotides from damaged DNA sites. However, characterizing how DNA deformability and/or distortions impact recognition has been challenging. Here, using fluorescence lifetime measurements empowered by a maximum entropy algorithm, we mapped the conformational heterogeneities of artificially destabilized mismatched DNA substrates of varying Rad4-binding specificities. The conformational distributions, as probed by FRET between a cytosine-analog pair exquisitely sensitive to DNA twisting/bending, reveal a direct connection between intrinsic DNA deformability and Rad4 recognition. High-specificity CCC/CCC mismatch, free in solution, sampled a strikingly broad range of conformations from B-DNA-like to highly distorted conformations that resembled those observed with Rad4 bound; the extent of these distortions increased with bound Rad4 and with temperature. Conversely, the non-specific TAT/TAT mismatch had a homogeneous, B-DNA-like conformation. Molecular dynamics simulations also revealed a wide distribution of conformations for CCC/CCC, complementing experimental findings. We propose that intrinsic deformability promotes Rad4 damage recognition, perhaps by stalling a diffusing protein and/or facilitating ‘conformational capture’ of pre-distorted damaged sites. Surprisingly, even mismatched DNA specifically bound to Rad4 remains highly dynamic, a feature that may reflect the versatility of Rad4/XPC to recognize many structurally dissimilar lesions. PMID:29267981

MutSα's Multi-Domain Allosteric Response to Three DNA Damage Types Revealed by Machine Learning

NASA Astrophysics Data System (ADS)

Melvin, Ryan L.; Thompson, William G.; Godwin, Ryan C.; Gmeiner, William H.; Salsbury, Freddie R.

2017-03-01

MutSalpha is a key component in the mismatch repair (MMR) pathway. This protein is responsible for initiating the signaling pathways for DNA repair or cell death. Herein we investigate this heterodimer’s post-recognition, post-binding response to three types of DNA damage involving cytotoxic, anti-cancer agents - carboplatin, cisplatin, and FdU. Through a combination of supervised and unsupervised machine learning techniques along with more traditional structural and kinetic analysis applied to all-atom molecular dynamics (MD) calculations, we predict that MutSalpha has a distinct response to each of the three damage types. Via a binary classification tree (a supervised machine learning technique), we identify key hydrogen bond motifs unique to each type of damage and suggest residues for experimental mutation studies. Through a combination of a recently developed clustering (unsupervised learning) algorithm, RMSF calculations, PCA, and correlated motions we predict that each type of damage causes MutS↵to explore a specific region of conformation space. Detailed analysis suggests a short range effect for carboplatin - primarily altering the structures and kinetics of residues within 10 angstroms of the damaged DNA - and distinct longer-range effects for cisplatin and FdU. In our simulations, we also observe that a key phenylalanine residue - known to stack with a mismatched or unmatched bases in MMR - stacks with the base complementary to the damaged base in 88.61% of MD frames containing carboplatinated DNA. Similarly, this Phe71 stacks with the base complementary to damage in 91.73% of frames with cisplatinated DNA. This residue, however, stacks with the damaged base itself in 62.18% of trajectory frames with FdU-substituted DNA and has no stacking interaction at all in 30.72% of these frames. Each drug investigated here induces a unique perturbation in the MutS↵complex, indicating the possibility of a distinct signaling event and specific repair or death pathway (or set of pathways) for a given type of damage.

Coherence-controlled holographic microscopy enabled recognition of necrosis as the mechanism of cancer cells death after exposure to cytopathic turbid emulsion

NASA Astrophysics Data System (ADS)

Collakova, Jana; Krizova, Aneta; Kollarova, Vera; Dostal, Zbynek; Slaba, Michala; Vesely, Pavel; Chmelik, Radim

2015-11-01

Coherence-controlled holographic microscopy (CCHM) in low-coherence mode possesses a pronounced coherence gate effect. This offers an option to investigate the details of cellular events leading to cell death caused by cytopathic turbid emulsions. CCHM capacity was first assessed in model situations that showed clear images obtained with low coherence of illumination but not with high coherence of illumination. Then, the form of death of human cancer cells induced by treatment with biologically active phospholipids (BAPs) preparation was investigated. The observed overall retraction of cell colony was apparently caused by the release of cell-to-substratum contacts. This was followed by the accumulation of granules decorating the nuclear membrane. Then, the occurrence of nuclear membrane indentations signaled the start of damage to the integrity of the cell nucleus. In the final stage, cells shrunk and disintegrated. This indicated that BAPs cause cell death by necrosis and not apoptosis. An intriguing option of checking the fate of cancer cells caused by the anticipated cooperative effect after adding another tested substance sodium dichloroacetate to turbid emulsion is discussed on grounds of pilot experiments. Such observations should reveal the impact and mechanism of action of the interacting drugs on cell behavior and fate that would otherwise remain hidden in turbid milieu.

Amnesiacs might get the gist: reduced false recognition in amnesia may be the result of impaired item-specific memory.

PubMed

Nissan, Jack; Abrahams, Sharon; Sala, Sergio Della

2013-01-01

It is a common finding in tests of false recognition that amnesic patients recognize fewer related lures than healthy controls, and this has led to assumptions that gist memory is damaged in these patients (Schacter, Verfaellie, & Anes, 1997, Neuropsychology, 11; Schacter, Verfaellie, Anes, & Racine, 1998, Journal of Cognitive Neuroscience, 10; Schacter, Verfaellie, & Pradere, 1996, Journal of Memory and Language, 35). However, clinical observations find that amnesic patients typically hold meaningful conversations and make relevant remarks, and there is some experimental evidence highlighting preserved immediate recall of prose (Baddeley & Wilson, 2002, Neuropsychologia, 40; Gooding, Isaac, & Mayes, 2005, Neuropsychologia, 43; Rosenbaum, Gilboa, Levine, Winocur, & Moscovitch, 2009, Neuropsychologia, 47), which suggests that amnesiacs can get the gist. The present experiment used false recognition paradigms to assess whether the reduced rate of false recognition found in amnesic patients may be a consequence of their impaired item-specific memory. It examined the effect of increasing the item-specific memory of amnesic patient DA by bringing her to criterion on relevant study-lists and compared her performance on a false recognition paradigm with a group of 32 healthy young adults. Results indicated that when DA's item-specific memory was increased she was more able to gist and her performance was no different to the healthy young adults. Previous assumptions that gist memory is necessarily damaged in amnesia might therefore be revisited, since the reduced rate of false recognition could be caused by impaired item-specific memory. The experiment also highlights a positive relationship between item-specific and gist memory which has not previously been accounted for in false-recognition experiments.

Uterine diseases in cattle after parturition

PubMed Central

Sheldon, I. Martin; Williams, Erin J.; Miller, Aleisha N.A.; Nash, Deborah M.; Herath, Shan

2008-01-01

Bacterial contamination of the uterine lumen is common in cattle after parturition, often leading to infection and uterine disease. Clinical disease can be diagnosed and scored by examination of the vaginal mucus, which reflects the presence of pathogenic bacteria such as Escherichia coli and Arcanobacterium pyogenes. Viruses may also cause uterine disease and bovine herpesvirus 4 (BoHV-4) is tropic for endometrial cells, causing a rapid cytopathic effect. The elimination of pathogens by the innate immune system is dependent on pattern recognition receptors binding pathogen-associated molecules. Uterine epithelial and stromal cells express receptors such as Toll-like Receptor 4 that binds E. coli lipopolysaccharide. The infertility associated with uterine disease is caused by damage to the endometrium and disruption of ovarian cyclic activity. Bacteria modulate endometrial prostaglandin secretion, and perturb ovarian follicle growth and function. Understanding the molecular basis of uterine disease will lead to novel approaches to treating infertility. PMID:18329302

Self-identity reprogrammed by a single residue switch in a cell surface receptor of a social bacterium.

PubMed

Cao, Pengbo; Wall, Daniel

2017-04-04

The ability to recognize close kin confers survival benefits on single-celled microbes that live in complex and changing environments. Microbial kinship detection relies on perceptible cues that reflect relatedness between individuals, although the mechanisms underlying recognition in natural populations remain poorly understood. In myxobacteria, cells identify related individuals through a polymorphic cell surface receptor, TraA. Recognition of compatible receptors leads to outer membrane exchange among clonemates and fitness consequences. Here, we investigated how a single receptor creates a diversity in recognition across myxobacterial populations. We first show that TraA requires its partner protein TraB to function in cell-cell adhesion. Recognition is shown to be traA allele-specific, where polymorphisms within TraA dictate binding selectivity. We reveal the malleability of TraA recognition, and seemingly minor changes to its variable region reprogram recognition outcomes. Strikingly, we identify a single residue (A/P205) as a molecular switch for TraA recognition. Substitutions at this position change the specificity of a diverse panel of environmental TraA receptors. In addition, we engineered a receptor with unique specificity by simply creating an A205P substitution, suggesting that modest changes in TraA can lead to diversification of new recognition groups in nature. We hypothesize that the malleable property of TraA has allowed it to evolve and create social barriers between myxobacterial populations and in turn avoid adverse interactions with relatives.

High-speed cell recognition algorithm for ultrafast flow cytometer imaging system.

PubMed

Zhao, Wanyue; Wang, Chao; Chen, Hongwei; Chen, Minghua; Yang, Sigang

2018-04-01

An optical time-stretch flow imaging system enables high-throughput examination of cells/particles with unprecedented high speed and resolution. A significant amount of raw image data is produced. A high-speed cell recognition algorithm is, therefore, highly demanded to analyze large amounts of data efficiently. A high-speed cell recognition algorithm consisting of two-stage cascaded detection and Gaussian mixture model (GMM) classification is proposed. The first stage of detection extracts cell regions. The second stage integrates distance transform and the watershed algorithm to separate clustered cells. Finally, the cells detected are classified by GMM. We compared the performance of our algorithm with support vector machine. Results show that our algorithm increases the running speed by over 150% without sacrificing the recognition accuracy. This algorithm provides a promising solution for high-throughput and automated cell imaging and classification in the ultrafast flow cytometer imaging platform. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

High-speed cell recognition algorithm for ultrafast flow cytometer imaging system

NASA Astrophysics Data System (ADS)

Zhao, Wanyue; Wang, Chao; Chen, Hongwei; Chen, Minghua; Yang, Sigang

2018-04-01

An optical time-stretch flow imaging system enables high-throughput examination of cells/particles with unprecedented high speed and resolution. A significant amount of raw image data is produced. A high-speed cell recognition algorithm is, therefore, highly demanded to analyze large amounts of data efficiently. A high-speed cell recognition algorithm consisting of two-stage cascaded detection and Gaussian mixture model (GMM) classification is proposed. The first stage of detection extracts cell regions. The second stage integrates distance transform and the watershed algorithm to separate clustered cells. Finally, the cells detected are classified by GMM. We compared the performance of our algorithm with support vector machine. Results show that our algorithm increases the running speed by over 150% without sacrificing the recognition accuracy. This algorithm provides a promising solution for high-throughput and automated cell imaging and classification in the ultrafast flow cytometer imaging platform.

Cell-cell recognition and social networking in bacteria

PubMed Central

Troselj, Vera; Cao, Pengbo; Wall, Daniel

2018-01-01

SUMMARY The ability to recognize self and to recognize partnering cells allows microorganisms to build social networks that perform functions beyond the capabilities of the individual. In bacteria, recognition typically involves genetic determinants that provide cell surface receptors or diffusible signaling chemicals to identify proximal cells at the molecular level that can participate in cooperative processes. Social networks also rely on discriminating mechanisms to exclude competing cells from joining and exploiting their groups. In addition to their appropriate genotypes, cell-cell recognition also requires compatible phenotypes, which vary according to environmental cues or exposures as well as stochastic processes that leads to heterogeneity and potential disharmony in the population. Understanding how bacteria identify their social partners and how they synchronize their behaviors to conduct multicellular functions is an expanding field of research. Here we review recent progress in the field and contrast the various strategies used in recognition and behavioral networking. PMID:29194914

Nematode Damage Functions: The Problems of Experimental and Sampling Error

PubMed Central

Ferris, H.

1984-01-01

The development and use of pest damage functions involves measurement and experimental errors associated with cultural, environmental, and distributional factors. Damage predictions are more valuable if considered with associated probability. Collapsing population densities into a geometric series of population classes allows a pseudo-replication removal of experimental and sampling error in damage function development. Recognition of the nature of sampling error for aggregated populations allows assessment of probability associated with the population estimate. The product of the probabilities incorporated in the damage function and in the population estimate provides a basis for risk analysis of the yield loss prediction and the ensuing management decision. PMID:19295865

DNA unwinding produced by site-specific intrastrand cross-links of the antitumor drug cis-diamminedichloroplatinum(II)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bellon, S.F.; Coleman, J.H.; Lippard, S.J.

The DNA unwinding produced by specific adducts of the antitumor drug cis-diamminedi-chloroplatinum(II) has been quantitatively determined. Synthetic DNA duplex oligonucleotides of varying lengths with two base pair cohesive ends were synthesized and characterized that contained site-specific intrastrand N7-purine/N7-purine cross-links. Included are cis-(Pt(NH{sub 3}){sub 2}(d(GpG))), cis-(Pt(NH){sub 3}{sub 2}(d(ApG))), and cis-(Pt(NH{sub 3}){sub 2}(d(GpTpG))) adducts, respectively referred to as cis-GG, cis-AG, and cis-GTG. Local DNA distortions at the site of platination were amplified by polymerization of these monomers and quantitatively evaluated by using polyacrylamide gel electrophoresis. The extent of DNA unwinding was determined by systematically varying the interplatinum distance, or phasing, in polymersmore » containing the adducts. The multimer that migrates most slowly gives the optimal phasing for cooperative bending, from which the degree of unwinding can be obtained. The authors find that the cis-GG and cis-AG adducts both unwind DNA by 13{degrees}, while the cis-GTG adduct unwinds DNA by 23{degrees}. In addition, experiments are presented that support previous studies revealing that a hinge joint forms at the sites of platination in DNA molecules containing trans-GTG adducts. On the basis of an analysis of the present and other published studies of site-specifically modified DNA. The authors propose that local duplex unwinding is a major determinant in the recognition of DNA damage by the Escherichia coli (A)BC excinuclease. In addition, local duplex unwinding of 13{degrees} and bending by 35{degrees} are shown to correlate well with the recognition of platinated DNA by a previously identified damage recognition protein (DRP) in human cells.« less

Mutations in ORC1, encoding the largest subunit of the origin recognition complex, cause microcephalic primordial dwarfism resembling Meier-Gorlin syndrome.

PubMed

Bicknell, Louise S; Walker, Sarah; Klingseisen, Anna; Stiff, Tom; Leitch, Andrea; Kerzendorfer, Claudia; Martin, Carol-Anne; Yeyati, Patricia; Al Sanna, Nouriya; Bober, Michael; Johnson, Diana; Wise, Carol; Jackson, Andrew P; O'Driscoll, Mark; Jeggo, Penny A

2011-02-27

Studies into disorders of extreme growth failure (for example, Seckel syndrome and Majewski osteodysplastic primordial dwarfism type II) have implicated fundamental cellular processes of DNA damage response signaling and centrosome function in the regulation of human growth. Here we report that mutations in ORC1, encoding a subunit of the origin recognition complex, cause microcephalic primordial dwarfism resembling Meier-Gorlin syndrome. We establish that these mutations disrupt known ORC1 functions including pre-replicative complex formation and origin activation. ORC1 deficiency perturbs S-phase entry and S-phase progression. Additionally, we show that Orc1 depletion in zebrafish is sufficient to markedly reduce body size during rapid embryonic growth. Our data suggest a model in which ORC1 mutations impair replication licensing, slowing cell cycle progression and consequently impeding growth during development, particularly at times of rapid proliferation. These findings establish a novel mechanism for the pathogenesis of microcephalic dwarfism and show a surprising but important developmental impact of impaired origin licensing.

Corneal complications of vernal keratoconjunctivitis.

PubMed

Solomon, Abraham

2015-10-01

Vernal keratoconjunctivitis (VKC) is a severe bilateral chronic allergic inflammatory disease of the ocular surface. In most of the cases, the disease is limited to the tarsal conjunctiva and to the limbus. However, in the more severe cases, the cornea may be involved, leading to potentially sight threatening complications. Prompt recognition of these complications is crucial in the management of VKC, which is one of the most severe ocular allergic diseases. A vicious cycle of inflammation occurs as a result of a set of reciprocal interactions between the conjunctiva and the cornea, which results in damage to the corneal epithelium and corneal stoma, and to the formation of shield ulcers and plaques, infectious keratitis, keratoconus, scarring, and limbal stem cell deficiency. These corneal complications can cause permanent decrease or loss of vision in children suffering from VKC. Corneal complications in VKC are the result of an on-going process of uncontrolled inflammation. Proper recognition of the corneal complications in VKC is crucial, as most of these can be managed or prevented by a combination of medical and surgical measures.

Cancer cells recovering from damage exhibit mitochondrial restructuring and increased aerobic glycolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akakura, Shin; Ostrakhovitch, Elena; Sanokawa-Akakura, Reiko

2014-06-13

Highlights: • Some cancer cells recover from severe damage that causes cell death in majority of cells. • Damage-Recovered (DR) cancer cells show reduced mitochondria, mDNA and mitochondrial enzymes. • DR cells show increased aerobic glycolysis, ATP, cell proliferation, and resistance to damage. • DR cells recovered from in vivo damage also show increased glycolysis and proliferation rate. - Abstract: Instead of relying on mitochondrial oxidative phosphorylation, most cancer cells rely heavily on aerobic glycolysis, a phenomenon termed as “the Warburg effect”. We considered that this effect is a direct consequence of damage which persists in cancer cells that recovermore » from damage. To this end, we studied glycolysis and rate of cell proliferation in cancer cells that recovered from severe damage. We show that in vitro Damage-Recovered (DR) cells exhibit mitochondrial structural remodeling, display Warburg effect, and show increased in vitro and in vivo proliferation and tolerance to damage. To test whether cancer cells derived from tumor microenvironment can show similar properties, we isolated Damage-Recovered (T{sup DR}) cells from tumors. We demonstrate that T{sup DR} cells also show increased aerobic glycolysis and a high proliferation rate. These findings show that Warburg effect and its consequences are induced in cancer cells that survive severe damage.« less

Molecular recognition in myxobacterial outer membrane exchange: functional, social and evolutionary implications.

PubMed

Wall, Daniel

2014-01-01

Through cooperative interactions, bacteria can build multicellular communities. To ensure that productive interactions occur, bacteria must recognize their neighbours and respond accordingly. Molecular recognition between cells is thus a fundamental behaviour, and in bacteria important discoveries have been made. This MicroReview focuses on a recently described recognition system in myxobacteria that is governed by a polymorphic cell surface receptor called TraA. TraA regulates outer membrane exchange (OME), whereby myxobacterial cells transiently fuse their OMs to efficiently transfer proteins and lipids between cells. Unlike other transport systems, OME is rather indiscriminate in what OM goods are transferred. In contrast, the recognition of partnering cells is discriminatory and only occurs between cells that bear identical or closely related TraA proteins. Therefore TraA functions in kin recognition and, in turn, OME helps regulate social interactions between myxobacteria. Here, I discuss and speculate on the social and evolutionary implications of OME and suggest it helps to guide their transition from free-living cells into coherent and functional populations. © 2013 John Wiley & Sons Ltd.

Exploratory behavior and recognition memory in medial septal electrolytic, neuro- and immunotoxic lesioned rats.

PubMed

Dashniani, M G; Burjanadze, M A; Naneishvili, T L; Chkhikvishvili, N C; Beselia, G V; Kruashvili, L B; Pochkhidze, N O; Chighladze, M R

2015-01-01

In the present study, the effect of the medial septal (MS) lesions on exploratory activity in the open field and the spatial and object recognition memory has been investigated. This experiment compares three types of MS lesions: electrolytic lesions that destroy cells and fibers of passage, neurotoxic - ibotenic acid lesions that spare fibers of passage but predominantly affect the septal noncholinergic neurons, and immunotoxin - 192 IgG-saporin infusions that only eliminate cholinergic neurons. The main results are: the MS electrolytic lesioned rats were impaired in habituating to the environment in the repeated spatial environment, but rats with immuno- or neurotoxic lesions of the MS did not differ from control ones; the MS electrolytic and ibotenic acid lesioned rats showed an increase in their exploratory activity to the objects and were impaired in habituating to the objects in the repeated spatial environment; rats with immunolesions of the MS did not differ from control rats; electrolytic lesions of the MS disrupt spatial recognition memory; rats with immuno- or neurotoxic lesions of the MS were normal in detecting spatial novelty; all of the MS-lesioned and control rats clearly reacted to the object novelty by exploring the new object more than familiar ones. Results observed across lesion techniques indicate that: (i) the deficits after nonselective damage of MS are limited to a subset of cognitive processes dependent on the hippocampus, (ii) MS is substantial for spatial, but not for object recognition memory - the object recognition memory can be supported outside the septohippocampal system; (iii) the selective loss of septohippocampal cholinergic or noncholinergic projections does not disrupt the function of the hippocampus to a sufficient extent to impair spatial recognition memory; (iv) there is dissociation between the two major components (cholinergic and noncholinergic) of the septohippocampal pathway in exploratory behavior assessed in the open field - the memory exhibited by decrements in exploration of repeated object presentations is affected by either electrolytic or ibotenic lesions, but not saporin.

Distinct roles of basal forebrain cholinergic neurons in spatial and object recognition memory.

PubMed

Okada, Kana; Nishizawa, Kayo; Kobayashi, Tomoko; Sakata, Shogo; Kobayashi, Kazuto

2015-08-06

Recognition memory requires processing of various types of information such as objects and locations. Impairment in recognition memory is a prominent feature of amnesia and a symptom of Alzheimer's disease (AD). Basal forebrain cholinergic neurons contain two major groups, one localized in the medial septum (MS)/vertical diagonal band of Broca (vDB), and the other in the nucleus basalis magnocellularis (NBM). The roles of these cell groups in recognition memory have been debated, and it remains unclear how they contribute to it. We use a genetic cell targeting technique to selectively eliminate cholinergic cell groups and then test spatial and object recognition memory through different behavioural tasks. Eliminating MS/vDB neurons impairs spatial but not object recognition memory in the reference and working memory tasks, whereas NBM elimination undermines only object recognition memory in the working memory task. These impairments are restored by treatment with acetylcholinesterase inhibitors, anti-dementia drugs for AD. Our results highlight that MS/vDB and NBM cholinergic neurons are not only implicated in recognition memory but also have essential roles in different types of recognition memory.

Physical exercise prevents short and long-term deficits on aversive and recognition memory and attenuates brain oxidative damage induced by maternal deprivation.

PubMed

Neves, Ben-Hur; Menezes, Jefferson; Souza, Mauren Assis; Mello-Carpes, Pâmela B

2015-12-01

It is known from previous research that physical exercise prevents long-term memory deficits induced by maternal deprivation in rats. But we could not assume similar effects of physical exercise on short-term memory, as short- and long-term memories are known to result from some different memory consolidation processes. Here we demonstrated that, in addition to long-term memory deficit, the short-term memory deficit resultant from maternal deprivation in object recognition and aversive memory tasks is also prevented by physical exercise. Additionally, one of the mechanisms by which the physical exercise influences the memory processes involves its effects attenuating the oxidative damage in the maternal deprived rats' hippocampus and prefrontal cortex.

MDC1: The art of keeping things in focus.

PubMed

Jungmichel, Stephanie; Stucki, Manuel

2010-08-01

The chromatin structure is important for recognition and repair of DNA damage. Many DNA damage response proteins accumulate in large chromatin domains flanking sites of DNA double-strand breaks. The assembly of these structures-usually termed DNA damage foci-is primarily regulated by MDC1, a large nuclear mediator/adaptor protein that is composed of several distinct structural and functional domains. Here, we are summarizing the latest discoveries about the mechanisms by which MDC1 mediates DNA damage foci formation, and we are reviewing the considerable efforts taken to understand the functional implication of these structures.

Earthquake Building Damage Mapping Based on Feature Analyzing Method from Synthetic Aperture Radar Data

NASA Astrophysics Data System (ADS)

An, L.; Zhang, J.; Gong, L.

2018-04-01

Playing an important role in gathering information of social infrastructure damage, Synthetic Aperture Radar (SAR) remote sensing is a useful tool for monitoring earthquake disasters. With the wide application of this technique, a standard method, comparing post-seismic to pre-seismic data, become common. However, multi-temporal SAR processes, are not always achievable. To develop a post-seismic data only method for building damage detection, is of great importance. In this paper, the authors are now initiating experimental investigation to establish an object-based feature analysing classification method for building damage recognition.

Identification of pyridinoline, a collagen crosslink, as a novel intrinsic ligand for the receptor for advanced glycation end-products (RAGE).

PubMed

Murakami, Yoto; Fujino, Takayuki; Kurachi, Ryotaro; Hasegawa, Toshiki; Usui, Teruyuki; Hayase, Fumitaka; Watanabe, Hirohito

2018-05-26

Advanced glycation end-products (AGEs) elicit inflammatory responses via the receptor for AGEs (RAGE) and participate in the pathogenesis of diabetic complications. An earlier study showed that 3-hydroxypyridinium (3-HP), a common moiety of toxic AGEs such as glyceraldehyde-derived pyridinium (GLAP) and GA-pyridine, is essential for the interaction with RAGE. However, the physiological significance of 3-HP recognition by RAGE remains unclear. We hypothesized that pyridinoline (Pyr), a collagen crosslink containing the 3-HP moiety, could have agonist activity with RAGE. To test this hypothesis, we purified Pyr from bovine achilles tendons and examined its cytotoxicity to rat neuronal PC12 cells. Pyr elicited toxicity to PC12 cells in a concentration-dependent manner, and this effect was attenuated in the presence of either the anti-RAGE antibody or the soluble form of RAGE. Moreover, surface plasmon resonance-based analysis showed specific binding of Pyr to RAGE. These data indicate that Pyr is an intrinsic ligand for RAGE. AGEs: advanced glycation end-products; RAGE: receptor for advanced glycation end-products; DAMPs: damage-associated molecular patterns; PRR: pattern recognition receptor; TLR: toll-like receptor; GLAP: glyceraldehyde-derived pyridinium; 3-HP: 3-hydroxypyridinium; Pyr: pyridinoline; HFBA: heptafluorobutyric acid; GST: glutathione S-transferase; SPR: surface plasmon resonance; ECM: extracellular matrix; EMT: epithelial to mesenchymal transition.

ɣδ T cell receptor ligands and modes of antigen recognition

PubMed Central

Champagne, Eric

2011-01-01

T lymphocytes expressing the γδ-type of T cell receptors for antigens contribute to all aspects of immune responses, including defenses against viruses, bacteria, parasites and tumors, allergy and autoimmunity. Multiple subsets have been individualized in humans as well as in mice and they appear to recognize in a TCR-dependent manner antigens as diverse as small non-peptidic molecules, soluble or membrane-anchored polypeptides and molecules related to MHC antigens on cell surfaces, implying diverse modes of antigen recognition. We review here the γδ TCR ligands which have been identified along the years and their characteristics, with emphasis on a few systems which have been extensively studied such as human γδ T cells responding to phosphoantigens or murine γδ T cells activated by allogeneic MHC antigens. We discuss a speculative model of antigen recognition involving simultaneous TCR recognition of MHC-like and non-MHC ligands which could fit with most available data and shares many similarities with the classical model of MHC-restricted antigen recognition for peptides or lipids by T cells subsets with αβ-type TCRs. PMID:21298486

γδ T cell receptor ligands and modes of antigen recognition.

PubMed

Champagne, Eric

2011-04-01

T lymphocytes expressing the γδ-type of T cell receptors (TCRs) for antigens contribute to all aspects of immune responses, including defenses against viruses, bacteria, parasites and tumors, allergy and autoimmunity. Multiple subsets have been individualized in humans as well as in mice and they appear to recognize in a TCR-dependent manner antigens as diverse as small non-peptidic molecules, soluble or membrane-anchored polypeptides and molecules related to MHC antigens on cell surfaces, implying diverse modes of antigen recognition. We review here the γδ TCR ligands which have been identified along the years and their characteristics, with emphasis on a few systems which have been extensively studied such as human γδ T cells responding to phosphoantigens or murine γδ T cells activated by allogeneic MHC antigens. We discuss a speculative model of antigen recognition involving simultaneous TCR recognition of MHC-like and non-MHC ligands which could fit with most available data and shares many similarities with the classical model of MHC-restricted antigen recognition for peptides or lipids by T cells subsets with αβ-type TCRs.

Identification, recognition and misidentification syndromes: a psychoanalytical perspective

PubMed Central

Thibierge, Stéphane; Morin, Catherine

2013-01-01

Misidentification syndromes are currently often understood as cognitive disorders of either the “sense of uniqueness” (Margariti and Kontaxakis, 2006) or the recognition of people (Ellis and Lewis, 2001). It is however, necessary to consider how a normal “sense of uniqueness” or normal person recognition are acquired by normal or neurotic subjects. It will be shown here that the normal conditions of cognition can be considered as one of the possible forms of a complex structure and not as just a setting for our sense and perception data. The consistency and the permanency of the body image in neurosis is what permits the recognition of other people and ourselves as unique beings. This consistency and permanency are related to object repression, as shown by neurological disorders of body image (somatoparaphrenia), which cause the object to come to the foreground in the patient’s words (Thibierge and Morin, 2010). In misidentification syndromes, as in other psychotic syndromes, one can also observe damage to the specular image as well as an absence of object repression. This leads us to question whether, in the psychiatric disorders related to a damaged specular image, disorders of cognition can be studied and managed using the same methods as for neurotic patients. PMID:24298262

The contribution of familiarity to recognition memory is a function of test format when using similar foils

PubMed Central

Migo, Ellen; Montaldi, Daniela; Norman, Kenneth A.; Quamme, Joel; Mayes, Andrew

2010-01-01

Patient Y.R., who suffered hippocampal damage that disrupted recollection but not familiarity, was impaired on a yes/no (YN) object recognition memory test with similar foils. However, she was not impaired on a forced-choice corresponding (FCC) version of the test that paired targets with corresponding similar foils (Holdstock et al. 2002). This dissociation is explained by the Complementary Learning Systems (CLS) neural-network model (Norman & O'Reilly 2003) if recollection is impaired but familiarity is preserved. The CLS model also predicts that participants relying exclusively on familiarity should be impaired on forced-choice non-corresponding (FCNC) tests, where targets are presented with foils similar to other targets. The present study tests these predictions for all three test formats (YN, FCC, FCNC) in normal participants using two variants of the remember/know procedure. As predicted, performance using familiarity alone was significantly worse than standard recognition on the YN and FCNC tests, but not on the FCC test. Recollection in the form of recall-to-reject was the major process driving YN recognition. This adds support to the interpretation of patient data according to which, hippocampal damage causes a recollection deficit that leads to poor performance on the YN test relative to FCC. PMID:19096990

[Myocardial mechanical injury in acute ischemia: a pathophysiologic and histopathologic review].

PubMed

Rossi, L; Matturri, L

1986-03-01

The recognition of histopathologic substrates of myocardial contractile damage in human acute ischemia is still very poor, notwithstanding the impressive advances in the inherent clinical diagnostic technology and concepts. The first and foremost inotropic abnormality ensuing ischemia, easily taken for atonic in origin, actually consists of a pathologic contracture of the injured myocardium, depending upon abrupt fall of ATP, and defective extrusion calcium pump with persistence of actomyosin rigor-complexes. In sustained ischemia, further membrane damage exposes the myocell to massive calcium intrusion, with eventual precipitation of it and cell death (reperfusion stone-heart). In case of transient, "hit and run" ischemia, the "stunned" myocardium undergoes prolonged contractile abnormalities. In keeping with fundamentals in pathophysiology of contraction, ischemic myofibrils in human hyperacute infarct, showed spare I bands, accounting for contracture and followed by loss of the regular cross-striation register; then, groups of adjacent sarcomeres were seen to join into true "contraction" bands, with Z lines impinging upon A bands and obliterating the I bands. Coagulative denaturation of contractile proteins follows, presenting as irregular, amorphous degeneration stripes astride irreversibly damaged myocells. As such, these cells can be passively overstretched by the nearby functioning muscle. In turn, the fixed waviness of viable, acutely ischemic myocardium was thought to configure, histologically, the loss of ATP-dependent "plasticity" of myofilaments, in a state of contracture. The "relaxant effect" of inotropic-chronotropic-positive catecholamines, favoring diastole, has been also pointed out. The present microscopic findings are cogent to clinicopathologic problems of coronary ischemia-reperfusion, and sudden death from cardiogenic shock.

Recognition-driven chemical labeling of endogenous proteins in multi-molecular crowding in live cells.

PubMed

Amaike, Kazuma; Tamura, Tomonori; Hamachi, Itaru

2017-11-14

Endogenous protein labeling is one of the most invaluable methods for studying the bona fide functions of proteins in live cells. However, multi-molecular crowding conditions, such as those that occur in live cells, hamper the highly selective chemical labeling of a protein of interest (POI). We herein describe how the efficient coupling of molecular recognition with a chemical reaction is crucial for selective protein labeling. Recognition-driven protein labeling is carried out by a synthetic labeling reagent containing a protein (recognition) ligand, a reporter tag, and a reactive moiety. The molecular recognition of a POI can be used to greatly enhance the reaction kinetics and protein selectivity, even under live cell conditions. In this review, we also briefly discuss how such selective chemical labeling of an endogenous protein can have a variety of applications at the interface of chemistry and biology.

Cdt2-mediated XPG degradation promotes gap-filling DNA synthesis in nucleotide excision repair

PubMed Central

Han, Chunhua; Wani, Gulzar; Zhao, Ran; Qian, Jiang; Sharma, Nidhi; He, Jinshan; Zhu, Qianzheng; Wang, Qi-En; Wani, Altaf A

2015-01-01

Xeroderma pigmentosum group G (XPG) protein is a structure-specific repair endonuclease, which cleaves DNA strands on the 3′ side of the DNA damage during nucleotide excision repair (NER). XPG also plays a crucial role in initiating DNA repair synthesis through recruitment of PCNA to the repair sites. However, the fate of XPG protein subsequent to the excision of DNA damage has remained unresolved. Here, we show that XPG, following its action on bulky lesions resulting from exposures to UV irradiation and cisplatin, is subjected to proteasome-mediated proteolytic degradation. Productive NER processing is required for XPG degradation as both UV and cisplatin treatment-induced XPG degradation is compromised in NER-deficient XP-A, XP-B, XP-C, and XP-F cells. In addition, the NER-related XPG degradation requires Cdt2, a component of an E3 ubiquitin ligase, CRL4Cdt2. Micropore local UV irradiation and in situ Proximity Ligation assays demonstrated that Cdt2 is recruited to the UV-damage sites and interacts with XPG in the presence of PCNA. Importantly, Cdt2-mediated XPG degradation is crucial to the subsequent recruitment of DNA polymerase δ and DNA repair synthesis. Collectively, our data support the idea of PCNA recruitment to damage sites which occurs in conjunction with XPG, recognition of the PCNA-bound XPG by CRL4Cdt2 for specific ubiquitylation and finally the protein degradation. In essence, XPG elimination from DNA damage sites clears the chromatin space needed for the subsequent recruitment of DNA polymerase δ to the damage site and completion of gap-filling DNA synthesis during the final stage of NER. PMID:25483071

Zinc enhances intestinal epithelial barrier function through the PI3K/AKT/mTOR signaling pathway in Caco-2 cells.

PubMed

Shao, Yuxin; Wolf, Patricia G; Guo, Shuangshuang; Guo, Yuming; Gaskins, H Rex; Zhang, Bingkun

2017-05-01

Zinc plays an important role in maintaining intestinal barrier function as well as modulating cellular signaling recognition and protein kinase activities. The phosphatidylinositol 3-kinase (PI3K) cascade has been demonstrated to affect intercellular integrity and tight junction (TJ) proteins. The current study investigated the hypothesis that zinc regulates intestinal intercellular junction integrity through the PI3K/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway. A transwell model of Caco-2 cell was incubated with 0, 50 and 100 μM of zinc at various time points. Transepithelial electrical resistance (TEER), paracellular permeability, TJ proteins, cell proliferation, differentiation and cell damage were measured. Compared with controls, 50 and 100 μM of zinc increased cell growth at 6, 12 and 24 h and the expression of proliferating cell nuclear antigen at 24 h. Zinc (100 μM) significantly elevated TEER at 6-24 h and reduced TJ permeability at 24 h, accompanied by the up-regulation of alkaline phosphatase (AP) activity and zonula occludens (ZO)-1 expression. In addition, zinc (100 μM) affected the PI3K/AKT/mTOR pathway by stimulating phosphorylation of AKT and the downstream target mTOR. Inhibition of PI3K signaling by LY294002 counteracted zinc promotion, as shown by a decrease in AP activity, TEER, the abundance of ZO-1 and phosphorylation of AKT and mTOR. Additionally, TJ permeability and the expression of caspase-3 and LC3II (markers of cell damage) were increased by addition of PI3K inhibitor. In conclusion, the activation of PI3K/AKT/mTOR signaling by zinc is involved in improving intestinal barrier function by enhancing cell differentiation and expression of TJ protein ZO-1. Copyright © 2017 Elsevier Inc. All rights reserved.

Ubiquitin-dependent Protein Degradation at the Yeast Endoplasmic Reticulum and Nuclear Envelope

PubMed Central

Zattas, Dimitrios; Hochstrasser, Mark

2014-01-01

The endoplasmic reticulum (ER) is the primary organelle in eukaryotic cells where membrane and secreted proteins are inserted into or across cell membranes. Its membrane bilayer and luminal compartments provide a favorable environment for the folding and assembly of thousands of newly synthesized proteins. However, protein folding is intrinsically error-prone, and various stress conditions can further increase levels of protein misfolding and damage, particularly in the ER, which can lead to cellular dysfunction and disease. The ubiquitin-proteasome system (UPS) is responsible for the selective destruction of a vast array of protein substrates, either for protein quality control or to allow rapid changes in the levels of specific regulatory proteins. In this review, we will focus on the components and mechanisms of ER-associated protein degradation (ERAD), an important branch of the UPS. ER membranes extend from subcortical regions of the cell to the nuclear envelope, with its continuous outer and inner membranes; the nuclear envelope is a specialized subdomain of the ER. ERAD presents additional challenges to the UPS beyond those faced with soluble substrates of the cytoplasm and nucleus. These include recognition of sugar modifications that occur in the ER, retrotranslocation of proteins across the membrane bilayer, and transfer of substrates from the ER extraction machinery to the proteasome. Here we review characteristics of ERAD substrate degradation signals (degrons), mechanisms underlying substrate recognition and processing by the ERAD machinery, and ideas on the still unresolved problem of how substrate proteins are moved across and extracted from the ER membrane. PMID:25231236

Innate lymphoid cells in tissue homeostasis and diseases.

PubMed

Ignacio, Aline; Breda, Cristiane Naffah Souza; Camara, Niels Olsen Saraiva

2017-08-18

Innate lymphoid cells (ILCs) are the most recently discovered family of innate immune cells. They are a part of the innate immune system, but develop from the lymphoid lineage. They lack pattern-recognition receptors and rearranged receptors, and therefore cannot directly mediate antigen specific responses. The progenitors specifically associated with the ILCs lineage have been uncovered, enabling the distinction between ILCs and natural killer cells. Based on the requirement of specific transcription factors and their patterns of cytokine production, ILCs are categorized into three subsets (ILC1, ILC2 and ILC3). First observed in mucosal surfaces, these cell populations interact with hematopoietic and non-hematopoietic cells throughout the body during homeostasis and diseases, promoting immunity, commensal microbiota tolerance, tissue repair and inflammation. Over the last 8 years, ILCs came into the spotlight as an essential cell type able to integrate diverse host immune responses. Recently, it became known that ILC subsets play a key role in immune responses at barrier surfaces, interacting with the microbiota, nutrients and metabolites. Since the liver receives the venous blood directly from the intestinal vein, the intestine and liver are essential to maintain tolerance and can rapidly respond to infections or tissue damage. Therefore, in this review, we discuss recent findings regarding ILC functions in homeostasis and disease, with a focus on the intestine and liver.

Segregation of anterior temporal regions critical for retrieving names of unique and non-unique entities reflects underlying long-range connectivity.

PubMed

Mehta, Sonya; Inoue, Kayo; Rudrauf, David; Damasio, Hanna; Tranel, Daniel; Grabowski, Thomas

2016-02-01

Lesion-deficit studies support the hypothesis that the left anterior temporal lobe (ATL) plays a critical role in retrieving names of concrete entities. They further suggest that different regions of the left ATL process different conceptual categories. Here we test the specificity of these relationships and whether the anatomical segregation is related to the underlying organization of white matter connections. We reanalyzed data from a previous lesion study of naming and recognition across five categories of concrete entities. In voxelwise logistic regressions of lesion-deficit associations, we formally incorporated measures of disconnection of long-range association fiber tracts (FTs) and covaried for recognition and non-category-specific naming deficits. We also performed fiber tractwise analyses to assess whether damage to specific FTs was preferentially associated with category-selective naming deficits. Damage to the basolateral ATL was associated with naming deficits for both unique (famous faces) and non-unique entities, whereas the damage to the temporal pole was associated with naming deficits for unique entities only. This segregation pattern remained after accounting for comorbid recognition deficits or naming deficits in other categories. The tractwise analyses showed that damage to the uncinate fasciculus (UNC) was associated with naming impairments for unique entities, while damage to the inferior longitudinal fasciculus (ILF) was associated with naming impairments for non-unique entities. Covarying for FT transection in voxelwise analyses rendered the cortical association for unique entities more focal. These results are consistent with the partial segregation of brain system support for name retrieval of unique and non-unique entities at both the level of cortical components and underlying white matter fiber bundles. Our study reconciles theoretic accounts of the functional organization of the left ATL by revealing both category-related processing and semantic hub sectors. Copyright © 2015 Elsevier Ltd. All rights reserved.

An intelligent signal processing and pattern recognition technique for defect identification using an active sensor network

NASA Astrophysics Data System (ADS)

Su, Zhongqing; Ye, Lin

2004-08-01

The practical utilization of elastic waves, e.g. Rayleigh-Lamb waves, in high-performance structural health monitoring techniques is somewhat impeded due to the complicated wave dispersion phenomena, the existence of multiple wave modes, the high susceptibility to diverse interferences, the bulky sampled data and the difficulty in signal interpretation. An intelligent signal processing and pattern recognition (ISPPR) approach using the wavelet transform and artificial neural network algorithms was developed; this was actualized in a signal processing package (SPP). The ISPPR technique comprehensively functions as signal filtration, data compression, characteristic extraction, information mapping and pattern recognition, capable of extracting essential yet concise features from acquired raw wave signals and further assisting in structural health evaluation. For validation, the SPP was applied to the prediction of crack growth in an alloy structural beam and construction of a damage parameter database for defect identification in CF/EP composite structures. It was clearly apparent that the elastic wave propagation-based damage assessment could be dramatically streamlined by introduction of the ISPPR technique.

The effects of chemotherapeutics on cellular metabolism and consequent immune recognition.

PubMed

Newell, M Karen; Melamede, Robert; Villalobos-Menuey, Elizabeth; Swartzendruber, Douglas; Trauger, Richard; Camley, Robert E; Crisp, William

2004-02-02

Awidely held view is that oncolytic agents induce death of tumor cells directly. In this report we review and discuss the apoptosis-inducing effects of chemotherapeutics, the effects of chemotherapeutics on metabolic function, and the consequent effects of metabolic function on immune recognition. Finally, we propose that effective chemotherapeutic and/or apoptosis-inducing agents, at concentrations that can be achieved physiologically, do not kill tumor cells directly. Rather, we suggest that effective oncolytic agents sensitize immunologically altered tumor cells to immune recognition and immune-directed cell death.

The effects of chemotherapeutics on cellular metabolism and consequent immune recognition

PubMed Central

Newell, M Karen; Melamede, Robert; Villalobos-Menuey, Elizabeth; Swartzendruber, Douglas; Trauger, Richard; Camley, Robert E; Crisp, William

2004-01-01

A widely held view is that oncolytic agents induce death of tumor cells directly. In this report we review and discuss the apoptosis-inducing effects of chemotherapeutics, the effects of chemotherapeutics on metabolic function, and the consequent effects of metabolic function on immune recognition. Finally, we propose that effective chemotherapeutic and/or apoptosis-inducing agents, at concentrations that can be achieved physiologically, do not kill tumor cells directly. Rather, we suggest that effective oncolytic agents sensitize immunologically altered tumor cells to immune recognition and immune-directed cell death. PMID:14756899

Damage detection methodology under variable load conditions based on strain field pattern recognition using FBGs, nonlinear principal component analysis, and clustering techniques

NASA Astrophysics Data System (ADS)

Sierra-Pérez, Julián; Torres-Arredondo, M.-A.; Alvarez-Montoya, Joham

2018-01-01

Structural health monitoring consists of using sensors integrated within structures together with algorithms to perform load monitoring, damage detection, damage location, damage size and severity, and prognosis. One possibility is to use strain sensors to infer structural integrity by comparing patterns in the strain field between the pristine and damaged conditions. In previous works, the authors have demonstrated that it is possible to detect small defects based on strain field pattern recognition by using robust machine learning techniques. They have focused on methodologies based on principal component analysis (PCA) and on the development of several unfolding and standardization techniques, which allow dealing with multiple load conditions. However, before a real implementation of this approach in engineering structures, changes in the strain field due to conditions different from damage occurrence need to be isolated. Since load conditions may vary in most engineering structures and promote significant changes in the strain field, it is necessary to implement novel techniques for uncoupling such changes from those produced by damage occurrence. A damage detection methodology based on optimal baseline selection (OBS) by means of clustering techniques is presented. The methodology includes the use of hierarchical nonlinear PCA as a nonlinear modeling technique in conjunction with Q and nonlinear-T 2 damage indices. The methodology is experimentally validated using strain measurements obtained by 32 fiber Bragg grating sensors bonded to an aluminum beam under dynamic bending loads and simultaneously submitted to variations in its pitch angle. The results demonstrated the capability of the methodology for clustering data according to 13 different load conditions (pitch angles), performing the OBS and detecting six different damages induced in a cumulative way. The proposed methodology showed a true positive rate of 100% and a false positive rate of 1.28% for a 99% of confidence.

Inhibition of exportin-1 function results in rapid cell cycle-associated DNA damage in cancer cells

PubMed Central

Burke, Russell T.; Marcus, Joshua M.; Orth, James D.

2017-01-01

Selective inhibitors of nuclear export (SINE) are small molecules in development as anti-cancer agents. The first-in-class SINE, selinexor, is in clinical trials for blood and solid cancers. Selinexor forms a covalent bond with exportin-1 at cysteine-528, and blocks its ability to export cargos. Previous work has shown strong cell cycle effects and drug-induced cell death across many different cancer-derived cell lines. Here, we report strong cell cycle-associated DNA double-stranded break formation upon the treatment of cancer cells with SINE. In multiple cell models, selinexor treatment results in the formation of clustered DNA damage foci in 30-40% of cells within 8 hours that is dependent upon cysteine-528. DNA damage strongly correlates with G1/S-phase and decreased DNA replication. Live cell microscopy reveals an association between DNA damage and cell fate. Cells that form damage in G1-phase more often die or arrest, while those damaged in S/G2-phase frequently progress to cell division. Up to half of all treated cells form damage foci, and most cells that die after being damaged, were damaged in G1-phase. By comparison, non-transformed cell lines show strong cell cycle effects but little DNA damage and less death than cancer cells. Significant drug combination effects occur when selinexor is paired with different classes of agents that either cause DNA damage or that diminish DNA damage repair. These data present a novel effect of exportin-1 inhibition and provide a strong rationale for multiple combination treatments of selinexor with agents that are currently in use for the treatment of different solid cancers. PMID:28467801

Cancer cells recovering from damage exhibit mitochondrial restructuring and increased aerobic glycolysis.

PubMed

Akakura, Shin; Ostrakhovitch, Elena; Sanokawa-Akakura, Reiko; Tabibzadeh, Siamak

2014-06-13

Instead of relying on mitochondrial oxidative phosphorylation, most cancer cells rely heavily on aerobic glycolysis, a phenomenon termed as "the Warburg effect". We considered that this effect is a direct consequence of damage which persists in cancer cells that recover from damage. To this end, we studied glycolysis and rate of cell proliferation in cancer cells that recovered from severe damage. We show that in vitro Damage-Recovered (DR) cells exhibit mitochondrial structural remodeling, display Warburg effect, and show increased in vitro and in vivo proliferation and tolerance to damage. To test whether cancer cells derived from tumor microenvironment can show similar properties, we isolated Damage-Recovered (T(DR)) cells from tumors. We demonstrate that T(DR) cells also show increased aerobic glycolysis and a high proliferation rate. These findings show that Warburg effect and its consequences are induced in cancer cells that survive severe damage. Copyright © 2014 Elsevier Inc. All rights reserved.

Profiling of Glycan Receptors for Minute Virus of Mice in Permissive Cell Lines Towards Understanding the Mechanism of Cell Recognition

PubMed Central

Halder, Sujata; Cotmore, Susan; Heimburg-Molinaro, Jamie; Smith, David F.; Cummings, Richard D.; Chen, Xi; Trollope, Alana J.; North, Simon J.; Haslam, Stuart M.; Dell, Anne; Tattersall, Peter; McKenna, Robert; Agbandje-McKenna, Mavis

2014-01-01

The recognition of sialic acids by two strains of minute virus of mice (MVM), MVMp (prototype) and MVMi (immunosuppressive), is an essential requirement for successful infection. To understand the potential for recognition of different modifications of sialic acid by MVM, three types of capsids, virus-like particles, wild type empty (no DNA) capsids, and DNA packaged virions, were screened on a sialylated glycan microarray (SGM). Both viruses demonstrated a preference for binding to 9-O-methylated sialic acid derivatives, while MVMp showed additional binding to 9-O-acetylated and 9-O-lactoylated sialic acid derivatives, indicating recognition differences. The glycans recognized contained a type-2 Galβ1-4GlcNAc motif (Neu5Acα2-3Galβ1-4GlcNAc or 3′SIA-LN) and were biantennary complex-type N-glycans with the exception of one. To correlate the recognition of the 3′SIA-LN glycan motif as well as the biantennary structures to their natural expression in cell lines permissive for MVMp, MVMi, or both strains, the N- and O-glycans, and polar glycolipids present in three cell lines used for in vitro studies, A9 fibroblasts, EL4 T lymphocytes, and the SV40 transformed NB324K cells, were analyzed by MALDI-TOF/TOF mass spectrometry. The cells showed an abundance of the sialylated glycan motifs recognized by the viruses in the SGM and previous glycan microarrays supporting their role in cellular recognition by MVM. Significantly, the NB324K showed fucosylation at the non-reducing end of their biantennary glycans, suggesting that recognition of these cells is possibly mediated by the Lewis X motif as in 3′SIA-LeX identified in a previous glycan microarray screen. PMID:24475195

Quantitative Expression and Immunogenicity of MAGE-3 and -6 in Upper Aerodigestive Tract Cancer

PubMed Central

Andrade Filho, Pedro A.; López-Albaitero, Andrés; Xi, Liqiang; Gooding, William; Godfrey, Tony; Ferris, Robert L.

2009-01-01

The MAGE antigens are frequently expressed cancer vaccine targets. However, quantitative analysis of MAGE expression in upper aero-digestive tract (UADT) tumor cells and its association with T cell recognition has not been performed, hindering the selection of appropriate candidates for MAGE specific immunotherapy. Using quantitative RT-PCR (QRT-PCR), we evaluated the expression of MAGE-3/6 in 65 UADT cancers, 48 normal samples from tumor matched sites and 7 HLA-A*0201+squamous cell carcinoma of the head and neck (SCCHN) cell lines. Expression results were confirmed using western blot. HLA-A*0201:MAGE-3(271–279) specific cytotoxic T lymphocytes (MAGE-CTL) from SCCHN patients and healthy donors showed that MAGE-3/6 expression was highly associated with CTL recognition in vitro. Based on MAGE-3/6 expression we could identify 31 (47%) of the 65 UADT tumors which appeared to express MAGE-3/6 at levels that correlated with efficient CTL recognition. To confirm that the level of MAGE-3 expression was responsible for CTL recognition, two MAGE-3/6 mRNAhigh SCCHN cell lines, PCI-13 and PCI-30, were subjected to MAGE-3/6 specific knockdown. RNAi–transfected cells showed that MAGE expression, and MAGE-CTL recognition, were significantly reduced. Furthermore, treatment of cells expressing low MAGE-3/6 mRNA with a demethylating agent, 5-aza-2'-deoxycytidine (DAC), increased the expression of MAGE-3/6 and CTL recognition. Thus, using QRT-PCR UADT cancers frequently express MAGE-3/6 at levels sufficient for CTL recognition, supporting the use of a QRT-PCR based assay for the selection of candidates likely to respond to MAGE-3/6 immunotherapy. Demethylating agents could increase the number of patients amenable for targeting epigenetically modified tumor antigens in vaccine trials. PMID:19610063

Quantitative expression and immunogenicity of MAGE-3 and -6 in upper aerodigestive tract cancer.

PubMed

Filho, Pedro A Andrade; López-Albaitero, Andrés; Xi, Liqiang; Gooding, William; Godfrey, Tony; Ferris, Robert L

2009-10-15

The MAGE antigens are frequently expressed cancer vaccine targets. However, quantitative analysis of MAGE expression in upper aerodigestive tract (UADT) tumor cells and its association with T-cell recognition has not been performed, hindering the selection of appropriate candidates for MAGE-specific immunotherapy. Using quantitative RT-PCR (QRT-PCR), we evaluated the expression of MAGE-3/6 in 65 UADT cancers, 48 normal samples from tumor matched sites and 7 HLA-A*0201+ squamous cell carcinoma of the head and neck (SCCHN) cell lines. Expression results were confirmed using Western blot. HLA-A*0201:MAGE-3- (271-279) specific cytotoxic T lymphocytes (MAGE-CTL) from SCCHN patients and healthy donors showed that MAGE-3/6 expression was highly associated with CTL recognition in vitro. On the basis of the MAGE-3/6 expression, we could identify 31 (47%) of the 65 UADT tumors, which appeared to express MAGE-3/6 at levels that correlated with efficient CTL recognition. To confirm that the level of MAGE-3 expression was responsible for CTL recognition, 2 MAGE-3/6 mRNA(high) SCCHN cell lines, PCI-13 and PCI-30, were subjected to MAGE-3/6-specific knockdown. RNAi-transfected cells showed that MAGE expression and MAGE-CTL recognition were significantly reduced. Furthermore, treatment of cells expressing low MAGE-3/6 mRNA with a demethylating agent, 5-aza-2'-deoxycytidine (DAC), increased the expression of MAGE-3/6 and CTL recognition. Thus, using QRT-PCR UADT cancers frequently express MAGE-3/6 at levels sufficient for CTL recognition, supporting the use of a QRT-PCR-based assay for the selection of candidates likely to respond to MAGE-3/6 immunotherapy. Demethylating agents could increase the number of patients amenable for targeting epigenetically modified tumor antigens in vaccine trials.

Complement factor H in host defense and immune evasion.

PubMed

Parente, Raffaella; Clark, Simon J; Inforzato, Antonio; Day, Anthony J

2017-05-01

Complement is the major humoral component of the innate immune system. It recognizes pathogen- and damage-associated molecular patterns, and initiates the immune response in coordination with innate and adaptive immunity. When activated, the complement system unleashes powerful cytotoxic and inflammatory mechanisms, and thus its tight control is crucial to prevent damage to host tissues and allow restoration of immune homeostasis. Factor H is the major soluble inhibitor of complement, where its binding to self markers (i.e., particular glycan structures) prevents complement activation and amplification on host surfaces. Not surprisingly, mutations and polymorphisms that affect recognition of self by factor H are associated with diseases of complement dysregulation, such as age-related macular degeneration and atypical haemolytic uremic syndrome. In addition, pathogens (i.e., non-self) and cancer cells (i.e., altered-self) can hijack factor H to evade the immune response. Here we review recent (and not so recent) literature on the structure and function of factor H, including the emerging roles of this protein in the pathophysiology of infectious diseases and cancer.

Variability in the impairment of recognition memory in patients with frontal lobe lesions.

PubMed

Bastin, Christine; Van der Linden, Martial; Lekeu, Françoise; Andrés, Pilar; Salmon, Eric

2006-10-01

Fourteen patients with frontal lobe lesions and 14 normal subjects were tested on a recognition memory task that required discriminating between target words, new words that are synonyms of the targets and unrelated distractors. A deficit was found in 12 of the patients. Moreover, three different patterns of recognition impairment were identified: (I) poor memory for targets, (II) normal hits but increased false recognitions for both types of distractors, (III) normal hit rates, but increased false recognitions for synonyms only. Differences in terms of location of the damage and behavioral characteristics between these subgroups were examined. An encoding deficit was proposed to explain the performance of patients in subgroup I. The behavioral patterns of the patients in subgroups II and III could be interpreted as deficient post-retrieval verification processes and an inability to recollect item-specific information, respectively.

Distinct Modes of Macrophage Recognition for Apoptotic and Necrotic Cells Are Not Specified Exclusively by Phosphatidylserine Exposure

PubMed Central

Cocco, Regina E.; Ucker, David S.

2001-01-01

The distinction between physiological (apoptotic) and pathological (necrotic) cell deaths reflects mechanistic differences in cellular disintegration and is of functional significance with respect to the outcomes that are triggered by the cell corpses. Mechanistically, apoptotic cells die via an active and ordered pathway; necrotic deaths, conversely, are chaotic and passive. Macrophages and other phagocytic cells recognize and engulf these dead cells. This clearance is believed to reveal an innate immunity, associated with inflammation in cases of pathological but not physiological cell deaths. Using objective and quantitative measures to assess these processes, we find that macrophages bind and engulf native apoptotic and necrotic cells to similar extents and with similar kinetics. However, recognition of these two classes of dying cells occurs via distinct and noncompeting mechanisms. Phosphatidylserine, which is externalized on both apoptotic and necrotic cells, is not a specific ligand for the recognition of either one. The distinct modes of recognition for these different corpses are linked to opposing responses from engulfing macrophages. Necrotic cells, when recognized, enhance proinflammatory responses of activated macrophages, although they are not sufficient to trigger macrophage activation. In marked contrast, apoptotic cells profoundly inhibit phlogistic macrophage responses; this represents a cell-associated, dominant-acting anti-inflammatory signaling activity acquired posttranslationally during the process of physiological cell death. PMID:11294896

Chaperone-Mediated Autophagy in the Kidney: The Road More Traveled

PubMed Central

Franch, Harold A.

2014-01-01

Summary Chaperone-mediated autophagy (CMA) is a lysosomal proteolytic pathway in which cytosolic substrate proteins contain specific chaperone recognition sequences required for degradation and are translocated directly across the lysosomal membrane for destruction. CMA proteolytic activity has a reciprocal relationship with macroautophagy: CMA is most active in cells in which macroautophagy is least active. Normal renal proximal tubular cells have low levels of macroautophagy, but high basal levels of CMA activity. CMA activity is regulated by starvation, growth factors, oxidative stress, lipids, aging, and retinoic acid signaling. The physiological consequences of changes in CMA activity depend on the substrate proteins present in a given cell type. In the proximal tubule, increased CMA results from protein or calorie starvation and from oxidative stress. Overactivity of CMA can be associated with tubular lysosomal pathology and certain cancers. Reduced CMA activity contributes to protein accumulation in renal tubular hypertrophy, but may contribute to oxidative tissue damage in diabetes and aging. Although there are more questions than answers about the role of high basal CMA activity, this remarkable feature of tubular protein metabolism appears to influence a variety of chronic diseases. PMID:24485032

A Subset of Latency-Reversing Agents Expose HIV-Infected Resting CD4+ T-Cells to Recognition by Cytotoxic T-Lymphocytes

PubMed Central

Jones, R. Brad; Mueller, Stefanie; O’Connor, Rachel; Rimpel, Katherine; Sloan, Derek D.; Karel, Dan; Wong, Hing C.; Jeng, Emily K.; Thomas, Allison S.; Whitney, James B.; Lim, So-Yon; Kovacs, Colin; Benko, Erika; Karandish, Sara; Huang, Szu-Han; Buzon, Maria J.; Lichterfeld, Mathias; Irrinki, Alivelu; Murry, Jeffrey P.; Tsai, Angela; Yu, Helen; Geleziunas, Romas; Trocha, Alicja; Ostrowski, Mario A.; Irvine, Darrell J.; Walker, Bruce D.

2016-01-01

Resting CD4+ T-cells harboring inducible HIV proviruses are a critical reservoir in antiretroviral therapy (ART)-treated subjects. These cells express little to no viral protein, and thus neither die by viral cytopathic effects, nor are efficiently cleared by immune effectors. Elimination of this reservoir is theoretically possible by combining latency-reversing agents (LRAs) with immune effectors, such as CD8+ T-cells. However, the relative efficacy of different LRAs in sensitizing latently-infected cells for recognition by HIV-specific CD8+ T-cells has not been determined. To address this, we developed an assay that utilizes HIV-specific CD8+ T-cell clones as biosensors for HIV antigen expression. By testing multiple CD8+ T-cell clones against a primary cell model of HIV latency, we identified several single agents that primed latently-infected cells for CD8+ T-cell recognition, including IL-2, IL-15, two IL-15 superagonists (IL-15SA and ALT-803), prostratin, and the TLR-2 ligand Pam3CSK4. In contrast, we did not observe CD8+ T-cell recognition of target cells following treatment with histone deacetylase inhibitors or with hexamethylene bisacetamide (HMBA). In further experiments we demonstrate that a clinically achievable concentration of the IL-15 superagonist ‘ALT-803’, an agent presently in clinical trials for solid and hematological tumors, primes the natural ex vivo reservoir for CD8+ T-cell recognition. Thus, our results establish a novel experimental approach for comparative evaluation of LRAs, and highlight ALT-803 as an LRA with the potential to synergize with CD8+ T-cells in HIV eradication strategies. PMID:27082643

A Subset of Latency-Reversing Agents Expose HIV-Infected Resting CD4+ T-Cells to Recognition by Cytotoxic T-Lymphocytes.

PubMed

Jones, R Brad; Mueller, Stefanie; O'Connor, Rachel; Rimpel, Katherine; Sloan, Derek D; Karel, Dan; Wong, Hing C; Jeng, Emily K; Thomas, Allison S; Whitney, James B; Lim, So-Yon; Kovacs, Colin; Benko, Erika; Karandish, Sara; Huang, Szu-Han; Buzon, Maria J; Lichterfeld, Mathias; Irrinki, Alivelu; Murry, Jeffrey P; Tsai, Angela; Yu, Helen; Geleziunas, Romas; Trocha, Alicja; Ostrowski, Mario A; Irvine, Darrell J; Walker, Bruce D

2016-04-01

Resting CD4+ T-cells harboring inducible HIV proviruses are a critical reservoir in antiretroviral therapy (ART)-treated subjects. These cells express little to no viral protein, and thus neither die by viral cytopathic effects, nor are efficiently cleared by immune effectors. Elimination of this reservoir is theoretically possible by combining latency-reversing agents (LRAs) with immune effectors, such as CD8+ T-cells. However, the relative efficacy of different LRAs in sensitizing latently-infected cells for recognition by HIV-specific CD8+ T-cells has not been determined. To address this, we developed an assay that utilizes HIV-specific CD8+ T-cell clones as biosensors for HIV antigen expression. By testing multiple CD8+ T-cell clones against a primary cell model of HIV latency, we identified several single agents that primed latently-infected cells for CD8+ T-cell recognition, including IL-2, IL-15, two IL-15 superagonists (IL-15SA and ALT-803), prostratin, and the TLR-2 ligand Pam3CSK4. In contrast, we did not observe CD8+ T-cell recognition of target cells following treatment with histone deacetylase inhibitors or with hexamethylene bisacetamide (HMBA). In further experiments we demonstrate that a clinically achievable concentration of the IL-15 superagonist 'ALT-803', an agent presently in clinical trials for solid and hematological tumors, primes the natural ex vivo reservoir for CD8+ T-cell recognition. Thus, our results establish a novel experimental approach for comparative evaluation of LRAs, and highlight ALT-803 as an LRA with the potential to synergize with CD8+ T-cells in HIV eradication strategies.

The cell clone ecology hypothesis and the cell fusion model of cancer progression and metastasis (II): three pathways for spontaneous cell-cell fusion and escape from the intercellular matrix.

PubMed

Parris, George

2006-01-01

The two-stage initiation-progression model of cancer is widely accepted. Initiation appears to result most often from accumulation of damage to the DNA expressed as multiple mutations in the phenotype. Unsymmetrical chromosome segregation during mitosis of normal or mutated cells produces aneuploid cells and also contributes to the evolution of neoplasia. However, it has been pointed out (Parris GE. Med Hypotheses 2005;65:993-4 and 2006;66:76-83) that DNA damage and loss of chromosomes are much more likely to lead the mutant clones of cells to extinction than to successful expansion (e.g., an example of Muller's Ratchet). It was argued that aneuploid neoplasia represent new parasite species that successfully evolve to devour their hosts by incorporating sex-like redistribution of chromosomes through spontaneous or virus-catalyzed cell-cell fusion into their life-cycle. Spontaneous cell-cell fusion is generally blocked by the intercellular matrix to which the cells are bound via surface adhesion molecules (frequently glycoproteins, e.g., CD44). In order for progression of matrix-contained neoplasia toward clinically significant cancer to occur, the parasite cells must escape from the matrix and fuse. Release from the matrix also allows the parasite cells to invade adjacent tissues and metastasize to remote locations. Both invasion and metastasis likely involve fusion of the migrating parasite cells with fusion-prone blast cells. There are at least three pathways through which parasite cells can be liberated from the confining matrix: (i) Their adhesion molecules may be modified (e.g., by hyper-glycosylation) so that they can no longer grip the matrix. (ii) Their adhesion molecules or matrix may be saturated with other ligands (e.g., polyamines). (iii) Their adhesion molecules may be cleaved from the cell surface or the matrix itself may be cleaved (e.g., by MMPs or ADAMs). It is hypothesized that mobilization of parasite cells and cell-cell fusion go hand-in-hand in the progression of neoplasia to clinically significant cancer through invasion and metastasis. The latency between tumor recognition and exposure to mutagens and the increased incidence of cancer with age can probably be related to slow breakdown of the intercellular matrix that provides a barrier to cell-cell fusion.

Mechanisms regulating enhanced HLA class II-mediated CD4+ T cell recognition of human B-cell lymphoma by resveratrol

PubMed Central

RADWAN, FAISAL F. Y.; ZHANG, LIXIA; HOSSAIN, AZIM; DOONAN, BENTLY P.; GOD, JASON; HAQUE, AZIZUL

2015-01-01

Malignant B-cells express measurable levels of HLA class II proteins, but often escape immune recognition by CD4+ T cells. Resveratrol (Resv) has been the focus of numerous investigations due to its potential chemopreventive and anti-cancer effects, but it has never been tested in the regulation of immune components in B-cell tumors. Here, we show for the first time that Resv treatment enhances HLA class II-mediated immune detection of B-cell lymphomas by altering immune components and class II presentation in tumor cells. Resv treatment induced an upregulation of both classical and non-classical HLA class II proteins (DR and DM) in B-lymphoma cells. Resv also altered endolysosomal cathepsins (Cat S, B and D) and a thiol reductase (GILT), increasing HLA class II-mediated antigen (Ag) processing in B-cell lymphomas and their subsequent recognition by CD4+ T cells. Mechanistic study demonstrated that Resv treatment activated the recycling class II pathway of Ag presentation through upregulation of Rab 4B protein expression in B-lymphoma cells. These findings suggest that HLA class II-mediated immune recognition of malignant B-cells can be improved by Resv treatment, thus encouraging its potential use in chemoimmunotherapy of B-cell lymphoma. PMID:21854084

Disruption of HLA class II antigen presentation in Burkitt lymphoma: implication of a 47 000 MW acid labile protein in CD4+ T-cell recognition

PubMed Central

God, Jason M; Zhao, Dan; Cameron, Christine A; Amria, Shereen; Bethard, Jennifer R; Haque, Azizul

2014-01-01

While Burkitt lymphoma (BL) has a well-known defect in HLA class I-mediated antigen presentation, the exact role of BL-associated HLA class II in generating a poor CD4+ T-cell response remains unresolved. Here, we found that BL cells are deficient in their ability to optimally stimulate CD4+ T cells via the HLA class II pathway. This defect in CD4+ T-cell recognition was not associated with low levels of co-stimulatory molecules on BL cells, as addition of external co-stimulation failed to elicit CD4+ T-cell activation by BL. Further, the defect was not caused by faulty antigen/class II interaction, because antigenic peptides bound with measurable affinity to BL-associated class II molecules. Interestingly, functional class II–peptide complexes were formed at acidic pH 5·5, which restored immune recognition. Acidic buffer (pH 5·5) eluate from BL cells contained molecules that impaired class II-mediated antigen presentation and CD4+ T-cell recognition. Biochemical analysis showed that these molecules were greater than 30 000 molecular weight in size, and proteinaceous in nature. In addition, BL was found to have decreased expression of a 47 000 molecular weight enolase-like molecule that enhances class II-mediated antigen presentation in B cells, macrophages and dendritic cells, but not in BL cells. These findings demonstrate that BL likely has multiple defects in HLA class II-mediated antigen presentation and immune recognition, which may be exploited for future immunotherapies. PMID:24628049

A new hand-held microfluidic cytometer for evaluating irradiation damage by analysis of the damaged cells distribution.

PubMed

Wang, Junsheng; Fan, Zhiqiang; Zhao, Yile; Song, Younan; Chu, Hui; Song, Wendong; Song, Yongxin; Pan, Xinxiang; Sun, Yeqing; Li, Dongqing

2016-03-17

Space radiation brings uneven damages to cells. The detection of the distribution of cell damage plays a very important role in radiation medicine and the related research. In this paper, a new hand-held microfluidic flow cytometer was developed to evaluate the degree of radiation damage of cells. The device we propose overcomes the shortcomings (e.g., large volume and high cost) of commercial flow cytometers and can evaluate the radiation damage of cells accurately and quickly with potential for onsite applications. The distribution of radiation-damaged cells is analyzed by a simultaneous detection of immunofluorescence intensity of γ-H2AX and resistance pulse sensor (RPS) signal. The γ-H2AX fluorescence intensity provides information of the degree of radiation damage in cells. The ratio of the number of cells with γ-H2AX fluorescence signals to the total numbers of cells detected by RPS indicates the percentage of the cells that are damaged by radiation. The comparison experiment between the developed hand-held microfluidic flow cytometer and a commercial confocal microscope indicates a consistent and comparable detection performance.

A new hand-held microfluidic cytometer for evaluating irradiation damage by analysis of the damaged cells distribution

NASA Astrophysics Data System (ADS)

Wang, Junsheng; Fan, Zhiqiang; Zhao, Yile; Song, Younan; Chu, Hui; Song, Wendong; Song, Yongxin; Pan, Xinxiang; Sun, Yeqing; Li, Dongqing

2016-03-01

Space radiation brings uneven damages to cells. The detection of the distribution of cell damage plays a very important role in radiation medicine and the related research. In this paper, a new hand-held microfluidic flow cytometer was developed to evaluate the degree of radiation damage of cells. The device we propose overcomes the shortcomings (e.g., large volume and high cost) of commercial flow cytometers and can evaluate the radiation damage of cells accurately and quickly with potential for onsite applications. The distribution of radiation-damaged cells is analyzed by a simultaneous detection of immunofluorescence intensity of γ-H2AX and resistance pulse sensor (RPS) signal. The γ-H2AX fluorescence intensity provides information of the degree of radiation damage in cells. The ratio of the number of cells with γ-H2AX fluorescence signals to the total numbers of cells detected by RPS indicates the percentage of the cells that are damaged by radiation. The comparison experiment between the developed hand-held microfluidic flow cytometer and a commercial confocal microscope indicates a consistent and comparable detection performance.

Cell damage evaluation of mammalian cells in cell manipulation by amplified femtosecond ytterbium laser

NASA Astrophysics Data System (ADS)

Hong, Z.-Y.; Iino, T.; Hagihara, H.; Maeno, T.; Okano, K.; Yasukuni, R.; Hosokawa, Y.

2018-03-01

A micrometer-scale explosion with cavitation bubble generation is induced by focusing a femtosecond laser in an aqueous solution. We have proposed to apply the explosion as an impulsive force to manipulate mammalian cells especially in microfluidic chip. Herein, we employed an amplified femtosecond ytterbium laser as an excitation source for the explosion and evaluated cell damage in the manipulation process to clarify the application potential. The damage of C2C12 myoblast cell prepared as a representative mammalian cell was investigated as a function of distance between cell and laser focal point. Although the cell received strong damage on the direct laser irradiation condition, the damage sharply decreased with increasing distance. Since the threshold distance, above which the cell had no damage, was consistent with radius of the cavitation bubble, impact of the cavitation bubble would be a critical factor for the cell damage. The damage had strong nonlinearity in the pulse energy dependence. On the other hand, cell position shift by the impact of the cavitation bubble was almost proportional to the pulse energy. In balance between the cell viability and the cell position shift, we elucidated controllability of the cell manipulation in microfluidic chip.

[Computer diagnosis of traumatic impact by hepatic lesion].

PubMed

Kimbar, V I; Sevankeev, V V

2007-01-01

A method of computer-assisted diagnosis of traumatic affection by liver damage (HEPAR-test program) is described. The program is based on calculated diagnostic coefficients using Bayes' probability method with Wald's recognition procedure.

Impairment of recollection but not familiarity in a case of developmental amnesia.

PubMed

Brandt, Karen R; Gardiner, John M; Vargha-Khadem, Faraneh; Baddeley, Alan D; Mishkin, Mortimer

2008-01-01

In a re-examination of the recognition memory of Jon, a young adult with developmental amnesia due to perinatal hippocampal damage, we used a test procedure that provides estimates of the separate contributions to recognition of recollection and familiarity. Comparison between Jon and his controls revealed that, whereas he was unimpaired in the familiarity process, he showed abnormally low levels of recollection, supporting the view that the hippocampus mediates the latter process selectively.

Machine recognition of navel orange worm damage in x-ray images of pistachio nuts

NASA Astrophysics Data System (ADS)

Keagy, Pamela M.; Parvin, Bahram; Schatzki, Thomas F.

1995-01-01

Insect infestation increases the probability of aflatoxin contamination in pistachio nuts. A non- destructive test is currently not available to determine the insect content of pistachio nuts. This paper uses film X-ray images of various types of pistachio nuts to assess the possibility of machine recognition of insect infested nuts. Histogram parameters of four derived images are used in discriminant functions to select insect infested nuts from specific processing streams.

Bioelectric Control of a 757 Class High Fidelity Aircraft Simulation

NASA Technical Reports Server (NTRS)

Jorgensen, Charles; Wheeler, Kevin; Stepniewski, Slawomir; Norvig, Peter (Technical Monitor)

2000-01-01

This paper presents results of a recent experiment in fine grain Electromyographic (EMG) signal recognition, We demonstrate bioelectric flight control of 757 class simulation aircraft landing at San Francisco International Airport. The physical instrumentality of a pilot control stick is not used. A pilot closes a fist in empty air and performs control movements which are captured by a dry electrode array on the arm, analyzed and routed through a flight director permitting full pilot outer loop control of the simulation. A Vision Dome immersive display is used to create a VR world for the aircraft body mechanics and flight changes to pilot movements. Inner loop surfaces and differential aircraft thrust is controlled using a hybrid neural network architecture that combines a damage adaptive controller (Jorgensen 1998, Totah 1998) with a propulsion only based control system (Bull & Kaneshige 1997). Thus the 757 aircraft is not only being flown bioelectrically at the pilot level but also demonstrates damage adaptive neural network control permitting adaptation to severe changes in the physical flight characteristics of the aircraft at the inner loop level. To compensate for accident scenarios, the aircraft uses remaining control surface authority and differential thrust from the engines. To the best of our knowledge this is the first time real time bioelectric fine-grained control, differential thrust based control, and neural network damage adaptive control have been integrated into a single flight demonstration. The paper describes the EMG pattern recognition system and the bioelectric pattern recognition methodology.

Mechanism for recognition of polyubiquitin chains: balancing affinity through interplay between multivalent binding and dynamics.

PubMed

Markin, Craig J; Xiao, Wei; Spyracopoulos, Leo

2010-08-18

RAP80 plays a key role in signal transduction in the DNA damage response by recruiting proteins to DNA damage foci by binding K63-polyubiquitin chains with two tandem ubiquitin-interacting motifs (tUIM). It is generally recognized that the typically weak interaction between ubiquitin (Ub) and various recognition motifs is intensified by themes such as tandem recognition motifs and Ub polymerization to achieve biological relevance. However, it remains an intricate problem to develop a detailed molecular mechanism to describe the process that leads to amplification of the Ub signal. A battery of solution-state NMR methods and molecular dynamics simulations were used to demonstrate that RAP80-tUIM employs mono- and multivalent interactions with polyUb chains to achieve enhanced affinity in comparison to monoUb interactions for signal amplification. The enhanced affinity is balanced by unfavorable entropic effects that include partial quenching of rapid reorientation between individual UIM domains and individual Ub domains in the bound state. For the RAP80-tUIM-polyUb interaction, increases in affinity with increasing chain length are a result of increased numbers of mono- and multivalent binding sites in the longer polyUb chains. The mono- and multivalent interactions are characterized by intrinsically weak binding and fast off-rates; these weak interactions with fast kinetics may be an important factor underlying the transient nature of protein-protein interactions that comprise DNA damage foci.

Recognition mechanism of p63 by the E3 ligase Itch: novel strategy in the study and inhibition of this interaction.

PubMed

Bellomaria, Alessia; Barbato, Gaetano; Melino, Gerry; Paci, Maurizio; Melino, Sonia

2012-10-01

The HECT-containing E3 ubiquitin ligase Itch mediates the degradation of several proteins, including p63 and p73, involved in cell specification and fate. Itch contains four WW domains, which are essential for recognition on the target substrate, which contains a short proline-rich sequence. Several signaling complexes containing these domains have been associated with human diseases such as muscular dystrophy, Alzheimer's or Huntington's diseases. To gain further insight into the structural determinants of the Itch-WW2 domain, we investigated its interaction with p63. We assigned, by 3D heteronuclear NMR experiments, the backbone and side chains of the uniformly (13)C-(15)N-labeled Itch-WW2. In vitro interaction of Itch-WW2 domain with p63 was studied using its interactive p63 peptide, pep63. Pep63 is an 18-mer peptide corresponding to the region from 534-551 residue of p63, encompassing the PPxY motif that interacts with the Itch-WW domains, and we identified the residues involved in this molecular recognition. Moreover, here, a strategy of stabilization of the conformation of the PPxY peptide has been adopted, increasing the WW-ligand binding. We demonstrated that cyclization of pep63 leads to an increase of both the biological stability of the peptide and of the WW-ligand complex. Stable metal-binding complexes of the pep63 have been also obtained, and localized oxidative damage on Itch-WW2 domain has been induced, demonstrating the possibility of use of metal-pep63 complexes as models for the design of metal drugs to inhibit the Itch-WW-p63 recognition in vivo. Thus, our data suggest a novel strategy to study and inhibit the recognition mechanism of Itch E3-ligase.

Three-dimensional fingerprint recognition by using convolution neural network

NASA Astrophysics Data System (ADS)

Tian, Qianyu; Gao, Nan; Zhang, Zonghua

2018-01-01

With the development of science and technology and the improvement of social information, fingerprint recognition technology has become a hot research direction and been widely applied in many actual fields because of its feasibility and reliability. The traditional two-dimensional (2D) fingerprint recognition method relies on matching feature points. This method is not only time-consuming, but also lost three-dimensional (3D) information of fingerprint, with the fingerprint rotation, scaling, damage and other issues, a serious decline in robustness. To solve these problems, 3D fingerprint has been used to recognize human being. Because it is a new research field, there are still lots of challenging problems in 3D fingerprint recognition. This paper presents a new 3D fingerprint recognition method by using a convolution neural network (CNN). By combining 2D fingerprint and fingerprint depth map into CNN, and then through another CNN feature fusion, the characteristics of the fusion complete 3D fingerprint recognition after classification. This method not only can preserve 3D information of fingerprints, but also solves the problem of CNN input. Moreover, the recognition process is simpler than traditional feature point matching algorithm. 3D fingerprint recognition rate by using CNN is compared with other fingerprint recognition algorithms. The experimental results show that the proposed 3D fingerprint recognition method has good recognition rate and robustness.

Pattern-recognition receptors: signaling pathways and dysregulation in canine chronic enteropathies-brief review.

PubMed

Heilmann, Romy M; Allenspach, Karin

2017-11-01

Pattern-recognition receptors (PRRs) are expressed by innate immune cells and recognize pathogen-associated molecular patterns (PAMPs) as well as endogenous damage-associated molecular pattern (DAMP) molecules. With a large potential for synergism or convergence between their signaling pathways, PRRs orchestrate a complex interplay of cellular mediators and transcription factors, and thus play a central role in homeostasis and host defense. Aberrant activation of PRR signaling, mutations of the receptors and/or their downstream signaling molecules, and/or DAMP/PAMP complex-mediated receptor signaling can potentially lead to chronic auto-inflammatory diseases or development of cancer. PRR signaling pathways appear to also present an interesting new avenue for the modulation of inflammatory responses and to serve as potential novel therapeutic targets. Evidence for a dysregulation of the PRR toll-like receptor (TLR)2, TLR4, TLR5, and TLR9, nucleotide-binding oligomerization domain-containing protein (NOD)2, and the receptor of advanced glycation end products (RAGE) exists in dogs with chronic enteropathies. We describe the TLR, NOD2, and RAGE signaling pathways and evaluate the current veterinary literature-in comparison to human medicine-to determine the role of TLRs, NOD2, and RAGE in canine chronic enteropathies.

Complement in the Initiation and Evolution of Rheumatoid Arthritis

PubMed Central

Holers, V. Michael; Banda, Nirmal K.

2018-01-01

The complement system is a major component of the immune system and plays a central role in many protective immune processes, including circulating immune complex processing and clearance, recognition of foreign antigens, modulation of humoral and cellular immunity, removal of apoptotic and dead cells, and engagement of injury resolving and tissue regeneration processes. In stark contrast to these beneficial roles, however, inadequately controlled complement activation underlies the pathogenesis of human inflammatory and autoimmune diseases, including rheumatoid arthritis (RA) where the cartilage, bone, and synovium are targeted. Recent studies of this disease have demonstrated that the autoimmune response evolves over time in an asymptomatic preclinical phase that is associated with mucosal inflammation. Notably, experimental models of this disease have demonstrated that each of the three major complement activation pathways plays an important role in recognition of injured joint tissue, although the lectin and amplification pathways exhibit particularly impactful roles in the initiation and amplification of damage. Herein, we review the complement system and focus on its multi-factorial role in human patients with RA and experimental murine models. This understanding will be important to the successful integration of the emerging complement therapeutics pipeline into clinical care for patients with RA. PMID:29892280

Emerging technologies with potential for objectively evaluating speech recognition skills.

PubMed

Rawool, Vishakha Waman

2016-01-01

Work-related exposure to noise and other ototoxins can cause damage to the cochlea, synapses between the inner hair cells, the auditory nerve fibers, and higher auditory pathways, leading to difficulties in recognizing speech. Procedures designed to determine speech recognition scores (SRS) in an objective manner can be helpful in disability compensation cases where the worker claims to have poor speech perception due to exposure to noise or ototoxins. Such measures can also be helpful in determining SRS in individuals who cannot provide reliable responses to speech stimuli, including patients with Alzheimer's disease, traumatic brain injuries, and infants with and without hearing loss. Cost-effective neural monitoring hardware and software is being rapidly refined due to the high demand for neurogaming (games involving the use of brain-computer interfaces), health, and other applications. More specifically, two related advances in neuro-technology include relative ease in recording neural activity and availability of sophisticated analysing techniques. These techniques are reviewed in the current article and their applications for developing objective SRS procedures are proposed. Issues related to neuroaudioethics (ethics related to collection of neural data evoked by auditory stimuli including speech) and neurosecurity (preservation of a person's neural mechanisms and free will) are also discussed.

Modeling the Interaction between Quinolinate and the Receptor for Advanced Glycation End Products (RAGE): Relevance for Early Neuropathological Processes

PubMed Central

Serratos, Iris N.; Castellanos, Pilar; Pastor, Nina; Millán-Pacheco, César; Rembao, Daniel; Pérez-Montfort, Ruy; Cabrera, Nallely; Reyes-Espinosa, Francisco; Díaz-Garrido, Paulina; López-Macay, Ambar; Martínez-Flores, Karina; López-Reyes, Alberto; Sánchez-García, Aurora; Cuevas, Elvis; Santamaria, Abel

2015-01-01

The receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor involved in neurodegenerative and inflammatory disorders. RAGE induces cellular signaling upon binding to a variety of ligands. Evidence suggests that RAGE up-regulation is involved in quinolinate (QUIN)-induced toxicity. We investigated the QUIN-induced toxic events associated with early noxious responses, which might be linked to signaling cascades leading to cell death. The extent of early cellular damage caused by this receptor in the rat striatum was characterized by image processing methods. To document the direct interaction between QUIN and RAGE, we determined the binding constant (Kb) of RAGE (VC1 domain) with QUIN through a fluorescence assay. We modeled possible binding sites of QUIN to the VC1 domain for both rat and human RAGE. QUIN was found to bind at multiple sites to the VC1 dimer, each leading to particular mechanistic scenarios for the signaling evoked by QUIN binding, some of which directly alter RAGE oligomerization. This work contributes to the understanding of the phenomenon of RAGE-QUIN recognition, leading to the modulation of RAGE function. PMID:25757085

Toll-Like Receptors in Secondary Obstructive Cholangiopathy

PubMed Central

Miranda-Díaz, A. G.; Alonso-Martínez, H.; Hernández-Ojeda, J.; Arias-Carvajal, O.; Rodríguez-Carrizalez, A. D.; Román-Pintos, L. M.

2011-01-01

Secondary obstructive cholangiopathy is characterized by intra- or extrahepatic bile tract obstruction. Liver inflammation and structural alterations develop due to progressive bile stagnation. Most frequent etiologies are biliary atresia in children, and hepatolithiasis, postcholecystectomy bile duct injury, and biliary primary cirrhosis in adults, which causes chronic biliary cholangitis. Bile ectasia predisposes to multiple pathogens: viral infections in biliary atresia; Gram-positive and/or Gram-negative bacteria cholangitis found in hepatolithiasis and postcholecystectomy bile duct injury. Transmembrane toll-like receptors (TLRs) are activated by virus, bacteria, fungi, and parasite stimuli. Even though TLR-2 and TLR-4 are the most studied receptors related to liver infectious diseases, other TLRs play an important role in response to microorganism damage. Acquired immune response is not vertically transmitted and reflects the infectious diseases history of individuals; in contrast, innate immunity is based on antigen recognition by specific receptors designated as pattern recognition receptors and is transmitted vertically through the germ cells. Understanding the mechanisms for bile duct inflammation is essential for the future development of therapeutic alternatives in order to avoid immune-mediated destruction on secondary obstructive cholangiopathy. The role of TLRs in biliary atresia, hepatolithiasis, bile duct injury, and primary biliary cirrhosis is described in this paper. PMID:22114589

Unstable solar lentigo: A defined separate entity.

PubMed

Byrom, Lisa; Barksdale, Sarah; Weedon, David; Muir, Jim

2016-08-01

An unstable solar lentigo is a solar lentigo with areas of melanocytic hyperplasia not extending past the margin of the lesion. They are discrete, macular, pigmented lesions arising on sun-damaged skin and a subset of typical solar lentigos. Clinically they differ from usual solar lentigines in often being solitary or larger and darker than adjacent solar lentigines. These lesions are of clinical importance as they can arise in close proximity to lentigo maligna and in a single lesion there can be demonstrated changes of solar lentigo, unstable solar lentigo and lentigo maligna. These observations led us to conjecture that unstable solar lentigos could be a precursor lesion to lentigo maligna. In this article we examine the possibility that lentigo maligna can arise within a solar lentigo through an intermediate lesion, the unstable solar lentigo. We propose that the histopathological recognition of this entity will allow for future research into its behaviour and thus management. We review difficulties in the diagnosis of single cell predominant melanocytic proliferations and the concept of unstable lentigo in view of the literature and clinical experience supporting the proposal of its recognition as a separate entity. © 2016 The Australasian College of Dermatologists.

Speech recognition systems on the Cell Broadband Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Y; Jones, H; Vaidya, S

In this paper we describe our design, implementation, and first results of a prototype connected-phoneme-based speech recognition system on the Cell Broadband Engine{trademark} (Cell/B.E.). Automatic speech recognition decodes speech samples into plain text (other representations are possible) and must process samples at real-time rates. Fortunately, the computational tasks involved in this pipeline are highly data-parallel and can receive significant hardware acceleration from vector-streaming architectures such as the Cell/B.E. Identifying and exploiting these parallelism opportunities is challenging, but also critical to improving system performance. We observed, from our initial performance timings, that a single Cell/B.E. processor can recognize speech from thousandsmore » of simultaneous voice channels in real time--a channel density that is orders-of-magnitude greater than the capacity of existing software speech recognizers based on CPUs (central processing units). This result emphasizes the potential for Cell/B.E.-based speech recognition and will likely lead to the future development of production speech systems using Cell/B.E. clusters.« less

Orchestration of DNA Damage Checkpoint Dynamics across the Human Cell Cycle.

PubMed

Chao, Hui Xiao; Poovey, Cere E; Privette, Ashley A; Grant, Gavin D; Chao, Hui Yan; Cook, Jeanette G; Purvis, Jeremy E

2017-11-22

Although molecular mechanisms that prompt cell-cycle arrest in response to DNA damage have been elucidated, the systems-level properties of DNA damage checkpoints are not understood. Here, using time-lapse microscopy and simulations that model the cell cycle as a series of Poisson processes, we characterize DNA damage checkpoints in individual, asynchronously proliferating cells. We demonstrate that, within early G1 and G2, checkpoints are stringent: DNA damage triggers an abrupt, all-or-none cell-cycle arrest. The duration of this arrest correlates with the severity of DNA damage. After the cell passes commitment points within G1 and G2, checkpoint stringency is relaxed. By contrast, all of S phase is comparatively insensitive to DNA damage. This checkpoint is graded: instead of halting the cell cycle, increasing DNA damage leads to slower S phase progression. In sum, we show that a cell's response to DNA damage depends on its exact cell-cycle position and that checkpoints are phase-dependent, stringent or relaxed, and graded or all-or-none. Copyright © 2017 Elsevier Inc. All rights reserved.

The RNA recognition motif domains of RBM5 are required for RNA binding and cancer cell proliferation inhibition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Lei; Zhang, Qing; Yang, Yu

Highlights: • RNA recognition motif domains of RBM5 are essential for cell proliferation inhibition. • RNA recognition motif domains of RBM5 are essential for apoptosis induction. • RNA recognition motif domains of RBM5 are essential for RNA binding. • RNA recognition motif domains of RBM5 are essential for caspase-2 alternative splicing. - Abstract: RBM5 is a known putative tumor suppressor gene that has been shown to function in cell growth inhibition by modulating apoptosis. RBM5 also plays a critical role in alternative splicing as an RNA binding protein. However, it is still unclear which domains of RBM5 are required formore » RNA binding and related functional activities. We hypothesized the two putative RNA recognition motif (RRM) domains of RBM5 spanning from amino acids 98–178 and 231–315 are essential for RBM5-mediated cell growth inhibition, apoptosis regulation, and RNA binding. To investigate this hypothesis, we evaluated the activities of the wide-type and mutant RBM5 gene transfer in low-RBM5 expressing A549 cells. We found that, unlike wild-type RBM5 (RBM5-wt), a RBM5 mutant lacking the two RRM domains (RBM5-ΔRRM), is unable to bind RNA, has compromised caspase-2 alternative splicing activity, lacks cell proliferation inhibition and apoptosis induction function in A549 cells. These data provide direct evidence that the two RRM domains of RBM5 are required for RNA binding and the RNA binding activity of RBM5 contributes to its function on apoptosis induction and cell growth inhibition.« less

Recognition and classification of colon cells applying the ensemble of classifiers.

PubMed

Kruk, M; Osowski, S; Koktysz, R

2009-02-01

The paper presents the application of an ensemble of classifiers for the recognition of colon cells on the basis of the microscope colon image. The solved task include: segmentation of the individual cells from the image using the morphological operations, the preprocessing stages, leading to the extraction of features, selection of the most important features, and the classification stage applying the classifiers arranged in the form of ensemble. The paper presents and discusses the results concerning the recognition of four most important colon cell types: eosinophylic granulocyte, neutrophilic granulocyte, lymphocyte and plasmocyte. The proposed system is able to recognize the cells with the accuracy comparable to the human expert (around 5% of discrepancy of both results).

Host Innate Immunity against Hepatitis E Virus and Viral Evasion Mechanisms.

PubMed

Kang, Sangmin; Myoung, Jinjong

2017-10-28

Hepatitis E virus (HEV) infections cause epidemic or sporadic acute hepatitis, which are mostly self-limiting. However, viral infection in immunocompromised patients and pregnant women may result in serious consequences, such as chronic hepatitis and liver damage, mortality of the latter of which reaches up to 20-30%. Type I interferon (IFN)-induced antiviral immunity is known to be the first-line defense against virus infection. Upon HEV infection in the cell, the virus genome is recognized by pathogen recognition receptors, leading to rapid activation of intracellular signaling cascades. Expression of type I IFN triggers induction of a barrage of IFN-stimulated genes, helping the cells cope with viral infection. Interestingly, some of the HEV-encoded genes seem to be involved in disrupting signaling cascades for antiviral immune responses, and thus crippling cytokine/chemokine production. Antagonistic mechanisms of type I IFN responses by HEV have only recently begun to emerge, and in this review, we summarize known HEV evasion strategies and compare them with those of other hepatitis viruses.

Exploring family communication about sickle cell disease in adolescence.

PubMed

Graff, J Carolyn; Hankins, Jane; Graves, Rebecca J; Robitaille, Kimberly Y; Roberts, Ruth; Cejda, Katherine; Hardy, Belinda T; Johnson, Margery; Porter, Jerlym S

2012-01-01

Sickle cell disease (SCD) is a lifelong disorder that involves progressive organ damage and requires ongoing medical attention to prevent and treat episodic acute complications. Children with SCD need ongoing monitoring and extra attention that may be stressful to family members. Communication within families can help resolve family stress and may be associated with medical follow-up and management of SCD. Focus groups were conducted with 12 African American families to explore the communication that occurred within and outside of the family from the perspectives of adolescents with SCD, siblings, and parents. Factors that influence family communication were explored. The extended family was an important social network and resource to adolescents, siblings, and parents. Family member knowledge of SCD was an important factor that influenced communication about SCD; adolescents and parents communicated more easily than siblings and also reported having more knowledge of SCD than siblings. Future research focusing on the knowledge of immediate and extended family members and their recognition of their contribution to the child with SCD is recommended.

[Immune response in cervical cancer. Strategies for the development of therapeutic vaccines].

PubMed

Mora-García, María Lourdes; Monroy-García, Alberto

2015-01-01

High-risk human papillomaviruses (HR-HPV), as HPV-16, evade immune recognition through the inactivation of cells of the innate immune response. HPV-16 E6 and E7 genes down-regulate type I interferon response. They do not produce viremia or cell death; therefore, they do not cause inflammation or damage signal that alerts the immune system. Virus-like particles (VLPs), consisting of structural proteins (L1 and L2) of the main HR-HPV types that infect the genitourinary tract, are the most effective prophylactic vaccines against HR-HPV infection. While for the high grade neoplastic lesions, therapeutic vaccines based on viral vectors, peptides, DNA or complete HR-HPV E6 and E7 proteins as antigens, have had limited effectiveness. Chimeric virus-like particles (cVLPs) that carry immunogenic peptides derived from E6 and E7 viral proteins, capable to induce activation of specific cytotoxic T lymphocytes, emerge as an important alternative to provide prophylactic and therapeutic activity against HR-HPV infection and cervical cancer.

Evaluation of the damage of cell wall and cell membrane for various extracellular polymeric substance extractions of activated sludge.

PubMed

Guo, Xuesong; Liu, Junxin; Xiao, Benyi

2014-10-20

Extracellular polymeric substances (EPS) are susceptible to contamination by intracellular substances released during the extraction of EPS owing to the damage caused to microbial cell structures. The damage to cell walls and cell membranes in nine EPS extraction processes of activated sludge was evaluated in this study. The extraction of EPS (including proteins, carbohydrates and DNA) was the highest using the NaOH extraction method and the lowest using formaldehyde extraction. All nine EPS extraction methods in this study resulted in cell wall and membrane damage. The damage to cell walls, evaluated by 2-keto-3-deoxyoctonate (KDO) and N-acetylglucosamine content changes in extracted EPS, was the most significant in the NaOH extraction process. Formaldehyde extraction showed a similar extent of damage to cell walls to those detected in the control method (centrifugation), while those in the formaldehyde-NaOH and cation exchange resin extractions were slightly higher than those detected in the control. N-acetylglucosamine was more suitable than KDO for the evaluation of cell wall damage in the EPS extraction of activated sludge. The damage to cell membranes was characterized by two fluorochromes (propidium iodide and FITC Annexin V) with flow cytometry (FCM) measurement. The highest proportion of membrane-damaged cells was detected in NaOH extraction (26.54% of total cells) while membrane-damaged cells comprised 8.19% of total cells in the control. Copyright © 2014 Elsevier B.V. All rights reserved.

Damage classification and estimation in experimental structures using time series analysis and pattern recognition

NASA Astrophysics Data System (ADS)

de Lautour, Oliver R.; Omenzetter, Piotr

2010-07-01

Developed for studying long sequences of regularly sampled data, time series analysis methods are being increasingly investigated for the use of Structural Health Monitoring (SHM). In this research, Autoregressive (AR) models were used to fit the acceleration time histories obtained from two experimental structures: a 3-storey bookshelf structure and the ASCE Phase II Experimental SHM Benchmark Structure, in undamaged and limited number of damaged states. The coefficients of the AR models were considered to be damage-sensitive features and used as input into an Artificial Neural Network (ANN). The ANN was trained to classify damage cases or estimate remaining structural stiffness. The results showed that the combination of AR models and ANNs are efficient tools for damage classification and estimation, and perform well using small number of damage-sensitive features and limited sensors.

Emotion recognition deficits associated with ventromedial prefrontal cortex lesions are improved by gaze manipulation.

PubMed

Wolf, Richard C; Pujara, Maia; Baskaya, Mustafa K; Koenigs, Michael

2016-09-01

Facial emotion recognition is a critical aspect of human communication. Since abnormalities in facial emotion recognition are associated with social and affective impairment in a variety of psychiatric and neurological conditions, identifying the neural substrates and psychological processes underlying facial emotion recognition will help advance basic and translational research on social-affective function. Ventromedial prefrontal cortex (vmPFC) has recently been implicated in deploying visual attention to the eyes of emotional faces, although there is mixed evidence regarding the importance of this brain region for recognition accuracy. In the present study of neurological patients with vmPFC damage, we used an emotion recognition task with morphed facial expressions of varying intensities to determine (1) whether vmPFC is essential for emotion recognition accuracy, and (2) whether instructed attention to the eyes of faces would be sufficient to improve any accuracy deficits. We found that vmPFC lesion patients are impaired, relative to neurologically healthy adults, at recognizing moderate intensity expressions of anger and that recognition accuracy can be improved by providing instructions of where to fixate. These results suggest that vmPFC may be important for the recognition of facial emotion through a role in guiding visual attention to emotionally salient regions of faces. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Novel Rrm3 Function in Restricting DNA Replication via an Orc5-Binding Domain Is Genetically Separable from Rrm3 Function as an ATPase/Helicase in Facilitating Fork Progression.

PubMed

Syed, Salahuddin; Desler, Claus; Rasmussen, Lene J; Schmidt, Kristina H

2016-12-01

In response to replication stress cells activate the intra-S checkpoint, induce DNA repair pathways, increase nucleotide levels, and inhibit origin firing. Here, we report that Rrm3 associates with a subset of replication origins and controls DNA synthesis during replication stress. The N-terminal domain required for control of DNA synthesis maps to residues 186-212 that are also critical for binding Orc5 of the origin recognition complex. Deletion of this domain is lethal to cells lacking the replication checkpoint mediator Mrc1 and leads to mutations upon exposure to the replication stressor hydroxyurea. This novel Rrm3 function is independent of its established role as an ATPase/helicase in facilitating replication fork progression through polymerase blocking obstacles. Using quantitative mass spectrometry and genetic analyses, we find that the homologous recombination factor Rdh54 and Rad5-dependent error-free DNA damage bypass act as independent mechanisms on DNA lesions that arise when Rrm3 catalytic activity is disrupted whereas these mechanisms are dispensable for DNA damage tolerance when the replication function is disrupted, indicating that the DNA lesions generated by the loss of each Rrm3 function are distinct. Although both lesion types activate the DNA-damage checkpoint, we find that the resultant increase in nucleotide levels is not sufficient for continued DNA synthesis under replication stress. Together, our findings suggest a role of Rrm3, via its Orc5-binding domain, in restricting DNA synthesis that is genetically and physically separable from its established catalytic role in facilitating fork progression through replication blocks.

A Novel Rrm3 Function in Restricting DNA Replication via an Orc5-Binding Domain Is Genetically Separable from Rrm3 Function as an ATPase/Helicase in Facilitating Fork Progression

PubMed Central

Syed, Salahuddin; Desler, Claus; Rasmussen, Lene J.; Schmidt, Kristina H.

2016-01-01

In response to replication stress cells activate the intra-S checkpoint, induce DNA repair pathways, increase nucleotide levels, and inhibit origin firing. Here, we report that Rrm3 associates with a subset of replication origins and controls DNA synthesis during replication stress. The N-terminal domain required for control of DNA synthesis maps to residues 186–212 that are also critical for binding Orc5 of the origin recognition complex. Deletion of this domain is lethal to cells lacking the replication checkpoint mediator Mrc1 and leads to mutations upon exposure to the replication stressor hydroxyurea. This novel Rrm3 function is independent of its established role as an ATPase/helicase in facilitating replication fork progression through polymerase blocking obstacles. Using quantitative mass spectrometry and genetic analyses, we find that the homologous recombination factor Rdh54 and Rad5-dependent error-free DNA damage bypass act as independent mechanisms on DNA lesions that arise when Rrm3 catalytic activity is disrupted whereas these mechanisms are dispensable for DNA damage tolerance when the replication function is disrupted, indicating that the DNA lesions generated by the loss of each Rrm3 function are distinct. Although both lesion types activate the DNA-damage checkpoint, we find that the resultant increase in nucleotide levels is not sufficient for continued DNA synthesis under replication stress. Together, our findings suggest a role of Rrm3, via its Orc5-binding domain, in restricting DNA synthesis that is genetically and physically separable from its established catalytic role in facilitating fork progression through replication blocks. PMID:27923055

Sensor histidine kinase is a β-lactam receptor and induces resistance to β-lactam antibiotics.

PubMed

Li, Lu; Wang, Qiyao; Zhang, Hui; Yang, Minjun; Khan, Mazhar I; Zhou, Xiaohui

2016-02-09

β-Lactams disrupt bacterial cell wall synthesis, and these agents are the most widely used antibiotics. One of the principle mechanisms by which bacteria resist the action of β-lactams is by producing β-lactamases, enzymes that degrade β-lactams. In Gram-negative bacteria, production of β-lactamases is often induced in response to the antibiotic-associated damage to the cell wall. Here, we have identified a previously unidentified mechanism that governs β-lactamase production. In the Gram-negative enteric pathogen Vibrio parahaemolyticus, we found a histidine kinase/response regulator pair (VbrK/VbrR) that controls expression of a β-lactamase. Mutants lacking either VbrK or VbrR do not produce the β-lactamase and are no longer resistant to β-lactam antibiotics. Notably, VbrK autophosphorylation is activated by β-lactam antibiotics, but not by other lactams. However, single amino acid substitutions in the putative periplasmic binding pocket of VbrK leads its phosphorylation in response to both β-lactam and other lactams, suggesting that this kinase is a β-lactam receptor that can directly detect β-lactam antibiotics instead of detecting the damage to cell wall resulting from β-lactams. In strong support of this idea, we found that purified periplasmic sensor domain of VbrK binds penicillin, and that such binding is critical for VbrK autophosphorylation and β-lactamase production. Direct recognition of β-lactam antibiotics by a histidine kinase receptor may represent an evolutionarily favorable mechanism to defend against β-lactam antibiotics.

Drug-induced lung injury associated with sorafenib: analysis of all-patient post-marketing surveillance in Japan.

PubMed

Horiuchi-Yamamoto, Yuka; Gemma, Akihiko; Taniguchi, Hiroyuki; Inoue, Yoshikazu; Sakai, Fumikazu; Johkoh, Takeshi; Fujimoto, Kiminori; Kudoh, Shoji

2013-08-01

Sorafenib is a multi-kinase inhibitor currently approved in Japan for unresectable and/or metastatic renal cell carcinoma and unresectable hepatocellular carcinoma. Although drug-induced lung injury has recently been the focus of interest in Japanese patients treated with molecular targeting agents, the clinical features of patients receiving sorafenib remain to be completely investigated. All-patient post-marketing surveillance data was obtained within the frame of Special Drug Use Investigation; between April 2008 and March 2011, we summarized the clinical information of 62 cases with drug-induced lung injury among approximately 13,600 sorafenib-treated patients in Japan. In addition, we summarized the results of evaluation by a safety board of Japanese experts in 34 patients in whom pulmonary images were available. For the calculation of reporting frequency, interim results of Special Drug Use Investigation were used. In the sets of completed reports (2,407 in renal cell carcinoma and 647 in hepatocellular carcinoma), the reporting frequency was 0.33 % (8 patients; fatal, 4/8) and 0.62 % (4 patients; fatal, 2/4), respectively. Major clinical symptoms included dyspnea, cough, and fever. Evaluation of the images showed that 18 cases out of 34 patients had a pattern of diffuse alveolar damage. The patients with hepatocellular carcinoma showed a greater incidence and earlier onset of lung injury than those with renal cell carcinoma. Although the overall reporting frequency of sorafenib-induced lung injury is not considered high, the radiological diffuse alveolar damage pattern led to a fatal outcome. Therefore, early recognition of sorafenib-induced lung injury is crucial for physicians and patients.

Sensor histidine kinase is a β-lactam receptor and induces resistance to β-lactam antibiotics

PubMed Central

Li, Lu; Wang, Qiyao; Zhang, Hui; Yang, Minjun; Khan, Mazhar I.; Zhou, Xiaohui

2016-01-01

β-Lactams disrupt bacterial cell wall synthesis, and these agents are the most widely used antibiotics. One of the principle mechanisms by which bacteria resist the action of β-lactams is by producing β-lactamases, enzymes that degrade β-lactams. In Gram-negative bacteria, production of β-lactamases is often induced in response to the antibiotic-associated damage to the cell wall. Here, we have identified a previously unidentified mechanism that governs β-lactamase production. In the Gram-negative enteric pathogen Vibrio parahaemolyticus, we found a histidine kinase/response regulator pair (VbrK/VbrR) that controls expression of a β-lactamase. Mutants lacking either VbrK or VbrR do not produce the β-lactamase and are no longer resistant to β-lactam antibiotics. Notably, VbrK autophosphorylation is activated by β-lactam antibiotics, but not by other lactams. However, single amino acid substitutions in the putative periplasmic binding pocket of VbrK leads its phosphorylation in response to both β-lactam and other lactams, suggesting that this kinase is a β-lactam receptor that can directly detect β-lactam antibiotics instead of detecting the damage to cell wall resulting from β-lactams. In strong support of this idea, we found that purified periplasmic sensor domain of VbrK binds penicillin, and that such binding is critical for VbrK autophosphorylation and β-lactamase production. Direct recognition of β-lactam antibiotics by a histidine kinase receptor may represent an evolutionarily favorable mechanism to defend against β-lactam antibiotics. PMID:26831117

Emotional System for Military Target Identification

DTIC Science & Technology

2009-10-01

algorithm [23], and used it to solve a facial recognition problem. In other works [24,25], we explored the potential of using emotional neural...other application areas, such as security ( facial recognition ) and medical (blood cell identification), can be also efficiently used in military...Application of an emotional neural network to facial recognition . Neural Computing and Applications, 18(4), 309-320. [25] Khashman, A. (2009). Blood cell

Unraveling the non-senescence phenomenon in Hydra.

PubMed

Dańko, Maciej J; Kozłowski, Jan; Schaible, Ralf

2015-10-07

Unlike other metazoans, Hydra does not experience the distinctive rise in mortality with age known as senescence, which results from an increasing imbalance between cell damage and cell repair. We propose that the Hydra controls damage accumulation mainly through damage-dependent cell selection and cell sloughing. We examine our hypothesis with a model that combines cellular damage with stem cell renewal, differentiation, and elimination. The Hydra individual can be seen as a large single pool of three types of stem cells with some features of differentiated cells. This large stem cell community prevents "cellular damage drift," which is inevitable in complex conglomerate (differentiated) metazoans with numerous and generally isolated pools of stem cells. The process of cellular damage drift is based on changes in the distribution of damage among cells due to random events, and is thus similar to Muller's ratchet in asexual populations. Events in the model that are sources of randomness include budding, cellular death, and cellular damage and repair. Our results suggest that non-senescence is possible only in simple Hydra-like organisms which have a high proportion and number of stem cells, continuous cell divisions, an effective cell selection mechanism, and stem cells with the ability to undertake some roles of differentiated cells. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Enhancement of cell recognition in vitro by dual-ligand cancer targeting gold naoparticles

PubMed Central

Li, Xi; Zhou, Hongyu; Yang, Lei; Du, Guoqing; Pai-Panandiker, Atmaram; Huang, Xuefei; Yan, Bing

2011-01-01

A dual-ligand gold nanoparticle (DLGNP) was designed and synthesized to explore the therapeutic benefits of multivalent interactions between gold nanoparticles (GNPs) and cancer cells. DLGNP was tested on human epidermal cancer cells (KB), which had high expression of folate receptor. The cellular uptake of DLGNP was increased by 3.9 and 12.7 folds compared with GNP-folate or GNP-glucose. The enhanced cell recognition was due to multivalent interactions between both ligands on GNPs and cancer cells as shown by the ligand competition experiments. Furthermore, the multivalent interactions increased contrast between cells with high and low expression of folate receptors. The enhanced cell recognition enabled DLGNP to kill KB cells under X-ray irradiation at a dose that was safe to folate receptor low-expression (such as normal) cells. Thus DLGP has the potential to be a cancer-specific nano-theranostic agent. PMID:21232787

Impact of TLR4 on behavioral and cognitive dysfunctions associated with alcohol-induced neuroinflammatory damage.

PubMed

Pascual, María; Baliño, Pablo; Alfonso-Loeches, Silvia; Aragón, Carlos M G; Guerri, Consuelo

2011-06-01

Toll-like receptors (TLRs) play an important role in the innate immune response, and emerging evidence indicates their role in brain injury and neurodegeneration. Our recent results have demonstrated that ethanol is capable of activating glial TLR4 receptors and that the elimination of these receptors in mice protects against ethanol-induced glial activation, induction of inflammatory mediators and apoptosis. This study was designed to assess whether ethanol-induced inflammatory damage causes behavioral and cognitive consequences, and if behavioral alterations are dependent of TLR4 functions. Here we show in mice drinking alcohol for 5months, followed by a 15-day withdrawal period, that activation of the astroglial and microglial cells in frontal cortex and striatum is maintained and that these events are associated with cognitive and anxiety-related behavioral impairments in wild-type (WT) mice, as demonstrated by testing the animals with object memory recognition, conditioned taste aversion and dark and light box anxiety tasks. Mice lacking TLR4 receptors are protected against ethanol-induced inflammatory damage, and behavioral associated effects. We further assess the possibility of the epigenetic modifications participating in short- or long-term behavioral effects associated with neuroinflammatory damage. We show that chronic alcohol treatment decreases H4 histone acetylation and histone acetyltransferases activity in frontal cortex, striatum and hippocampus of WT mice. Alterations in chromatin structure were not observed in TLR4(-/-) mice. These results provide the first evidence of the role that TLR4 functions play in the behavioral consequences of alcohol-induced inflammatory damage and suggest that the epigenetic modifications mediated by TLR4 could contribute to short- or long-term alcohol-induced behavioral or cognitive dysfunctions. Copyright © 2011 Elsevier Inc. All rights reserved.

Differences in antigen presentation to MHC class I-and class II- restricted influenza virus-specific cytolytic T lymphocyte clones

PubMed Central

1986-01-01

We have examined requirements for antigen presentation to a panel of MHC class I-and class II-restricted, influenza virus-specific CTL clones by controlling the form of virus presented on the target cell surface. Both H-2K/D- and I region-restricted CTL recognize target cells exposed to infectious virus, but only the I region-restricted clones efficiently lysed histocompatible target cells pulsed with inactivated virus preparations. The isolated influenza hemagglutinin (HA) polypeptide also could sensitize target cells for recognition by class II-restricted, HA-specific CTL, but not by class I-restricted, HA- specific CTL. Inhibition of nascent viral protein synthesis abrogated the ability of target cells to present viral antigen relevant for class I-restricted CTL recognition. Significantly, presentation for class II- restricted recognition was unaffected in target cells exposed to preparations of either inactivated or infectious virus. This differential sensitivity suggested that these H-2I region-restricted CTL recognized viral polypeptides derived from the exogenously introduced virions, rather than viral polypeptides newly synthesized in the infected cell. In support of this contention, treatment of the target cells with the lysosomotropic agent chloroquine abolished recognition of infected target cells by class II-restricted CTL without diminishing class I-restricted recognition of infected target cells. Furthermore, when the influenza HA gene was introduced into target cells without exogenous HA polypeptide, the target cells that expressed the newly synthesized protein product of the HA gene were recognized only by H-2K/D-restricted CTL. These observations suggest that important differences may exist in requirements for antigen presentation between H-2K/D and H-2I region-restricted CTL. These differences may reflect the nature of the antigenic epitopes recognized by these two CTL subsets. PMID:3485173

Impact of genomic damage and ageing on stem cell function

PubMed Central

Behrens, Axel; van Deursen, Jan M.; Rudolph, K. Lenhard; Schumacher, Björn

2014-01-01

Impairment of stem cell function contributes to the progressive deterioration of tissue maintenance and repair with ageing. Evidence is mounting that age-dependent accumulation of DNA damage in both stem cells and cells that comprise the stem cell microenvironment are partly responsible for stem cell dysfunction with ageing. Here, we review the impact of the various types of DNA damage that accumulate with ageing on stem cell functionality, as well as the development of cancer. We discuss DNA-damage-induced cell intrinsic and extrinsic alterations that influence these processes, and review recent advances in understanding systemic adjustments to DNA damage and how they affect stem cells. PMID:24576896

Progressive damage and rupture in polymers

NASA Astrophysics Data System (ADS)

Talamini, Brandon; Mao, Yunwei; Anand, Lallit

2018-02-01

Progressive damage, which eventually leads to failure, is ubiquitous in biological and synthetic polymers. The simplest case to consider is that of elastomeric materials which can undergo large reversible deformations with negligible rate dependence. In this paper we develop a theory for modeling progressive damage and rupture of such materials. We extend the phase-field method, which is widely used to describe the damage and fracture of brittle materials, to elastomeric materials undergoing large deformations. A central feature of our theory is the recognition that the free energy of elastomers is not entirely entropic in nature - there is also an energetic contribution from the deformation of the bonds in the chains. It is the energetic part in the free energy which is the driving force for progressive damage and fracture.

Machine recognition of navel orange worm damage in X-ray images of pistachio nuts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keagy, P.M.; Schatzki, T.F.; Parvin, B.

Insect infestation increases the probability of aflatoxin contamination in pistachio nuts. A non-destructive test is currently not available to determine the insect content of pistachio nuts. This paper presents the use of film X-ray images of various types of pistachio nuts to assess the possibility of machine recognition of insect infested nuts. Histogram parameters of four derived images are used in discriminant functions to select insect infested nuts from specific processing streams.

Endogenous Molecules Induced by a Pathogen-Associated Molecular Pattern (PAMP) Elicit Innate Immunity in Shrimp

PubMed Central

Chen, Yu-Yuan; Chen, Jiann-Chu; Lin, Yong-Chin; Kitikiew, Suwaree; Li, Hui-Fang; Bai, Jia-Chin; Tseng, Kuei-Chi; Lin, Bo-Wei; Liu, Po-Chun; Shi, Yin-Ze; Kuo, Yi-Hsuan; Chang, Yu-Hsuan

2014-01-01

Invertebrates rely on an innate immune system to combat invading pathogens. The system is initiated in the presence of cell wall components from microbes like lipopolysaccharide (LPS), β-1,3-glucan (βG) and peptidoglycan (PG), altogether known as pathogen-associated molecular patterns (PAMPs), via a recognition of pattern recognition protein (PRP) or receptor (PRR) through complicated reactions. We show herein that shrimp hemocytes incubated with LPS, βG, and PG caused necrosis and released endogenous molecules (EMs), namely EM-L, EM-β, and EM-P, and found that shrimp hemocytes incubated with EM-L, EM-β, and EM-P caused changes in cell viability, degranulation and necrosis of hemocytes, and increased phenoloxidase (PO) activity and respiratory burst (RB) indicating activation of immunity in vitro. We found that shrimp receiving EM-L, EM-β, and EM-P had increases in hemocyte count and other immune parameters as well as higher phagocytic activity toward a Vibrio pathogen, and found that shrimp receiving EM-L had increases in proliferation cell ratio and mitotic index of hematopoietic tissues (HPTs). We identified proteins of EMs deduced from SDS-PAGE and LC-ESI-MS/MS analyses. EM-L and EM-P contained damage-associated molecular patterns (DAMPs) including HMGBa, HMGBb, histone 2A (H2A), H2B, and H4, and other proteins including proPO, Rab 7 GPTase, and Rab 11 GPTase, which were not observed in controls (EM-C, hemocytes incubated in shrimp salt solution). We concluded that EMs induced by PAMPs contain DAMPs and other immune molecules, and they could elicit innate immunity in shrimp. Further research is needed to identify which individual molecule or combined molecules of EMs cause the results, and determine the mechanism of action in innate immunity. PMID:25517999

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hang, Bo; Rodriguez, Ben; Yang, Yanu

Benzene, a ubiquitous human carcinogen, forms DNA adducts through its metabolites such as p-benzoquinone (p-BQ) and hydroquinone (HQ). N(2)-(4-Hydroxyphenyl)-2'-deoxyguanosine (N(2)-4-HOPh-dG) is the principal adduct identified in vivo by (32)P-postlabeling in cells or animals treated with p-BQ or HQ. To study its effect on repair specificity and replication fidelity, we recently synthesized defined oligonucleotides containing a site-specific adduct using phosphoramidite chemistry. We here report the repair of this adduct by Escherichia coli UvrABC complex, which performs the initial damage recognition and incision steps in the nucleotide excision repair (NER) pathway. We first showed that the p-BQ-treated plasmid was efficiently cleaved bymore » the complex, indicating the formation of DNA lesions that are substrates for NER. Using a 40-mer substrate, we found that UvrABC incises the DNA strand containing N(2)-4-HOPh-dG in a dose- and time-dependent manner. The specificity of such repair was also compared with that of DNA glycosylases and damage-specific endonucleases of E. coli, both of which were found to have no detectable activity toward N(2)-4-HOPh-dG. To understand why this adduct is specifically recognized and processed by UvrABC, molecular modeling studies were performed. Analysis of molecular dynamics trajectories showed that stable G:C-like hydrogen bonding patterns of all three Watson-Crick hydrogen bonds are present within the N(2)-4-HOPh-G:C base pair, with the hydroxyphenyl ring at an almost planar position. In addition, N(2)-4-HOPh-dG has a tendency to form more stable stacking interactions than a normal G in B-type DNA. These conformational properties may be critical in differential recognition of this adduct by specific repair enzymes.« less

Oxidation-Specific Epitopes are Danger Associated Molecular Patterns Recognized by Pattern Recognition Receptors of Innate Immunity

PubMed Central

Miller, Yury I.; Choi, Soo-Ho; Wiesner, Philipp; Fang, Longhou; Harkewicz, Richard; Hartvigsen, Karsten; Boullier, Agnès; Gonen, Ayelet; Diehl, Cody J.; Que, Xuchu; Montano, Erica; Shaw, Peter X.; Tsimikas, Sotirios; Binder, Christoph J.; Witztum, Joseph L.

2010-01-01

Oxidation reactions are vital parts of metabolism and signal transduction. However, they also produce reactive oxygen species, which damage lipids, proteins and DNA, generating “oxidation-specific” epitopes. In this review, we will discuss the hypothesis that such common oxidation-specific epitopes are a major target of innate immunity, recognized by a variety of “pattern recognition receptors” (PRRs). By analogy with microbial “pathogen associated molecular patterns” (PAMPs), we postulate that host-derived, oxidation-specific epitopes can be considered to represent “danger (or damage) associated molecular patterns” (DAMPs). We also argue that oxidation-specific epitopes present on apoptotic cells and their cellular debris provided the primary evolutionary pressure for the selection of such PRRs. Further, because many PAMPs on microbes share molecular identity and/or mimicry with oxidation-specific epitopes, such PAMPs provided a strong secondary selecting pressure for the same set of oxidation-specific PRRs as well. Because lipid peroxidation is ubiquitous and a major component of the inflammatory state associated with atherosclerosis, the understanding that oxidation-specific epitopes are DAMPs, and thus the target of multiple arcs of innate immunity, provides novel insights into the pathogenesis of atherosclerosis. As examples, we show that both cellular and soluble PRRs, such as CD36, toll-like receptor-4, natural antibodies, and CRP recognize common oxidation-specific DAMPs, such as oxidized phospholipids and oxidized cholesteryl esters, and mediate a variety of immune responses, from expression of proinflammatory genes to excessive intracellular lipoprotein accumulation to atheroprotective humoral immunity. These insights may lead to improved understanding of inflammation and atherogenesis and suggest new approaches to diagnosis and therapy. PMID:21252151

Research study on high energy radiation effect and environment solar cell degradation methods

NASA Technical Reports Server (NTRS)

Horne, W. E.; Wilkinson, M. C.

1974-01-01

The most detailed and comprehensively verified analytical model was used to evaluate the effects of simplifying assumptions on the accuracy of predictions made by the external damage coefficient method. It was found that the most serious discrepancies were present in heavily damaged cells, particularly proton damaged cells, in which a gradient in damage across the cell existed. In general, it was found that the current damage coefficient method tends to underestimate damage at high fluences. An exception to this rule was thick cover-slipped cells experiencing heavy degradation due to omnidirectional electrons. In such cases, the damage coefficient method overestimates the damage. Comparisons of degradation predictions made by the two methods and measured flight data confirmed the above findings.

Innate lymphoid cells in tissue homeostasis and diseases

PubMed Central

Ignacio, Aline; Breda, Cristiane Naffah Souza; Camara, Niels Olsen Saraiva

2017-01-01

Innate lymphoid cells (ILCs) are the most recently discovered family of innate immune cells. They are a part of the innate immune system, but develop from the lymphoid lineage. They lack pattern-recognition receptors and rearranged receptors, and therefore cannot directly mediate antigen specific responses. The progenitors specifically associated with the ILCs lineage have been uncovered, enabling the distinction between ILCs and natural killer cells. Based on the requirement of specific transcription factors and their patterns of cytokine production, ILCs are categorized into three subsets (ILC1, ILC2 and ILC3). First observed in mucosal surfaces, these cell populations interact with hematopoietic and non-hematopoietic cells throughout the body during homeostasis and diseases, promoting immunity, commensal microbiota tolerance, tissue repair and inflammation. Over the last 8 years, ILCs came into the spotlight as an essential cell type able to integrate diverse host immune responses. Recently, it became known that ILC subsets play a key role in immune responses at barrier surfaces, interacting with the microbiota, nutrients and metabolites. Since the liver receives the venous blood directly from the intestinal vein, the intestine and liver are essential to maintain tolerance and can rapidly respond to infections or tissue damage. Therefore, in this review, we discuss recent findings regarding ILC functions in homeostasis and disease, with a focus on the intestine and liver. PMID:28878863

Semantic and visual determinants of face recognition in a prosopagnosic patient.

PubMed

Dixon, M J; Bub, D N; Arguin, M

1998-05-01

Prosopagnosia is the neuropathological inability to recognize familiar people by their faces. It can occur in isolation or can coincide with recognition deficits for other nonface objects. Often, patients whose prosopagnosia is accompanied by object recognition difficulties have more trouble identifying certain categories of objects relative to others. In previous research, we demonstrated that objects that shared multiple visual features and were semantically close posed severe recognition difficulties for a patient with temporal lobe damage. We now demonstrate that this patient's face recognition is constrained by these same parameters. The prosopagnosic patient ELM had difficulties pairing faces to names when the faces shared visual features and the names were semantically related (e.g., Tonya Harding, Nancy Kerrigan, and Josee Chouinard -three ice skaters). He made tenfold fewer errors when the exact same faces were associated with semantically unrelated people (e.g., singer Celine Dion, actress Betty Grable, and First Lady Hillary Clinton). We conclude that prosopagnosia and co-occurring category-specific recognition problems both stem from difficulties disambiguating the stored representations of objects that share multiple visual features and refer to semantically close identities or concepts.

Identification of novel binding partners (annexins) for the cell death signal phosphatidylserine and definition of their recognition motif.

PubMed

Rosenbaum, Sabrina; Kreft, Sandra; Etich, Julia; Frie, Christian; Stermann, Jacek; Grskovic, Ivan; Frey, Benjamin; Mielenz, Dirk; Pöschl, Ernst; Gaipl, Udo; Paulsson, Mats; Brachvogel, Bent

2011-02-18

Identification and clearance of apoptotic cells prevents the release of harmful cell contents thereby suppressing inflammation and autoimmune reactions. Highly conserved annexins may modulate the phagocytic cell removal by acting as bridging molecules to phosphatidylserine, a characteristic phagocytosis signal of dying cells. In this study five members of the structurally and functionally related annexin family were characterized for their capacity to interact with phosphatidylserine and dying cells. The results showed that AnxA3, AnxA4, AnxA13, and the already described interaction partner AnxA5 can bind to phosphatidylserine and apoptotic cells, whereas AnxA8 lacks this ability. Sequence alignment experiments located the essential amino residues for the recognition of surface exposed phosphatidylserine within the calcium binding motifs common to all annexins. These amino acid residues were missing in the evolutionary young AnxA8 and when they were reintroduced by site directed mutagenesis AnxA8 gains the capability to interact with phosphatidylserine containing liposomes and apoptotic cells. By defining the evolutionary conserved amino acid residues mediating phosphatidylserine binding of annexins we show that the recognition of dying cells represent a common feature of most annexins. Hence, the individual annexin repertoire bound to the cell surface of dying cells may fulfil opsonin-like function in cell death recognition.

Fungal Chitin Dampens Inflammation through IL-10 Induction Mediated by NOD2 and TLR9 Activation

PubMed Central

Wagener, Jeanette; Malireddi, R. K. Subbarao; Lenardon, Megan D.; Köberle, Martin; Vautier, Simon; MacCallum, Donna M.; Biedermann, Tilo; Schaller, Martin; Netea, Mihai G.; Kanneganti, Thirumala-Devi; Brown, Gordon D.; Brown, Alistair J. P.; Gow, Neil A. R.

2014-01-01

Chitin is an essential structural polysaccharide of fungal pathogens and parasites, but its role in human immune responses remains largely unknown. It is the second most abundant polysaccharide in nature after cellulose and its derivatives today are widely used for medical and industrial purposes. We analysed the immunological properties of purified chitin particles derived from the opportunistic human fungal pathogen Candida albicans, which led to the selective secretion of the anti-inflammatory cytokine IL-10. We identified NOD2, TLR9 and the mannose receptor as essential fungal chitin-recognition receptors for the induction of this response. Chitin reduced LPS-induced inflammation in vivo and may therefore contribute to the resolution of the immune response once the pathogen has been defeated. Fungal chitin also induced eosinophilia in vivo, underpinning its ability to induce asthma. Polymorphisms in the identified chitin receptors, NOD2 and TLR9, predispose individuals to inflammatory conditions and dysregulated expression of chitinases and chitinase-like binding proteins, whose activity is essential to generate IL-10-inducing fungal chitin particles in vitro, have also been linked to inflammatory conditions and asthma. Chitin recognition is therefore critical for immune homeostasis and is likely to have a significant role in infectious and allergic disease. Authors Summary Chitin is the second most abundant polysaccharide in nature after cellulose and an essential component of the cell wall of all fungal pathogens. The discovery of human chitinases and chitinase-like binding proteins indicates that fungal chitin is recognised by cells of the human immune system, shaping the immune response towards the invading pathogen. We show that three immune cell receptors– the mannose receptor, NOD2 and TLR9 recognise chitin and act together to mediate an anti-inflammatory response via secretion of the cytokine IL-10. This mechanism may prevent inflammation-based damage during fungal infection and restore immune balance after an infection has been cleared. By increasing the chitin content in the cell wall pathogenic fungi may influence the immune system in their favour, by down-regulating protective inflammatory immune responses. Furthermore, gene mutations and dysregulated enzyme activity in the described chitin recognition pathway are implicated in inflammatory conditions such as Crohn's Disease and asthma, highlighting the importance of the discovered mechanism in human health. PMID:24722226

Visual recognition and visually guided action after early bilateral lesion of occipital cortex: a behavioral study of a 4.6-year-old girl.

PubMed

Amicuzi, Ileana; Stortini, Massimo; Petrarca, Maurizio; Di Giulio, Paola; Di Rosa, Giuseppe; Fariello, Giuseppe; Longo, Daniela; Cannatà, Vittorio; Genovese, Elisabetta; Castelli, Enrico

2006-10-01

We report the case of a 4.6-year-old girl born pre-term with early bilateral occipital damage. It was revealed that the child had non-severely impaired basic visual abilities and ocular motility, a selective perceptual deficit of figure-ground segregation, impaired visual recognition and abnormal navigating through space. Even if the child's visual functioning was not optimal, this was the expression of adaptive anatomic and functional brain modifications that occurred following the early lesion. Anatomic brain structure was studied with anatomic MRI and Diffusor Tensor Imaging (DTI)-MRI. This behavioral study may provide an important contribution to understanding the impact of an early lesion of the visual system on the development of visual functions and on the immature brain's potential for reorganisation related to when the damage occurred.

Cortical visual dysfunction in children: a clinical study.

PubMed

Dutton, G; Ballantyne, J; Boyd, G; Bradnam, M; Day, R; McCulloch, D; Mackie, R; Phillips, S; Saunders, K

1996-01-01

Damage to the cerebral cortex was responsible for impairment in vision in 90 of 130 consecutive children referred to the Vision Assessment Clinic in Glasgow. Cortical blindness was seen in 16 children. Only 2 were mobile, but both showed evidence of navigational blind-sight. Cortical visual impairment, in which it was possible to estimate visual acuity but generalised severe brain damage precluded estimation of cognitive visual function, was observed in 9 children. Complex disorders of cognitive vision were seen in 20 children. These could be divided into five categories and involved impairment of: (1) recognition, (2) orientation, (3) depth perception, (4) perception of movement and (5) simultaneous perception. These disorders were observed in a variety of combinations. The remaining children showed evidence of reduced visual acuity and/ or visual field loss, but without detectable disorders of congnitive visual function. Early recognition of disorders of cognitive vision is required if active training and remediation are to be implemented.

Facial emotion recognition in patients with focal and diffuse axonal injury.

PubMed

Yassin, Walid; Callahan, Brandy L; Ubukata, Shiho; Sugihara, Genichi; Murai, Toshiya; Ueda, Keita

2017-01-01

Facial emotion recognition impairment has been well documented in patients with traumatic brain injury. Studies exploring the neural substrates involved in such deficits have implicated specific grey matter structures (e.g. orbitofrontal regions), as well as diffuse white matter damage. Our study aims to clarify whether different types of injuries (i.e. focal vs. diffuse) will lead to different types of impairments on facial emotion recognition tasks, as no study has directly compared these patients. The present study examined performance and response patterns on a facial emotion recognition task in 14 participants with diffuse axonal injury (DAI), 14 with focal injury (FI) and 22 healthy controls. We found that, overall, participants with FI and DAI performed more poorly than controls on the facial emotion recognition task. Further, we observed comparable emotion recognition performance in participants with FI and DAI, despite differences in the nature and distribution of their lesions. However, the rating response pattern between the patient groups was different. This is the first study to show that pure DAI, without gross focal lesions, can independently lead to facial emotion recognition deficits and that rating patterns differ depending on the type and location of trauma.

Hair cell recovery in mitotically blocked cultures of the bullfrog saccule

NASA Technical Reports Server (NTRS)

Baird, R. A.; Burton, M. D.; Fashena, D. S.; Naeger, R. A.

2000-01-01

Hair cells in many nonmammalian vertebrates are regenerated by the mitotic division of supporting cell progenitors and the differentiation of the resulting progeny into new hair cells and supporting cells. Recent studies have shown that nonmitotic hair cell recovery after aminoglycoside-induced damage can also occur in the vestibular organs. Using hair cell and supporting cell immunocytochemical markers, we have used confocal and electron microscopy to examine the fate of damaged hair cells and the origin of immature hair cells after gentamicin treatment in mitotically blocked cultures of the bullfrog saccule. Extruding and fragmenting hair cells, which undergo apoptotic cell death, are replaced by scar formations. After losing their bundles, sublethally damaged hair cells remain in the sensory epithelium for prolonged periods, acquiring supporting cell-like morphology and immunoreactivity. These modes of damage appear to be mutually exclusive, implying that sublethally damaged hair cells repair their bundles. Transitional cells, coexpressing hair cell and supporting cell markers, are seen near scar formations created by the expansion of neighboring supporting cells. Most of these cells have morphology and immunoreactivity similar to that of sublethally damaged hair cells. Ultrastructural analysis also reveals that most immature hair cells had autophagic vacuoles, implying that they originated from damaged hair cells rather than supporting cells. Some transitional cells are supporting cells participating in scar formations. Supporting cells also decrease in number during hair cell recovery, supporting the conclusion that some supporting cells undergo phenotypic conversion into hair cells without an intervening mitotic event.

Hair cell recovery in mitotically blocked cultures of the bullfrog saccule

PubMed Central

Baird, Richard A.; Burton, Miriam D.; Fashena, David S.; Naeger, Rebecca A.

2000-01-01

Hair cells in many nonmammalian vertebrates are regenerated by the mitotic division of supporting cell progenitors and the differentiation of the resulting progeny into new hair cells and supporting cells. Recent studies have shown that nonmitotic hair cell recovery after aminoglycoside-induced damage can also occur in the vestibular organs. Using hair cell and supporting cell immunocytochemical markers, we have used confocal and electron microscopy to examine the fate of damaged hair cells and the origin of immature hair cells after gentamicin treatment in mitotically blocked cultures of the bullfrog saccule. Extruding and fragmenting hair cells, which undergo apoptotic cell death, are replaced by scar formations. After losing their bundles, sublethally damaged hair cells remain in the sensory epithelium for prolonged periods, acquiring supporting cell-like morphology and immunoreactivity. These modes of damage appear to be mutually exclusive, implying that sublethally damaged hair cells repair their bundles. Transitional cells, coexpressing hair cell and supporting cell markers, are seen near scar formations created by the expansion of neighboring supporting cells. Most of these cells have morphology and immunoreactivity similar to that of sublethally damaged hair cells. Ultrastructural analysis also reveals that most immature hair cells had autophagic vacuoles, implying that they originated from damaged hair cells rather than supporting cells. Some transitional cells are supporting cells participating in scar formations. Supporting cells also decrease in number during hair cell recovery, supporting the conclusion that some supporting cells undergo phenotypic conversion into hair cells without an intervening mitotic event. PMID:11050201

Hair cell recovery in mitotically blocked cultures of the bullfrog saccule.

PubMed

Baird, R A; Burton, M D; Lysakowski, A; Fashena, D S; Naeger, R A

2000-10-24

Hair cells in many nonmammalian vertebrates are regenerated by the mitotic division of supporting cell progenitors and the differentiation of the resulting progeny into new hair cells and supporting cells. Recent studies have shown that nonmitotic hair cell recovery after aminoglycoside-induced damage can also occur in the vestibular organs. Using hair cell and supporting cell immunocytochemical markers, we have used confocal and electron microscopy to examine the fate of damaged hair cells and the origin of immature hair cells after gentamicin treatment in mitotically blocked cultures of the bullfrog saccule. Extruding and fragmenting hair cells, which undergo apoptotic cell death, are replaced by scar formations. After losing their bundles, sublethally damaged hair cells remain in the sensory epithelium for prolonged periods, acquiring supporting cell-like morphology and immunoreactivity. These modes of damage appear to be mutually exclusive, implying that sublethally damaged hair cells repair their bundles. Transitional cells, coexpressing hair cell and supporting cell markers, are seen near scar formations created by the expansion of neighboring supporting cells. Most of these cells have morphology and immunoreactivity similar to that of sublethally damaged hair cells. Ultrastructural analysis also reveals that most immature hair cells had autophagic vacuoles, implying that they originated from damaged hair cells rather than supporting cells. Some transitional cells are supporting cells participating in scar formations. Supporting cells also decrease in number during hair cell recovery, supporting the conclusion that some supporting cells undergo phenotypic conversion into hair cells without an intervening mitotic event.

Fine tuning cellular recognition: The function of the leucine rich repeat (LRR) trans-membrane protein, LRT, in muscle targeting to tendon cells.

PubMed

Gilsohn, Eli; Volk, Talila

2010-01-01

The formation of complex tissues during embryonic development is often accompanied by directed cellular migration towards a target tissue. Specific mutual recognition between the migrating cell and its target tissue leads to the arrest of the cell migratory behavior and subsequent contact formation between the two interacting cell types. Recent studies implicated a novel family of surface proteins containing a trans-membrane domain and single leucine-rich repeat (LRR) domain in inter-cellular recognition and the arrest of cell migration. Here, we describe the involvement of a novel LRR surface protein, LRT, in targeting migrating muscles towards their corresponding tendon cells in the Drosophila embryo. LRT is specifically expressed by the target tendon cells and is essential for arresting the migratory behavior of the muscle cells. Additional studies in Drosophila S2 cultured cells suggest that LRT forms a protein complex with the Roundabout (Robo) receptor, essential for guiding muscles towards their tendon partners. Genetic analysis supports a model in which LRT performs its activity non-autonomously through its interaction with the Robo receptors expressed on the muscle surfaces. These results suggest a novel mechanism of intercellular recognition through interactions between LRR family members and Robo receptors.

The role of the hippocampus in recognition memory.

PubMed

Bird, Chris M

2017-08-01

Many theories of declarative memory propose that it is supported by partially separable processes underpinned by different brain structures. The hippocampus plays a critical role in binding together item and contextual information together and processing the relationships between individual items. By contrast, the processing of individual items and their later recognition can be supported by extrahippocampal regions of the medial temporal lobes (MTL), particularly when recognition is based on feelings of familiarity without the retrieval of any associated information. These theories are domain-general in that "items" might be words, faces, objects, scenes, etc. However, there is mixed evidence that item recognition does not require the hippocampus, or that familiarity-based recognition can be supported by extrahippocampal regions. By contrast, there is compelling evidence that in humans, hippocampal damage does not affect recognition memory for unfamiliar faces, whilst recognition memory for several other stimulus classes is impaired. I propose that regions outside of the hippocampus can support recognition of unfamiliar faces because they are perceived as discrete items and have no prior conceptual associations. Conversely, extrahippocampal processes are inadequate for recognition of items which (a) have been previously experienced, (b) are conceptually meaningful, or (c) are perceived as being comprised of individual elements. This account reconciles findings from primate and human studies of recognition memory. Furthermore, it suggests that while the hippocampus is critical for binding and relational processing, these processes are required for item recognition memory in most situations. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Neural mechanisms of facial recognition].

PubMed

Nagai, Chiyoko

2007-01-01

We review recent researches in neural mechanisms of facial recognition in the light of three aspects: facial discrimination and identification, recognition of facial expressions, and face perception in itself. First, it has been demonstrated that the fusiform gyrus has a main role of facial discrimination and identification. However, whether the FFA (fusiform face area) is really a special area for facial processing or not is controversial; some researchers insist that the FFA is related to 'becoming an expert' for some kinds of visual objects, including faces. Neural mechanisms of prosopagnosia would be deeply concerned to this issue. Second, the amygdala seems to be very concerned to recognition of facial expressions, especially fear. The amygdala, connected with the superior temporal sulcus and the orbitofrontal cortex, appears to operate the cortical function. The amygdala and the superior temporal sulcus are related to gaze recognition, which explains why a patient with bilateral amygdala damage could not recognize only a fear expression; the information from eyes is necessary for fear recognition. Finally, even a newborn infant can recognize a face as a face, which is congruent with the innate hypothesis of facial recognition. Some researchers speculate that the neural basis of such face perception is the subcortical network, comprised of the amygdala, the superior colliculus, and the pulvinar. This network would relate to covert recognition that prosopagnosic patients have.

Cytomegalovirus immune evasion by perturbation of endosomal trafficking

PubMed Central

Lučin, Pero; Mahmutefendić, Hana; Blagojević Zagorac, Gordana; Ilić Tomaš, Maja

2015-01-01

Cytomegaloviruses (CMVs), members of the herpesvirus family, have evolved a variety of mechanisms to evade the immune response to survive in infected hosts and to establish latent infection. They effectively hide infected cells from the effector mechanisms of adaptive immunity by eliminating cellular proteins (major histocompatibility Class I and Class II molecules) from the cell surface that display viral antigens to CD8 and CD4 T lymphocytes. CMVs also successfully escape recognition and elimination of infected cells by natural killer (NK) cells, effector cells of innate immunity, either by mimicking NK cell inhibitory ligands or by downregulating NK cell-activating ligands. To accomplish these immunoevasion functions, CMVs encode several proteins that function in the biosynthetic pathway by inhibiting the assembly and trafficking of cellular proteins that participate in immune recognition and thereby, block their appearance at the cell surface. However, elimination of these proteins from the cell surface can also be achieved by perturbation of their endosomal route and subsequent relocation from the cell surface into intracellular compartments. Namely, the physiological route of every cellular protein, including immune recognition molecules, is characterized by specific features that determine its residence time at the cell surface. In this review, we summarize the current understanding of endocytic trafficking of immune recognition molecules and perturbations of the endosomal system during infection with CMVs and other members of the herpesvirus family that contribute to their immune evasion mechanisms. PMID:25263490

Damage of photoreceptor-derived cells in culture induced by light emitting diode-derived blue light

PubMed Central

Kuse, Yoshiki; Ogawa, Kenjiro; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Hara, Hideaki

2014-01-01

Our eyes are increasingly exposed to light from the emitting diode (LED) light of video display terminals (VDT) which contain much blue light. VDTs are equipped with televisions, personal computers, and smart phones. The present study aims to clarify the mechanism underlying blue LED light-induced photoreceptor cell damage. Murine cone photoreceptor-derived cells (661 W) were exposed to blue, white, or green LED light (0.38 mW/cm2). In the present study, blue LED light increased reactive oxygen species (ROS) production, altered the protein expression level, induced the aggregation of short-wavelength opsins (S-opsin), resulting in severe cell damage. While, blue LED light damaged the primary retinal cells and the damage was photoreceptor specific. N-Acetylcysteine (NAC), an antioxidant, protected against the cellular damage induced by blue LED light. Overall, the LED light induced cell damage was wavelength-, but not energy-dependent and may cause more severe retinal photoreceptor cell damage than the other LED light. PMID:24909301

Cell line name recognition in support of the identification of synthetic lethality in cancer from text

PubMed Central

Kaewphan, Suwisa; Van Landeghem, Sofie; Ohta, Tomoko; Van de Peer, Yves; Ginter, Filip; Pyysalo, Sampo

2016-01-01

Motivation: The recognition and normalization of cell line names in text is an important task in biomedical text mining research, facilitating for instance the identification of synthetically lethal genes from the literature. While several tools have previously been developed to address cell line recognition, it is unclear whether available systems can perform sufficiently well in realistic and broad-coverage applications such as extracting synthetically lethal genes from the cancer literature. In this study, we revisit the cell line name recognition task, evaluating both available systems and newly introduced methods on various resources to obtain a reliable tagger not tied to any specific subdomain. In support of this task, we introduce two text collections manually annotated for cell line names: the broad-coverage corpus Gellus and CLL, a focused target domain corpus. Results: We find that the best performance is achieved using NERsuite, a machine learning system based on Conditional Random Fields, trained on the Gellus corpus and supported with a dictionary of cell line names. The system achieves an F-score of 88.46% on the test set of Gellus and 85.98% on the independently annotated CLL corpus. It was further applied at large scale to 24 302 102 unannotated articles, resulting in the identification of 5 181 342 cell line mentions, normalized to 11 755 unique cell line database identifiers. Availability and implementation: The manually annotated datasets, the cell line dictionary, derived corpora, NERsuite models and the results of the large-scale run on unannotated texts are available under open licenses at http://turkunlp.github.io/Cell-line-recognition/. Contact: sukaew@utu.fi PMID:26428294

Building-associated neurological damage modeled in human cells: a mechanism of neurotoxic effects by exposure to mycotoxins in the indoor environment.

PubMed

Karunasena, Enusha; Larrañaga, Michael D; Simoni, Jan S; Douglas, David R; Straus, David C

2010-12-01

Damage to human neurological system cells resulting from exposure to mycotoxins confirms a previously controversial public health threat for occupants of water-damaged buildings. Leading scientific organizations disagree about the ability of inhaled mycotoxins in the indoor environment to cause adverse human health effects. Damage to the neurological system can result from exposure to trichothecene mycotoxins in the indoor environment. This study demonstrates that neurological system cell damage can occur from satratoxin H exposure to neurological cells at exposure levels that can be found in water-damaged buildings contaminated with fungal growth. The constant activation of inflammatory and apoptotic pathways at low levels of exposure in human brain capillary endothelial cells, astrocytes, and neural progenitor cells may amplify devastation to neurological tissues and lead to neurological system cell damage from indirect events triggered by the presence of trichothecenes.

Role of isolated and clustered DNA damage and the post-irradiating repair process in the effects of heavy ion beam irradiation.

PubMed

Tokuyama, Yuka; Furusawa, Yoshiya; Ide, Hiroshi; Yasui, Akira; Terato, Hiroaki

2015-05-01

Clustered DNA damage is a specific type of DNA damage induced by ionizing radiation. Any type of ionizing radiation traverses the target DNA molecule as a beam, inducing damage along its track. Our previous study showed that clustered DNA damage yields decreased with increased linear energy transfer (LET), leading us to investigate the importance of clustered DNA damage in the biological effects of heavy ion beam radiation. In this study, we analyzed the yield of clustered base damage (comprising multiple base lesions) in cultured cells irradiated with various heavy ion beams, and investigated isolated base damage and the repair process in post-irradiation cultured cells. Chinese hamster ovary (CHO) cells were irradiated by carbon, silicon, argon and iron ion beams with LETs of 13, 55, 90 and 200 keV µm(-1), respectively. Agarose gel electrophoresis of the cells with enzymatic treatments indicated that clustered base damage yields decreased as the LET increased. The aldehyde reactive probe procedure showed that isolated base damage yields in the irradiated cells followed the same pattern. To analyze the cellular base damage process, clustered DNA damage repair was investigated using DNA repair mutant cells. DNA double-strand breaks accumulated in CHO mutant cells lacking Xrcc1 after irradiation, and the cell viability decreased. On the other hand, mouse embryonic fibroblast (Mef) cells lacking both Nth1 and Ogg1 became more resistant than the wild type Mef. Thus, clustered base damage seems to be involved in the expression of heavy ion beam biological effects via the repair process. © The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Immunization with SV40-transformed cells yields mainly MHC-restricted monoclonal antibodies

PubMed Central

1986-01-01

Recognition of antigens on cell surfaces only in the context of the MHC- encoded alloantigens of the presenting cell (self + X) has classically been considered the province of T cells. However, evidence from several sources has indicated that B cells and antibodies can exhibit self + X- restricted recognition as well. This report concerns the mAb response to SV40-transformed H-2b fibroblast cell lines. The specificities of the antibodies obtained have been analyzed for binding to a panel of SV40-transformed H-2-syngeneic, H-2-allogeneic, and H-2b mutant fibroblast cell lines, as well as cell lines not bearing cell surface SV40 transformation-associated antigens. A large proportion of primary C57BL/6 (71%) and BALB/c (68%) splenic B cells responding to in vitro stimulation with SV40-transformed H-2b cells recognize cell surface antigens associated with SV40 transformation only when coexpressed with MHC antigens of the immunizing cell, particularly the Kb molecule, on transformed cells. To extensively define the nature of antigen recognition by these antibodies, we have generated and characterized nine hybridoma antibodies specific for SV40-transformed H-2-syngeneic cell lines. Seven of these hybridoma antibodies recognize SV40- associated transformation antigens in the context of H-2b molecules. Six of these are restricted by the Kb molecule and discriminate among a panel of SV40-transformed Kb mutant cell lines, thus confirming the participation of class I MHC-encoded molecules in the recognition by B cells of cell surface antigens. PMID:3014034

Structural health monitoring feature design by genetic programming

NASA Astrophysics Data System (ADS)

Harvey, Dustin Y.; Todd, Michael D.

2014-09-01

Structural health monitoring (SHM) systems provide real-time damage and performance information for civil, aerospace, and other high-capital or life-safety critical structures. Conventional data processing involves pre-processing and extraction of low-dimensional features from in situ time series measurements. The features are then input to a statistical pattern recognition algorithm to perform the relevant classification or regression task necessary to facilitate decisions by the SHM system. Traditional design of signal processing and feature extraction algorithms can be an expensive and time-consuming process requiring extensive system knowledge and domain expertise. Genetic programming, a heuristic program search method from evolutionary computation, was recently adapted by the authors to perform automated, data-driven design of signal processing and feature extraction algorithms for statistical pattern recognition applications. The proposed method, called Autofead, is particularly suitable to handle the challenges inherent in algorithm design for SHM problems where the manifestation of damage in structural response measurements is often unclear or unknown. Autofead mines a training database of response measurements to discover information-rich features specific to the problem at hand. This study provides experimental validation on three SHM applications including ultrasonic damage detection, bearing damage classification for rotating machinery, and vibration-based structural health monitoring. Performance comparisons with common feature choices for each problem area are provided demonstrating the versatility of Autofead to produce significant algorithm improvements on a wide range of problems.

Recognition and Quantification of Area Damaged by Oligonychus Perseae in Avocado Leaves

NASA Astrophysics Data System (ADS)

Díaz, Gloria; Romero, Eduardo; Boyero, Juan R.; Malpica, Norberto

The measure of leaf damage is a basic tool in plant epidemiology research. Measuring the area of a great number of leaves is subjective and time consuming. We investigate the use of machine learning approaches for the objective segmentation and quantification of leaf area damaged by mites in avocado leaves. After extraction of the leaf veins, pixels are labeled with a look-up table generated using a Support Vector Machine with a polynomial kernel of degree 3, on the chrominance components of YCrCb color space. Spatial information is included in the segmentation process by rating the degree of membership to a certain class and the homogeneity of the classified region. Results are presented on real images with different degrees of damage.

Ectopic ERK Expression Induces Phenotypic Conversion of C10 Cells and Alters DNA Methyltransferase Expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sontag, Ryan L.; Weber, Thomas J.

2012-05-04

In some model systems constitutive extracellular signal regulated kinase (ERK) activation is sufficient to promote an oncogenic phenotype. Here we investigate whether constitutive ERK expression influences phenotypic conversion in murine C10 type II alveolar epithelial cells. C10 cells were stably transduced with an ERK1-green fluorescent protein (ERK1-GFP) chimera or empty vector and ectopic ERK expression was associated with the acquisition of soft agar focus-forming potential in late passage, but not early passage cells. Late passage ERK1-GFP cells exhibited a significant increase in the expression of DNA methyl transferases (DNMT1 and 3b) and a marked increase in sensitivity to 5-azacytidine (5-azaC)-mediatedmore » toxicity, relative to early passage ERK1-GFP cells and vector controls. The expression of xeroderma pigmentosum complementation group A (XPA) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) were significantly increased in late passage cells, suggesting enhanced DNA damage recognition and repair activity which we interpret as a reflection of genomic instability. Phospho-ERK levels were dramatically decreased in late passage ERK1-GFP cells, relative to early passage and vector controls, and phospho-ERK levels were restored by treatment with sodium orthovanadate, indicating a role for phosphatase activity in this response. Collectively these observations suggest that ectopic ERK expression promotes phenotypic conversion of C10 cells that is associated with latent effects on epigenetic programming and phosphatase activities.« less

Transient blockade of Delta-like Notch ligands prevents allograft rejection mediated by cellular and humoral mechanisms in a mouse model of heart transplantation

PubMed Central

Wood, Sherri; Feng, Jiane; Chung, Jooho; Radojcic, Vedran; Sandy, Ashley R.; Friedman, Ann; Shelton, Amy; Yan, Minhong; Siebel, Christian W.; Bishop, D. Keith; Maillard, Ivan

2015-01-01

Rejection remains a major clinical challenge limiting allograft survival after solid organ transplantation. Both cellular and humoral immunity contribute to this complication, with increased recognition of antibody-mediated damage during acute and chronic rejection. Using a mouse model of MHC-mismatched heart transplantation, we report markedly protective effects of Notch inhibition, dampening both T cell and antibody-driven rejection. T cell-specific pan-Notch blockade prolonged heart allograft survival and decreased IFNγ and IL-4 production by alloreactive T cells, especially when combined with depletion of recipient CD8+ T cells. These effects were associated with decreased infiltration by conventional T cells and an increased proportion of regulatory T cells in the graft. Transient administration of neutralizing antibodies specific for Delta-like1/4 (Dll1/4) Notch ligands in the peri-transplant period led to prolonged acceptance of allogeneic hearts, with superior outcome over Notch inhibition only in T cells. Systemic Dll1/4 inhibition decreased T cell cytokines and graft infiltration, but also germinal center B cell and plasmablast numbers as well as production of donor-specific alloantibodies and complement deposition in the transplanted hearts. Dll1 or Dll4 inhibition alone provided partial protection. Thus, pathogenic signals delivered by Dll1/4 Notch ligands early after transplantation promote organ rejection through several complementary mechanisms. Transient interruption of theses signals represents a new attractive therapeutic strategy to enhance long-term allograft survival. PMID:25687759

Deep Learning for Image-Based Cassava Disease Detection.

PubMed

Ramcharan, Amanda; Baranowski, Kelsee; McCloskey, Peter; Ahmed, Babuali; Legg, James; Hughes, David P

2017-01-01

Cassava is the third largest source of carbohydrates for human food in the world but is vulnerable to virus diseases, which threaten to destabilize food security in sub-Saharan Africa. Novel methods of cassava disease detection are needed to support improved control which will prevent this crisis. Image recognition offers both a cost effective and scalable technology for disease detection. New deep learning models offer an avenue for this technology to be easily deployed on mobile devices. Using a dataset of cassava disease images taken in the field in Tanzania, we applied transfer learning to train a deep convolutional neural network to identify three diseases and two types of pest damage (or lack thereof). The best trained model accuracies were 98% for brown leaf spot (BLS), 96% for red mite damage (RMD), 95% for green mite damage (GMD), 98% for cassava brown streak disease (CBSD), and 96% for cassava mosaic disease (CMD). The best model achieved an overall accuracy of 93% for data not used in the training process. Our results show that the transfer learning approach for image recognition of field images offers a fast, affordable, and easily deployable strategy for digital plant disease detection.

Analysis on the Intention to Purchase Weather Index Insurance and Development Agenda

NASA Astrophysics Data System (ADS)

Park, K.; Jung, J.; Shin, J.; Kim, B.

2013-12-01

The purpose of this paper is to analyze how to revitalize weather insurance. Current state of weather insurance market is firstly described, and the necessity of insurance products and intention to purchase are analyzed based on the recognition survey regarding weather insurance focusing on the weather index insurance. The result of intention to purchase insurance products were examined with Ordered Logit Analysis (OLA), indicating that the amount of damages, the impacts of weather change, and experience of damage and loss have a positive relationship with the intention to purchase weather insurance. In addition, recognition of the amount of acceptable payment for insurance (i.e. willingness to pay) was analyzed for both the group who wants to purchase insurance (Group 1) and the group who does not want to (Group 2). The results demonstrate that Group 1 shows statistically higher significance than Group 2. Based on the results above with the increase in abnormal weather phenomena, we could predict that the amount of damages and losses will be rapidly increasing. The portion of weather insurance market is also expected to consistently develop and expand. This study could be a cornerstone for drawing a plan to revitalize weather insurance.

An autologous dendritic cell canine mammary tumor hybrid-cell fusion vaccine.

PubMed

Bird, R Curtis; Deinnocentes, Patricia; Church Bird, Allison E; van Ginkel, Frederik W; Lindquist, Joni; Smith, Bruce F

2011-01-01

Mammary cancer is among the most prevalent canine tumors and frequently resulting in death due to metastatic disease that is highly homologous to human breast cancer. Most canine tumors fail to raise effective immune reactions yet, some spontaneous remissions do occur. Hybrid canine dendritic cell-tumor cell fusion vaccines were designed to enhance antigen presentation and tumor immune recognition. Peripheral blood-derived autologous dendritic cell enriched populations were isolated from dogs based on CD11c(+) expression and fused with canine mammary tumor (CMT) cells for vaccination of laboratory Beagles. These hybrid cells were injected into popliteal lymph nodes of normal dogs, guided by ultrasound, and included CpG-oligonucleotide adjuvants. Three rounds of vaccination were delivered. Significant IgG responses were observed in all vaccinated dogs compared to vehicle-injected controls. Canine IgG antibodies recognized shared CMT antigens as was demonstrated by IgG-recognition of three unrelated/independently derived CMT cell lines, and recognition of freshly isolated, unrelated, primary biopsy-derived CMT cells. A bias toward an IgG2 isotype response was observed after two vaccinations in most dogs. Neither significant cytotoxic T cell responses were detected, nor adverse or side-effects due to vaccination or due to the induced immune responses noted. These data provide proof-of-principle for this cancer vaccine strategy and demonstrate the presence of shared CMT antigens that promote immune recognition of mammary cancer.

The recognition of emotional expression in prosopagnosia: decoding whole and part faces.

PubMed

Stephan, Blossom Christa Maree; Breen, Nora; Caine, Diana

2006-11-01

Prosopagnosia is currently viewed within the constraints of two competing theories of face recognition, one highlighting the analysis of features, the other focusing on configural processing of the whole face. This study investigated the role of feature analysis versus whole face configural processing in the recognition of facial expression. A prosopagnosic patient, SC made expression decisions from whole and incomplete (eyes-only and mouth-only) faces where features had been obscured. SC was impaired at recognizing some (e.g., anger, sadness, and fear), but not all (e.g., happiness) emotional expressions from the whole face. Analyses of his performance on incomplete faces indicated that his recognition of some expressions actually improved relative to his performance on the whole face condition. We argue that in SC interference from damaged configural processes seem to override an intact ability to utilize part-based or local feature cues.

The development of damage identification methods for buildings with image recognition and machine learning techniques utilizing aerial photographs of the 2016 Kumamoto earthquake

NASA Astrophysics Data System (ADS)

Shohei, N.; Nakamura, H.; Fujiwara, H.; Naoichi, M.; Hiromitsu, T.

2017-12-01

It is important to get schematic information of the damage situation immediately after the earthquake utilizing photographs shot from an airplane in terms of the investigation and the decision-making for authorities. In case of the 2016 Kumamoto earthquake, we have acquired more than 1,800 orthographic projection photographs adjacent to damaged areas. These photos have taken between April 16th and 19th by airplanes, then we have distinguished damages of all buildings with 4 levels, and organized as approximately 296,000 GIS data corresponding to the fundamental Geospatial data published by Geospatial Information Authority of Japan. These data have organized by effort of hundreds of engineers. However, it is not considered practical for more extensive disasters like the Nankai Trough earthquake by only human powers. So, we have been developing the automatic damage identification method utilizing image recognition and machine learning techniques. First, we have extracted training data of more than 10,000 buildings which have equally damage levels divided in 4 grades. With these training data, we have been raster scanning in each scanning ranges of entire images, then clipping patch images which represents damage levels each. By utilizing these patch images, we have been developing discriminant models by two ways. One is a model using the Support Vector Machine (SVM). First, extract a feature quantity of each patch images. Then, with these vector values, calculate the histogram density as a method of Bag of Visual Words (BoVW), then classify borders with each damage grades by SVM. The other one is a model using the multi-layered Neural Network. First, design a multi-layered Neural Network. Second, input patch images and damage levels based on a visual judgement, and then, optimize learning parameters with error backpropagation method. By use of both discriminant models, we are going to discriminate damage levels in each patches, then create the image that shows building damage situations. It would be helpful for more prompt and widespread damage detection than visual judgement. Acknowledgment: This work was supported by CSTI through the Cross-ministerial Strategic Innovation Promotion Program (SIP), titled "Enhancement of societal resiliency against natural disasters"(Funding agency: JST).

Phosphatidylserine exposure on stored red blood cells as a parameter for donor-dependent variation in product quality.

PubMed

Dinkla, Sip; Peppelman, Malou; Van Der Raadt, Jori; Atsma, Femke; Novotný, Vera M J; Van Kraaij, Marian G J; Joosten, Irma; Bosman, Giel J C G M

2014-04-01

Exposure of phosphatidylserine on the outside of red blood cells contributes to recognition and removal of old and damaged cells. The fraction of phosphatidylserine-exposing red blood cells varies between donors, and increases in red blood cell concentrates during storage. The susceptibility of red blood cells to stress-induced phosphatidylserine exposure increases with storage. Phosphatidylserine exposure may, therefore, constitute a link between donor variation and the quality of red blood cell concentrates. In order to examine the relationship between storage parameters and donor characteristics, the percentage of phosphatidylserine-exposing red blood cells was measured in red blood cell concentrates during storage and in fresh red blood cells from blood bank donors. The percentage of phosphatidylserine-exposing red blood cells was compared with red blood cell susceptibility to osmotic stress-induced phosphatidylserine exposure in vitro, with the regular red blood cell concentrate quality parameters, and with the donor characteristics age, body mass index, haemoglobin level, gender and blood group. Phosphatidylserine exposure varies between donors, both on red blood cells freshly isolated from the blood, and on red blood cells in red blood cell concentrates. Phosphatidylserine exposure increases with storage time, and is correlated with stress-induced phosphatidylserine exposure. Increased phosphatidylserine exposure during storage was found to be associated with haemolysis and vesicle concentration in red blood cell concentrates. The percentage of phosphatidylserine-exposing red blood cells showed a positive correlation with the plasma haemoglobin concentration of the donor. The fraction of phosphatidylserine-exposing red blood cells is a parameter of red blood cell integrity in red blood cell concentrates and may be an indicator of red blood cell survival after transfusion. Measurement of phosphatidylserine exposure may be useful in the selection of donors and red blood cell concentrates for specific groups of patients.

Epilepsy and innate immune system: A possible immunogenic predisposition and related therapeutic implications.

PubMed

Matin, Nassim; Tabatabaie, Omidreza; Falsaperla, Raffaele; Lubrano, Riccardo; Pavone, Piero; Mahmood, Fahad; Gullotta, Melissa; Serra, Agostino; Di Mauro, Paola; Cocuzza, Salvatore; Vitaliti, Giovanna

2015-01-01

Recent experimental studies and pathological analyses of patient brain tissue samples with refractory epilepsy suggest that inflammatory processes and neuroinflammation plays a key-role in the etiopathology of epilepsy and convulsive disorders. These inflammatory processes lead to the secretion of pro-inflammatory cytokines responsible for blood-brain-barrier disruption and involvement of resident immune cells in the inflammation pathway, occurring within the Central Nervous System (CNS). These elements are produced through activation of Toll-Like Receptors (TLRs) by exogenous and endogenous ligands thereby increasing expression of cytokines and co-stimulatory molecules through the activation of TLRs 2, 3, 4, and 9 as reported in murine studies.It has been demonstrated that IL-1β intracellular signaling and cascade is able to alter the neuronal excitability without cell loss. The activation of the IL-1β/ IL-1β R axis is strictly linked to the secretion of the intracellular protein MyD88, which interacts with other cell surface receptors, such as TLR4 during pathogenic recognition. Furthermore, TLR-signaling pathways are able to recognize molecules released from damaged tissues, such as damage-associated molecular patterns/proteins (DAMPs). Among these molecules, High-mobility group box-1 (HMGB1) is a component of chromatin that is passively released from necrotic cells and actively released by cells that are subject to profound stress. Moreover, recent studies have described models of epilepsy induced by the administration of bicuculline and kainic acid that highlight the nature of HMGB1-TLR4 interactions, their intracellular signaling pathway as well as their role in ictiogenesis and epileptic recurrence.The aim of our review is to focus on different branches of innate immunity and their role in epilepsy, emphasizing the role of immune related molecules in epileptogenesis and highlighting the research implications for novel therapeutic strategies.

Cryptococcus neoformans-induced macrophage lysosome damage crucially contributes to fungal virulence1

PubMed Central

Davis, Michael J.; Eastman, Alison J.; Qiu, Yafeng; Gregorka, Brian; Kozel, Thomas R.; Osterholzer, John J.; Curtis, Jeffrey L.; Swanson, Joel A.; Olszewski, Michal A.

2015-01-01

Upon ingestion by macrophages, Cryptococcus neoformans (Cn) can survive and replicate intracellularly unless the macrophages become classically activated. The mechanism enabling intracellular replication is not fully understood; neither are the mechanisms which allow classical activation to counteract replication. Cn-induced lysosome damage was observed in infected murine bone marrow-derived macrophages, increased with time and required yeast viability. To demonstrate lysosome damage in the infected host, we developed a novel flow-cytometric method for measuring lysosome damage. Increased lysosome damage was found in Cn-containing lung cells compared to Cn–free cells. Among Cn-containing myeloid cells, recently recruited cells displayed lower damage than resident cells, consistent with the protective role of recruited macrophages. The magnitude of lysosome damage correlated with increased Cn replication. Experimental induction of lysosome damage increased Cn replication. Activation of macrophages with IFN-γ abolished macrophage lysosome damage and enabled increased killing of Cn. We conclude that induction of lysosome damage is an important Cn survival strategy and that classical activation of host macrophages counters replication by preventing damage. Thus, therapeutic strategies which decrease lysosomal damage, or increase resistance to such damage, could be valuable in treating cryptococcal infections. PMID:25637026

Insulin Resistance in Alzheimer Disease: p53 and MicroRNAs as Important Players.

PubMed

Gasiorowski, Kazimierz; Brokos, Barbara; Leszek, Jerzy; Tarasov, Vadim V; Ashraf, Ghulam Md; Aliev, Gjumrakch

2017-01-01

Glucose homeostasis is crucial for neuronal survival, synaptic plasticity, and is indispensable for learning and memory. Reduced sensitivity of cells to insulin and impaired insulin signaling in brain neurons participate in the pathogenesis of Alzheimer disease (AD). The tumor suppressor protein p53 coordinates with multiple cellular pathways in response to DNA damage and cellular stresses. However, prolonged stress conditions unveil deleterious effects of p53-evoked insulin resistance in neurons; enhancement of transcription of pro-oxidant factors, accumulation of toxic metabolites (e.g. ceramide and products of advanced glycation) and ROS-modified cellular components, together with the activation of proapoptotic genes, could finally induce a suicide death program of autophagy/apoptosis in neurons. Recent studies reveal the impact of p53 on expression and processing of several microRNAs (miRs) under DNA damage-inducing conditions. Additionally, the role of miRs in promotion of insulin resistance and type 2 diabetes mellitus has been well documented. Detailed recognition of the role of p53/miRs crosstalk in driving insulin resistance in AD brains could improve the disease diagnostics and aid future therapy. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

The Clinical Relevance of Maintaining the Functional Integrity of the Stratum Corneum in both Healthy and Disease-affected Skin

PubMed Central

Del Rosso, James Q.; Levin, Jacqueline

2011-01-01

It has been recognized for approximately 50 years that the stratum corneum exhibits biological properties that contribute directly to maintaining and sustaining healthy skin. Continued basic science and clinical research coupled with keen clinical observation has led to more recent recognition and general acceptance that the stratum corneum completes many vital “barrier” tasks, including but not limited to regulating epidermal water content and the magnitude of water loss; mitigating exogenous oxidants that can damage components of skin via an innate antioxidant system; preventing or limiting cutaneous infection via multiple antimicrobial peptides; responding via innate immune mechanisms to “cutaneous invaders” of many origins, including microbes, true allergens, and other antigens; and protecting its neighboring cutaneous cells and structures that lie beneath from damaging effects of ultraviolet radiation. Additionally, specific abnormalities of the stratum corneum are associated with the clinical expression of certain disease states. This article provides a thorough “primer” for the clinician, reviewing the multiple normal homeostatic functions of the stratum corneum and the cutaneous challenges that arise when individual functions of this thin yet very active epidermal layer are compromised by exogenous and/or endogenous factors. PMID:21938268

Modulation of DNA Damage and Repair Pathways by Human Tumour Viruses

PubMed Central

Hollingworth, Robert; Grand, Roger J

2015-01-01

With between 10% and 15% of human cancers attributable to viral infection, there is great interest, from both a scientific and clinical viewpoint, as to how these pathogens modulate host cell functions. Seven human tumour viruses have been identified as being involved in the development of specific malignancies. It has long been known that the introduction of chromosomal aberrations is a common feature of viral infections. Intensive research over the past two decades has subsequently revealed that viruses specifically interact with cellular mechanisms responsible for the recognition and repair of DNA lesions, collectively known as the DNA damage response (DDR). These interactions can involve activation and deactivation of individual DDR pathways as well as the recruitment of specific proteins to sites of viral replication. Since the DDR has evolved to protect the genome from the accumulation of deleterious mutations, deregulation is inevitably associated with an increased risk of tumour formation. This review summarises the current literature regarding the complex relationship between known human tumour viruses and the DDR and aims to shed light on how these interactions can contribute to genomic instability and ultimately the development of human cancers. PMID:26008701

Repeated exposure of the developing rat brain to magnetic resonance imaging did not affect neurogenesis, cell death or memory function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Changlian; Department of Pediatrics, The Third Affiliated Hospital, Zhengzhou University; Gao, Jianfeng

2011-01-07

Research highlights: {yields} The effect of MRI on the developing brain is a matter of debate. {yields} Repeated exposure to MRI did not affect neurogenesis. {yields} Memory function was not affected by repeated MRI during development. {yields} Neither late gestation nor young postnatal brains were affected by MRI. {yields} Repeated MRI did not cause cell death in the neurogenic region of the hippocampus. -- Abstract: The effect of magnetic fields on the brain is a matter of debate. The objective of this study was to investigate whether repeated exposure to strong magnetic fields, such as during magnetic resonance imaging (MRI),more » could elicit changes in the developing rat brain. Embryonic day 15 (E15) and postnatal day 14 (P14) rats were exposed to MRI using a 7.05 T MR system. The animals were anesthetized and exposed for 35 min per day for 4 successive days. Control animals were anesthetized but no MRI was performed. Body temperature was maintained at 37 {sup o}C. BrdU was injected after each session (50 mg/kg). One month later, cell proliferation, neurogenesis and astrogenesis in the dentate gyrus were evaluated, revealing no effects of MRI, neither in the E15, nor in the P14 group. DNA damage in the dentate gyrus in the P14 group was evaluated on P18, 1 day after the last session, using TUNEL staining. There was no difference in the number of TUNEL-positive cells after MRI compared with controls, neither in mature neurons, nor in newborn progenitors (BrdU/TUNEL double-labeled cells). Novel object recognition was performed to assess memory function 1 month after MRI. There was no difference in the recognition index observed after MRI compared with the control rats, neither for the E15, nor for the P14 group. In conclusion, repeated exposure to MRI did not appear to affect neurogenesis, cell death or memory function in rats, neither in late gestation (E15-E18) nor in young postnatal (P14-P17) rats.« less

Photothermal and photoacoustic processes of laser activated nano-thermolysis of cells

NASA Astrophysics Data System (ADS)

Lapotko, Dmitri; Lukianova, Ekaterina; Mitskevich, Pavel; Smolnikova, Victoria; Potapnev, Michail; Konopleva, Marina; Andreeff, Michael; Oraevsky, Alexander

2007-02-01

Laser Activated Nano-Thermolysis was recently proposed for selective damage of individual target (cancer) cells by pulsed laser induced microbubbles around superheated clusters of optically absorbing nanoparticles (NP). One of the clinical applications of this technology is the elimination of residual tumor cells from human blood and bone marrow. Clinical standards for the safety and efficacy of such procedure require the development and verification of highly selective and controllable mechanisms of cell killing. Our previous experiments showed that laser-induced microbubble is the main damaging factor in the case cell irradiation by short laser pulses above the threshold. Our current aim was to study the cell damage mechanisms and analyze selectivity and efficacy of cell damage as a function of NP parameters, NP-cell interaction conditions, and conditions of bubble generation around NP and NP clusters in cells. Generation of laser-induced bubbles around gold NP with diameters 10-250 nm was studied in Acute Myeloblast Leukemia (AML) cultures, normal stem and model K562 human cells. Short laser pulses (10 ns, 532 nm) were applied to those cells in vitro and the processes in cells were investigated with photothermal, fluorescent and atomic force microscopies and also with fluorescence flow cytometry. We have found that the best selectivity of cell damage is achieved by (1) forming large clusters of optically absorbing NP in target cells and (2) irradiating the cells with single laser pulses with the lowest fluence that can generate microbubble only around large clusters but not around single NP. Laser microbubbles with the lifetime from 20 ns to 2000 ns generated in individual cells caused damage and lysis of the cellular membrane and consequently cell death. Laser microbubbles did not damage normal cells around the damaged target (tumor) cell. Laser irradiation with equal fluence did not cause any damage of cells without accumulated NP clusters.

Damage Thresholds for Exposure to NIR and Blue Lasers in an In Vitro RPE Cell System

DTIC Science & Technology

2006-07-01

damage , and to identify antioxidants capable of protecting these cells from laser-in- duced cell death. MATERIALS AND METHODS The human RPE cell...melanosomes in blue laser-induced damage in vitro, which confirms the view that melanin plays an important role in photochemical damage mechanisms in...community has only a validating role in the animal ED50 damage threshold data used by safety committees. Systems of in vitro analysis must be

Metabolic responses induced by DNA damage and poly (ADP-ribose) polymerase (PARP) inhibition in MCF-7 cells

PubMed Central

Bhute, Vijesh J.; Palecek, Sean P.

2015-01-01

Genomic instability is one of the hallmarks of cancer. Several chemotherapeutic drugs and radiotherapy induce DNA damage to prevent cancer cell replication. Cells in turn activate different DNA damage response (DDR) pathways to either repair the damage or induce cell death. These DDR pathways also elicit metabolic alterations which can play a significant role in the proper functioning of the cells. The understanding of these metabolic effects resulting from different types of DNA damage and repair mechanisms is currently lacking. In this study, we used NMR metabolomics to identify metabolic pathways which are altered in response to different DNA damaging agents. By comparing the metabolic responses in MCF-7 cells, we identified the activation of poly (ADP-ribose) polymerase (PARP) in methyl methanesulfonate (MMS)-induced DNA damage. PARP activation led to a significant depletion of NAD+. PARP inhibition using veliparib (ABT-888) was able to successfully restore the NAD+ levels in MMS-treated cells. In addition, double strand break induction by MMS and veliparib exhibited similar metabolic responses as zeocin, suggesting an application of metabolomics to classify the types of DNA damage responses. This prediction was validated by studying the metabolic responses elicited by radiation. Our findings indicate that cancer cell metabolic responses depend on the type of DNA damage responses and can also be used to classify the type of DNA damage. PMID:26478723

Sibling Rivalry in Myxococcus xanthus Is Mediated by Kin Recognition and a Polyploid Prophage.

PubMed

Dey, Arup; Vassallo, Christopher N; Conklin, Austin C; Pathak, Darshankumar T; Troselj, Vera; Wall, Daniel

2016-01-19

Myxobacteria form complex social communities that elicit multicellular behaviors. One such behavior is kin recognition, in which cells identify siblings via their polymorphic TraA cell surface receptor, to transiently fuse outer membranes and exchange their contents. In addition, outer membrane exchange (OME) regulates behaviors, such as inhibition of wild-type Myxococcus xanthus (DK1622) from swarming. Here we monitored the fate of motile cells and surprisingly found they were killed by nonmotile siblings. The kill phenotype required OME (i.e., was TraA dependent). The genetic basis of killing was traced to ancestral strains used to construct DK1622. Specifically, the kill phenotype mapped to a large "polyploid prophage," Mx alpha. Sensitive strains contained a 200-kb deletion that removed two of three Mx alpha units. To explain these results, we suggest that Mx alpha expresses a toxin-antitoxin cassette that uses the OME machinery of M. xanthus to transfer a toxin that makes the population "addicted" to Mx alpha. Thus, siblings that lost Mx alpha units (no immunity) are killed by cells that harbor the element. To test this, an Mx alpha-harboring laboratory strain was engineered (by traA allele swap) to recognize a closely related species, Myxococcus fulvus. As a result, M. fulvus, which lacks Mx alpha, was killed. These TraA-mediated antagonisms provide an explanation for how kin recognition specificity might have evolved in myxobacteria. That is, recognition specificity is determined by polymorphisms in traA, which we hypothesize were selected for because OME with non-kin leads to lethal outcomes. The transition from single cell to multicellular life is considered a major evolutionary event. Myxobacteria have successfully made this transition. For example, in response to starvation, individual cells aggregate into multicellular fruiting bodies wherein cells differentiate into spores. To build fruits, cells need to recognize their siblings, and in part, this is mediated by the TraA cell surface receptor. Surprisingly, we report that TraA recognition can also involve sibling killing. We show that killing originates from a prophage-like element that has apparently hijacked the TraA system to deliver a toxin to kin. We hypothesize that this killing system has imposed selective pressures on kin recognition, which in turn has resulted in TraA polymorphisms and hence many different recognition groups. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Sibling Rivalry in Myxococcus xanthus Is Mediated by Kin Recognition and a Polyploid Prophage

PubMed Central

Dey, Arup; Vassallo, Christopher N.; Conklin, Austin C.; Pathak, Darshankumar T.; Troselj, Vera

2016-01-01

ABSTRACT Myxobacteria form complex social communities that elicit multicellular behaviors. One such behavior is kin recognition, in which cells identify siblings via their polymorphic TraA cell surface receptor, to transiently fuse outer membranes and exchange their contents. In addition, outer membrane exchange (OME) regulates behaviors, such as inhibition of wild-type Myxococcus xanthus (DK1622) from swarming. Here we monitored the fate of motile cells and surprisingly found they were killed by nonmotile siblings. The kill phenotype required OME (i.e., was TraA dependent). The genetic basis of killing was traced to ancestral strains used to construct DK1622. Specifically, the kill phenotype mapped to a large “polyploid prophage,” Mx alpha. Sensitive strains contained a 200-kb deletion that removed two of three Mx alpha units. To explain these results, we suggest that Mx alpha expresses a toxin-antitoxin cassette that uses the OME machinery of M. xanthus to transfer a toxin that makes the population “addicted” to Mx alpha. Thus, siblings that lost Mx alpha units (no immunity) are killed by cells that harbor the element. To test this, an Mx alpha-harboring laboratory strain was engineered (by traA allele swap) to recognize a closely related species, Myxococcus fulvus. As a result, M. fulvus, which lacks Mx alpha, was killed. These TraA-mediated antagonisms provide an explanation for how kin recognition specificity might have evolved in myxobacteria. That is, recognition specificity is determined by polymorphisms in traA, which we hypothesize were selected for because OME with non-kin leads to lethal outcomes. IMPORTANCE The transition from single cell to multicellular life is considered a major evolutionary event. Myxobacteria have successfully made this transition. For example, in response to starvation, individual cells aggregate into multicellular fruiting bodies wherein cells differentiate into spores. To build fruits, cells need to recognize their siblings, and in part, this is mediated by the TraA cell surface receptor. Surprisingly, we report that TraA recognition can also involve sibling killing. We show that killing originates from a prophage-like element that has apparently hijacked the TraA system to deliver a toxin to kin. We hypothesize that this killing system has imposed selective pressures on kin recognition, which in turn has resulted in TraA polymorphisms and hence many different recognition groups. PMID:26787762

Cutaneous Manifestations of Diabetes Mellitus: A Review.

PubMed

Lima, Ana Luiza; Illing, Tanja; Schliemann, Sibylle; Elsner, Peter

2017-08-01

Diabetes mellitus is a widespread endocrine disease with severe impact on health systems worldwide. Increased serum glucose causes damage to a wide range of cell types, including endothelial cells, neurons, and renal cells, but also keratinocytes and fibroblasts. Skin disorders can be found in about one third of all people with diabetes and frequently occur before the diagnosis, thus playing an important role in the initial recognition of underlying disease. Noninfectious as well as infectious diseases have been described as dermatologic manifestations of diabetes mellitus. Moreover, diabetic neuropathy and angiopathy may also affect the skin. Pruritus, necrobiosis lipoidica, scleredema adultorum of Buschke, and granuloma annulare are examples of frequent noninfectious skin diseases. Bacterial and fungal skin infections are more frequent in people with diabetes. Diabetic neuropathy and angiopathy are responsible for diabetic foot syndrome and diabetic dermopathy. Furthermore, antidiabetic therapies may provoke dermatologic adverse events. Treatment with insulin may evoke local reactions like lipohypertrophy, lipoatrophy and both instant and delayed type allergy. Erythema multiforme, leukocytoclastic vasculitis, drug eruptions, and photosensitivity have been described as adverse reactions to oral antidiabetics. The identification of lesions may be crucial for the first diagnosis and for proper therapy of diabetes.

Burst annealing of high temperature GaAs solar cells

NASA Technical Reports Server (NTRS)

Brothers, P. R.; Horne, W. E.

1991-01-01

One of the major limitations of solar cells in space power systems is their vulnerability to radiation damage. One solution to this problem is to periodically heat the cells to anneal the radiation damage. Annealing was demonstrated with silicon cells. The obstacle to annealing of GaAs cells was their susceptibility to thermal damage at the temperatures required to completely anneal the radiation damage. GaAs cells with high temperature contacts and encapsulation were developed. The cells tested are designed for concentrator use at 30 suns AMO. The circular active area is 2.5 mm in diameter for an area of 0.05 sq cm. Typical one sun AMO efficiency of these cells is over 18 percent. The cells were demonstrated to be resistant to damage after thermal excursions in excess of 600 C. This high temperature tolerance should allow these cells to survive the annealing of radiation damage. A limited set of experiments were devised to investigate the feasibility of annealing these high temperature cells. The effect of repeated cycles of electron and proton irradiation was tested. The damage mechanisms were analyzed. Limitations in annealing recovery suggested improvements in cell design for more complete recovery. These preliminary experiments also indicate the need for further study to isolate damage mechanisms. The primary objective of the experiments was to demonstrate and quantify the annealing behavior of high temperature GaAs cells. Secondary objectives were to measure the radiation degradation and to determine the effect of repeated irradiation and anneal cycles.

Ambient ozone and pulmonary innate immunity

PubMed Central

Al-Hegelan, Mashael; Tighe, Robert M.; Castillo, Christian; Hollingsworth, John W.

2013-01-01

Ambient ozone is a criteria air pollutant that impacts both human morbidity and mortality. The effect of ozone inhalation includes both toxicity to lung tissue and alteration of the host immunologic response. The innate immune system facilitates immediate recognition of both foreign pathogens and tissue damage. Emerging evidence supports that ozone can modify the host innate immune response and that this response to inhaled ozone is dependent on genes of innate immunity. Improved understanding of the complex interaction between environmental ozone and host innate immunity will provide fundamental insight into the pathogenesis of inflammatory airways disease. We review the current evidence supporting that environmental ozone inhalation: (1) modifies cell types required for intact innate immunity, (2) is partially dependent on genes of innate immunity, (3) primes pulmonary innate immune responses to LPS, and (4) contributes to innate-adaptive immune system cross-talk. PMID:21132467

Self-recognition is crucial for maintaining the peripheral CD4+ T-cell pool in a nonlymphopenic environment.

PubMed

Martin, Bruno; Bécourt, Chantal; Bienvenu, Boris; Lucas, Bruno

2006-07-01

The role of self-recognition in the maintenance of the peripheral CD4+ T-cell pool has been extensively studied, but no clear answer has so far emerged. Indeed, in studies of the role of self-major histocompatibility complex (MHC) molecules in CD4+ T-cell survival, several parameters must be taken into account when interpreting the results: (1) in a lymphopenic environment, observations are biased by concomitant proliferation of T cells arising in MHC-expressing mice; (2) the peripheral T-cell compartment is qualitatively and quantitatively different in nonlymphopenic, normal, and MHC class II-deficient mice; and (3) in C57BL/6 Abeta(-/-) mice (traditionally considered MHC class II-deficient), the Aalpha chain and the Ebeta chain associate to form a hybrid AalphaEbeta MHC class II molecule. In light of these considerations, we revisited the role of interactions with MHC class II molecules in the survival of peripheral CD4+ T cells. We found that the answer to the question "is self-recognition required for CD4+ T cells to survive?" is not a simple yes or no. Indeed, although long-term survival of CD4+ T cells does not depend on self-recognition in lymphopenic mice, interactions with MHC class II molecules are required for maintaining the peripheral CD4+ T-cell pool in a nonlymphopenic environment.

Toll-Like Receptor Function in Acute Wounds

PubMed Central

Chen, Lin; DiPietro, Luisa A.

2017-01-01

Significance: Inflammation is an integral part of immune response and supports optimal wound healing in adults. Inflammatory cells such as neutrophils, macrophages, dendritic cells, lymphocytes, and mast cells produce important cytokines, chemokines, and growth factors. These immune cells interact with keratinocytes, fibroblasts, and endothelial cells (ECs), as well as the extracellular matrix within a complicated network that promotes and regulates wound healing. Aberrant and persistent inflammation may result in delayed wound healing, scar formation, or chronic wounds. Targeting the molecules involved in the inflammatory response may have great potential therapeutic value. Recent Advances and Critical Issues: Toll-like receptors (TLRs) are pattern recognition receptors that recognize pathogen-associated molecular patterns from microbes or danger-associated molecular patterns from damaged cells. The discovery of TLRs sheds new light on the mechanism by which the inflammatory or innate immune response is initiated in wound healing. Convincing evidence now shows that multiple types of cells, including infiltrating or resident inflammatory cells, keratinocytes, fibroblasts, and ECs, express specific types of TLRs. Experimental reduction of certain TLRs or treatment of wounds with TLR ligands has been shown to affect wound healing. A better understanding of the involvement of TLRs in the innate immune response during skin wound healing may suggest novel strategies to improve the quality of tissue repair. Future Directions: Despite the indisputable role of TLRs in regulating the immune response in acute wound healing, the functions of TLRs that are relevant to human wound healing and chronic wounds are poorly understood. PMID:29062591

Binding Affinity of Glycoconjugates to BACILLUS Spores and Toxins

NASA Astrophysics Data System (ADS)

Rasol, Aveen; Eassa, Souzan; Tarasenko, Olga

2010-04-01

Early recognition of Bacillus cereus group species is important since they can cause food-borne illnesses and deadly diseases in humans. Glycoconjugates (GCs) are carbohydrates covalently linked to non-sugar moieties including lipids, proteins or other entities. GCs are involved in recognition and signaling processes intrinsic to biochemical functions in cells. They also stimulate cell-cell adhesion and subsequent recognition and activation of receptors. We have demonstrated that GCs are involved in Bacillus cereus spore recognition. In the present study, we have investigated whether GCs possess the ability to bind and recognize B. cereus spores and Bacillus anthracis recombinant single toxins (sTX) and complex toxins (cTX). The affinity of GCs to spores + sTX and spores + cTX toxins was studied in the binding essay. Our results demonstrated that GC9 and GC10 were able to selectively bind to B. cereus spores and B. anthracis toxins. Different binding affinities for GCs were found toward Bacillus cereus spores + sTX and spores + cTX. Dilution of GCs does not impede the recognition and binding. Developed method provides a tool for simultaneous recognition and targeting of spores, bacteria toxins, and/or other entities.

Functions of galectins as 'self/non-self'-recognition and effector factors.

PubMed

Vasta, Gerardo R; Feng, Chiguang; González-Montalbán, Nuria; Mancini, Justin; Yang, Lishi; Abernathy, Kelsey; Frost, Graeme; Palm, Cheyenne

2017-07-31

Carbohydrate structures on the cell surface encode complex information that through specific recognition by carbohydrate-binding proteins (lectins) modulates interactions between cells, cells and the extracellular matrix, or mediates recognition of potential microbial pathogens. Galectins are a family of ß-galactoside-binding lectins, which are evolutionary conserved and have been identified in most organisms, from fungi to invertebrates and vertebrates, including mammals. Since their discovery in the 1970s, their biological roles, initially understood as limited to recognition of endogenous carbohydrate ligands in embryogenesis and development, have expanded in recent years by the discovery of their roles in tissue repair and regulation of immune homeostasis. More recently, evidence has accumulated to support the notion that galectins can also bind glycans on the surface of potentially pathogenic microbes, and function as recognition and effector factors in innate immunity, thus establishing a new paradigm. Furthermore, some parasites 'subvert' the recognition roles of the vector/host galectins for successful attachment or invasion. These recent findings have revealed a striking functional diversification in this structurally conserved lectin family. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Polyphosphate is a key factor for cell survival after DNA damage in eukaryotic cells.

PubMed

Bru, Samuel; Samper-Martín, Bàrbara; Quandt, Eva; Hernández-Ortega, Sara; Martínez-Laínez, Joan M; Garí, Eloi; Rafel, Marta; Torres-Torronteras, Javier; Martí, Ramón; Ribeiro, Mariana P C; Jiménez, Javier; Clotet, Josep

2017-09-01

Cells require extra amounts of dNTPs to repair DNA after damage. Polyphosphate (polyP) is an evolutionary conserved linear polymer of up to several hundred inorganic phosphate (Pi) residues that is involved in many functions, including Pi storage. In the present article, we report on findings demonstrating that polyP functions as a source of Pi when required to sustain the dNTP increment essential for DNA repair after damage. We show that mutant yeast cells without polyP produce less dNTPs upon DNA damage and that their survival is compromised. In contrast, when polyP levels are ectopically increased, yeast cells become more resistant to DNA damage. More importantly, we show that when polyP is reduced in HEK293 mammalian cell line cells and in human dermal primary fibroblasts (HDFa), these cells become more sensitive to DNA damage, suggesting that the protective role of polyP against DNA damage is evolutionary conserved. In conclusion, we present polyP as a molecule involved in resistance to DNA damage and suggest that polyP may be a putative target for new approaches in cancer treatment or prevention. Copyright © 2017 Elsevier B.V. All rights reserved.

How cortical neurons help us see: visual recognition in the human brain

PubMed Central

Blumberg, Julie; Kreiman, Gabriel

2010-01-01

Through a series of complex transformations, the pixel-like input to the retina is converted into rich visual perceptions that constitute an integral part of visual recognition. Multiple visual problems arise due to damage or developmental abnormalities in the cortex of the brain. Here, we provide an overview of how visual information is processed along the ventral visual cortex in the human brain. We discuss how neurophysiological recordings in macaque monkeys and in humans can help us understand the computations performed by visual cortex. PMID:20811161

CYTOMEGALOVIRUS VECTORS VIOLATE CD8+ T CELL EPITOPE RECOGNITION PARADIGMS

PubMed Central

Hansen, Scott G.; Sacha, Jonah B.; Hughes, Colette M.; Ford, Julia C.; Burwitz, Benjamin J.; Scholz, Isabel; Gilbride, Roxanne M.; Lewis, Matthew S.; Gilliam, Awbrey N.; Ventura, Abigail B.; Malouli, Daniel; Xu, Guangwu; Richards, Rebecca; Whizin, Nathan; Reed, Jason S.; Hammond, Katherine B.; Fischer, Miranda; Turner, John M.; Legasse, Alfred W.; Axthelm, Michael K.; Edlefsen, Paul T.; Nelson, Jay A.; Lifson, Jeffrey D.; Früh, Klaus; Picker, Louis J.

2013-01-01

CD8+ T cell responses focus on a small fraction of pathogen- or vaccine-encoded peptides, and for some pathogens, these restricted recognition hierarchies limit the effectiveness of anti-pathogen immunity. We found that simian immunodeficiency virus (SIV) protein-expressing Rhesus Cytomegalovirus (RhCMV) vectors elicit SIV-specific CD8+ T cells that recognize unusual, diverse and highly promiscuous epitopes, including dominant responses to epitopes restricted by class II major histocompatibility complex (MHC) molecules. Induction of canonical SIV epitope-specific CD8+ T cell responses is suppressed by the RhCMV-encoded Rh189 (US11) gene, and the promiscuous MHC class I- and class II-restricted CD8+ T cell responses only occur in the absence of the Rh157.4-.6 (UL128-131) genes. Thus, CMV vectors can be genetically programmed to achieve distinct patterns of CD8+ T cell epitope recognition. PMID:23704576

Large-scale detection of antigen-specific T cells using peptide-MHC-I multimers labeled with DNA barcodes.

PubMed

Bentzen, Amalie Kai; Marquard, Andrea Marion; Lyngaa, Rikke; Saini, Sunil Kumar; Ramskov, Sofie; Donia, Marco; Such, Lina; Furness, Andrew J S; McGranahan, Nicholas; Rosenthal, Rachel; Straten, Per Thor; Szallasi, Zoltan; Svane, Inge Marie; Swanton, Charles; Quezada, Sergio A; Jakobsen, Søren Nyboe; Eklund, Aron Charles; Hadrup, Sine Reker

2016-10-01

Identification of the peptides recognized by individual T cells is important for understanding and treating immune-related diseases. Current cytometry-based approaches are limited to the simultaneous screening of 10-100 distinct T-cell specificities in one sample. Here we use peptide-major histocompatibility complex (MHC) multimers labeled with individual DNA barcodes to screen >1,000 peptide specificities in a single sample, and detect low-frequency CD8 T cells specific for virus- or cancer-restricted antigens. When analyzing T-cell recognition of shared melanoma antigens before and after adoptive cell therapy in melanoma patients, we observe a greater number of melanoma-specific T-cell populations compared with cytometry-based approaches. Furthermore, we detect neoepitope-specific T cells in tumor-infiltrating lymphocytes and peripheral blood from patients with non-small cell lung cancer. Barcode-labeled pMHC multimers enable the combination of functional T-cell analysis with large-scale epitope recognition profiling for the characterization of T-cell recognition in various diseases, including in small clinical samples.

From Immunity and Vaccines to Mammalian Regeneration.

PubMed

Heber-Katz, Ellen

2015-07-15

Our current understanding of major histocompatibility complex (MHC)-mediated antigen presentation in self and nonself immune recognition was derived from immunological studies of autoimmunity and virus-host interactions, respectively. The trimolecular complex of the MHC molecule, antigen, and T-cell receptor accounts for the phenomena of immunodominance and MHC degeneracy in both types of responses and constrains vaccine development. Out of such considerations, we developed a simple peptide vaccine construct that obviates immunodominance, resulting in a broadly protective T-cell response in the absence of antibody. In the course of autoimmunity studies, we identified the MRL mouse strain as a mammalian model of amphibian-like regeneration. A significant level of DNA damage in the cells from this mouse pointed to the role of the cell cycle checkpoint gene CDKN1a, or p21(cip1/waf1). The MRL mouse has highly reduced levels of this molecule, and a genetic knockout of this single gene in otherwise nonregenerating strains led to an MRL-type regenerative response, indicating that the ability to regenerate has not been lost during evolution. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Measurement of caspase-2 activation during different anti-tumor drugs induced apoptosis by FRET technique

NASA Astrophysics Data System (ADS)

Lin, Juqiang; Zeng, Shaoqun; Luo, Qingming; Rong, Chen; Zhang, Zhihong

2007-11-01

Caspase-2 is important for the engagement of the mitochondrial apoptotic pathway, in the presence of DNA-damaging agents, such as cisplatin; however, the mechanism by which caspase-2 executes apoptosis remains obscure. In this study, we carried out the measurements of the dynamics of caspase-2 activation in a single living cell by a FRET (fluorescence resonance energy transfer) probe. A FRET probe was constructed that encoded a CRS (caspase-2 recognition site) fused with a cyan fluorescent protein (CFP) and a red fluorescent protein (DsRed) (CFP-CRS-DsRed). Using this probe, we found that during TRAIL-induced apoptosis, caspase-2 was not activated, and caspase-2 activation occurred in etoposide and cisplatin treated cells. However, during cisplatin-induced apoptosis caspase-2 activation was initiated much earlier than that of etoposide. Cisplatin and etoposide is one of the most broadly used drugs in the Clinical applications of cancer chemotherapy, and TRAIL, which belongs to the TNF family proteins, can selectively induce apoptosis in many transformed cells but not in normal cells. Most of anticancer drugs can induce apoptosis mediated by the activation of caspase pathway. Thus, the perfect synergistic effect group of multi-drug can be selected by using our FRET probe.

CD56 Is a Pathogen Recognition Receptor on Human Natural Killer Cells.

PubMed

Ziegler, Sabrina; Weiss, Esther; Schmitt, Anna-Lena; Schlegel, Jan; Burgert, Anne; Terpitz, Ulrich; Sauer, Markus; Moretta, Lorenzo; Sivori, Simona; Leonhardt, Ines; Kurzai, Oliver; Einsele, Hermann; Loeffler, Juergen

2017-07-21

Aspergillus (A.) fumigatus is an opportunistic fungal mold inducing invasive aspergillosis (IA) in immunocompromised patients. Although antifungal activity of human natural killer (NK) cells was shown in previous studies, the underlying cellular mechanisms and pathogen recognition receptors (PRRs) are still unknown. Using flow cytometry we were able to show that the fluorescence positivity of the surface receptor CD56 significantly decreased upon fungal contact. To visualize the interaction site of NK cells and A. fumigatus we used SEM, CLSM and dSTORM techniques, which clearly demonstrated that NK cells directly interact with A. fumigatus via CD56 and that CD56 is re-organized and accumulated at this interaction site time-dependently. The inhibition of the cytoskeleton showed that the receptor re-organization was an active process dependent on actin re-arrangements. Furthermore, we could show that CD56 plays a role in the fungus mediated NK cell activation, since blocking of CD56 surface receptor reduced fungal mediated NK cell activation and reduced cytokine secretion. These results confirmed the direct interaction of NK cells and A. fumigatus, leading to the conclusion that CD56 is a pathogen recognition receptor. These findings give new insights into the functional role of CD56 in the pathogen recognition during the innate immune response.

Improved localization of cellular membrane receptors using combined fluorescence microscopy and simultaneous topography and recognition imaging

NASA Astrophysics Data System (ADS)

Duman, M.; Pfleger, M.; Zhu, R.; Rankl, C.; Chtcheglova, L. A.; Neundlinger, I.; Bozna, B. L.; Mayer, B.; Salio, M.; Shepherd, D.; Polzella, P.; Moertelmaier, M.; Kada, G.; Ebner, A.; Dieudonne, M.; Schütz, G. J.; Cerundolo, V.; Kienberger, F.; Hinterdorfer, P.

2010-03-01

The combination of fluorescence microscopy and atomic force microscopy has a great potential in single-molecule-detection applications, overcoming many of the limitations coming from each individual technique. Here we present a new platform of combined fluorescence and simultaneous topography and recognition imaging (TREC) for improved localization of cellular receptors. Green fluorescent protein (GFP) labeled human sodium-glucose cotransporter (hSGLT1) expressed Chinese Hamster Ovary (CHO) cells and endothelial cells (MyEnd) from mouse myocardium stained with phalloidin-rhodamine were used as cell systems to study AFM topography and fluorescence microscopy on the same surface area. Topographical AFM images revealed membrane features such as lamellipodia, cytoskeleton fibers, F-actin filaments and small globular structures with heights ranging from 20 to 30 nm. Combined fluorescence and TREC imaging was applied to detect density, distribution and localization of YFP-labeled CD1d molecules on α-galactosylceramide (αGalCer)-loaded THP1 cells. While the expression level, distribution and localization of CD1d molecules on THP1 cells were detected with fluorescence microscopy, the nanoscale distribution of binding sites was investigated with molecular recognition imaging by using a chemically modified AFM tip. Using TREC on the inverted light microscope, the recognition sites of cell receptors were detected in recognition images with domain sizes ranging from ~ 25 to ~ 160 nm, with the smaller domains corresponding to a single CD1d molecule.

γδ T cell receptors recognize the non-classical major histocompatibility complex (MHC) molecule T22 via conserved anchor residues in a MHC peptide-like fashion.

PubMed

Sandstrom, Andrew; Scharf, Louise; McRae, Gabrielle; Hawk, Andrew J; Meredith, Stephen C; Adams, Erin J

2012-02-17

The molecular mechanisms by which γδ T cells recognize ligand remain a mystery. The non-classical MHC molecule T22 represents the best characterized ligand for murine γδ T cells, with a motif (W … EGYEL) present in the γδ T cell receptor complementary-determining region 3δ (CDR3δ) loop mediating γδ T cell recognition of this molecule. Produced through V(D)J recombination, this loop is quite diverse, with different numbers and chemical types of amino acids between Trp and EGYEL, which have unknown functional consequences for T22 recognition. We have investigated the biophysical and structural effects of CDR3δ loop diversity, revealing a range of affinities for T22 but a common thermodynamic pattern. Mutagenesis of these CDR3δ loops defines the key anchor residues involved in T22 recognition as W … EGYEL, similar to those found for the G8 CDR3δ loop, and demonstrates that spacer residues modulate but are not required for T22 recognition. Comparison of the location of these residues in the T22 interface reveals a striking similarity to peptide anchor residues in classically presented MHC peptides, with the key Trp residue of the CDR3δ motif completing the deficient peptide-binding groove of T22. This suggests that γδ T cell recognition of T22 utilizes the conserved ligand-presenting nature of the MHC fold.

Improved localization of cellular membrane receptors using combined fluorescence microscopy and simultaneous topography and recognition imaging.

PubMed

Duman, M; Pfleger, M; Zhu, R; Rankl, C; Chtcheglova, L A; Neundlinger, I; Bozna, B L; Mayer, B; Salio, M; Shepherd, D; Polzella, P; Moertelmaier, M; Kada, G; Ebner, A; Dieudonne, M; Schütz, G J; Cerundolo, V; Kienberger, F; Hinterdorfer, P

2010-03-19

The combination of fluorescence microscopy and atomic force microscopy has a great potential in single-molecule-detection applications, overcoming many of the limitations coming from each individual technique. Here we present a new platform of combined fluorescence and simultaneous topography and recognition imaging (TREC) for improved localization of cellular receptors. Green fluorescent protein (GFP) labeled human sodium-glucose cotransporter (hSGLT1) expressed Chinese Hamster Ovary (CHO) cells and endothelial cells (MyEnd) from mouse myocardium stained with phalloidin-rhodamine were used as cell systems to study AFM topography and fluorescence microscopy on the same surface area. Topographical AFM images revealed membrane features such as lamellipodia, cytoskeleton fibers, F-actin filaments and small globular structures with heights ranging from 20 to 30 nm. Combined fluorescence and TREC imaging was applied to detect density, distribution and localization of YFP-labeled CD1d molecules on alpha-galactosylceramide (alphaGalCer)-loaded THP1 cells. While the expression level, distribution and localization of CD1d molecules on THP1 cells were detected with fluorescence microscopy, the nanoscale distribution of binding sites was investigated with molecular recognition imaging by using a chemically modified AFM tip. Using TREC on the inverted light microscope, the recognition sites of cell receptors were detected in recognition images with domain sizes ranging from approximately 25 to approximately 160 nm, with the smaller domains corresponding to a single CD1d molecule.

Scalloped and Yorkie are required for cell cycle re-entry of quiescent cells after tissue damage.

PubMed

Meserve, Joy H; Duronio, Robert J

2015-08-15

Regeneration of damaged tissues typically requires a population of active stem cells. How damaged tissue is regenerated in quiescent tissues lacking a stem cell population is less well understood. We used a genetic screen in the developing Drosophila melanogaster eye to investigate the mechanisms that trigger quiescent cells to re-enter the cell cycle and proliferate in response to tissue damage. We discovered that Hippo signaling regulates compensatory proliferation after extensive cell death in the developing eye. Scalloped and Yorkie, transcriptional effectors of the Hippo pathway, drive Cyclin E expression to induce cell cycle re-entry in cells that normally remain quiescent in the absence of damage. Ajuba, an upstream regulator of Hippo signaling that functions as a sensor of epithelial integrity, is also required for cell cycle re-entry. Thus, in addition to its well-established role in modulating proliferation during periods of tissue growth, Hippo signaling maintains homeostasis by regulating quiescent cell populations affected by tissue damage. © 2015. Published by The Company of Biologists Ltd.

A new chemotherapy agent-free theranostic system composed of graphene oxide nano-complex and aptamers for treatment of cancer cells.

PubMed

Bahreyni, Amirhossein; Yazdian-Robati, Rezvan; Hashemitabar, Shirin; Ramezani, Mohammad; Ramezani, Pouria; Abnous, Khalil; Taghdisi, Seyed Mohammad

2017-06-30

The common cancer treatment strategies like chemotherapy and radiotherapy are nonspecific and can trigger severe side effects by damaging normal cells. So, targeted cancer therapies, such as apoptosis induction, have attracted great attention in recent years. In this project, two nano-complexes, MUC1 aptamer-NAS-24 aptamer-Graphene oxide (GO) and MUC1 aptamer-Cytochrome C aptamer-GO, were designed to induce cell programmed death in MDA-MB-231 and MCF-7 cells (breast cancer cell lines) and to verify the level of apoptosis in both cell lines. MUC1 aptamer was a molecular recognition probe that led the internalization of two nano-complexes into MDA-MB-231 and MCF-7 cells (MUC1 positive cells) but not into HepG2 cell (liver cancer cell line, MUC1 negative cells). The apoptosis induction relied on binding of NAS-24 aptamer to its target, vimentin, in MDA-MB-231 and MCF-7 (target cells) with different levels of vimentin content. The function of first nano-complex was confirmed by binding of FAM-labeled cytochrome C aptamer to its target (cytochrome C) which was released from mitochondria, based on the function of the first nano-complex. Fluorometric analysis and gel retardation assay proved the formation of nano-complexes. The results of flow cytometry and fluorescence microscopy indicated efficient apoptosis induction just in target cells (MDA-MB-231 and MCF-7 cells) but not in non-target cells (HepG2 cell). The results of MTT assay also confirmed cell death process. Overall, our results proved excellent targeted apoptosis in breast cancer cells by designed nano-complexes which can be applied as an efficient cancer therapy method. Copyright © 2017 Elsevier B.V. All rights reserved.

Hyperoxic exposure of immature mice increases the inflammatory response to subsequent rhinovirus infection: Association with danger signals

PubMed Central

Cui, Tracy X.; Maheshwer, Bhargavi; Hong, Jun Y.; Goldsmith, Adam M.; Bentley, J. Kelley; Popova, Antonia P.

2016-01-01

Infants with a history of prematurity and bronchopulmonary dysplasia (BPD) have a high risk of asthma and viral-induced exacerbations later in life. We hypothesized that hyperoxic exposure, a predisposing factor to BPD, modulates the innate immune response, producing an exaggerated pro-inflammatory reaction to viral infection. Two-to-3 day-old C57BL/6J mice were exposed to air or 75% oxygen for 14 days. Mice were infected intranasally with rhinovirus (RV) immediately after O2 exposure. Lung mRNA and protein expression, histology, dendritic cells (DCs) and airways responsiveness were assessed 1-12 days after infection. Tracheal aspirates from premature human infants were collected for mRNA detection. Hyperoxia increased lung IL-12 expression which persisted up to 12 days post-exposure. Hyperoxia-exposed RV-infected mice showed further increases in IL-12 and increased expression of IFN-γ, TNF-α, CCL2, CCL3 and CCL4, as well as increased airway inflammation and responsiveness. In RV-infected, air-exposed mice the response was not significant. Induced IL-12 expression in hyperoxia-exposed, RV-infected mice was associated with increased IL-12-producing CD103+ lung DCs. Hyperoxia also increased expression of Clec9a, a CD103+ DC-specific damaged cell-recognition molecule. Hyperoxia increased levels of ATP metabolites and expression of adenosine receptor A1, further evidence of cell damage and related signaling. In human preterm infants, tracheal aspirate Clec9a expression positively correlated with the level of prematurity. Hyperoxic exposure increases the activation of CD103+, Clec9a+ DCs, leading to increased inflammation and airway hyperresponsiveness upon RV infection. In premature infants, danger signal-induced DC activation may promote pro-inflammatory airway responses, thereby increasing respiratory morbidity. PMID:27183577

Cellular Assays for Studying the Fe-S Cluster Containing Base Excision Repair Glycosylase MUTYH and Homologs.

PubMed

Majumdar, Chandrima; Nuñez, Nicole N; Raetz, Alan G; Khuu, Cindy; David, Sheila S

2018-01-01

Many DNA repair enzymes, including the human adenine glycosylase MUTYH, require iron-sulfur (Fe-S) cluster cofactors for DNA damage recognition and subsequent repair. MUTYH prokaryotic and eukaryotic homologs are a family of adenine (A) glycosylases that cleave A when mispaired with the oxidatively damaged guanine lesion, 8-oxo-7,8-dihydroguanine (OG). Faulty OG:A repair has been linked to the inheritance of missense mutations in the MUTYH gene. These inherited mutations can result in the onset of a familial colorectal cancer disorder known as MUTYH-associated polyposis (MAP). While in vitro studies can be exceptional at unraveling how MutY interacts with its OG:A substrate, cell-based assays are needed to provide a cellular context to these studies. In addition, strategic comparison of in vitro and in vivo studies can provide exquisite insight into the search, selection, excision process, and the coordination with protein partners, required to mediate full repair of the lesion. A commonly used assay is the rifampicin resistance assay that provides an indirect evaluation of the intrinsic mutation rate in Escherichia coli (E. coli or Ec), read out as antibiotic-resistant cell growth. Our laboratory has also developed a bacterial plasmid-based assay that allows for direct evaluation of repair of a defined OG:A mispair. This assay provides a means to assess the impact of catalytic defects in affinity and excision on overall repair. Finally, a mammalian GFP-based reporter assay has been developed that more accurately models features of mammalian cells. Taken together, these assays provide a cellular context to the repair activity of MUTYH and its homologs that illuminates the role these enzymes play in preventing mutations and disease. © 2018 Elsevier Inc. All rights reserved.

Curcumin causes DNA damage and affects associated protein expression in HeLa human cervical cancer cells.

PubMed

Shang, Hung-Sheng; Chang, Chuan-Hsun; Chou, Yu-Ru; Yeh, Ming-Yang; Au, Man-Kuan; Lu, Hsu-Feng; Chu, Yung-Lin; Chou, Hsiao-Min; Chou, Hsiu-Chen; Shih, Yung-Luen; Chung, Jing-Gung

2016-10-01

Cervical cancer is one of the most common cancers in women worldwide and it is a prominent cause of cancer mortality. Curcumin is one of the major compounds from Turmeric and has been shown to induce cytotoxic cell death in human cervical cancer cells. However, there is no study to show curcumin induced DNA damage action via the effect on the DNA damage and repair protein in cervical cancer cells in detail. In this study, we investigated whether or not curcumin induced cell death via DNA damage, chromatin condensation in human cervical cancer HeLa cells by using comet assay and DAPI staining, respectively, we found that curcumin induced cell death through the induction of DNA damage, and chromatin condensation. Western blotting and confocal laser microscopy examination were used to examine the effects of curcumin on protein expression associated with DNA damage, repair and translocation of proteins. We found that curcumin at 13 µM increased the protein levels associated with DNA damage and repair, such as O6-methylguanine-DNA methyltransferase, early-onset breast cancer 1 (BRCA1), mediator of DNA damage checkpoint 1, p-p53 and p-H2A.XSer140 in HeLa cells. Results from confocal laser systems microscopy indicated that curcumin increased the translocation of p-p53 and p-H2A.XSer140 from cytosol to nuclei in HeLa cells. In conclusion, curcumin induced cell death in HeLa cells via induction of DNA damage, and chromatin condensation in vitro.

Unrepaired DNA damage facilitates elimination of uniparental chromosomes in interspecific hybrid cells

PubMed Central

Wang, Zheng; Yin, Hao; Lv, Lei; Feng, Yingying; Chen, Shaopeng; Liang, Junting; Huang, Yun; Jiang, Xiaohua; Jiang, Hanwei; Bukhari, Ihtisham; Wu, Lijun; Cooke, Howard J; Shi, Qinghua

2014-01-01

Elimination of uniparental chromosomes occurs frequently in interspecific hybrid cells. For example, human chromosomes are always eliminated during clone formation when human cells are fused with mouse cells. However, the underlying mechanisms are still elusive. Here, we show that the elimination of human chromosomes in human–mouse hybrid cells is accompanied by continued cell division at the presence of DNA damage on human chromosomes. Deficiency in DNA damage repair on human chromosomes occurs after cell fusion. Furthermore, increasing the level of DNA damage on human chromosomes by irradiation accelerates human chromosome loss in hybrid cells. Our results indicate that the elimination of human chromosomes in human–mouse hybrid cells results from unrepaired DNA damage on human chromosomes. We therefore provide a novel mechanism underlying chromosome instability which may facilitate the understanding of carcinogenesis. PMID:24608870

Self/nonself perception in plants in innate immunity and defense

PubMed Central

Sanabria, Natasha M; Huang, Ju-Chi

2010-01-01

The ability to distinguish ‘self’ from ‘nonself’ is the most fundamental aspect of any immune system. The evolutionary solution in plants to the problems of perceiving and responding to pathogens involves surveillance of nonself, damaged-self and altered-self as danger signals. This is reflected in basal resistance or non-host resistance, which is the innate immune response that protects plants against the majority of pathogens. In the case of surveillance of nonself, plants utilize receptor-like proteins or -kinases (RLP/Ks) as pattern recognition receptors (PRRs), which can detect conserved pathogen/microbe-associated molecular pattern (P/MAMP) molecules. P/MAMP detection serves as an early warning system for the presence of a wide range of potential pathogens and the timely activation of plant defense mechanisms. However, adapted microbes express a suite of effector proteins that often interfere or act as suppressors of these defenses. In response, plants have evolved a second line of defense that includes intracellular nucleotide binding leucine-rich repeat (NB-LRR)-containing resistance proteins, which recognize isolate-specific pathogen effectors once the cell wall has been compromised. This host-immunity acts within the species level and is controlled by polymorphic host genes, where resistance protein-mediated activation of defense is based on an ‘altered-self’ recognition mechanism. PMID:21559176

The Fanconi Anemia DNA Repair Pathway Is Regulated by an Interaction between Ubiquitin and the E2-like Fold Domain of FANCL*

PubMed Central

Miles, Jennifer A.; Frost, Mark G.; Carroll, Eilis; Rowe, Michelle L.; Howard, Mark J.; Sidhu, Ateesh; Chaugule, Viduth K.; Alpi, Arno F.; Walden, Helen

2015-01-01

The Fanconi Anemia (FA) DNA repair pathway is essential for the recognition and repair of DNA interstrand crosslinks (ICL). Inefficient repair of these ICL can lead to leukemia and bone marrow failure. A critical step in the pathway is the monoubiquitination of FANCD2 by the RING E3 ligase FANCL. FANCL comprises 3 domains, a RING domain that interacts with E2 conjugating enzymes, a central domain required for substrate interaction, and an N-terminal E2-like fold (ELF) domain. The ELF domain is found in all FANCL homologues, yet the function of the domain remains unknown. We report here that the ELF domain of FANCL is required to mediate a non-covalent interaction between FANCL and ubiquitin. The interaction involves the canonical Ile44 patch on ubiquitin, and a functionally conserved patch on FANCL. We show that the interaction is not necessary for the recognition of the core complex, it does not enhance the interaction between FANCL and Ube2T, and is not required for FANCD2 monoubiquitination in vitro. However, we demonstrate that the ELF domain is required to promote efficient DNA damage-induced FANCD2 monoubiquitination in vertebrate cells, suggesting an important function of ubiquitin binding by FANCL in vivo. PMID:26149689

Alkaline ceramidase 2 and its bioactive product sphingosine are novel regulators of the DNA damage response

PubMed Central

Xu, Ruijuan; Wang, Kai; Mileva, Izolda; Hannun, Yusuf A.; Obeid, Lina M.; Mao, Cungui

2016-01-01

Human cells respond to DNA damage by elevating sphingosine, a bioactive sphingolipid that induces programmed cell death (PCD) in response to various forms of stress, but its regulation and role in the DNA damage response remain obscure. Herein we demonstrate that DNA damage increases sphingosine levels in tumor cells by upregulating alkaline ceramidase 2 (ACER2) and that the upregulation of the ACER2/sphingosine pathway induces PCD in response to DNA damage by increasing the production of reactive oxygen species (ROS). Treatment with the DNA damaging agent doxorubicin increased both ACER2 expression and sphingosine levels in HCT116 cells in a dose-dependent manner. ACER2 overexpression increased sphingosine in HeLa cells whereas knocking down ACER2 inhibited the doxorubicin-induced increase in sphingosine in HCT116 cells, suggesting that DNA damage elevates sphingosine by upregulating ACER2. Knocking down ACER2 inhibited an increase in the apoptotic and necrotic cell population and the cleavage of poly ADP ribose polymerase (PARP) in HCT116 cells in response to doxorubicin as well as doxorubicin-induced release of lactate dehydrogenase (LDH) from these cells. Similar to treatment with doxorubicin, ACER2 overexpression induced an increase in the apoptotic and necrotic cell population and PARP cleavage in HeLa cells and LDH release from cells, suggesting that ACER2 upregulation mediates PCD in response to DNA damage through sphingosine. Mechanistic studies demonstrated that the upregulation of the ACER2/sphingosine pathway induces PCD by increasing ROS levels. Taken together, these results suggest that the ACER2/sphingosine pathway mediates PCD in response to DNA damage through ROS production. PMID:26943039

Evaluation of saw damage using diamond-coated wire in crystalline silicon solar cells by photoluminescence imaging

NASA Astrophysics Data System (ADS)

Kinoshita, Kosuke; Kojima, Takuto; Suzuki, Ryota; Kawatsu, Tomoyuki; Nakamura, Kyotaro; Ohshita, Yoshio; Ogura, Atsushi

2018-05-01

Si ingots were sliced using a diamond-coated wire, and saw damage was observed even after damage removal etching and texturization. Since invisible microscopic damage was observed only under uncontrolled slice conditions, such damage was identified as saw damage. The wafers with saw damage exhibited the degradation of solar cell conversion efficiency (approximately 1–2% absolute). The results of external quantum efficiency (EQE) measurements showed a slight deterioration of EQE in the short wavelength region. Current–voltage characteristic measurements showed similar results that agreed with the EQE measurement results. In addition, EQE mapping measurements were carried out at various irradiation wavelengths between 350 and 1150 nm. Areas with dark contrasts in EQE mapping correspond to saw damage. In the cells with a low conversion efficiency, both EQE mapping and PL images exhibited dark areas and lines. On the other hand, in the cells with a high conversion efficiency, a uniform distribution of saw damage was observed even with the saw damage in the PL images. We believe that sophisticated control to suppress saw damage during sawing is required to realize higher conversion efficiency solar cells in the future.

Health Monitoring System for Composite Structures

NASA Technical Reports Server (NTRS)

Tang, S. S.; Riccardella, P. C.; Andrews, R. J.; Grady, J. E.; Mucciaradi, A. N.

1996-01-01

An automated system was developed to monitor the health status of composites. It uses the vibration characteristics of composites to identify a component's damage condition. The vibration responses are characterized by a set of signal features defined in the time, frequency and spatial domains. The identification of these changes in the vibration characteristics corresponding to different health conditions was performed using pattern recognition principles. This allows efficient data reduction and interpretation of vast amounts of information. Test components were manufactured from isogrid panels to evaluate performance of the monitoring system. The components were damaged by impact to simulate different health conditions. Free vibration response was induced by a tap test on the test components. The monitoring system was trained using these free vibration responses to identify three different health conditions. They are undamaged vs. damaged, damage location and damage zone size. High reliability in identifying the correct component health condition was achieved by the monitoring system.

Radiosensitizing effects of neem (Azadirachta indica) oil.

PubMed

Kumar, Ashok; Rao, A R; Kimura, H

2002-02-01

Radiosensitization by neem oil was studied using Balbc/3T3 cells and SCID cells. Neem oil enhanced the radiosensitivity of the cells when applied both during and after x-irradiation under aerobic conditions. Neem oil completely inhibited the repair of sublethal damage and potentially lethal damage repair in Balbc/3T3 cells. The cytofluorimeter data show that neem oil treatment before and after x-irradiation reduced the G(2) + M phase, thus inhibiting the expression of the radiation induced arrest of cells in the G(2) phase of the cell cycle. However, SCIK cells (derived from the SCID mouse), deficient in DSB repair, treated with neem oil did not show any enhancement in the radiosensitivity. There was no effect of neem oil on SLD repair or its inhibition in SCIK cells. These results suggest that neem oil enhanced the radiosensitivity of cells by interacting with residual damage after x-irradiation, thereby converting the sublethal damage or potentially lethal damage into lethal damage, inhibiting the double-strand break repair or reducing the G(2) phase of the cell cycle. Copyright 2002 John Wiley & Sons, Ltd.

Structural features facilitating tumor cell targeting and internalization by bleomycin and its disaccharide.

PubMed

Yu, Zhiqiang; Paul, Rakesh; Bhattacharya, Chandrabali; Bozeman, Trevor C; Rishel, Michael J; Hecht, Sidney M

2015-05-19

We have shown previously that the bleomycin (BLM) carbohydrate moiety can recapitulate the tumor cell targeting effects of the entire BLM molecule, that BLM itself is modular in nature consisting of a DNA-cleaving aglycone which is delivered selectively to the interior of tumor cells by its carbohydrate moiety, and that there are disaccharides structurally related to the BLM disaccharide which are more efficient than the natural disaccharide at tumor cell targeting/uptake. Because BLM sugars can deliver molecular cargoes selectively to tumor cells, and thus potentially form the basis for a novel antitumor strategy, it seemed important to consider additional structural features capable of affecting the efficiency of tumor cell recognition and delivery. These included the effects of sugar polyvalency and net charge (at physiological pH) on tumor cell recognition, internalization, and trafficking. Since these parameters have been shown to affect cell surface recognition, internalization, and distribution in other contexts, this study has sought to define the effects of these structural features on tumor cell recognition by bleomycin and its disaccharide. We demonstrate that both can have a significant effect on tumor cell binding/internalization, and present data which suggests that the metal ions normally bound by bleomycin following clinical administration may significantly contribute to the efficiency of tumor cell uptake, in addition to their characterized function in DNA cleavage. A BLM disaccharide-Cy5** conjugate incorporating the positively charged dipeptide d-Lys-d-Lys was found to associate with both the mitochondria and the nuclear envelope of DU145 cells, suggesting possible cellular targets for BLM disaccharide-cytotoxin conjugates.

Structural Features Facilitating Tumor Cell Targeting and Internalization by Bleomycin and Its Disaccharide

PubMed Central

2016-01-01

We have shown previously that the bleomycin (BLM) carbohydrate moiety can recapitulate the tumor cell targeting effects of the entire BLM molecule, that BLM itself is modular in nature consisting of a DNA-cleaving aglycone which is delivered selectively to the interior of tumor cells by its carbohydrate moiety, and that there are disaccharides structurally related to the BLM disaccharide which are more efficient than the natural disaccharide at tumor cell targeting/uptake. Because BLM sugars can deliver molecular cargoes selectively to tumor cells, and thus potentially form the basis for a novel antitumor strategy, it seemed important to consider additional structural features capable of affecting the efficiency of tumor cell recognition and delivery. These included the effects of sugar polyvalency and net charge (at physiological pH) on tumor cell recognition, internalization, and trafficking. Since these parameters have been shown to affect cell surface recognition, internalization, and distribution in other contexts, this study has sought to define the effects of these structural features on tumor cell recognition by bleomycin and its disaccharide. We demonstrate that both can have a significant effect on tumor cell binding/internalization, and present data which suggests that the metal ions normally bound by bleomycin following clinical administration may significantly contribute to the efficiency of tumor cell uptake, in addition to their characterized function in DNA cleavage. A BLM disaccharide-Cy5** conjugate incorporating the positively charged dipeptide d-Lys-d-Lys was found to associate with both the mitochondria and the nuclear envelope of DU145 cells, suggesting possible cellular targets for BLM disaccharide–cytotoxin conjugates. PMID:25905565

The medial dorsal thalamic nucleus and the medial prefrontal cortex of the rat function together to support associative recognition and recency but not item recognition.

PubMed

Cross, Laura; Brown, Malcolm W; Aggleton, John P; Warburton, E Clea

2012-12-21

In humans recognition memory deficits, a typical feature of diencephalic amnesia, have been tentatively linked to mediodorsal thalamic nucleus (MD) damage. Animal studies have occasionally investigated the role of the MD in single-item recognition, but have not systematically analyzed its involvement in other recognition memory processes. In Experiment 1 rats with bilateral excitotoxic lesions in the MD or the medial prefrontal cortex (mPFC) were tested in tasks that assessed single-item recognition (novel object preference), associative recognition memory (object-in-place), and recency discrimination (recency memory task). Experiment 2 examined the functional importance of the interactions between the MD and mPFC using disconnection techniques. Unilateral excitotoxic lesions were placed in both the MD and the mPFC in either the same (MD + mPFC Ipsi) or opposite hemispheres (MD + mPFC Contra group). Bilateral lesions in the MD or mPFC impaired object-in-place and recency memory tasks, but had no effect on novel object preference. In Experiment 2 the MD + mPFC Contra group was significantly impaired in the object-in-place and recency memory tasks compared with the MD + mPFC Ipsi group, but novel object preference was intact. Thus, connections between the MD and mPFC are critical for recognition memory when the discriminations involve associative or recency information. However, the rodent MD is not necessary for single-item recognition memory.

Voice tracking and spoken word recognition in the presence of other voices

NASA Astrophysics Data System (ADS)

Litong-Palima, Marisciel; Violanda, Renante; Saloma, Caesar

2004-12-01

We study the human hearing process by modeling the hair cell as a thresholded Hopf bifurcator and compare our calculations with experimental results involving human subjects in two different multi-source listening tasks of voice tracking and spoken-word recognition. In the model, we observed noise suppression by destructive interference between noise sources which weakens the effective noise strength acting on the hair cell. Different success rate characteristics were observed for the two tasks. Hair cell performance at low threshold levels agree well with results from voice-tracking experiments while those of word-recognition experiments are consistent with a linear model of the hearing process. The ability of humans to track a target voice is robust against cross-talk interference unlike word-recognition performance which deteriorates quickly with the number of uncorrelated noise sources in the environment which is a response behavior that is associated with linear systems.

Molecular recognition and colorimetric detection of cholera toxin by poly(diacetylene) liposomes incorporating G{sub m1} ganglioside

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, J.J.; Charych, D.

1997-03-19

Molecular recognition sites on cell membranes serve as the main communication channels between the inside of a cell and its surroundings. Upon receptor binding, cellular messages such as ion channel opening or activation of enzymes are triggered. In this report, we demonstrate that artificial cell membranes made from conjugated lipid polymers (poly(diacetylene)) can, on a simple level, mimic membrane processes of molecular recognition and signal transduction. The ganglioside GM1 was incorporated into poly(diacetylene) liposomes. Molecular recognition of cholera toxin at the interface of the liposome resulted in a change of the membrane color due to conformational charges in the conjugatedmore » (ene-yne) polymer backbone. The `colored liposomes` might be used as simple colorimetric sensors for drug screening or as new tools to study membrane-membrane or membrane-receptor interactions. 21 refs., 3 figs.« less

Technologies for developing an advanced intelligent ATM with self-defence capabilities

NASA Astrophysics Data System (ADS)

Sako, Hiroshi

2010-01-01

We have developed several technologies for protecting automated teller machines. These technologies are based mainly on pattern recognition and are used to implement various self-defence functions. They include (i) banknote recognition and information retrieval for preventing machines from accepting counterfeit and damaged banknotes and for retrieving information about detected counterfeits from a relational database, (ii) form processing and character recognition for preventing machines from accepting remittance forms without due dates and/or insufficient payment, (iii) person identification to prevent machines from transacting with non-customers, and (iv) object recognition to guard machines against foreign objects such as spy cams that might be surreptitiously attached to them and to protect users against someone attempting to peek at their user information such as their personal identification number. The person identification technology has been implemented in most ATMs in Japan, and field tests have demonstrated that the banknote recognition technology can recognise more then 200 types of banknote from 30 different countries. We are developing an "advanced intelligent ATM" that incorporates all of these technologies.

Ultraviolet Radiation-Induced Skin Aging: The Role of DNA Damage and Oxidative Stress in Epidermal Stem Cell Damage Mediated Skin Aging

PubMed Central

Panich, Uraiwan; Sittithumcharee, Gunya; Rathviboon, Natwarath

2016-01-01

Skin is the largest human organ. Skin continually reconstructs itself to ensure its viability, integrity, and ability to provide protection for the body. Some areas of skin are continuously exposed to a variety of environmental stressors that can inflict direct and indirect damage to skin cell DNA. Skin homeostasis is maintained by mesenchymal stem cells in inner layer dermis and epidermal stem cells (ESCs) in the outer layer epidermis. Reduction of skin stem cell number and function has been linked to impaired skin homeostasis (e.g., skin premature aging and skin cancers). Skin stem cells, with self-renewal capability and multipotency, are frequently affected by environment. Ultraviolet radiation (UVR), a major cause of stem cell DNA damage, can contribute to depletion of stem cells (ESCs and mesenchymal stem cells) and damage of stem cell niche, eventually leading to photoinduced skin aging. In this review, we discuss the role of UV-induced DNA damage and oxidative stress in the skin stem cell aging in order to gain insights into the pathogenesis and develop a way to reduce photoaging of skin cells. PMID:27148370

The DNA damage response during mitosis.

PubMed

Heijink, Anne Margriet; Krajewska, Małgorzata; van Vugt, Marcel A T M

2013-10-01

Cells are equipped with a cell-intrinsic signaling network called the DNA damage response (DDR). This signaling network recognizes DNA lesions and initiates various downstream pathways to coordinate a cell cycle arrest with the repair of the damaged DNA. Alternatively, the DDR can mediate clearance of affected cells that are beyond repair through apoptosis or senescence. The DDR can be activated in response to DNA damage throughout the cell cycle, although the extent of DDR signaling is different in each cell cycle phase. Especially in response to DNA double strand breaks, only a very marginal response was observed during mitosis. Early on it was recognized that cells which are irradiated during mitosis continued division without repairing broken chromosomes. Although these initial observations indicated diminished DNA repair and lack of an acute DNA damage-induced cell cycle arrest, insight into the mechanistic re-wiring of DDR signaling during mitosis was only recently provided. Different mechanisms appear to be at play to inactivate specific signaling axes of the DDR network in mitosis. Importantly, mitotic cells not simply inactivate the entire DDR, but appear to mark their DNA damage for repair after mitotic exit. Since the treatment of cancer frequently involves agents that induce DNA damage as well as agents that block mitotic progression, it is clinically relevant to obtain a better understanding of how cancer cells deal with DNA damage during interphase versus mitosis. In this review, the molecular details concerning DDR signaling during mitosis as well as the consequences of encountering DNA damage during mitosis for cellular fate are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

The good, the (not so) bad and the ugly of immune homeostasis in melanoma.

PubMed

da Gama Duarte, Jessica; Woods, Katherine; Andrews, Miles C; Behren, Andreas

2018-05-01

Within the immune system multiple mechanisms balance the need for efficient pathogen recognition and destruction with the prevention of tissue damage by excessive, inappropriate or even self-targeting (auto)immune reactions. This immune homeostasis is a tightly regulated system which fails during tumor development, often due to the hijacking of its essential self-regulatory mechanisms by cancer cells. It is facilitated not only by tumor intrinsic properties, but also by the microbiome, host genetics and other factors. In certain ways many cancers can therefore be considered a rare failure of immune control rather than an uncommon or rare disease of the tissue of origin, as the acquisition of potentially oncogenic traits through mutation occurs constantly in most tissues during proliferation. Normally, aberrant cells are well-controlled by cell intrinsic (repair or apoptosis) and extrinsic (immune) mechanisms. However, occasionally oncogenic cells survive and escape control. Melanoma is one of the first cancer types where treatments aimed at restoring and enhancing an immune response to regain control over the tumor have been used with various success rates. With the advent of "modern" immunotherapeutics such as anti-CTLA-4 or anti-PD-1 antibodies that both target negative immune-regulatory pathways on immune cells resulting in durable responses in a proportion of patients, the importance of the interplay between the immune system and cancer has been established beyond doubt. © 2017 Australasian Society for Immunology Inc.

The impact of FANCD2 deficiency on formaldehyde-induced toxicity in human lymphoblastoid cell lines

PubMed Central

Ren, Xuefeng; Ji, Zhiying; McHale, Cliona M.; Yuh, Jessica; Bersonda, Jessica; Tang, Maycky; Smith, Martyn T.; Zhang, Luoping

2015-01-01

Formaldehyde (FA), a major industrial chemical and ubiquitous environmental pollutant, has recently been classified by the International Agency for Research on Cancer as a human leukemogen. The major mode of action of FA is thought to be the formation of DNA-protein crosslinks (DPCs). Repair of DPCs may be mediated by the Fanconi anemia pathway; however, data supporting the involvement of this pathway is limited, particularly in human hematopoietic cells. Therefore, we assessed the role of FANCD2, a critical component of the Fanconi anemia pathway, in FA-induced toxicity in human lymphoblast cell models of FANCD2-deficiency (PD20 cells) and FANCD2-sufficiency (PD20-D2 cells). After treatment of the cells with 0-150 μM FA for 24 hours, DPCs were increased in a dose-dependent manner in both cell lines, with greater increases in FANCD2-deficient PD20 cells. FA also induced cytotoxicity, micronuclei, chromosome aberrations, and apoptosis in a dose-dependent manner in both cell lines, with greater increases in cytotoxicity and apoptosis in PD20 cells. Increased levels of γ-ATR and γ-H2AX in both cell lines suggested the recognition of FA-induced DNA damage; however, the induction of BRCA2 was compromised in FANCD2-deficient PD20 cells, potentially reducing the capacity to repair DPCs. Together, these findings suggest that FANCD2 protein and the Fanconi anemia pathway are essential to protect human lymphoblastoid cells against FA toxicity. Future studies are needed to delineate the role of this pathway in mitigating FA-induced toxicity, particularly in hematopoietic stem cells, the target cells in leukemia. PMID:22872141

High-fidelity in vivo replication of DNA base shape mimics without Watson–Crick hydrogen bonds

PubMed Central

Delaney, James C.; Henderson, Paul T.; Helquist, Sandra A.; Morales, Juan C.; Essigmann, John M.; Kool, Eric T.

2003-01-01

We report studies testing the importance of Watson–Crick hydrogen bonding, base-pair geometry, and steric effects during DNA replication in living bacterial cells. Nonpolar DNA base shape mimics of thymine and adenine (abbreviated F and Q, respectively) were introduced into Escherichia coli by insertion into a phage genome followed by transfection of the vector into bacteria. Genetic assays showed that these two base mimics were bypassed with moderate to high efficiency in the cells and with very high efficiency under damage-response (SOS induction) conditions. Under both sets of conditions, the T-shape mimic (F) encoded genetic information in the bacteria as if it were thymine, directing incorporation of adenine opposite it with high fidelity. Similarly, the A mimic (Q) directed incorporation of thymine opposite itself with high fidelity. The data establish that Watson–Crick hydrogen bonding is not necessary for high-fidelity replication of a base pair in vivo. The results suggest that recognition of DNA base shape alone serves as the most powerful determinant of fidelity during transfer of genetic information in a living organism. PMID:12676985

RPA and Rad51 constitute a cell intrinsic mechanism to protect the cytosol from self DNA.

PubMed

Wolf, Christine; Rapp, Alexander; Berndt, Nicole; Staroske, Wolfgang; Schuster, Max; Dobrick-Mattheuer, Manuela; Kretschmer, Stefanie; König, Nadja; Kurth, Thomas; Wieczorek, Dagmar; Kast, Karin; Cardoso, M Cristina; Günther, Claudia; Lee-Kirsch, Min Ae

2016-05-27

Immune recognition of cytosolic DNA represents a central antiviral defence mechanism. Within the host, short single-stranded DNA (ssDNA) continuously arises during the repair of DNA damage induced by endogenous and environmental genotoxic stress. Here we show that short ssDNA traverses the nuclear membrane, but is drawn into the nucleus by binding to the DNA replication and repair factors RPA and Rad51. Knockdown of RPA and Rad51 enhances cytosolic leakage of ssDNA resulting in cGAS-dependent type I IFN activation. Mutations in the exonuclease TREX1 cause type I IFN-dependent autoinflammation and autoimmunity. We demonstrate that TREX1 is anchored within the outer nuclear membrane to ensure immediate degradation of ssDNA leaking into the cytosol. In TREX1-deficient fibroblasts, accumulating ssDNA causes exhaustion of RPA and Rad51 resulting in replication stress and activation of p53 and type I IFN. Thus, the ssDNA-binding capacity of RPA and Rad51 constitutes a cell intrinsic mechanism to protect the cytosol from self DNA.

An on-chip imaging droplet-sorting system: a real-time shape recognition method to screen target cells in droplets with single cell resolution

NASA Astrophysics Data System (ADS)

Girault, Mathias; Kim, Hyonchol; Arakawa, Hisayuki; Matsuura, Kenji; Odaka, Masao; Hattori, Akihiro; Terazono, Hideyuki; Yasuda, Kenji

2017-01-01

A microfluidic on-chip imaging cell sorter has several advantages over conventional cell sorting methods, especially to identify cells with complex morphologies such as clusters. One of the remaining problems is how to efficiently discriminate targets at the species level without labelling. Hence, we developed a label-free microfluidic droplet-sorting system based on image recognition of cells in droplets. To test the applicability of this method, a mixture of two plankton species with different morphologies (Dunaliella tertiolecta and Phaeodactylum tricornutum) were successfully identified and discriminated at a rate of 10 Hz. We also examined the ability to detect the number of objects encapsulated in a droplet. Single cell droplets sorted into collection channels showed 91 ± 4.5% and 90 ± 3.8% accuracy for D. tertiolecta and P. tricornutum, respectively. Because we used image recognition to confirm single cell droplets, we achieved highly accurate single cell sorting. The results indicate that the integrated method of droplet imaging cell sorting can provide a complementary sorting approach capable of isolating single target cells from a mixture of cells with high accuracy without any staining.

An on-chip imaging droplet-sorting system: a real-time shape recognition method to screen target cells in droplets with single cell resolution.

PubMed

Girault, Mathias; Kim, Hyonchol; Arakawa, Hisayuki; Matsuura, Kenji; Odaka, Masao; Hattori, Akihiro; Terazono, Hideyuki; Yasuda, Kenji

2017-01-06

A microfluidic on-chip imaging cell sorter has several advantages over conventional cell sorting methods, especially to identify cells with complex morphologies such as clusters. One of the remaining problems is how to efficiently discriminate targets at the species level without labelling. Hence, we developed a label-free microfluidic droplet-sorting system based on image recognition of cells in droplets. To test the applicability of this method, a mixture of two plankton species with different morphologies (Dunaliella tertiolecta and Phaeodactylum tricornutum) were successfully identified and discriminated at a rate of 10 Hz. We also examined the ability to detect the number of objects encapsulated in a droplet. Single cell droplets sorted into collection channels showed 91 ± 4.5% and 90 ± 3.8% accuracy for D. tertiolecta and P. tricornutum, respectively. Because we used image recognition to confirm single cell droplets, we achieved highly accurate single cell sorting. The results indicate that the integrated method of droplet imaging cell sorting can provide a complementary sorting approach capable of isolating single target cells from a mixture of cells with high accuracy without any staining.

An on-chip imaging droplet-sorting system: a real-time shape recognition method to screen target cells in droplets with single cell resolution

PubMed Central

Girault, Mathias; Kim, Hyonchol; Arakawa, Hisayuki; Matsuura, Kenji; Odaka, Masao; Hattori, Akihiro; Terazono, Hideyuki; Yasuda, Kenji

2017-01-01

A microfluidic on-chip imaging cell sorter has several advantages over conventional cell sorting methods, especially to identify cells with complex morphologies such as clusters. One of the remaining problems is how to efficiently discriminate targets at the species level without labelling. Hence, we developed a label-free microfluidic droplet-sorting system based on image recognition of cells in droplets. To test the applicability of this method, a mixture of two plankton species with different morphologies (Dunaliella tertiolecta and Phaeodactylum tricornutum) were successfully identified and discriminated at a rate of 10 Hz. We also examined the ability to detect the number of objects encapsulated in a droplet. Single cell droplets sorted into collection channels showed 91 ± 4.5% and 90 ± 3.8% accuracy for D. tertiolecta and P. tricornutum, respectively. Because we used image recognition to confirm single cell droplets, we achieved highly accurate single cell sorting. The results indicate that the integrated method of droplet imaging cell sorting can provide a complementary sorting approach capable of isolating single target cells from a mixture of cells with high accuracy without any staining. PMID:28059147

Automatic voltage imbalance detector

DOEpatents

Bobbett, Ronald E.; McCormick, J. Byron; Kerwin, William J.

1984-01-01

A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

How Does the Macula Protect Itself from Oxidative Stress?

PubMed Central

Handa, James T.

2012-01-01

Oxidative stress has been hypothesized to contribute to the development of age-related macular degeneration (AMD), the most common cause of blindness in the United States. At present, there is no treatment for early disease. Reactive oxygen species (ROS) play a physiological role in the retinal pigment epithelium (RPE), a key cell type in this disease, but with excessive ROS, oxidative damage or excessive innate immune system activation can result. The RPE has developed a robust antioxidant system driven by the transcription factor Nrf2. Impaired Nrf2 signaling can lead to oxidative damage or activate the innate immune response, both of which can lead to RPE apoptosis, a defining change in AMD. Several mouse models simulating environmental stressors or targeting specific antioxidant enzymes such as superoxide dismutase or Nrf2, have simulated some of the features of AMD. While ROS are short-lived, oxidatively damaged molecules termed oxidation specific epitopes (OSEs), can be long-lived and a source of chronic stress that activates the innate immune system through pattern recognition receptors (PRRs). The macula accumulates a number of OSEs including carboxyethylpyrrole, malondialdehyde, 4-hydroxynonenal, and advanced glycation endproducts, as well as their respective neutralizing PRRs. Excessive accumulation of OSEs results in pathologic immune activation. For example, mice immunized with the carboxyethylpyrrole develop cardinal features of AMD. Regulating ROS in the RPE by modulating antioxidant systems or neutralizing OSEs through an appropriate innate immune response are potential modalities to treat or prevent early AMD. PMID:22503691

How does the macula protect itself from oxidative stress?

PubMed

Handa, James T

2012-08-01

Oxidative stress has been hypothesized to contribute to the development of age-related macular degeneration (AMD), the most common cause of blindness in the United States. At present, there is no treatment for early disease. Reactive oxygen species (ROS) play a physiological role in the retinal pigment epithelium (RPE), a key cell type in this disease, but with excessive ROS, oxidative damage or excessive innate immune system activation can result. The RPE has developed a robust antioxidant system driven by the transcription factor Nrf2. Impaired Nrf2 signaling can lead to oxidative damage or activate the innate immune response, both of which can lead to RPE apoptosis, a defining change in AMD. Several mouse models simulating environmental stressors or targeting specific antioxidant enzymes such as superoxide dismutase or Nrf2, have simulated some of the features of AMD. While ROS are short-lived, oxidatively damaged molecules termed oxidation specific epitopes (OSEs), can be long-lived and a source of chronic stress that activates the innate immune system through pattern recognition receptors (PRRs). The macula accumulates a number of OSEs including carboxyethylpyrrole, malondialdehyde, 4-hydroxynonenal, and advanced glycation endproducts, as well as their respective neutralizing PRRs. Excessive accumulation of OSEs results in pathologic immune activation. For example, mice immunized with the carboxyethylpyrrole develop cardinal features of AMD. Regulating ROS in the RPE by modulating antioxidant systems or neutralizing OSEs through an appropriate innate immune response are potential modalities to treat or prevent early AMD. Copyright © 2012 Elsevier Ltd. All rights reserved.

Extent of hippocampal atrophy predicts degree of deficit in recall

PubMed Central

Patai, Eva Zita; Gadian, David G.; Cooper, Janine M.; Dzieciol, Anna M.; Mishkin, Mortimer; Vargha-Khadem, Faraneh

2015-01-01

Which specific memory functions are dependent on the hippocampus is still debated. The availability of a large cohort of patients who had sustained relatively selective hippocampal damage early in life enabled us to determine which type of mnemonic deficit showed a correlation with extent of hippocampal injury. We assessed our patient cohort on a test that provides measures of recognition and recall that are equated for difficulty and found that the patients' performance on the recall tests correlated significantly with their hippocampal volumes, whereas their performance on the equally difficult recognition tests did not and, indeed, was largely unaffected regardless of extent of hippocampal atrophy. The results provide new evidence in favor of the view that the hippocampus is essential for recall but not for recognition. PMID:26417089

Extent of hippocampal atrophy predicts degree of deficit in recall.

PubMed

Patai, Eva Zita; Gadian, David G; Cooper, Janine M; Dzieciol, Anna M; Mishkin, Mortimer; Vargha-Khadem, Faraneh

2015-10-13

Which specific memory functions are dependent on the hippocampus is still debated. The availability of a large cohort of patients who had sustained relatively selective hippocampal damage early in life enabled us to determine which type of mnemonic deficit showed a correlation with extent of hippocampal injury. We assessed our patient cohort on a test that provides measures of recognition and recall that are equated for difficulty and found that the patients' performance on the recall tests correlated significantly with their hippocampal volumes, whereas their performance on the equally difficult recognition tests did not and, indeed, was largely unaffected regardless of extent of hippocampal atrophy. The results provide new evidence in favor of the view that the hippocampus is essential for recall but not for recognition.

The Alarmin Properties of DNA and DNA-associated Nuclear Proteins.

PubMed

Magna, Melinda; Pisetsky, David S

2016-05-01

The communication of cell injury and death is a critical element in host defense. Although immune cells can serve this function by elaborating cytokines and chemokines, somatic cells can repurpose nuclear macromolecules to function as damage-associated molecular patterns (DAMPs) or alarmins to exert similar activity. Among these molecules, DNA, high-mobility group box-1, and histone proteins can all act as DAMPs once they are in an extracellular location. This review describes current information on the role of the nuclear DAMPs, their translocation to the outside of cells, and pathways of activation after uptake into the inside of immune cells. MEDLINE and PubMed databases were searched for citations (1990-2016) in English related to the following terms: DAMPs, high-mobility group box-1, DNA, histones, cell death, danger, and immune activation. Selected articles with the most relevant studies were included for a more detailed consideration. Although nuclear molecules have important structural and genetic regulatory roles inside the cell nucleus, when released into the extracellular space during cell death, these molecules can acquire immune activity and serve as alarmins or DAMPs. Although apoptosis is generally considered the source of extracellular nuclear material, other cell death pathways such as necroptosis, NETosis, and pyroptosis can contribute to the release of nuclear molecules. Importantly, the release of nuclear DAMPs occurs with both soluble and particulate forms of these molecules. The activity of nuclear molecules may depend on posttranslational modifications, redox changes, and the binding of other molecules. Once in an extracellular location, nuclear DAMPs can engage the same pattern recognition receptors as do pathogen-associated molecular patterns. These interactions can activate immune cells and lead to cytokine and chemokine production. Among these receptors, internal receptors for DNA are key to the response to this molecule; the likely function of these internal sensors is the recognition of DNA from intracellular infection by bacteria or viruses. Activation of these receptors requires translocation of extracellular DNA into specialized compartments. In addition to nuclear DNA, mitochondrial DNA can also serve as a DAMP. The communication of cell injury and death is a critical element in host defense and involves the repurposing of nuclear molecules as immune triggers. As such, the presence of extracellular nuclear material can serve as novel biomarkers for conditions involving cell injury and death. Targeting of these molecules may also represent an important new approach to therapy. Published by Elsevier Inc.

Expanding the universe of cytokines and pattern recognition receptors: galectins and glycans in innate immunity.

PubMed

Cerliani, Juan P; Stowell, Sean R; Mascanfroni, Iván D; Arthur, Connie M; Cummings, Richard D; Rabinovich, Gabriel A

2011-02-01

Effective immunity relies on the recognition of pathogens and tumors by innate immune cells through diverse pattern recognition receptors (PRRs) that lead to initiation of signaling processes and secretion of pro- and anti-inflammatory cytokines. Galectins, a family of endogenous lectins widely expressed in infected and neoplastic tissues have emerged as part of the portfolio of soluble mediators and pattern recognition receptors responsible for eliciting and controlling innate immunity. These highly conserved glycan-binding proteins can control immune cell processes through binding to specific glycan structures on pathogens and tumors or by acting intracellularly via modulation of selective signaling pathways. Recent findings demonstrate that various galectin family members influence the fate and physiology of different innate immune cells including polymorphonuclear neutrophils, mast cells, macrophages, and dendritic cells. Moreover, several pathogens may actually utilize galectins as a mechanism of host invasion. In this review, we aim to highlight and integrate recent discoveries that have led to our current understanding of the role of galectins in host-pathogen interactions and innate immunity. Challenges for the future will embrace the rational manipulation of galectin-glycan interactions to instruct and shape innate immunity during microbial infections, inflammation, and cancer.

Escin-induced DNA damage promotes escin-induced apoptosis in human colorectal cancer cells via p62 regulation of the ATM/γH2AX pathway.

PubMed

Wang, Zhong; Chen, Qiang; Li, Bin; Xie, Jia-Ming; Yang, Xiao-Dong; Zhao, Kui; Wu, Yong; Ye, Zhen-Yu; Chen, Zheng-Rong; Qin, Zheng-Hong; Xing, Chun-Gen

2018-05-31

Escin, a triterpene saponin isolated from horse chestnut seed, has been used to treat encephaledema, tissue swelling and chronic venous insufficiency. Recent studies show that escin induces cell cycle arrest, tumor proliferation inhibition and tumor cell apoptosis. But the relationship between escin-induced DNA damage and cell apoptosis in tumor cells remains unclear. In this study, we investigated whether and how escin-induced DNA damage contributed to escin-induced apoptosis in human colorectal cancer cells. Escin (5-80 μg/mL) dose-dependently inhibited the cell viability and colony formation in HCT116 and HCT8 cells. Escin treatment induced DNA damage, leading to p-ATM and γH2AX upregulation. Meanwhile, escin treatment increased the expression of p62, an adaptor protein, which played a crucial role in controlling cell survival and tumorigenesis, and had a protective effect against escin-induced DNA damage: knockdown of p62 apparently enhanced escin-induced DNA damage, whereas overexpression of p62 reduced escin-induced DNA damage. In addition, escin treatment induced concentration- and time-dependent apoptosis. Similarly, knockdown of p62 significantly increased escin-induced apoptosis in vitro and produced en escin-like antitumor effect in vivo. Overexpression of p62 decreased the rate of apoptosis. Further studies revealed that the functions of p62 in escin-induced DNA damage were associated with escin-induced apoptosis, and p62 knockdown combined with the ATM inhibitor KU55933 augmented escin-induced DNA damage and further increased escin-induced apoptosis. In conclusion, our results demonstrate that p62 regulates ATM/γH2AX pathway-mediated escin-induced DNA damage and apoptosis.

The use of highway underpasses by large mammals in Virginia and factors influencing their effectiveness.

DOT National Transportation Integrated Search

2005-01-01

The rapid increase in animal-vehicle collisions on U.S. roadways is a growing concern in terms of human safety, property damage and injury costs, and viability of wildlife populations. Wildlife crossing structures are gaining national recognition by ...

Adaptability to Changes in Temporal Structure Is Fornix-Dependent

ERIC Educational Resources Information Center

Kwok, Sze Chai; Mitchell, Anna S.; Buckley, Mark J.

2015-01-01

Recognition memory deficits, even after short delays, are sometimes observed following hippocampal damage. One hypothesis links the hippocampus with processes in updating contextual memory representation. Here, we used fornix transection, which partially disconnects the hippocampal system, and compares the performance of fornix-transected monkeys…

Adaptability to Changes Intemporal Structure Is Fornix-Dependent

ERIC Educational Resources Information Center

Kwok, Sze Chai; Mitchell, Anna S.; Buckley, Mark J.

2015-01-01

Recognition memory deficits, even after short delays, are sometimes observed following hippocampal damage. One hypothesis links the hippocampus with processes in updating contextual memory representation. Here, we used fornix transection, which partially disconnects the hippocampal system, and compares the performance of fornix-transected monkeys…

Report on the Sixth Workshop on Chinese Linguistics.

ERIC Educational Resources Information Center

Shen, Zhongwei

1987-01-01

Summarizes 10 presentations made at the workshop on a variety of topics including: classification of Chinese dialects; the importance of semantic units in tone sandhi; insights on Chinese character recognition among brain-damaged patients; and a cognitive approach to the study of Chinese grammar. (TR)

Recognition and repair of chemically heterogeneous structures at DNA ends

PubMed Central

Andres, Sara N.; Schellenberg, Matthew J.; Wallace, Bret D.; Tumbale, Percy; Williams, R. Scott

2014-01-01

Exposure to environmental toxicants and stressors, radiation, pharmaceutical drugs, inflammation, cellular respiration, and routine DNA metabolism all lead to the production of cytotoxic DNA strand breaks. Akin to splintered wood, DNA breaks are not “clean”. Rather, DNA breaks typically lack DNA 5'-phosphate and 3'-hydroxyl moieties required for DNA synthesis and DNA ligation. Failure to resolve damage at DNA ends can lead to abnormal DNA replication and repair, and is associated with genomic instability, mutagenesis, neurological disease, ageing and carcinogenesis. An array of chemically heterogeneous DNA termini arises from spontaneously generated DNA single-strand and double-strand breaks (SSBs and DSBs), and also from normal and/or inappropriate DNA metabolism by DNA polymerases, DNA ligases and topoisomerases. As a front line of defense to these genotoxic insults, eukaryotic cells have accrued an arsenal of enzymatic first responders that bind and protect damaged DNA termini, and enzymatically tailor DNA ends for DNA repair synthesis and ligation. These nucleic acid transactions employ direct damage reversal enzymes including Aprataxin (APTX), Polynucleotide kinase phosphatase (PNK), the tyrosyl DNA phosphodiesterases (TDP1 and TDP2), the Ku70/80 complex and DNA polymerase β (POLβ). Nucleolytic processing enzymes such as the MRE11/RAD50/NBS1/CtIP complex, Flap endonuclease (FEN1) and the apurinic endonucleases (APE1 and APE2) also act in the chemical "cleansing" of DNA breaks to prevent genomic instability and disease, and promote progression of DNA- and RNA-DNA damage response (DDR and RDDR) pathways. Here, we provide an overview of cellular first responders dedicated to the detection and repair of abnormal DNA termini. PMID:25111769

Zebrafish hair cell mechanics and physiology through the lens of noise-induced hair cell death

NASA Astrophysics Data System (ADS)

Coffin, Allison B.; Xu, Jie; Uribe, Phillip M.

2018-05-01

Hair cells are exquisitely sensitive to auditory stimuli, but also to damage from a variety of sources including noise trauma and ototoxic drugs. Mammals cannot regenerate cochlear hair cells, while non-mammalian vertebrates exhibit robust regenerative capacity. Our research group uses the lateral line system of larval zebrafish to explore the mechanisms underlying hair cell damage, identify protective therapies, and determine molecular drivers of innate regeneration. The lateral line system contains externally located sensory organs called neuromasts, each composed of ˜8-20 hair cells. Lateral line hair cells are homologous to vertebrate inner ear hair cells and share similar susceptibility to ototoxic damage. In the last decade, the lateral line has emerged as a powerful model system for understanding hair cell death mechanisms and for identifying novel protective compounds. Here we demonstrate that the lateral line is a tractable model for noise-induced hair cell death. We have developed a novel noise damage system capable of inducing over 50% loss of lateral line hair cells, with hair cell death occurring in a dose- and time-dependent manner. Cell death is greatest 72 hours post-exposure. However, early signs of hair cell damage, including changes in membrane integrity and reduced mechanotransduction, are apparent within hours of noise exposure. These features, early signs of damage followed by delayed hair cell death, are consistent with mammalian data, suggesting that noise acts similarly on zebrafish and mammalian hair cells. In our future work we will use our new model system to investigate noise damage events in real time, and to develop protective therapies for future translational research.

Link between DNA damage and centriole disengagement/reduplication in untransformed human cells.

PubMed

Douthwright, Stephen; Sluder, Greenfield

2014-10-01

The radiation and radiomimetic drugs used to treat human tumors damage DNA in both cancer cells and normal proliferating cells. Centrosome amplification after DNA damage is well established for transformed cell types but is sparsely reported and not fully understood in untransformed cells. We characterize centriole behavior after DNA damage in synchronized untransformed human cells. One hour treatment of S phase cells with the radiomimetic drug, Doxorubicin, prolongs G2 by at least 72 h, though 14% of the cells eventually go through mitosis in that time. By 72 h after DNA damage we observe a 52% incidence of centriole disengagement plus a 10% incidence of extra centrioles. We find that either APC/C or Plk activities can disengage centrioles after DNA damage, though they normally work in concert. All disengaged centrioles are associated with γ-tubulin and maturation markers and thus, should in principle be capable of reduplicating and organizing spindle poles. The low incidence of reduplication of disengaged centrioles during G2 is due to the p53-dependent expression of p21 and the consequent loss of Cdk2 activity. We find that 26% of the cells going through mitosis after DNA damage contain disengaged or extra centrioles. This could produce genomic instability through transient or persistent spindle multipolarity. Thus, for cancer patients the use of DNA damaging therapies raises the chances of genomic instability and evolution of transformed characteristics in proliferating normal cell populations. © 2014 Wiley Periodicals, Inc.

DNA glycosylases search for and remove oxidized DNA bases.

PubMed

Wallace, Susan S

2013-12-01

This review article presents, an overview of the DNA glycosylases that recognize oxidized DNA bases using the Fpg/Nei family of DNA glycosylases as models for how structure can inform function. For example, even though human NEIL1 and the plant and fungal orthologs lack the zinc finger shown to be required for binding, DNA crystal structures revealed a "zincless finger" with the same properties. Moreover, the "lesion recognition loop" is not involved in lesion recognition, rather, it stabilizes 8-oxoG in the active site pocket. Unlike the other Fpg/Nei family members, Neil3 lacks two of the three void-filling residues that stabilize the DNA duplex and interact with the opposite strand to the damage which may account for its preference for lesions in single-stranded DNA. Also single-molecule approaches show that DNA glycosylases search for their substrates in a sea of undamaged DNA by using a wedge residue that is inserted into the DNA helix to probe for the presence of damage. Copyright © 2013 Wiley Periodicals, Inc.

Brain angiogenesis inhibitor 1 (BAI1) is a pattern recognition receptor that mediates macrophage binding and engulfment of Gram-negative bacteria

PubMed Central

Das, Soumita; Owen, Katherine A.; Ly, Kim T.; Park, Daeho; Black, Steven G.; Wilson, Jeffrey M.; Sifri, Costi D.; Ravichandran, Kodi S.; Ernst, Peter B.; Casanova, James E.

2011-01-01

Bacterial recognition by host cells is essential for initiation of infection and the host response. Bacteria interact with host cells via multiple pattern recognition receptors that recognize microbial products or pathogen-associated molecular patterns. In response to this interaction, host cell signaling cascades are activated that lead to inflammatory responses and/or phagocytic clearance of attached bacteria. Brain angiogenesis inhibitor 1 (BAI1) is a receptor that recognizes apoptotic cells through its conserved type I thrombospondin repeats and triggers their engulfment through an ELMO1/Dock/Rac1 signaling module. Because thrombospondin repeats in other proteins have been shown to bind bacterial surface components, we hypothesized that BAI1 may also mediate the recognition and clearance of pathogenic bacteria. We found that preincubation of bacteria with recombinant soluble BAI1 ectodomain or knockdown of endogenous BAI1 in primary macrophages significantly reduced binding and internalization of the Gram-negative pathogen Salmonella typhimurium. Conversely, overexpression of BAI1 enhanced attachment and engulfment of Salmonella in macrophages and in heterologous nonphagocytic cells. Bacterial uptake is triggered by the BAI1-mediated activation of Rac through an ELMO/Dock-dependent mechanism, and inhibition of the BAI1/ELMO1 interaction prevents both Rac activation and bacterial uptake. Moreover, inhibition of ELMO1 or Rac function significantly impairs the proinflammatory response to infection. Finally, we show that BAI1 interacts with a variety of Gram-negative, but not Gram-positive, bacteria through recognition of their surface lipopolysaccharide. Together these findings identify BAI1 as a pattern recognition receptor that mediates nonopsonic phagocytosis of Gram-negative bacteria by macrophages and directly affects the host response to infection. PMID:21245295

The Immune System as a Model for Pattern Recognition and Classification

PubMed Central

Carter, Jerome H.

2000-01-01

Objective: To design a pattern recognition engine based on concepts derived from mammalian immune systems. Design: A supervised learning system (Immunos-81) was created using software abstractions of T cells, B cells, antibodies, and their interactions. Artificial T cells control the creation of B-cell populations (clones), which compete for recognition of “unknowns.” The B-cell clone with the “simple highest avidity” (SHA) or “relative highest avidity” (RHA) is considered to have successfully classified the unknown. Measurement: Two standard machine learning data sets, consisting of eight nominal and six continuous variables, were used to test the recognition capabilities of Immunos-81. The first set (Cleveland), consisting of 303 cases of patients with suspected coronary artery disease, was used to perform a ten-way cross-validation. After completing the validation runs, the Cleveland data set was used as a training set prior to presentation of the second data set, consisting of 200 unknown cases. Results: For cross-validation runs, correct recognition using SHA ranged from a high of 96 percent to a low of 63.2 percent. The average correct classification for all runs was 83.2 percent. Using the RHA metric, 11.2 percent were labeled “too close to determine” and no further attempt was made to classify them. Of the remaining cases, 85.5 percent were correctly classified. When the second data set was presented, correct classification occurred in 73.5 percent of cases when SHA was used and in 80.3 percent of cases when RHA was used. Conclusions: The immune system offers a viable paradigm for the design of pattern recognition systems. Additional research is required to fully exploit the nuances of immune computation. PMID:10641961

Use of Displacement Damage Dose in an Engineering Model of GaAs Solar Cell Radiation Damage

NASA Technical Reports Server (NTRS)

Morton, T. L.; Chock, R.; Long, K. J.; Bailey, S.; Messenger, S. R.; Walters, R. J.; Summers, G. P.

2005-01-01

Current methods for calculating damage to solar cells are well documented in the GaAs Solar Cell Radiation Handbook (JPL 96-9). An alternative, the displacement damage dose (D(sub d)) method, has been developed by Summers, et al. This method is currently being implemented in the SAVANT computer program.

Systemic treatment of focal brain injury in the rat by human umbilical cord blood cells being at different level of neural commitment.

PubMed

Gornicka-Pawlak, El Bieta; Janowski, Miroslaw; Habich, Aleksandra; Jablonska, Anna; Drela, Katarzyna; Kozlowska, Hanna; Lukomska, Barbara; Sypecka, Joanna; Domanska-Janik, Krystyna

2011-01-01

The aim of the study was to evaluate therapeutic effectiveness of intra-arterial infusion of human umbilical cord blood (HUCB) derived cells at different stages of their neural conversion. Freshly isolated mononuclear cells (D-0), neurally directed progenitors (D-3) and neural-like stem cells derived from umbilical cord blood (NSC) were compared. Focal brain damage was induced in rats by stereotactic injection of ouabain into dorsolateral striatum Three days later 10(7) of different subsets of HUCB cells were infused into the right internal carotid artery. Following surgery rats were housed in enriched environment for 30 days. Behavioral assessment consisted of tests for sensorimotor deficits (walking beam, rotarod, vibrissae elicited forelimb placing, apomorphine induced rotations), cognitive impairments (habit learning and object recognition) and exploratory behavior (open field). Thirty days after surgery the lesion volume was measured and the presence of donor cells was detected in the brain at mRNA level. At the same time immunohistochemical analysis of brain tissue was performed to estimate the local tissue response of ouabain injured rats and its modulation after HUCB cells systemic treatment. Functional effects of different subsets of cord blood cells shared substantial diversity in various behavioral tests. An additional analysis showed that D-0 HUCB cells were the most effective in functional restoration and reduction of brain lesion volume. None of transplanted cord blood derived cell fractions were detected in rat's brains at 30(th) day after treatment. This may suggest that the mechanism(s) underlying positive effects of HUCB derived cell may concern the other than direct neural cell supplementation. In addition increased immunoreactivity of markers indicating local cells proliferation and migration suggests stimulation of endogenous reparative processes by HUCB D-0 cell interarterial infusion.

Changes in motor function, cognition, and emotion-related behavior after right hemispheric intracerebral hemorrhage in various brain regions of mouse.

PubMed

Zhu, Wei; Gao, Yufeng; Wan, Jieru; Lan, Xi; Han, Xiaoning; Zhu, Shanshan; Zang, Weidong; Chen, Xuemei; Ziai, Wendy; Hanley, Daniel F; Russo, Scott J; Jorge, Ricardo E; Wang, Jian

2018-03-01

Intracerebral hemorrhage (ICH) is a detrimental type of stroke. Mouse models of ICH, induced by collagenase or blood infusion, commonly target striatum, but not other brain sites such as ventricular system, cortex, and hippocampus. Few studies have systemically investigated brain damage and neurobehavioral deficits that develop in animal models of ICH in these areas of the right hemisphere. Therefore, we evaluated the brain damage and neurobehavioral dysfunction associated with right hemispheric ICH in ventricle, cortex, hippocampus, and striatum. The ICH model was induced by autologous whole blood or collagenase VII-S (0.075 units in 0.5 µl saline) injection. At different time points after ICH induction, mice were assessed for brain tissue damage and neurobehavioral deficits. Sham control mice were used for comparison. We found that ICH location influenced features of brain damage, microglia/macrophage activation, and behavioral deficits. Furthermore, the 24-point neurologic deficit scoring system was most sensitive for evaluating locomotor abnormalities in all four models, especially on days 1, 3, and 7 post-ICH. The wire-hanging test was useful for evaluating locomotor abnormalities in models of striatal, intraventricular, and cortical ICH. The cylinder test identified locomotor abnormalities only in the striatal ICH model. The novel object recognition test was effective for evaluating recognition memory dysfunction in all models except for striatal ICH. The tail suspension test, forced swim test, and sucrose preference test were effective for evaluating emotional abnormality in all four models but did not correlate with severity of brain damage. These results will help to inform future preclinical studies of ICH outcomes. Copyright © 2018 Elsevier Inc. All rights reserved.

Recognition of DHN-melanin by a C-type lectin receptor is required for immunity to Aspergillus.

PubMed

Stappers, Mark H T; Clark, Alexandra E; Aimanianda, Vishukumar; Bidula, Stefan; Reid, Delyth M; Asamaphan, Patawee; Hardison, Sarah E; Dambuza, Ivy M; Valsecchi, Isabel; Kerscher, Bernhard; Plato, Anthony; Wallace, Carol A; Yuecel, Raif; Hebecker, Betty; da Glória Teixeira Sousa, Maria; Cunha, Cristina; Liu, Yan; Feizi, Ten; Brakhage, Axel A; Kwon-Chung, Kyung J; Gow, Neil A R; Zanda, Matteo; Piras, Monica; Zanato, Chiara; Jaeger, Martin; Netea, Mihai G; van de Veerdonk, Frank L; Lacerda, João F; Campos, António; Carvalho, Agostinho; Willment, Janet A; Latgé, Jean-Paul; Brown, Gordon D

2018-03-15

Resistance to infection is critically dependent on the ability of pattern recognition receptors to recognize microbial invasion and induce protective immune responses. One such family of receptors are the C-type lectins, which are central to antifungal immunity. These receptors activate key effector mechanisms upon recognition of conserved fungal cell-wall carbohydrates. However, several other immunologically active fungal ligands have been described; these include melanin, for which the mechanism of recognition is hitherto undefined. Here we identify a C-type lectin receptor, melanin-sensing C-type lectin receptor (MelLec), that has an essential role in antifungal immunity through recognition of the naphthalene-diol unit of 1,8-dihydroxynaphthalene (DHN)-melanin. MelLec recognizes melanin in conidial spores of Aspergillus fumigatus as well as in other DHN-melanized fungi. MelLec is ubiquitously expressed by CD31 + endothelial cells in mice, and is also expressed by a sub-population of these cells that co-express epithelial cell adhesion molecule and are detected only in the lung and the liver. In mouse models, MelLec was required for protection against disseminated infection with A. fumigatus. In humans, MelLec is also expressed by myeloid cells, and we identified a single nucleotide polymorphism of this receptor that negatively affected myeloid inflammatory responses and significantly increased the susceptibility of stem-cell transplant recipients to disseminated Aspergillus infections. MelLec therefore recognizes an immunologically active component commonly found on fungi and has an essential role in protective antifungal immunity in both mice and humans.

Recognition and Blocking of Innate Immunity Cells by Candida albicans Chitin ▿ †

PubMed Central

Mora-Montes, Héctor M.; Netea, Mihai G.; Ferwerda, Gerben; Lenardon, Megan D.; Brown, Gordon D.; Mistry, Anita R.; Kullberg, Bart Jan; O'Callaghan, Chris A.; Sheth, Chirag C.; Odds, Frank C.; Brown, Alistair J. P.; Munro, Carol A.; Gow, Neil A. R.

2011-01-01

Chitin is a skeletal cell wall polysaccharide of the inner cell wall of fungal pathogens. As yet, little about its role during fungus-host immune cell interactions is known. We show here that ultrapurified chitin from Candida albicans cell walls did not stimulate cytokine production directly but blocked the recognition of C. albicans by human peripheral blood mononuclear cells (PBMCs) and murine macrophages, leading to significant reductions in cytokine production. Chitin did not affect the induction of cytokines stimulated by bacterial cells or lipopolysaccharide (LPS), indicating that blocking was not due to steric masking of specific receptors. Toll-like receptor 2 (TLR2), TLR4, and Mincle (the macrophage-inducible C-type lectin) were not required for interactions with chitin. Dectin-1 was required for immune blocking but did not bind chitin directly. Cytokine stimulation was significantly reduced upon stimulation of PBMCs with heat-killed chitin-deficient C. albicans cells but not with live cells. Therefore, chitin is normally not exposed to cells of the innate immune system but is capable of influencing immune recognition by blocking dectin-1-mediated engagement with fungal cell walls. PMID:21357722

Shape recognition of microbial cells by colloidal cell imprints

NASA Astrophysics Data System (ADS)

Borovička, Josef; Stoyanov, Simeon D.; Paunov, Vesselin N.

2013-08-01

We have engineered a class of colloids which can recognize the shape and size of targeted microbial cells and selectively bind to their surfaces. These imprinted colloid particles, which we called ``colloid antibodies'', were fabricated by partial fragmentation of silica shells obtained by templating the targeted microbial cells. We successfully demonstrated the shape and size recognition between such colloidal imprints and matching microbial cells. High percentage of binding events of colloidal imprints with the size matching target particles was achieved. We demonstrated selective binding of colloidal imprints to target microbial cells in a binary mixture of cells of different shapes and sizes, which also resulted in high binding selectivity. We explored the role of the electrostatic interactions between the target cells and their colloid imprints by pre-coating both of them with polyelectrolytes. Selective binding occurred predominantly in the case of opposite surface charges of the colloid cell imprint and the targeted cells. The mechanism of the recognition is based on the amplification of the surface adhesion in the case of shape and size match due to the increased contact area between the target cell and the colloidal imprint. We also tested the selective binding for colloid imprints of particles of fixed shape and varying sizes. The concept of cell recognition by colloid imprints could be used for development of colloid antibodies for shape-selective binding of microbes. Such colloid antibodies could be additionally functionalized with surface groups to enhance their binding efficiency to cells of specific shape and deliver a drug payload directly to their surface or allow them to be manipulated using external fields. They could benefit the pharmaceutical industry in developing selective antimicrobial therapies and formulations.

Using X-ray Crystallography, Biophysics, and Functional Assays to Determine the Mechanisms Governing T-cell Receptor Recognition of Cancer Antigens.

PubMed

MacLachlan, Bruce J; Greenshields-Watson, Alexander; Mason, Georgina H; Schauenburg, Andrea J; Bianchi, Valentina; Rizkallah, Pierre J; Sewell, Andrew K; Fuller, Anna; Cole, David K

2017-02-06

Human CD8+ cytotoxic T lymphocytes (CTLs) are known to play an important role in tumor control. In order to carry out this function, the cell surface-expressed T-cell receptor (TCR) must functionally recognize human leukocyte antigen (HLA)-restricted tumor-derived peptides (pHLA). However, we and others have shown that most TCRs bind sub-optimally to tumor antigens. Uncovering the molecular mechanisms that define this poor recognition could aid in the development of new targeted therapies that circumnavigate these shortcomings. Indeed, present therapies that lack this molecular understanding have not been universally effective. Here, we describe methods that we commonly employ in the laboratory to determine how the nature of the interaction between TCRs and pHLA governs T-cell functionality. These methods include the generation of soluble TCRs and pHLA and the use of these reagents for X-ray crystallography, biophysical analysis, and antigen-specific T-cell staining with pHLA multimers. Using these approaches and guided by structural analysis, it is possible to modify the interaction between TCRs and pHLA and to then test how these modifications impact T-cell antigen recognition. These findings have already helped to clarify the mechanism of T-cell recognition of a number of cancer antigens and could direct the development of altered peptides and modified TCRs for new cancer therapies.

Substance P promotes the recovery of oxidative stress-damaged retinal pigmented epithelial cells by modulating Akt/GSK-3β signaling.

PubMed

Baek, Sang-Min; Yu, Seung-Young; Son, Youngsook; Hong, Hyun Sook

2016-01-01

Senescence of the retina causes an accumulation of reactive oxygen species (ROS). Oxidative stress associated with ROS can damage RPE cells, leading to neovascularization and severe ocular disorders, including age-related macular degeneration (AMD). Thus, the early treatment of the damage caused by oxidative stress is critical for preventing the development of ocular diseases such as AMD. In this study, we examined the role of substance P (SP) in the recovery of RPE cells damaged by oxidative stress. To induce oxidative stress, RPE cells were treated with H2O2 at various doses. Recovery from oxidative stress was studied following treatment with SP by analyzing cell viability, cell proliferation, cell apoptosis, and Akt/glycogen synthase kinase (GSK)-3β activation in RPE cells in vitro. H2O2 treatment reduced cellular viability in a dose-dependent manner. SP inhibited the reduction of cell viability due to H2O2 and caused increased cell proliferation and decreased cell apoptosis. Cell survival under oxidative stress requires the activation of Akt signaling that enables cells to resist oxidative stress-induced damage. SP treatment activated Akt/GSK-3β signaling in RPE cells, which were damaged due to oxidative stress, and the inhibition of Akt signaling in SP-treated RPE cells prevented SP-induced recovery. Pretreatment with the neurokinin 1 receptor (NK1R) antagonist reduced the recovery effect of SP on damaged RPE cells. SP can protect RPE cells from oxidant-induced cell death by activating Akt/GSK-3β signaling via NK1R. This study suggests the possibility of SP as a treatment for oxidative stress-related diseases.

Characterization of two porcine macrophage cell lines for the expression of pathogen-recognition receptors, defensins, cytokines, chemokines, and surface sialic acid

USDA-ARS?s Scientific Manuscript database

Macrophages express various pathogen-recognition receptors (PRRs) which recognize pathogen-associated molecular patterns (PAMPs) and activate genes responsible for host defense. The aim of this study was to characterize two porcine macrophage cell lines (Cdelta+ and Cdelta–) for the expression of P...

Co-ordination of incoming and outgoing traffic in antigen-presenting cells by pattern recognition receptors and T cells.

PubMed

Nair, Priyanka; Amsen, Derk; Blander, J Magarian

2011-12-01

Dendritic cells are innate sentinels of the immune system and potent activators of naÏve T cells. Mechanisms must exist to enable these cells to achieve maximal activation of T cells specific for microbial antigens, while avoiding activation of T cells specific for self-antigens. Here we discuss how a combination of signals from pattern recognition receptors and T cells co-ordinates subcellular trafficking of antigen with both major histocompatibility complex class I and class II molecules and T-cell costimulatory molecules, resulting in the preferential presentation of microbial peptides within a stimulatory context. © 2011 John Wiley & Sons A/S.

Damage and recovery characteristics of lithium-containing solar cells.

NASA Technical Reports Server (NTRS)

Faith, T. J.

1971-01-01

Damage and recovery characteristics were measured on lithium-containing solar cells irradiated by 1-MeV electrons. Empirical expressions for cell recovery time, diffusion-length damage coefficient immediately after irradiation, and diffusion-length damage coefficient after recovery were derived using results of short-circuit current, diffusion-length, and reverse-bias capacitance measurements. The damage coefficients were expressed in terms of a single lithium density parameter, the lithium gradient. A fluence dependence was also established, this dependence being the same for both the immediate-post-irradiation and post-recovery cases. Cell recovery rates were found to increase linearly with lithium gradient.

Pattern recognition monitoring of PEM fuel cell

DOEpatents

Meltser, M.A.

1999-08-31

The CO-concentration in the H{sub 2} feed stream to a PEM fuel cell stack is monitored by measuring current and voltage behavior patterns from an auxiliary cell attached to the end of the stack. The auxiliary cell is connected to the same oxygen and hydrogen feed manifolds that supply the stack, and discharges through a constant load. Pattern recognition software compares the current and voltage patterns from the auxiliary cell to current and voltage signature determined from a reference cell similar to the auxiliary cell and operated under controlled conditions over a wide range of CO-concentrations in the H{sub 2} fuel stream. 4 figs.

Pattern recognition monitoring of PEM fuel cell

DOEpatents

Meltser, Mark Alexander

1999-01-01

The CO-concentration in the H.sub.2 feed stream to a PEM fuel cell stack is monitored by measuring current and voltage behavior patterns from an auxiliary cell attached to the end of the stack. The auxiliary cell is connected to the same oxygen and hydrogen feed manifolds that supply the stack, and discharges through a constant load. Pattern recognition software compares the current and voltage patterns from the auxiliary cell to current and voltage signature determined from a reference cell similar to the auxiliary cell and operated under controlled conditions over a wide range of CO-concentrations in the H.sub.2 fuel stream.

Unrepaired DNA damage in macrophages causes elevation of particulate matter- induced airway inflammatory response.

PubMed

Luo, Man; Bao, Zhengqiang; Xu, Feng; Wang, Xiaohui; Li, Fei; Li, Wen; Chen, Zhihua; Ying, Songmin; Shen, Huahao

2018-04-14

The inflammatory cascade can be initiated with the recognition of damaged DNA. Macrophages play an essential role in particulate matter (PM)-induced airway inflammation. In this study, we aim to explore the PM induced DNA damage response of macrophages and its function in airway inflammation. The DNA damage response and inflammatory response were assessed using bone marrow-derived macrophages following PM treatment and mouse model instilled intratracheally with PM. We found that PM induced significant DNA damage both in vitro and in vivo and simultaneously triggered a rapid DNA damage response, represented by nuclear RPA, 53BP1 and γH2AX foci formation. Genetic ablation or chemical inhibition of the DNA damage response sensor amplified the production of cytokines including Cxcl1, Cxcl2 and Ifn-γ after PM stimulation in bone marrow-derived macrophages. Similar to that seen in vitro , mice with myeloid-specific deletion of RAD50 showed higher levels of airway inflammation in response to the PM challenge, suggesting a protective role of DNA damage sensor during inflammation. These data demonstrate that PM exposure induces DNA damage and activation of DNA damage response sensor MRN complex in macrophages. Disruption of MRN complex lead to persistent, unrepaired DNA damage that causes elevated inflammatory response.

Molecular recognition of microbial lipid-based antigens by T cells.

PubMed

Gras, Stephanie; Van Rhijn, Ildiko; Shahine, Adam; Le Nours, Jérôme

2018-05-01

The immune system has evolved to protect hosts from pathogens. T cells represent a critical component of the immune system by their engagement in host defence mechanisms against microbial infections. Our knowledge of the molecular recognition by T cells of pathogen-derived peptidic antigens that are presented by the major histocompatibility complex glycoproteins is now well established. However, lipids represent an additional, distinct chemical class of molecules that when presented by the family of CD1 antigen-presenting molecules can serve as antigens, and be recognized by specialized subsets of T cells leading to antigen-specific activation. Over the past decades, numerous CD1-presented self- and bacterial lipid-based antigens have been isolated and characterized. However, our understanding at the molecular level of T cell immunity to CD1 molecules presenting microbial lipid-based antigens is still largely unexplored. Here, we review the insights and the molecular basis underpinning the recognition of microbial lipid-based antigens by T cells.

Mitochondria damage checkpoint in apoptosis and genome stability.

PubMed

Singh, Keshav K

2004-11-01

Mitochondria perform multiple cellular functions including energy production, cell proliferation and apoptosis. Studies described in this paper suggest a role for mitochondria in maintaining genomic stability. Genomic stability appears to be dependent on mitochondrial functions involved in maintenance of proper intracellular redox status, ATP-dependent transcription, DNA replication, DNA repair and DNA recombination. To further elucidate the role of mitochondria in genomic stability, I propose a mitochondria damage checkpoint (mitocheckpoint) that monitors and responds to damaged mitochondria. Mitocheckpoint can coordinate and maintain proper balance between apoptotic and anti-apoptotic signals. When mitochondria are damaged, mitocheckpoint can be activated to help cells repair damaged mitochondria, to restore normal mitochondrial function and avoid production of mitochondria-defective cells. If mitochondria are severely damaged, mitocheckpoint may not be able to repair the damage and protect cells. Such an event triggers apoptosis. If damage to mitochondria is continuous or persistent such as damage to mitochondrial DNA resulting in mutations, mitocheckpoint may fail which can lead to genomic instability and increased cell survival in yeast. In human it can cause cancer. In support of this proposal we provide evidence that mitochondrial genetic defects in both yeast and mammalian systems lead to impaired DNA repair, increased genomic instability and increased cell survival. This study reveals molecular genetic mechanisms underlying a role for mitochondria in carcinogenesis in humans.

A model for proton-irradiated GaAs solar cells

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Walker, G. H.; Outlaw, R. A.; Stock, L. V.

1982-01-01

A simple model for proton radiation damage in GaAs heteroface solar cells is developed. The model includes the effects of spatial nonuniformity of low energy proton damage. Agreement between the model and experimental proton damage data for GaAs heteroface solar cells is satisfactory. An extension of the model to include angular isotropy, as is appropriate for protons in space, is shown to result in significantly less cell damage than for normal proton incidence.

The budding yeast Rad9 checkpoint protein is subjected to Mec1/Tel1-dependent hyperphosphorylation and interacts with Rad53 after DNA damage.

PubMed

Vialard, J E; Gilbert, C S; Green, C M; Lowndes, N F

1998-10-01

The Saccharomyces cerevisiae RAD9 checkpoint gene is required for transient cell-cycle arrests and transcriptional induction of DNA repair genes in response to DNA damage. Polyclonal antibodies raised against the Rad9 protein recognized several polypeptides in asynchronous cultures, and in cells arrested in S or G2/M phases while a single form was observed in G1-arrested cells. Treatment with various DNA damaging agents, i.e. UV, ionizing radiation or methyl methane sulfonate, resulted in the appearance of hypermodified forms of the protein. All modifications detected during a normal cell cycle and after DNA damage were sensitive to phosphatase treatment, indicating that they resulted from phosphorylation. Damage-induced hyperphosphorylation of Rad9 correlated with checkpoint functions (cell-cycle arrest and transcriptional induction) and was cell-cycle stage- and progression-independent. In asynchronous cultures, Rad9 hyperphosphorylation was dependent on MEC1 and TEL1, homologues of the ATR and ATM genes. In G1-arrested cells, damage-dependent hyperphosphorylation required functional MEC1 in addition to RAD17, RAD24, MEC3 and DDC1, demonstrating cell-cycle stage specificity of the checkpoint genes in this response to DNA damage. Analysis of checkpoint protein interactions after DNA damage revealed that Rad9 physically associates with Rad53.

Development and validation of a modified comet assay to phenotypically assess nucleotide excision repair.

PubMed

Langie, Sabine A S; Knaapen, Ad M; Brauers, Karen J J; van Berlo, Damien; van Schooten, Frederik-Jan; Godschalk, Roger W L

2006-03-01

There is an increasing need for simple and reliable approaches to phenotypically assess DNA repair capacities. Therefore, a modification of the alkaline comet assay was developed to determine the ability of human lymphocyte extracts to perform the initial steps of the nucleotide excision repair (NER) process, i.e. damage recognition and incision. Gel-embedded nucleoids from A549 cells, pre-exposed to 1 microM benzo[a]pyrene-diol-epoxide, were incubated with cell extracts from frozen or freshly isolated lymphocytes. The rate at which incisions are introduced and the subsequent increase in tail moment is indicative for the repair capacity of the extracts. Freshly prepared extracts from lymphocytes of human volunteers (n = 8) showed significant inter-individual variations in their DNA repair capacity, which correlated with the removal of bulky DNA lesions over a period of 48 h determined by (32)P-post-labelling (R(2) = 0.76, P = 0.005). Repeated measurements revealed a low inter-assay variation (11%). Storage of cell extracts for more than 3 weeks significantly reduced (up to 80%) the capacity to incise the damaged DNA as compared to freshly isolated extracts. This reduction was completely restored by addition of ATP to the extracts before use, as it is required for the incision step of NER. In contrast, extracts freshly prepared from frozen lymphocyte pellets can be used without loss of repair activity. DNA repair deficient XPA-/- and XPC-/- fibroblasts were used to further validate the assay. Although some residual capacity to incise the DNA was observed in these cells, the repair activity was restored to normal wild-type levels when a complementary mixture of both extracts (thereby restoring XPA and XPC deficiency) was used. These results demonstrate that this repair assay can be applied in molecular epidemiological studies to assess inter-individual differences in NER.

Structural damage detection based on stochastic subspace identification and statistical pattern recognition: II. Experimental validation under varying temperature

NASA Astrophysics Data System (ADS)

Lin, Y. Q.; Ren, W. X.; Fang, S. E.

2011-11-01

Although most vibration-based damage detection methods can acquire satisfactory verification on analytical or numerical structures, most of them may encounter problems when applied to real-world structures under varying environments. The damage detection methods that directly extract damage features from the periodically sampled dynamic time history response measurements are desirable but relevant research and field application verification are still lacking. In this second part of a two-part paper, the robustness and performance of the statistics-based damage index using the forward innovation model by stochastic subspace identification of a vibrating structure proposed in the first part have been investigated against two prestressed reinforced concrete (RC) beams tested in the laboratory and a full-scale RC arch bridge tested in the field under varying environments. Experimental verification is focused on temperature effects. It is demonstrated that the proposed statistics-based damage index is insensitive to temperature variations but sensitive to the structural deterioration or state alteration. This makes it possible to detect the structural damage for the real-scale structures experiencing ambient excitations and varying environmental conditions.

Evaluation of various glyphosate concentrations on DNA damage in human Raji cells and its impact on cytotoxicity.

PubMed

Townsend, Michelle; Peck, Connor; Meng, Wei; Heaton, Matthew; Robison, Richard; O'Neill, Kim

2017-04-01

Glyphosate is a highly used active compound in agriculturally based pesticides. The literature regarding the toxicity of glyphosate to human cells has been highly inconsistent. We studied the resulting DNA damage and cytotoxicity of various glyphosate concentrations on human cells to evaluate DNA damaging potential. Utilizing human Raji cells, DNA damage was quantified using the comet assay, while cytotoxicity was further analyzed using MTT viability assays. Several glyphosate concentrations were assessed, ranging from 15 mM to 0.1 μM. We found that glyphosate treatment is lethal to Raji cells at concentrations above 10 mM, yet has no cytotoxic effects at concentrations at or below 100 μM. Treatment concentrations of 1 mM and 5 mM induce statistically significant DNA damage to Raji cells following 30-60 min of treatment, however, cells show a slow recovery from initial damage and cell viability is unaffected after 2 h. At these same concentrations, cells treated with additional compound did not recover and maintained high levels of DNA damage. While the cytotoxicity of glyphosate appears to be minimal for physiologically relevant concentrations, the compound has a definitive cytotoxic nature in human cells at high concentrations. Our data also suggests a mammalian metabolic pathway for the degradation of glyphosate may be present. Copyright © 2017 Elsevier Inc. All rights reserved.

A multi-approach feature extractions for iris recognition

NASA Astrophysics Data System (ADS)

Sanpachai, H.; Settapong, M.

2014-04-01

Biometrics is a promising technique that is used to identify individual traits and characteristics. Iris recognition is one of the most reliable biometric methods. As iris texture and color is fully developed within a year of birth, it remains unchanged throughout a person's life. Contrary to fingerprint, which can be altered due to several aspects including accidental damage, dry or oily skin and dust. Although iris recognition has been studied for more than a decade, there are limited commercial products available due to its arduous requirement such as camera resolution, hardware size, expensive equipment and computational complexity. However, at the present time, technology has overcome these obstacles. Iris recognition can be done through several sequential steps which include pre-processing, features extractions, post-processing, and matching stage. In this paper, we adopted the directional high-low pass filter for feature extraction. A box-counting fractal dimension and Iris code have been proposed as feature representations. Our approach has been tested on CASIA Iris Image database and the results are considered successful.

Acquired resistance to rechallenge injury in rats recovered from subclinical renal damage with uranyl acetate-Importance of proliferative activity of tubular cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yuan; Fujigaki, Yoshihide, E-mail: yf0516@hama-med.ac.j; Sakakima, Masanori

Animals recovered from acute renal failure are resistant to subsequent insult. We investigated whether rats recovered from mild proximal tubule (PT) injury without renal dysfunction (subclinical renal damage) acquire the same resistance. Rats 14 days after recovering from subclinical renal damage, which was induced by 0.2 mg/kg of uranyl acetate (UA) (sub-toxic dose), were rechallenged with 4 mg/kg of UA (nephrotoxic dose). Fate of PT cells and renal function were examined in response to nephrotoxic dose of UA. All divided cells after sub-toxic dose of UA insult were labeled with bromodeoxyuridine (BrdU) for 14 days then the number of PTmore » cells with or without BrdU-labeling was counted following nephrotoxic dose of UA insult. Rats recovered from subclinical renal damage gained resistance to nephrotoxic dose of UA with reduced renal dysfunction, less severity of peak damage (necrotic and TUNEL+ apoptotic cells) and accelerated PT cell proliferation, but with earlier peak of PT damage. The decrease in number of PT cells in the early phase of rechallenge injury with nephrotoxic UA was more in rats pretreated with sub-toxic dose of UA than vehicle pretreated rats. The exaggerated loss of PT cells was mainly caused by the exaggerated loss of BrdU+ divided cells. In contrast, accelerated cell proliferation in rats recovered from sub-toxic dose of UA was observed mainly in BrdU- non-divided cells. The findings suggest that rats recovered from subclinical renal damage showed partial acquired resistance to nephrotoxic insult. Accelerated recovery with increased proliferative activity of non-divided PT cells after subclinical renal damage may mainly contribute to acquired resistance.« less

Gallium arsenide solar cell radiation damage study

NASA Technical Reports Server (NTRS)

Maurer, R. H.; Herbert, G. A.; Kinnison, J. D.; Meulenberg, A.

1989-01-01

A thorough analysis has been made of electron- and proton- damaged GaAs solar cells suitable for use in space. It is found that, although some electrical parametric data and spectral response data are quite similar, the type of damage due to the two types of radiation is different. An I-V analysis model shows that electrons damage the bulk of the cell and its currents relatively more, while protons damage the junction of the cell and its voltages more. It is suggested that multiple defects due to protons in a strong field region such as a p/n junction cause the greater degradation in cell voltage, whereas the individual point defects in the quasi-neutral minority-carrier-diffusion regions due to electrons cause the greater degradation in cell current and spectral response.

Decoding Tuckerellidae and Tenuipalpidae

USDA-ARS?s Scientific Manuscript database

Flat and peacock mites are pests on crops, ornamental plants, and forest and fruit trees. They are very small and some have been associated with severe leaf damage or the spread of plant viruses. Artifacts from mounting media and type of microscope used are complicating the recognition of the key c...

Category-Specificity in Visual Object Recognition

ERIC Educational Resources Information Center

Gerlach, Christian

2009-01-01

Are all categories of objects recognized in the same manner visually? Evidence from neuropsychology suggests they are not: some brain damaged patients are more impaired in recognizing natural objects than artefacts whereas others show the opposite impairment. Category-effects have also been demonstrated in neurologically intact subjects, but the…

How We Recognize Our Own Actions

NASA Astrophysics Data System (ADS)

Blakemore, Sarah-Jayne

This chapter first describes how predicting the sensory consequences of action contributes to the recognition of one's own actions. Second, the chapter discusses three symptoms in which this prediction mechanism is proposed to be impaired: the consequences of parietal lobe damage, passivity experiences associated with schizophrenia, and phantom limbs.

The species recognition system: a new corollary for the human fetoembryonic defense system hypothesis.

PubMed

Clark, G F; Dell, A; Morris, H R; Patankar, M S; Easton, R L

2001-01-01

We have previously suggested that the human fetus is protected during human development by a system of both soluble and cell surface associated glycoconjugates that utilize their carbohydrate sequences as functional groups to enable them to evoke tolerance. The proposed model has been referred to as the human fetoembryonic defense system hypothesis (hu-FEDS). In this paradigm, it has previously been proposed that similar oligosaccharides are used to mediate crucial recognition events required during both human sperm-egg binding and immune-inflammatory cell interactions. This vertical integration suggested to us that the sperm-egg binding itself is related to universal recognition events that occur between immune and inflammatory cells, except that in this case recognition of 'species' rather than recognition of 'self' is being manifested. In this paper, we have designated this component of hu-FEDS as the species recognition system (SRS). We propose that the SRS is an integral component of the hu-FEDS used to enable sperm-egg recognition and protection of the gametes from potential immune responses. Recent structural data indicates that the glycan sequences implicated in mediating murine gamete recognition are also expressed on CD45 in activated murine T lymphocytes and cytotoxic T lymphocytes. This overlap supports our contention that there is an overlap between the immune and gamete recognition systems. Therefore the hu-FEDS paradigm may be a subset of a larger model that also applies to other placental mammals. We therefore propose that the hu-FEDS model for protection should in the future be referred to as the eutherian fetoembryonic defense system hypothesis (eu-FEDS) to account for this extension. The possibility exists that the SRS component of eu-FEDS could predate eutherians and extend to all sexually reproducing organisms. Future investigation of the interactions between the immune and gamete recognition system will be required to determine the degree of overlap. Copyright 2001 S. Karger AG, Basel

Selective autophagy: ubiquitin-mediated recognition and beyond.

PubMed

Kraft, Claudine; Peter, Matthias; Hofmann, Kay

2010-09-01

Eukaryotic cells use autophagy and the ubiquitin-proteasome system as their major protein degradation pathways. Whereas the ubiquitin-proteasome system is involved in the rapid degradation of proteins, autophagy pathways can selectively remove protein aggregates and damaged or excess organelles. Proteasome-mediated degradation requires previous ubiquitylation of the cargo, which is then recognized by ubiquitin receptors directing it to 26S proteasomes. Although autophagy has long been viewed as a random cytoplasmic degradation system, the involvement of ubiquitin as a specificity factor for selective autophagy is rapidly emerging. Recent evidence also suggests active crosstalk between proteasome-mediated degradation and selective autophagy. Here, we discuss the molecular mechanisms that link autophagy and the proteasome system, as well as the emerging roles of ubiquitin and ubiquitin-binding proteins in selective autophagy. On the basis of the evolutionary history of autophagic ubiquitin receptors, we propose a common origin for metazoan ubiquitin-dependent autophagy and the cytoplasm-to-vacuole targeting pathway of yeast.

Key issues in the management of patients with systemic lupus erythematosus: latest developments and clinical implications

PubMed Central

Jordan, Natasha; D’Cruz, David

2015-01-01

Systemic lupus erythematous (SLE) is a chronic multisystem disease with significant associated morbidity and mortality. A deeper understanding of the pathogenesis of SLE has led to the development of biologic agents, primarily targeting B cells and others inhibiting costimulatory molecules, type I interferons and cytokines such as interleukin-6. Several of these agents have been studied in clinical trials; some have shown promise while others have yielded disappointing results. Economic and regulatory issues continue to hamper the availability of such therapies for SLE patients. With increasing recognition that recurrent flares of disease activity lead to long-term damage accrual, one of the most important recent developments in patient management has been the concept of treat-to-target in SLE while minimizing patient exposure to excessive corticosteroid and other immunosuppressive therapy. This article reviews these key issues in SLE management, outlining recent developments and clinical implications for patients. PMID:26622325

(CAG)(n)-hairpin DNA binds to Msh2-Msh3 and changes properties of mismatch recognition.

PubMed

Owen, Barbara A L; Yang, Zungyoon; Lai, Maoyi; Gajec, Maciej; Gajek, Maciez; Badger, John D; Hayes, Jeffrey J; Edelmann, Winfried; Kucherlapati, Raju; Wilson, Teresa M; McMurray, Cynthia T

2005-08-01

Cells have evolved sophisticated DNA repair systems to correct damaged DNA. However, the human DNA mismatch repair protein Msh2-Msh3 is involved in the process of trinucleotide (CNG) DNA expansion rather than repair. Using purified protein and synthetic DNA substrates, we show that Msh2-Msh3 binds to CAG-hairpin DNA, a prime candidate for an expansion intermediate. CAG-hairpin binding inhibits the ATPase activity of Msh2-Msh3 and alters both nucleotide (ADP and ATP) affinity and binding interfaces between protein and DNA. These changes in Msh2-Msh3 function depend on the presence of A.A mispaired bases in the stem of the hairpin and on the hairpin DNA structure per se. These studies identify critical functional defects in the Msh2-Msh3-CAG hairpin complex that could misdirect the DNA repair process.

Functional MRI study of diencephalic amnesia in Wernicke-Korsakoff syndrome.

PubMed

Caulo, M; Van Hecke, J; Toma, L; Ferretti, A; Tartaro, A; Colosimo, C; Romani, G L; Uncini, A

2005-07-01

Anterograde amnesia in Wernicke-Korsakoff syndrome is associated with diencephalic lesions, mainly in the anterior thalamic nuclei. Whether diencephalic and temporal lobe amnesias are distinct entities is still not clear. We investigated episodic memory for faces using functional MRI (fMRI) in eight controls and in a 34-year-old man with Wernicke-Korsakoff syndrome and diencephalic lesions but without medial temporal lobe (MTL) involvement at MRI. fMRI was performed with a 1.5 tesla unit. Three dual-choice tasks were employed: (i) face encoding (18 faces were randomly presented three times and subjects were asked to memorize the faces); (ii) face perception (subjects indicated which of two faces matched a third face); and (iii) face recognition (subjects indicated which of two faces belonged to the group they had been asked to memorize during encoding). All activation was greater in the right hemisphere. In controls both the encoding and recognition tasks activated two hippocampal regions (anterior and posterior). The anterior hippocampal region was more activated during recognition. Activation in the prefrontal cortex was greater during recognition. In the subject with Wernicke-Korsakoff syndrome, fMRI did not show hippocampal activation during either encoding or recognition. During recognition, although behavioural data showed defective retrieval, the prefrontal regions were activated as in controls, except for the ventrolateral prefrontal cortex. fMRI activation of the visual cortices and the behavioural score on the perception task indicated that the subject with Wernicke-Korsakoff syndrome perceived the faces, paid attention to the task and demonstrated accurate judgement. In the subject with Wernicke-Korsakoff syndrome, although the anatomical damage does not involve the MTL, the hippocampal memory encoding has been lost, possibly as a consequence of the hippocampal-anterior thalamic axis involvement. Anterograde amnesia could therefore be the expression of damage to an extended hippocampal system, and the distinction between temporal lobe and diencephalic amnesia has limited value. In the subject with Wernicke-Korsakoff syndrome, the preserved dorsolateral prefrontal cortex activation during incorrect recognition suggests that this region is more involved in either the orientation or attention at retrieval than in retrieval. The lack of activation of the prefrontal ventrolateral cortex confirms the role of this area in episodic memory formation.

Dissociated active and passive tactile shape recognition: a case study of pure tactile apraxia.

PubMed

Valenza, N; Ptak, R; Zimine, I; Badan, M; Lazeyras, F; Schnider, A

2001-11-01

Disorders of tactile object recognition (TOR) may result from primary motor or sensory deficits or higher cognitive impairment of tactile shape representations or semantic memory. Studies with healthy participants suggest the existence of exploratory motor procedures directly linked to the extraction of specific properties of objects. A pure deficit of these procedures without concomitant gnostic disorders has never been described in a brain-damaged patient. Here, we present a patient with a right hemispheric infarction who, in spite of intact sensorimotor functions, had impaired TOR with the left hand. Recognition of 2D shapes and objects was severely deficient under the condition of spontaneous exploration. Tactile exploration of shapes was disorganized and exploratory procedures, such as the contour-following strategy, which is necessary to identify the precise shape of an object, were severely disturbed. However, recognition of 2D shapes under manually or verbally guided exploration and the recognition of shapes traced on the skin were intact, indicating a dissociation in shape recognition between active and passive touch. Functional MRI during sensory stimulation of the left hand showed preserved activation of the spared primary sensory cortex in the right hemisphere. We interpret the deficit of our patient as a pure tactile apraxia without tactile agnosia, i.e. a specific inability to use tactile feedback to generate the exploratory procedures necessary for tactile shape recognition.

The Mechanism of Anaphylaxis: Specificity of Antigen-Induced Mast Cell Damage in Anaphylaxis in the Guinea Pig

PubMed Central

Humphrey, J. H.; Mota, I.

1959-01-01

Mast cell damage, characterized by loss of granules, occurs when the tissues of sensitized guinea pigs are brought into contact with antigen in vivo or in vitro. Quantitative studies on the mesenteries of passively sensitized guinea pigs show that the mast cell response to antigen is well correlated with the development of anaphylactic shock. After multiple sensitization contact with different antigens caused cumulative, but not complete, disappearance of mast cells. Antigen-antibody interactions, in which antisera were from species which do not sensitize guinea pigs passively for anaphylaxis, did not cause mast cell damage. Reversed passive anaphylaxis and mast cell damage were elicited when the antigen was a suitable γ-globulin, but not an albumin. Antiserum against homologous γ-globulin causes typical anaphylaxis and mast cell degranulation, whereas antiserum against Forssman antigen causes capillary damage without mast cell changes, and antiserum against homologous albumin is ineffective. These findings can be explained by the hypothesis that mast cell damage occurs as a result of antigen-antibody interaction, when one of the reagents is reversibly adsorbed at the mast cell surface, and when they are together capable of activating some process or agent whose further action depends upon the metabolic integrity of the cells. PMID:13640678

Corrupting the DNA damage response: a critical role for Rad52 in tumor cell survival.

PubMed

Lieberman, Rachel; You, Ming

2017-07-15

The DNA damage response enables cells to survive, maintain genome integrity, and to safeguard the transmission of high-fidelity genetic information. Upon sensing DNA damage, cells respond by activating this multi-faceted DNA damage response leading to restoration of the cell, senescence, programmed cell death, or genomic instability if the cell survives without proper repair. However, unlike normal cells, cancer cells maintain a marked level of genomic instability. Because of this enhanced propensity to accumulate DNA damage, tumor cells rely on homologous recombination repair as a means of protection from the lethal effect of both spontaneous and therapy-induced double-strand breaks (DSBs) in DNA. Thus, modulation of DNA repair pathways have important consequences for genomic instability within tumor cell biology and viability maintenance under high genotoxic stress. Efforts are underway to manipulate specific components of the DNA damage response in order to selectively induce tumor cell death by augmenting genomic instability past a viable threshold. New evidence suggests that RAD52, a component of the homologous recombination pathway, is important for the maintenance of tumor genome integrity. This review highlights recent reports indicating that reducing homologous recombination through inhibition of RAD52 may represent an important focus for cancer therapy and the specific efforts that are already demonstrating potential.

Measurement of DNA damage in rat urinary bladder transitional cells: improved selective harvest of transitional cells and detailed Comet assay protocols.

PubMed

Wang, Amy; Robertson, John L; Holladay, Steven D; Tennant, Alan H; Lengi, Andrea J; Ahmed, S Ansar; Huckle, William R; Kligerman, Andrew D

2007-12-01

Urinary bladder transitional epithelium is the main site of bladder cancer, and the use of transitional cells to study carcinogenesis/genotoxicity is recommended over the use of whole bladders. Because the transitional epithelium is only a small fraction of the whole bladder, the alkaline single cell gel electrophoresis assay (Comet assay), which requires only a small number of cells per sample, is especially suitable for measuring DNA damage in transitional cells. However, existed procedures of cell collection did not yield transitional cells with a high purity, and pooling of samples was needed for Comet assay. The goal of this study was to develop an optimized protocol to evaluate DNA damage in the urinary bladder transitional epithelium. This was achieved by an enzymatic stripping method (trypsin-EDTA incubation plus gentle scraping) to selectively harvest transitional cells from rat bladders, and the use of the alkaline Comet assay to detect DNA strand breaks, alkaline labile sites, and DNA-protein crosslinks. Step by step procedures are reported here. Cells collected from a single rat bladder were sufficient for multiple Comet assays. With this new protocol, increases in DNA damage were detected in transitional cells after in vitro exposure to the positive control agents, hydrogen peroxide or formaldehyde. Repair of the induced DNA damage occurred within 4h. This indicated the capacity for DNA repair was maintained in the harvested cells. The new protocol provides a simple and inexpensive method to detect various types of DNA damage and to measure DNA damage repair in urinary bladder transitional cells.

Genoprotective effect of hyaluronic acid against benzalkonium chloride-induced DNA damage in human corneal epithelial cells

PubMed Central

Wu, Han; Zhang, Huina; Wang, Changjun; Wu, Yihua; Xie, Jiajun; Jin, Xiuming; Yang, Jun

2011-01-01

Purpose The aim of this study was to investigate hyaluronic acid (HA) protection on cultured human corneal epithelial cells (HCEs) against benzalkonium chloride (BAC)-induced DNA damage and intracellular reactive oxygen species (ROS) increase. Methods Cells were incubated with different concentrations of BAC with or without the presence of 0.2% HA for 30 min. DNA damage to HCEs was examined by alkaline comet assay and by immunofluorescence microscopic detection of the phosphorylated form of histone variant H2AX (γH2AX) foci. ROS production was assessed by the fluorescent probe, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). Cell apoptosis was determined with annexin V staining by flow cytometry. Results HA significantly reduced BAC-induced DNA damage as indicated by the tail length (TL) and tail moment (TM) of alkaline comet assay and by γH2AX foci formation, respectively. Moreover, HA significantly decreased BAC-induced ROS increase and cell apoptosis. However, exposure to HA alone did not produce any significant change in DNA damage, ROS generation, or cell apoptosis. Conclusions BAC could induce DNA damage and cell apoptosis in HCEs, probably through increasing oxidative stress. Furthermore, HA was an effective protective agent that had antioxidant properties and could decrease DNA damage and cell apoptosis induced by BAC. PMID:22219631

Periodic annealing of radiation damage in GaAs solar cells

NASA Technical Reports Server (NTRS)

Loo, R. Y.; Knechtli, R. C.; Kamath, G. S.

1980-01-01

Continuous annealing of GaAs solar cells is compared with periodic annealing to determine their relative effectiveness in minimizing proton radiation damage. It is concluded that continuous annealing of the cells in space at 150 C can effectively reduce the proton radiation damage to the GaAs solar cells. Periodic annealing is most effective if it can be initiated at relatively low fluences (approximating continuous annealing), especially if low temperatures of less than 200 C are to be used. If annealing is started only after the fluence of the damaging protons has accumulated to a high value 10 to the 11th power sq/pcm), effective annealing is still possible at relatively high temperatures. Finally, since electron radiation damage anneals even more easily than proton radiation damage, substantial improvements in GaAs solar cell life can be achieved by incorporating the proper annealing capabilities in solar panels for practical space missions where both electron and proton radiation damage have to be minimized.

DNA Damage during G2 Phase Does Not Affect Cell Cycle Progression of the Green Alga Scenedesmus quadricauda

PubMed Central

Vítová, Milada; Bišová, Kateřina; Zachleder, Vilém

2011-01-01

DNA damage is a threat to genomic integrity in all living organisms. Plants and green algae are particularly susceptible to DNA damage especially that caused by UV light, due to their light dependency for photosynthesis. For survival of a plant, and other eukaryotic cells, it is essential for an organism to continuously check the integrity of its genetic material and, when damaged, to repair it immediately. Cells therefore utilize a DNA damage response pathway that is responsible for sensing, reacting to and repairing damaged DNA. We have studied the effect of 5-fluorodeoxyuridine, zeocin, caffeine and combinations of these on the cell cycle of the green alga Scenedesmus quadricauda. The cells delayed S phase and underwent a permanent G2 phase block if DNA metabolism was affected prior to S phase; the G2 phase block imposed by zeocin was partially abolished by caffeine. No cell cycle block was observed if the treatment with zeocin occurred in G2 phase and the cells divided normally. CDKA and CDKB kinases regulate mitosis in S. quadricauda; their kinase activities were inhibited by Wee1. CDKA, CDKB protein levels were stabilized in the presence of zeocin. In contrast, the protein level of Wee1 was unaffected by DNA perturbing treatments. Wee1 therefore does not appear to be involved in the DNA damage response in S. quadricauda. Our results imply a specific reaction to DNA damage in S. quadricauda, with no cell cycle arrest, after experiencing DNA damage during G2 phase. PMID:21603605

The structural neuroanatomy of music emotion recognition: Evidence from frontotemporal lobar degeneration

PubMed Central

Omar, Rohani; Henley, Susie M.D.; Bartlett, Jonathan W.; Hailstone, Julia C.; Gordon, Elizabeth; Sauter, Disa A.; Frost, Chris; Scott, Sophie K.; Warren, Jason D.

2011-01-01

Despite growing clinical and neurobiological interest in the brain mechanisms that process emotion in music, these mechanisms remain incompletely understood. Patients with frontotemporal lobar degeneration (FTLD) frequently exhibit clinical syndromes that illustrate the effects of breakdown in emotional and social functioning. Here we investigated the neuroanatomical substrate for recognition of musical emotion in a cohort of 26 patients with FTLD (16 with behavioural variant frontotemporal dementia, bvFTD, 10 with semantic dementia, SemD) using voxel-based morphometry. On neuropsychological evaluation, patients with FTLD showed deficient recognition of canonical emotions (happiness, sadness, anger and fear) from music as well as faces and voices compared with healthy control subjects. Impaired recognition of emotions from music was specifically associated with grey matter loss in a distributed cerebral network including insula, orbitofrontal cortex, anterior cingulate and medial prefrontal cortex, anterior temporal and more posterior temporal and parietal cortices, amygdala and the subcortical mesolimbic system. This network constitutes an essential brain substrate for recognition of musical emotion that overlaps with brain regions previously implicated in coding emotional value, behavioural context, conceptual knowledge and theory of mind. Musical emotion recognition may probe the interface of these processes, delineating a profile of brain damage that is essential for the abstraction of complex social emotions. PMID:21385617

Anodal tDCS targeting the right orbitofrontal cortex enhances facial expression recognition

PubMed Central

Murphy, Jillian M.; Ridley, Nicole J.; Vercammen, Ans

2015-01-01

The orbitofrontal cortex (OFC) has been implicated in the capacity to accurately recognise facial expressions. The aim of the current study was to determine if anodal transcranial direct current stimulation (tDCS) targeting the right OFC in healthy adults would enhance facial expression recognition, compared with a sham condition. Across two counterbalanced sessions of tDCS (i.e. anodal and sham), 20 undergraduate participants (18 female) completed a facial expression labelling task comprising angry, disgusted, fearful, happy, sad and neutral expressions, and a control (social judgement) task comprising the same expressions. Responses on the labelling task were scored for accuracy, median reaction time and overall efficiency (i.e. combined accuracy and reaction time). Anodal tDCS targeting the right OFC enhanced facial expression recognition, reflected in greater efficiency and speed of recognition across emotions, relative to the sham condition. In contrast, there was no effect of tDCS to responses on the control task. This is the first study to demonstrate that anodal tDCS targeting the right OFC boosts facial expression recognition. This finding provides a solid foundation for future research to examine the efficacy of this technique as a means to treat facial expression recognition deficits, particularly in individuals with OFC damage or dysfunction. PMID:25971602

The structural neuroanatomy of music emotion recognition: evidence from frontotemporal lobar degeneration.

PubMed

Omar, Rohani; Henley, Susie M D; Bartlett, Jonathan W; Hailstone, Julia C; Gordon, Elizabeth; Sauter, Disa A; Frost, Chris; Scott, Sophie K; Warren, Jason D

2011-06-01

Despite growing clinical and neurobiological interest in the brain mechanisms that process emotion in music, these mechanisms remain incompletely understood. Patients with frontotemporal lobar degeneration (FTLD) frequently exhibit clinical syndromes that illustrate the effects of breakdown in emotional and social functioning. Here we investigated the neuroanatomical substrate for recognition of musical emotion in a cohort of 26 patients with FTLD (16 with behavioural variant frontotemporal dementia, bvFTD, 10 with semantic dementia, SemD) using voxel-based morphometry. On neuropsychological evaluation, patients with FTLD showed deficient recognition of canonical emotions (happiness, sadness, anger and fear) from music as well as faces and voices compared with healthy control subjects. Impaired recognition of emotions from music was specifically associated with grey matter loss in a distributed cerebral network including insula, orbitofrontal cortex, anterior cingulate and medial prefrontal cortex, anterior temporal and more posterior temporal and parietal cortices, amygdala and the subcortical mesolimbic system. This network constitutes an essential brain substrate for recognition of musical emotion that overlaps with brain regions previously implicated in coding emotional value, behavioural context, conceptual knowledge and theory of mind. Musical emotion recognition may probe the interface of these processes, delineating a profile of brain damage that is essential for the abstraction of complex social emotions. Copyright © 2011 Elsevier Inc. All rights reserved.

[Recognition of facial expression of emotions in Parkinson's disease: a theoretical review].

PubMed

Alonso-Recio, L; Serrano-Rodriguez, J M; Carvajal-Molina, F; Loeches-Alonso, A; Martin-Plasencia, P

2012-04-16

Emotional facial expression is a basic guide during social interaction and, therefore, alterations in their expression or recognition are important limitations for communication. To examine facial expression recognition abilities and their possible impairment in Parkinson's disease. First, we review the studies on this topic which have not found entirely similar results. Second, we analyze the factors that may explain these discrepancies and, in particular, as third objective, we consider the relationship between emotional recognition problems and cognitive impairment associated with the disease. Finally, we propose alternatives strategies for the development of studies that could clarify the state of these abilities in Parkinson's disease. Most studies suggest deficits in facial expression recognition, especially in those with negative emotional content. However, it is possible that these alterations are related to those that also appear in the course of the disease in other perceptual and executive processes. To advance in this issue, we consider necessary to design emotional recognition studies implicating differentially the executive or visuospatial processes, and/or contrasting cognitive abilities with facial expressions and non emotional stimuli. The precision of the status of these abilities, as well as increase our knowledge of the functional consequences of the characteristic brain damage in the disease, may indicate if we should pay special attention in their rehabilitation inside the programs implemented.

Stem cells: Balancing resistance and sensitivity to DNA damage

PubMed Central

Liu, Julia C.; Lerou, Paul H.; Lahav, Galit

2015-01-01

Embryonic stem cells are known to be very sensitive to DNA damage and undergo rapid apoptosis even after low damage doses. In contrast, adult stem cells show variable sensitivity to damage. Here we describe the multiple pathways that have been proposed to affect the sensitivity of stem cells to damage, including proximity to the apoptotic threshold (mitochondrial priming) and the p53 signaling pathway, through activation of transcription or direct interaction with pro apoptotic proteins in the cytoplasm. We also discuss which cellular factors might connect mitochondrial priming with pluripotency and the potential therapeutic advances that can be achieved by better understanding the molecular mechanisms leading to sensitivity or resistance of embryonic or adult stem cells from different tissues. PMID:24721782

Heat Shock Protein-90 Inhibitors Enhance Antigen Expression on Melanomas and Increase T Cell Recognition of Tumor Cells

PubMed Central

Haggerty, Timothy J.; Dunn, Ian S.; Rose, Lenora B.; Newton, Estelle E.; Pandolfi, Franco; Kurnick, James T.

2014-01-01

In an effort to enhance antigen-specific T cell recognition of cancer cells, we have examined numerous modulators of antigen-expression. In this report we demonstrate that twelve different Hsp90 inhibitors (iHsp90) share the ability to increase the expression of differentiation antigens and MHC Class I antigens. These iHsp90 are active in several molecular and cellular assays on a series of tumor cell lines, including eleven human melanomas, a murine B16 melanoma, and two human glioma-derived cell lines. Intra-cytoplasmic antibody staining showed that all of the tested iHsp90 increased expression of the melanocyte differentiation antigens Melan-A/MART-1, gp100, and TRP-2, as well as MHC Class I. The gliomas showed enhanced gp100 and MHC staining. Quantitative analysis of mRNA levels showed a parallel increase in message transcription, and a reporter assay shows induction of promoter activity for Melan-A/MART-1 gene. In addition, iHsp90 increased recognition of tumor cells by T cells specific for Melan-A/MART-1. In contrast to direct Hsp90 client proteins, the increased levels of full-length differentiation antigens that result from iHsp90 treatment are most likely the result of transcriptional activation of their encoding genes. In combination, these results suggest that iHsp90 improve recognition of tumor cells by T cells specific for a melanoma-associated antigen as a result of increasing the expressed intracellular antigen pool available for processing and presentation by MHC Class I, along with increased levels of MHC Class I itself. As these Hsp90 inhibitors do not interfere with T cell function, they could have potential for use in immunotherapy of cancer. PMID:25503774

Cell-free chromatin from dying cancer cells integrate into genomes of bystander healthy cells to induce DNA damage and inflammation

PubMed Central

Mittra, Indraneel; Samant, Urmila; Sharma, Suvarna; Raghuram, Gorantla V; Saha, Tannistha; Tidke, Pritishkumar; Pancholi, Namrata; Gupta, Deepika; Prasannan, Preeti; Gaikwad, Ashwini; Gardi, Nilesh; Chaubal, Rohan; Upadhyay, Pawan; Pal, Kavita; Rane, Bhagyeshri; Shaikh, Alfina; Salunkhe, Sameer; Dutt, Shilpee; Mishra, Pradyumna K; Khare, Naveen K; Nair, Naveen K; Dutt, Amit

2017-01-01

Bystander cells of the tumor microenvironment show evidence of DNA damage and inflammation that can lead to their oncogenic transformation. Mediator(s) of cell–cell communication that brings about these pro-oncogenic pathologies has not been identified. We show here that cell-free chromatin (cfCh) released from dying cancer cells are the key mediators that trigger both DNA damage and inflammation in the surrounding healthy cells. When dying human cancer cells were cultured along with NIH3T3 mouse fibroblast cells, numerous cfCh emerged from them and rapidly entered into nuclei of bystander NIH3T3 cells to integrate into their genomes. This led to activation of H2AX and inflammatory cytokines NFκB, IL-6, TNFα and IFNγ. Genomic integration of cfCh triggered global deregulation of transcription and upregulation of pathways related to phagocytosis, DNA damage and inflammation. None of these activities were observed when living cancer cells were co-cultivated with NIH3T3 cells. However, upon intravenous injection into mice, both dead and live cells were found to be active. Living cancer cells are known to undergo extensive cell death when injected intravenously, and we observed that cfCh emerging from both types of cells integrated into genomes of cells of distant organs and induced DNA damage and inflammation. γH2AX and NFκB were frequently co-expressed in the same cells suggesting that DNA damage and inflammation are closely linked pathologies. As concurrent DNA damage and inflammation is a potent stimulus for oncogenic transformation, our results suggest that cfCh from dying cancer cells can transform cells of the microenvironment both locally and in distant organs providing a novel mechanism of tumor invasion and metastasis. The afore-described pro-oncogenic pathologies could be abrogated by concurrent treatment with chromatin neutralizing/degrading agents suggesting therapeutic possibilities. PMID:28580170

Enhanced targeting of invasive glioblastoma cells by peptide-functionalized gold nanorods in hydrogel-based 3D cultures.

PubMed

Gonçalves, Diana P N; Rodriguez, Raul D; Kurth, Thomas; Bray, Laura J; Binner, Marcus; Jungnickel, Christiane; Gür, Fatih N; Poser, Steve W; Schmidt, Thorsten L; Zahn, Dietrich R T; Androutsellis-Theotokis, Andreas; Schlierf, Michael; Werner, Carsten

2017-08-01

Cancer stem cells (CSCs) are responsible for drug resistance, tumor recurrence, and metastasis in several cancer types, making their eradication a primary objective in cancer therapy. Glioblastoma Multiforme (GBM) tumors are usually composed of a highly infiltrating CSC subpopulation, which has Nestin as a putative marker. Since the majority of these infiltrating cells are able to elude conventional therapies, we have developed gold nanorods (AuNRs) functionalized with an engineered peptide capable of specific recognition and selective eradication of Nestin positive infiltrating GBM-CSCs. These AuNRs generate heat when irradiated by a near-infrared laser, and cause localized cell damage. Nanoparticle internalization assays performed with GBM-CSCs or Nestin negative cells cultured as two-dimensional (2D) monolayers or embedded in three-dimensional (3D) biodegradable-hydrogels of tunable mechanical properties, revealed that the AuNRs were mainly internalized by GBM-CSCs, and not by Nestin negative cells. The AuNRs were taken up via energy-dependent and caveolae-mediated endocytic mechanisms, and were localized inside endosomes. Photothermal treatments resulted in the selective elimination of GBM-CSCs through cell apoptosis, while Nestin negative cells remained viable. Results also indicated that GBM-CSCs embedded in hydrogels were more resistant to AuNR photothermal treatments than when cultured as 2D monolayers. In summary, the combination of our engineered AuNRs with our tunable hydrogel system has shown the potential to provide an in vitro platform for the evaluation and screening of AuNR-based cancer therapeutics, leading to a substantial advancement in the application of AuNRs for targeted GBM-CSC therapy. There is an urgent need for reliable and efficient therapies for the treatment of Glioblastoma Multiforme (GBM), which is currently an untreatable brain tumor form with a very poor patient survival rate. GBM tumors are mostly comprised of cancer stem cells (CSCs), which are responsible for tumor reoccurrence and therapy resistance. We have developed gold nanorods functionalized with an engineered peptide capable of selective recognition and eradication of GBM-CSCs via heat generation by nanorods upon NIR irradiation. An in vitro evaluation of nanorod therapeutic activities was performed in 3D synthetic-biodegradable hydrogel models with distinct biomechanical cues, and compared to 2D cultures. Results indicated that cells cultured in 3D were more resistant to photothermolysis than in 2D systems. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Quantifying Low Energy Proton Damage in Multijunction Solar Cells

NASA Technical Reports Server (NTRS)

Messenger, Scott R.; Burke, Edward A.; Walters, Robert J.; Warner, Jeffrey H.; Summers, Geoffrey P.; Lorentzen, Justin R.; Morton, Thomas L.; Taylor, Steven J.

2007-01-01

An analysis of the effects of low energy proton irradiation on the electrical performance of triple junction (3J) InGaP2/GaAs/Ge solar cells is presented. The Monte Carlo ion transport code (SRIM) is used to simulate the damage profile induced in a 3J solar cell under the conditions of typical ground testing and that of the space environment. The results are used to present a quantitative analysis of the defect, and hence damage, distribution induced in the cell active region by the different radiation conditions. The modelling results show that, in the space environment, the solar cell will experience a uniform damage distribution through the active region of the cell. Through an application of the displacement damage dose analysis methodology, the implications of this result on mission performance predictions are investigated.

Elevated false recognition in patients with frontal lobe damage is neither a general nor a unitary phenomenon.

PubMed

Verfaellie, Mieke; Rapcsak, Steven Z; Keane, Margaret M; Alexander, Michael P

2004-01-01

This study examined verbal recognition memory in amnesic patients with frontal lesions (AF), nonamnesic patients with frontal lesions (NAF), and amnesic patients with medial temporal lesions (MT). To examine susceptibility to false alarms, the number of studied words drawn from various categories was varied. The AF and MT groups demonstrated reduced hits and increased false alarms. False alarms were especially elevated when item-specific recollection was strongest in control participants. The NAF group performed indistinguishably from control participants, but several patients showed excessive false alarms in the context of normal hit rates. These patients exhibited impaired monitoring and verification processes. The findings demonstrate that elevated false recognition is not characteristic of all frontal patients and may result from more than 1 underlying mechanism. ((c) 2004 APA, all rights reserved)

Reduced susceptibility to Xanthomonas citri in transgenic citrus expressing the FLS2 receptor from Nicotiana benthamiana

USDA-ARS?s Scientific Manuscript database

Overexpression of plant pattern-recognition receptors (PRRs) by genetic engineering provides a novel approach to enhance plant immunity and broad-spectrum disease resistance. The citrus canker disease associated with Xanthomonas citri is one of the important diseases damaging citrus production world...

45 CFR 2552.46 - What cost reimbursements are provided to Foster Grandparents?

Code of Federal Regulations, 2012 CFR

2012-10-01

... assigned children, for earned leave, and for attendance at official project events. (b) Insurance. A Foster... property damage. (ii) Foster Grandparents who drive their personal vehicles to or on assignments or project... provide supportive service without injury to themselves or the children served. (e) Meals and recognition...

45 CFR 2552.46 - What cost reimbursements are provided to Foster Grandparents?

Code of Federal Regulations, 2014 CFR

2014-10-01

... assigned children, for earned leave, and for attendance at official project events. (b) Insurance. A Foster... property damage. (ii) Foster Grandparents who drive their personal vehicles to or on assignments or project... provide supportive service without injury to themselves or the children served. (e) Meals and recognition...

45 CFR 2552.46 - What cost reimbursements are provided to Foster Grandparents?

Code of Federal Regulations, 2013 CFR

2013-10-01

... assigned children, for earned leave, and for attendance at official project events. (b) Insurance. A Foster... property damage. (ii) Foster Grandparents who drive their personal vehicles to or on assignments or project... provide supportive service without injury to themselves or the children served. (e) Meals and recognition...

64Cu antibody-targeting of the T-cell receptor and subsequent internalization enables in vivo tracking of lymphocytes by PET

PubMed Central

Griessinger, Christoph M.; Maurer, Andreas; Kesenheimer, Christian; Kehlbach, Rainer; Reischl, Gerald; Ehrlichmann, Walter; Bukala, Daniel; Harant, Maren; Cay, Funda; Brück, Jürgen; Nordin, Renate; Kohlhofer, Ursula; Rammensee, Hans-Georg; Quintanilla-Martinez, Leticia; Schaller, Martin; Röcken, Martin; Pichler, Bernd J.; Kneilling, Manfred

2015-01-01

T cells are key players in inflammation, autoimmune diseases, and immunotherapy. Thus, holistic and noninvasive in vivo characterizations of the temporal distribution and homing dynamics of lymphocytes in mammals are of special interest. Herein, we show that PET-based T-cell labeling facilitates quantitative, highly sensitive, and holistic monitoring of T-cell homing patterns in vivo. We developed a new T-cell receptor (TCR)-specific labeling approach for the intracellular labeling of mouse T cells. We found that continuous TCR plasma membrane turnover and the endocytosis of the specific 64Cu-monoclonal antibody (mAb)–TCR complex enables a stable labeling of T cells. The TCR–mAb complex was internalized within 24 h, whereas antigen recognition was not impaired. Harmful effects of the label on the viability, DNA-damage and apoptosis-necrosis induction, could be minimized while yielding a high contrast in in vivo PET images. We were able to follow and quantify the specific homing of systemically applied 64Cu-labeled chicken ovalbumin (cOVA)-TCR transgenic T cells into the pulmonary and perithymic lymph nodes (LNs) of mice with cOVA-induced airway delayed-type hypersensitivity reaction (DTHR) but not into pulmonary and perithymic LNs of naïve control mice or mice diseased from turkey or pheasant OVA-induced DTHR. Our protocol provides consequent advancements in the detection of small accumulations of immune cells in single LNs and specific homing to the sites of inflammation by PET using the internalization of TCR-specific mAbs as a specific label of T cells. Thus, our labeling approach is applicable to other cells with constant membrane receptor turnover. PMID:25587131

DNA damage in cells exhibiting radiation-induced genomic instability

DOE PAGES

Keszenman, Deborah J.; Kolodiuk, Lucia; Baulch, Janet E.

2015-02-22

Cells exhibiting radiation induced genomic instability exhibit varied spectra of genetic and chromosomal aberrations. Even so, oxidative stress remains a common theme in the initiation and/or perpetuation of this phenomenon. Isolated oxidatively modified bases, abasic sites, DNA single strand breaks and clustered DNA damage are induced in normal mammalian cultured cells and tissues due to endogenous reactive oxygen species generated during normal cellular metabolism in an aerobic environment. While sparse DNA damage may be easily repaired, clustered DNA damage may lead to persistent cytotoxic or mutagenic events that can lead to genomic instability. In this study, we tested the hypothesismore » that DNA damage signatures characterised by altered levels of endogenous, potentially mutagenic, types of DNA damage and chromosomal breakage are related to radiation-induced genomic instability and persistent oxidative stress phenotypes observed in the chromosomally unstable progeny of irradiated cells. The measurement of oxypurine, oxypyrimidine and abasic site endogenous DNA damage showed differences in non-double-strand breaks (DSB) clusters among the three of the four unstable clones evaluated as compared to genomically stable clones and the parental cell line. These three unstable clones also had increased levels of DSB clusters. The results of this study demonstrate that each unstable cell line has a unique spectrum of persistent damage and lead us to speculate that alterations in DNA damage signaling and repair may be related to the perpetuation of genomic instability.« less

Temporal and speech processing skills in normal hearing individuals exposed to occupational noise.

PubMed

Kumar, U Ajith; Ameenudin, Syed; Sangamanatha, A V

2012-01-01

Prolonged exposure to high levels of occupational noise can cause damage to hair cells in the cochlea and result in permanent noise-induced cochlear hearing loss. Consequences of cochlear hearing loss on speech perception and psychophysical abilities have been well documented. Primary goal of this research was to explore temporal processing and speech perception Skills in individuals who are exposed to occupational noise of more than 80 dBA and not yet incurred clinically significant threshold shifts. Contribution of temporal processing skills to speech perception in adverse listening situation was also evaluated. A total of 118 participants took part in this research. Participants comprised three groups of train drivers in the age range of 30-40 (n= 13), 41 50 ( = 13), 41-50 (n = 9), and 51-60 (n = 6) years and their non-noise-exposed counterparts (n = 30 in each age group). Participants of all the groups including the train drivers had hearing sensitivity within 25 dB HL in the octave frequencies between 250 and 8 kHz. Temporal processing was evaluated using gap detection, modulation detection, and duration pattern tests. Speech recognition was tested in presence multi-talker babble at -5dB SNR. Differences between experimental and control groups were analyzed using ANOVA and independent sample t-tests. Results showed a trend of reduced temporal processing skills in individuals with noise exposure. These deficits were observed despite normal peripheral hearing sensitivity. Speech recognition scores in the presence of noise were also significantly poor in noise-exposed group. Furthermore, poor temporal processing skills partially accounted for the speech recognition difficulties exhibited by the noise-exposed individuals. These results suggest that noise can cause significant distortions in the processing of suprathreshold temporal cues which may add to difficulties in hearing in adverse listening conditions.

Estradiol prevents ozone-induced increases in brain lipid peroxidation and impaired social recognition memory in female rats.

PubMed

Guevara-Guzmán, R; Arriaga, V; Kendrick, K M; Bernal, C; Vega, X; Mercado-Gómez, O F; Rivas-Arancibia, S

2009-03-31

There is increasing concern about the neurodegenerative and behavioral consequences of ozone pollution in industrialized urban centers throughout the world and that women may be more susceptible to brain neurodegenerative disorders. In the present study we have investigated the effects of chronic (30 or 60 days) exposure to ozone on olfactory perception and memory and on levels of lipid peroxidation, alpha and beta estrogen receptors and dopamine beta-hydroxylase in the olfactory bulb in ovariectomized female rats. The ability of 17beta-estradiol to prevent these effects was then assessed. Results showed that ozone exposure for 30 or 60 days impaired formation/retention of a selective olfactory recognition memory 120 min after exposure to a juvenile stimulus animal with the effect at 60 days being significantly greater than at 30 days. They also showed impaired speed in locating a buried chocolate reward after 60 days of ozone exposure indicating some loss of olfactory perception. These functional impairments could all be prevented by coincident estradiol treatment. In the olfactory bulb, levels of lipid peroxidation were increased at both 30- and 60-day time-points and numbers of cells with immunohistochemical staining for alpha and beta estrogen receptors, and dopamine beta-hydroxylase were reduced as were alpha and beta estrogen receptor protein levels. These effects were prevented by estradiol treatment. Oxidative stress damage caused by chronic exposure to ozone does therefore impair olfactory perception and social recognition memory and may do so by reducing noradrenergic and estrogen receptor activity in the olfactory bulb. That these effects can be prevented by estradiol treatment suggests increased susceptibility to neurodegenerative disorders in aging women may be contributed to by reduced estrogen levels post-menopause.

Inhibition of SIRT1 Catalytic Activity Increases p53 Acetylation but Does Not Alter Cell Survival following DNA Damage

PubMed Central

Solomon, Jonathan M.; Pasupuleti, Rao; Xu, Lei; McDonagh, Thomas; Curtis, Rory; DiStefano, Peter S.; Huber, L. Julie

2006-01-01

Human SIRT1 is an enzyme that deacetylates the p53 tumor suppressor protein and has been suggested to modulate p53-dependent functions including DNA damage-induced cell death. In this report, we used EX-527, a novel, potent, and specific small-molecule inhibitor of SIRT1 catalytic activity to examine the role of SIRT1 in p53 acetylation and cell survival after DNA damage. Treatment with EX-527 dramatically increased acetylation at lysine 382 of p53 after different types of DNA damage in primary human mammary epithelial cells and several cell lines. Significantly, inhibition of SIRT1 catalytic activity by EX-527 had no effect on cell growth, viability, or p53-controlled gene expression in cells treated with etoposide. Acetyl-p53 was also increased by the histone deacetylase (HDAC) class I/II inhibitor trichostatin A (TSA). EX-527 and TSA acted synergistically to increase acetyl-p53 levels, confirming that p53 acetylation is regulated by both SIRT1 and HDACs. While TSA alone reduced cell survival after DNA damage, the combination of EX-527 and TSA had no further effect on cell viability and growth. These results show that, although SIRT1 deacetylates p53, this does not play a role in cell survival following DNA damage in certain cell lines and primary human mammary epithelial cells. PMID:16354677

The neuro-immunological interface in an evolutionary perspective: the dynamic relationship between effector and recognition systems.

PubMed

Ottaviani, E; Valensin, S; Franceschi, C

1998-04-16

The evolutionary perspective indicates that an immune-neuroendocrine effector system integrating innate immunity, stress and inflammation is present in invertebrates. This defense network, centered on the macrophage and exerting primitive and highly promiscuous recognition units, is very effective, ancestral and appears to have been conserved throughout evolution from invertebrates to higher vertebrates. It would seem that there was a "big bang" in the recognition system of lower vertebrates, and T and B cell repertoires, MHC and antibodies suddenly appeared. We argue that this phenomenon is the counterpart of the increasing complexity of the internal circuitry and recognition units in the effector system. The immediate consequences were a progressive enlargement of the pathogen repertoire and new problems regarding self/not-self discrimination. Probably not by chance, a new organ appeared, capable of purging cells able of excessive self recognition. This organ, the thymus, appears to be the result of a well known evolutionary strategy of re-using pre-existing material (neuroendocrine cells and mediators constituting the thymic microenvironment). This bricolage at an organ level is similar to the effect we have already described at the level of molecules and functions of the defense network, and has a general counterpart at genetic level. Thus, in vertebrates, the conserved immune-neuroendocrine effector system remains of fundamental importance in defense against pathogens, while its efficiency has increased through synergy with the new, clonotipical recognition repertoire.

DAMPs, ageing, and cancer: The 'DAMP Hypothesis'.

PubMed

Huang, Jin; Xie, Yangchun; Sun, Xiaofang; Zeh, Herbert J; Kang, Rui; Lotze, Michael T; Tang, Daolin

2015-11-01

Ageing is a complex and multifactorial process characterized by the accumulation of many forms of damage at the molecular, cellular, and tissue level with advancing age. Ageing increases the risk of the onset of chronic inflammation-associated diseases such as cancer, diabetes, stroke, and neurodegenerative disease. In particular, ageing and cancer share some common origins and hallmarks such as genomic instability, epigenetic alteration, aberrant telomeres, inflammation and immune injury, reprogrammed metabolism, and degradation system impairment (including within the ubiquitin-proteasome system and the autophagic machinery). Recent advances indicate that damage-associated molecular pattern molecules (DAMPs) such as high mobility group box 1, histones, S100, and heat shock proteins play location-dependent roles inside and outside the cell. These provide interaction platforms at molecular levels linked to common hallmarks of ageing and cancer. They can act as inducers, sensors, and mediators of stress through individual plasma membrane receptors, intracellular recognition receptors (e.g., advanced glycosylation end product-specific receptors, AIM2-like receptors, RIG-I-like receptors, and NOD1-like receptors, and toll-like receptors), or following endocytic uptake. Thus, the DAMP Hypothesis is novel and complements other theories that explain the features of ageing. DAMPs represent ideal biomarkers of ageing and provide an attractive target for interventions in ageing and age-associated diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

The toll of the gridiron: damage-associated molecular patterns and hypertension in American football

PubMed Central

McCarthy, Cameron G.; Webb, R. Clinton

2016-01-01

American football has unequivocally been linked to elevations in blood pressure and hypertension, especially in linemen. However, the mechanisms of this increase cannot be attributed solely to increased body weight and associated cardiometabolic risk factors (e.g.,dyslipidemia or hyperglycemia). Therefore, understanding the etiology of football-associated hypertension is essential for improving the quality of life in this mostly young population, as well as for lowering the potential for chronic disease in the future. We propose that inflammatogenic damage–associated molecular patterns (DAMPs) released into the circulation from football-induced musculoskeletal trauma activate pattern-recognition receptors of the innate immune system—specifically, high mobility group box 1 protein (HMGB1) and mitochondrial (mt)DNA which activate Toll-like receptor (TLR)4 and -9, respectively. Previously, we observed that circulating levels of these 2 DAMPs are increased in hypertension, and activation of TLR4 and -9 causes endothelial dysfunction and hypertension. Therefore, our novel hypothesis is that musculoskeletal injury from repeated hits in football players, particularly in linemen, leads to elevated circulating HMGB1 and mtDNA to activate TLRs on endothelial cells leading to impaired endothelium-dependent vasodilation, increased vascular tone, and hypertension.—McCarthy, C. G., Webb, R. C. The toll of the gridiron: damage-associated molecular patterns and hypertension in American football. PMID:26316270

The Immune Interplay between the Host and the Pathogen in Aspergillus fumigatus Lung Infection

PubMed Central

Sales-Campos, Helioswilton; Tonani, Ludmilla; Cardoso, Cristina Ribeiro Barros; Kress, Márcia Regina Von Zeska

2013-01-01

The interplay between Aspergillus fumigatus and the host immune response in lung infection has been subject of studies over the last years due to its importance in immunocompromised patients. The multifactorial virulence factors of A. fumigatus are related to the fungus biological characteristics, for example, structure, ability to grow and adapt to high temperatures and stress conditions, besides capability of evading the immune system and causing damage to the host. In this context, the fungus recognition by the host innate immunity occurs when the pathogen disrupts the natural and chemical barriers followed by the activation of acquired immunity. It seems clear that a Th1 response has a protective role, whereas Th2 reactions are often associated with higher fungal burden, and Th17 response is still controversial. Furthermore, a fine regulation of the effector immunity is required to avoid excessive tissue damage associated with fungal clearance, and this role could be attributed to regulatory T cells. Finally, in this work we reviewed the aspects involved in the complex interplay between the host immune response and the pathogen virulence factors, highlighting the immunological issues and the importance of its better understanding to the development of novel therapeutic approaches for invasive lung aspergillosis. PMID:23984400

Steric Shielding of Surface Epitopes and Impaired Immune Recognition Induced by the Ebola Virus Glycoprotein

PubMed Central

Francica, Joseph R.; Varela-Rohena, Angel; Medvec, Andrew; Plesa, Gabriela; Riley, James L.; Bates, Paul

2010-01-01

Many viruses alter expression of proteins on the surface of infected cells including molecules important for immune recognition, such as the major histocompatibility complex (MHC) class I and II molecules. Virus-induced downregulation of surface proteins has been observed to occur by a variety of mechanisms including impaired transcription, blocks to synthesis, and increased turnover. Viral infection or transient expression of the Ebola virus (EBOV) glycoprotein (GP) was previously shown to result in loss of staining of various host cell surface proteins including MHC1 and β1 integrin; however, the mechanism responsible for this effect has not been delineated. In the present study we demonstrate that EBOV GP does not decrease surface levels of β1 integrin or MHC1, but rather impedes recognition by steric occlusion of these proteins on the cell surface. Furthermore, steric occlusion also occurs for epitopes on the EBOV glycoprotein itself. The occluded epitopes in host proteins and EBOV GP can be revealed by removal of the surface subunit of GP or by removal of surface N- and O- linked glycans, resulting in increased surface staining by flow cytometry. Importantly, expression of EBOV GP impairs CD8 T-cell recognition of MHC1 on antigen presenting cells. Glycan-mediated steric shielding of host cell surface proteins by EBOV GP represents a novel mechanism for a virus to affect host cell function, thereby escaping immune detection. PMID:20844579

Ultrastructural study of mitochondrial damage in CHO cells exposed to hyperthermia.

PubMed

Cole, A; Armour, E P

1988-09-01

A unique direct-view stereo electron microscope technique was used to visualize the structure and three-dimensional distributions of mitochondria in CHO cells in situ following hyperthermic treatments. Aberrations induced by various heating regimens were recorded. The protocol included a trypsin digestion that may have enhanced the expression of the initial heat damage. The developed damage was observed as increasing levels of mitochondrial distortion, swelling, and dissociation. Minimal damage was induced at 42 degrees C for exposures of up to 4 h, while significant damage was induced at 43 degrees C for exposures of more than 30 min and at 45 degrees C for exposures of more than 10 min. For moderate exposures, a partial recovery of mitochondrial integrity was observed when the heat treatment was followed by incubation at 37 degrees C for 24 h. Mitochondrial damage was related to the heat dose in that increasing treatment temperature resulted in greater damage, but when compared to cell survival the damage did not parallel cell killing under all time-temperature conditions.

Sun Exposure

MedlinePlus

... pass through your skin and damage your skin cells. Sunburns are a sign of skin damage. Suntans ... after the sun's rays have already killed some cells and damaged others. UV rays can cause skin ...

pRb phosphorylation regulates the proliferation of supporting cells in gentamicin-damaged neonatal avian utricle.

PubMed

Wu, Jingfang; Sun, Shan; Li, Wenyan; Chen, Yan; Li, Huawei

2014-10-01

The ability of nonmammalian vertebrates to regenerate hair cells (HCs) after damage-induced HC loss has stimulated and inspired research in the field of HC regeneration. The protein pRb encoded by retinoblastoma gene Rb1 forces sensory progenitor cells to exit cell cycle and maintain differentiated HCs and supporting cells (SCs) in a quiescent state. pRb function is regulated by phosphorylation through the MEK/ERK or the pRb/Raf-1 signaling pathway. In our previous study, we have shown that pRb phosphorylation is crucial for progenitor cell proliferation and survival during the early embryonic stage of avian otocyst sensory epithelium development. However, in damaged avian utricle, the role of pRb in regulating the cell cycling of SCs or HCs regeneration still remains unclear. To further elucidate the function of pRb phosphorylation on SCs re-entering the cell cycle triggered by gentamycin-induced HCs damage, we isolated neonatal chicken utricles and treated them with the MEK inhibitor U0126 or the pRb/Raf-1 inhibitor RRD-251, respectively in vitro. We found that after gentamycin-induced HCs damage, pRb phosphorylation is important for the quiescent SCs re-entering the cell cycle in the neonatal chicken utricle. In addition, the proliferation of SCs decreased in a dose-dependent manner in response to both U0126 and RRD-251, which indicates that both the MEK/ERK and the pRb/Raf-1 signaling pathway play important roles in pRb phosphorylation in damaged neonatal chicken utricle. Together, these findings on the function of pRb in damaged neonatal chicken utricle improve our understanding of the regulation of the cell cycle of SCs after HCs loss and may shed light on the mammalian HC regeneration from SCs in damaged organs.

Presentation of lipid antigens to T cells.

PubMed

Mori, Lucia; De Libero, Gennaro

2008-04-15

T cells specific for lipid antigens participate in regulation of the immune response during infections, tumor immunosurveillance, allergy and autoimmune diseases. T cells recognize lipid antigens as complexes formed with CD1 antigen-presenting molecules, thus resembling recognition of MHC-peptide complexes. The biophysical properties of lipids impose unique mechanisms for their delivery, internalization into antigen-presenting cells, membrane trafficking, processing, and loading of CD1 molecules. Each of these steps is controlled at molecular and celular levels and determines lipid immunogenicity. Lipid antigens may derive from microbes and from the cellular metabolism, thus allowing the immune system to survey a large repertoire of immunogenic molecules. Recognition of lipid antigens facilitates the detection of infectious agents and the initiation of responses involved in immunoregulation and autoimmunity. This review focuses on the presentation mechanisms and specific recognition of self and bacterial lipid antigens and discusses the important open issues.

Automated thematic mapping and change detection of ERTS-A images

NASA Technical Reports Server (NTRS)

Gramenopoulos, N. (Principal Investigator)

1975-01-01

The author has identified the following significant results. In the first part of the investigation, spatial and spectral features were developed which were employed to automatically recognize terrain features through a clustering algorithm. In this part of the investigation, the size of the cell which is the number of digital picture elements used for computing the spatial and spectral features was varied. It was determined that the accuracy of terrain recognition decreases slowly as the cell size is reduced and coincides with increased cluster diffuseness. It was also proven that a cell size of 17 x 17 pixels when used with the clustering algorithm results in high recognition rates for major terrain classes. ERTS-1 data from five diverse geographic regions of the United States were processed through the clustering algorithm with 17 x 17 pixel cells. Simple land use maps were produced and the average terrain recognition accuracy was 82 percent.

FACT is a sensor of DNA torsional stress in eukaryotic cells

PubMed Central

Safina, Alfiya; Cheney, Peter; Pal, Mahadeb; Brodsky, Leonid; Ivanov, Alexander; Kirsanov, Kirill; Lesovaya, Ekaterina; Naberezhnov, Denis; Nesher, Elimelech; Koman, Igor; Wang, Dan; Wang, Jianming; Yakubovskaya, Marianna; Winkler, Duane

2017-01-01

Abstract Transitions of B-DNA to alternative DNA structures (ADS) can be triggered by negative torsional strain, which occurs during replication and transcription, and may lead to genomic instability. However, how ADS are recognized in cells is unclear. We found that the binding of candidate anticancer drug, curaxin, to cellular DNA results in uncoiling of nucleosomal DNA, accumulation of negative supercoiling and conversion of multiple regions of genomic DNA into left-handed Z-form. Histone chaperone FACT binds rapidly to the same regions via the SSRP1 subunit in curaxin-treated cells. In vitro binding of purified SSRP1 or its isolated CID domain to a methylated DNA fragment containing alternating purine/pyrimidines, which is prone to Z-DNA transition, is much stronger than to other types of DNA. We propose that FACT can recognize and bind Z-DNA or DNA in transition from a B to Z form. Binding of FACT to these genomic regions triggers a p53 response. Furthermore, FACT has been shown to bind to other types of ADS through a different structural domain, which also leads to p53 activation. Thus, we propose that FACT acts as a sensor of ADS formation in cells. Recognition of ADS by FACT followed by a p53 response may explain the role of FACT in DNA damage prevention. PMID:28082391

Molecular basis of mycobacterial lipid antigen presentation by CD1c and its recognition by αβ T cells

PubMed Central

Roy, Sobhan; Ly, Dalam; Li, Nan-Sheng; Altman, John D.; Piccirilli, Joseph A.; Moody, D. Branch; Adams, Erin J.

2014-01-01

CD1c is a member of the group 1 CD1 family of proteins that are specialized for lipid antigen presentation. Despite high cell surface expression of CD1c on key antigen-presenting cells and the discovery of its mycobacterial lipid antigen presentation capability, the molecular basis of CD1c recognition by T cells is unknown. Here we present a comprehensive functional and molecular analysis of αβ T-cell receptor (TCR) recognition of CD1c presenting mycobacterial phosphomycoketide antigens. Our structure of CD1c with the mycobacterial phosphomycoketide (PM) shows similarities to that of CD1c-mannosyl-β1-phosphomycoketide in that the A' pocket accommodates the mycoketide alkyl chain; however, the phosphate head-group of PM is shifted ∼6 Å in relation to that of mannosyl-β1-PM. We also demonstrate a bona fide interaction between six human TCRs and CD1c-mycoketide complexes, measuring high to moderate affinities. The crystal structure of the DN6 TCR and mutagenic studies reveal a requirement of five complementarity determining region (CDR) loops for CD1c recognition. Furthermore, mutagenesis of CD1c reveals residues in both the α1 and α2 helices involved in TCR recognition, yet not entirely overlapping among the examined TCRs. Unlike patterns for MHC I, no archetypical binding footprint is predicted to be shared by CD1c-reactive TCRs, even when recognizing the same or similar antigens. PMID:25298532

Immunity to Intracellular Salmonella Depends on Surface-associated Antigens

PubMed Central

Claudi, Beatrice; Mazé, Alain; Schemmer, Anne K.; Kirchhoff, Dennis; Schmidt, Alexander; Burton, Neil; Bumann, Dirk

2012-01-01

Invasive Salmonella infection is an important health problem that is worsening because of rising antimicrobial resistance and changing Salmonella serovar spectrum. Novel vaccines with broad serovar coverage are needed, but suitable protective antigens remain largely unknown. Here, we tested 37 broadly conserved Salmonella antigens in a mouse typhoid fever model, and identified antigen candidates that conferred partial protection against lethal disease. Antigen properties such as high in vivo abundance or immunodominance in convalescent individuals were not required for protectivity, but all promising antigen candidates were associated with the Salmonella surface. Surprisingly, this was not due to superior immunogenicity of surface antigens compared to internal antigens as had been suggested by previous studies and novel findings for CD4 T cell responses to model antigens. Confocal microscopy of infected tissues revealed that many live Salmonella resided alone in infected host macrophages with no damaged Salmonella releasing internal antigens in their vicinity. In the absence of accessible internal antigens, detection of these infected cells might require CD4 T cell recognition of Salmonella surface-associated antigens that could be processed and presented even from intact Salmonella. In conclusion, our findings might pave the way for development of an efficacious Salmonella vaccine with broad serovar coverage, and suggest a similar crucial role of surface antigens for immunity to both extracellular and intracellular pathogens. PMID:23093937

Graft-versus-host disease: regulation by microbe-associated molecules and innate immune receptors.

PubMed

Penack, Olaf; Holler, Ernst; van den Brink, Marcel R M

2010-03-11

Acute graft-versus-host disease (GVHD) remains the major obstacle to a more favorable therapeutic outcome of allogeneic hematopoietic stem cell transplantation (HSCT). GVHD is characterized by tissue damage in gut, liver, and skin, caused by donor T cells that are critical for antitumor and antimicrobial immunity after HSCT. One obstacle in combating GVHD used to be the lack of understanding the molecular mechanisms that are involved in the initiation phase of this syndrome. Recent research has demonstrated that interactions between microbial-associated molecules (pathogen-associated molecular patterns [PAMPs]) and innate immune receptors (pathogen recognition receptors [PRRs]), such as NOD-like receptors (NLRs) and Toll-like receptors (TLRs), control adaptive immune responses in inflammatory disorders. Polymorphisms of the genes encoding NOD2 and TLR4 are associated with a higher incidence of GVHD in HSC transplant recipients. Interestingly, NOD2 regulates GVHD through its inhibitory effect on antigen-presenting cell (APC) function. These insights identify important mechanisms regarding the induction of GVHD through the interplay of microbial molecules and innate immunity, thus opening a new area for future therapeutic approaches. This review covers current knowledge of the role of PAMPs and PRRs in the control of adaptive immune responses during inflammatory diseases, particularly GVHD.

Direct Role for Proliferating Cell Nuclear Antigen in Substrate Recognition by the E3 Ubiquitin Ligase CRL4Cdt2*

PubMed Central

Havens, Courtney G.; Shobnam, Nadia; Guarino, Estrella; Centore, Richard C.; Zou, Lee; Kearsey, Stephen E.; Walter, Johannes C.

2012-01-01

The E3 ubiquitin ligase Cullin-ring ligase 4-Cdt2 (CRL4Cdt2) is emerging as an important cell cycle regulator that targets numerous proteins for destruction in S phase and after DNA damage, including Cdt1, p21, and Set8. CRL4Cdt2 substrates contain a “PIP degron,” which consists of a canonical proliferating cell nuclear antigen (PCNA) interaction motif (PIP box) and an adjacent basic amino acid. Substrates use their PIP box to form a binary complex with PCNA on chromatin and the basic residue to recruit CRL4Cdt2 for substrate ubiquitylation. Using Xenopus egg extracts, we identify an acidic residue in PCNA that is essential to support destruction of all CRL4Cdt2 substrates. This PCNA residue, which adjoins the basic amino acid of the bound PIP degron, is dispensable for substrate binding to PCNA but essential for CRL4Cdt2 recruitment to chromatin. Our data show that the interaction of CRL4Cdt2 with substrates requires molecular determinants not only in the substrate degron but also on PCNA. The results illustrate a potentially general mechanism by which E3 ligases can couple ubiquitylation to the formation of protein-protein interactions. PMID:22303007

The Goldilocks Conundrum: NLR Inflammasome Modulation of Gastrointestinal Inflammation during Inflammatory Bowel Disease

PubMed Central

Ringel-Scaia, Veronica M.; McDaniel, Dylan K.; Allen, Irving C.

2017-01-01

Recent advances have revealed significant insight into Inflammatory bowel disease (IBD) pathobiology. Ulcerative colitis and Crohn's disease, the chronic relapsing clinical manifestations of IBD, are complex disorders with genetic and environmental influences. These diseases are associated with the dysregulation of immune tolerance, excessive Inflammation, and damage to the epithelial cell barrier. Increasing evidence indicates that pattern recognition receptors, including Toll-like receptors (TLRs) and nucleotide-binding domain and leucine-rich repeat-containing proteins (NLRs), function to maintain immune system homeostasis, modulate the gastrointestinal microbiome, and promote proper intestinal epithelial cell regeneration and repair. New insights have revealed that NLR family members are essential components in maintaining this immune system homeostasis. To date, the vast majority of studies associated with NLRs have focused on family members that form a multiprotein signaling platform called the Inflammasome. These signaling complexes are responsible for the cleavage and activation of the potent pleotropic cytokines IL-1β and IL-18, and they facilitate a unique form of cell death defined as pyroptosis. In this review, we summarize the current paradigms associated with NLR Inflammasome maintenance of immune system homeostasis in the gastrointestinal system. New concepts related to canonical and noncanonical Inflammasome signaling, as well as the implications of classical and alternative Inflammasomes in IBD pathogenesis, are also reviewed. PMID:28322135

Toll-like Receptor-mediated Down-regulation of the Deubiquitinase Cylindromatosis (CYLD) Protects Macrophages from Necroptosis in Wild-derived Mice*

PubMed Central

Schworer, Stephen A.; Smirnova, Irina I.; Kurbatova, Irina; Bagina, Uliana; Churova, Maria; Fowler, Trent; Roy, Ananda L.; Degterev, Alexei; Poltorak, Alexander

2014-01-01

Pathogen recognition by the innate immune system initiates the production of proinflammatory cytokines but can also lead to programmed host cell death. Necroptosis, a caspase-independent cell death pathway, can contribute to the host defense against pathogens or cause damage to host tissues. Receptor-interacting protein (RIP1) is a serine/threonine kinase that integrates inflammatory and necroptotic responses. To investigate the mechanisms of RIP1-mediated activation of immune cells, we established a genetic screen on the basis of RIP1-mediated necroptosis in wild-derived MOLF/EiJ mice, which diverged from classical laboratory mice over a million years ago. When compared with C57BL/6, MOLF/EiJ macrophages were resistant to RIP1-mediated necroptosis induced by Toll-like receptors. Using a forward genetic approach in a backcross panel of mice, we identified cylindromatosis (CYLD), a deubiquitinase known to act directly on RIP1 and promote necroptosis in TNF receptor signaling, as the gene conferring the trait. We demonstrate that CYLD is required for Toll-like receptor-induced necroptosis and describe a novel mechanism by which CYLD is down-regulated at the transcriptional level in MOLF/EiJ macrophages to confer protection from necroptosis. PMID:24706750

The Cell's Sophisticated Army to Defend Against Assaults on DNAThe Cell's Sophisticated Army to Defend Against Assaults on DNA | Center for Cancer Research

Cancer.gov

The maintenance of genome integrity and function is essen-tial for the survival of cells and organisms. Any damage to our genetic material must be immediately sensed and repaired to preserve a cell’s func-tional integrity. Cells are constantly faced with the challenge of protecting their DNA from assaults by damaging chemicals and ultraviolet light. DNA damage that escapes repair can lead to a variety of genetic disorders and diseases, particularly cancer. To avoid this catastrophe, the cell employs an army of DNA repair factors that “rush to the scene” and initiate a cascade of events to repair the damage. Exactly how different repair factors sense DNA damage and orchestrate their concert-ed response is not well understood.

Non-homologous end joining pathway is the major route of protection against 4β-hydroxywithanolide E-induced DNA damage in MCF-7 cells.

PubMed

You, B-J; Wu, Y-C; Lee, C-L; Lee, H-Z

2014-03-01

4β-Hydroxywithanolide E is a bioactive withanolide extracted from Physalis peruviana. 4β-Hydroxywithanolide E caused reactive oxygen species production and cell apoptosis in human breast cancer MCF-7 cells. We further found that 4β-hydroxywithanolide E induced DNA damage and regulated the DNA damage signaling in MCF-7 cells. The DNA damage sensors and repair proteins act promptly to remove DNA lesions by 4β-hydroxywithanolide E. The ataxia-telangiectasia mutated protein (ATM)-dependent DNA damage signaling pathway is involved in 4β-hydroxywithanolide E-induced apoptosis of MCF-7 cells. Non-homologous end joining pathway, but not homologous recombination, is the major route of protection of MCF-7 cells against 4β-hydroxywithanolide E-induced DNA damage. 4β-Hydroxywithanolide E had no significant impact on the base excision repair pathway. In this study, we examined the 4β-hydroxywithanolide E-induced DNA damage as a research tool in project investigating the DNA repair signaling in breast cancer cells. We also suggest that 4β-hydroxywithanolide E assert its anti-tumor activity in carcinogenic progression and develop into a dietary chemopreventive agent. Copyright © 2014 Elsevier Ltd. All rights reserved.

Induction and repair of DNA damage measured by the comet assay in human T lymphocytes separated by immunomagnetic cell sorting.

PubMed

Bausinger, Julia; Speit, Günter

2014-11-01

The comet assay is widely used in human biomonitoring to measure DNA damage in whole blood or isolated peripheral blood mononuclear cells (PBMC) as a marker of exposure to genotoxic agents. Cytogenetic assays with phytohemagglutinin (PHA)-stimulated cultured T lymphocytes are also frequently performed in human biomonitoring. Cytogenetic effects (micronuclei, chromosome aberrations, sister chromatid exchanges) may be induced in vivo but also occur ex vivo during the cultivation of lymphocytes as a consequence of DNA damage present in lymphocytes at the time of sampling. To better understand whether DNA damage measured by the comet assay in PBMC is representative for DNA damage in T cells, we comparatively investigated DNA damage and its repair in PBMC and T cells obtained by immunomagnetic cell sorting. PBMC cultures and T cell cultures were exposed to mutagens with different modes of genotoxic action and DNA damage was measured by the comet assay after the end of a 2h exposure and after 18h post-incubation. The mutagens tested were methyl methanesulfonate (MMS), (±)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), 4-nitroquinoline-1-oxide (4NQO), styrene oxide and potassium bromate. MMS and potassium bromate were also tested by the modified comet assay with formamido pyrimidine glycosylase (FPG) protein. The results indicate that the mutagens tested induce DNA damage in PBMC and T cells in the same range of concentrations and removal of induced DNA lesions occurs to a comparable extent. Based on these results, we conclude that the comet assay with PBMC is suited to predict DNA damage and its removal in T cells. Copyright © 2014 Elsevier B.V. All rights reserved.

ATM-dependent DNA damage checkpoint functions regulate gene expression in human fibroblasts

PubMed Central

Zhou, Tong; Chou, Jeff; Zhou, Yingchun; Simpson, Dennis A.; Cao, Feng; Bushel, Pierre R.; Paules, Richard S.; Kaufmann, William K.

2013-01-01

The relationships between profiles of global gene expression and DNA damage checkpoint functions were studied in cells from patients with ataxia telangiectasia (AT). Three telomerase-expressing AT fibroblast lines displayed the expected hypersensitivity to ionizing radiation (IR) and defects in DNA damage checkpoints. Profiles of global gene expression in AT cells were determined at 2, 6 and 24 h after treatment with 1.5 Gy IR or sham-treatment, and were compared to those previously recognized in normal human fibroblasts. Under basal conditions 160 genes or ESTs were differentially expressed in AT and normal fibroblasts, and these were associated by gene ontology with insulin-like growth factor binding and regulation of cell growth. Upon DNA damage, 1091 gene mRNAs were changed in at least two of the three AT cell lines. When compared with the 1811 genes changed in normal human fibroblasts after the same treatment, 715 were found in both AT and normal fibroblasts, including most genes categorized by gene ontology into cell cycle, cell growth and DNA damage response pathways. However, the IR-induced changes in these 715 genes in AT cells usually were delayed or attenuated in comparison to normal cells. The reduced change in DNA-damage-response genes and the attenuated repression of cell-cycle-regulated genes may account for the defects in cell cycle checkpoint function in AT cells. PMID:17699107

Beyond xeroderma pigmentosum: DNA damage and repair in an ecological context. A tribute to James E. Cleaver.

PubMed

Karentz, Deneb

2015-01-01

The ability to repair DNA is a ubiquitous characteristic of life on Earth and all organisms possess similar mechanisms for dealing with DNA damage, an indication of a very early evolutionary origin for repair processes. James E. Cleaver's career (initiated in the early 1960s) has been devoted to the study of mammalian ultraviolet radiation (UVR) photobiology, specifically the molecular genetics of xeroderma pigmentosum and other human diseases caused by defects in DNA damage recognition and repair. This work by Jim and others has influenced the study of DNA damage and repair in a variety of taxa. Today, the field of DNA repair is enhancing our understanding of not only how to treat and prevent human disease, but is providing insights on the evolutionary history of life on Earth and how natural populations are coping with UVR-induced DNA damage from anthropogenic changes in the environment such as ozone depletion. © 2014 The American Society of Photobiology.

Cidofovir is active against human papillomavirus positive and negative head and neck and cervical tumor cells by causing DNA damage as one of its working mechanisms.

PubMed

Mertens, Barbara; Nogueira, Tatiane; Stranska, Ruzena; Naesens, Lieve; Andrei, Graciela; Snoeck, Robert

2016-07-26

Human papillomavirus (HPV) causes cervical cancer and a large fraction of head and neck squamous cell carcinomas (HNSCC). Cidofovir (CDV) proved efficacious in the treatment of several HPV-induced benign and malignant hyper proliferations. To provide a better insight into how CDV selectively eradicates transformed cells, HPV+ and HPV- cervical carcinoma and HNSCC cell lines were compared to normal cells for antiproliferative effects, CDV metabolism, drug incorporation into cellular DNA, and DNA damage. Incorporation of CDV into cellular DNA was higher in tumor cells than in normal cells and correlated with CDV antiproliferative effects, which were independent of HPV status. Increase in phospho-ATM levels was detected following CDV exposure and higher levels of γ-H2AX (a quantitative marker of double-strand breaks) were measured in tumor cells compared to normal cells. A correlation between DNA damage and CDV incorporation into DNA was found but not between DNA damage and CDV antiproliferative effects. These data indicate that CDV antiproliferative effects result from incorporation of the drug into DNA causing DNA damage. However, the anti-tumor effects of CDV cannot be exclusively ascribed to DNA damage. Furthermore, CDV can be considered a promising broad spectrum anti-cancer agent, not restricted to HPV+ lesions.

The Self-Identity Protein IdsD Is Communicated between Cells in Swarming Proteus mirabilis Colonies.

PubMed

Saak, Christina C; Gibbs, Karine A

2016-12-15

Proteus mirabilis is a social bacterium that is capable of self (kin) versus nonself recognition. Swarming colonies of this bacterium expand outward on surfaces to centimeter-scale distances due to the collective motility of individual cells. Colonies of genetically distinct populations remain separate, while those of identical populations merge. Ids proteins are essential for this recognition behavior. Two of these proteins, IdsD and IdsE, encode identity information for each strain. These two proteins bind in vitro in an allele-restrictive manner. IdsD-IdsE binding is correlated with the merging of populations, whereas a lack of binding is correlated with the separation of populations. Key questions remained about the in vivo interactions of IdsD and IdsE, specifically, whether IdsD and IdsE bind within single cells or whether IdsD-IdsE interactions occur across neighboring cells and, if so, which of the two proteins is exchanged. Here we demonstrate that IdsD must originate from another cell to communicate identity and that this nonresident IdsD interacts with IdsE resident in the recipient cell. Furthermore, we show that unbound IdsD in recipient cells does not cause cell death and instead appears to contribute to a restriction in the expansion radius of the swarming colony. We conclude that P. mirabilis communicates IdsD between neighboring cells for nonlethal kin recognition, which suggests that the Ids proteins constitute a type of cell-cell communication. We demonstrate that self (kin) versus nonself recognition in P. mirabilis entails the cell-cell communication of an identity-encoding protein that is exported from one cell and received by another. We further show that this intercellular exchange affects swarm colony expansion in a nonlethal manner, which adds social communication to the list of potential swarm-related regulatory factors. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

The Self-Identity Protein IdsD Is Communicated between Cells in Swarming Proteus mirabilis Colonies

PubMed Central

Saak, Christina C.

2016-01-01

ABSTRACT Proteus mirabilis is a social bacterium that is capable of self (kin) versus nonself recognition. Swarming colonies of this bacterium expand outward on surfaces to centimeter-scale distances due to the collective motility of individual cells. Colonies of genetically distinct populations remain separate, while those of identical populations merge. Ids proteins are essential for this recognition behavior. Two of these proteins, IdsD and IdsE, encode identity information for each strain. These two proteins bind in vitro in an allele-restrictive manner. IdsD-IdsE binding is correlated with the merging of populations, whereas a lack of binding is correlated with the separation of populations. Key questions remained about the in vivo interactions of IdsD and IdsE, specifically, whether IdsD and IdsE bind within single cells or whether IdsD-IdsE interactions occur across neighboring cells and, if so, which of the two proteins is exchanged. Here we demonstrate that IdsD must originate from another cell to communicate identity and that this nonresident IdsD interacts with IdsE resident in the recipient cell. Furthermore, we show that unbound IdsD in recipient cells does not cause cell death and instead appears to contribute to a restriction in the expansion radius of the swarming colony. We conclude that P. mirabilis communicates IdsD between neighboring cells for nonlethal kin recognition, which suggests that the Ids proteins constitute a type of cell-cell communication. IMPORTANCE We demonstrate that self (kin) versus nonself recognition in P. mirabilis entails the cell-cell communication of an identity-encoding protein that is exported from one cell and received by another. We further show that this intercellular exchange affects swarm colony expansion in a nonlethal manner, which adds social communication to the list of potential swarm-related regulatory factors. PMID:27672195

Quinacrine pretreatment reduces microwave-induced neuronal damage by stabilizing the cell membrane

PubMed Central

Ding, Xue-feng; Wu, Yan; Qu, Wen-rui; Fan, Ming; Zhao, Yong-qi

2018-01-01

Quinacrine, widely used to treat parasitic diseases, binds to cell membranes. We previously found that quinacrine pretreatment reduced microwave radiation damage in rat hippocampal neurons, but the molecular mechanism remains poorly understood. Considering the thermal effects of microwave radiation and the protective effects of quinacrine on heat damage in cells, we hypothesized that quinacrine would prevent microwave radiation damage to cells in a mechanism associated with cell membrane stability. To test this, we used retinoic acid to induce PC12 cells to differentiate into neuron-like cells. We then pretreated the neurons with quinacrine (20 and 40 mM) and irradiated them with 50 mW/cm2 microwaves for 3 or 6 hours. Flow cytometry, atomic force microscopy and western blot assays revealed that irradiated cells pretreated with quinacrine showed markedly less apoptosis, necrosis, and membrane damage, and greater expression of heat shock protein 70, than cells exposed to microwave irradiation alone. These results suggest that quinacrine stabilizes the neuronal membrane structure by upregulating the expression of heat shock protein 70, thus reducing neuronal injury caused by microwave radiation. PMID:29623929

An improved, non-functionalized route to plasmonic nanoparticle based cellular probing through osmolyte mediation (Conference Presentation)

NASA Astrophysics Data System (ADS)

Siddhanta, Soumik; Barman, Ishan

2017-02-01

Engineering nanostructured probes for ultra-sensitive detection of specific molecular species, our research seeks to capture the complex changes in cells and tissues that can predict disease progression in an individual. While such nanoparticle-based platforms are rapidly gaining a foothold in cancer diagnostics, one of the most concerning factors is the vulnerability of cells to the interaction with functional nanoparticles thereby raising the specter of systemic toxicity. The nanoparticles end up damaging the cells and disrupting cellular functions thereby impeding their imaging aim. Furthermore, PEGylation, and similar routes, force a tradeoff between desired nanoparticle properties (recognition, uptake, and reduced toxicity) and sensitivity of plasmon-enhanced spectroscopic sensing methods, such as surface-enhanced Raman spectroscopy (SERS) where the proximal presence of noble metal NP and the organic molecule of interest is key. In this work, we report a trehalose-mediated, non-surface functionalized route for cell-nanoparticle interactions that maintains cell viability while allowing selective interaction of the nanoparticle with the cell surface receptors and subsequent internalization. Through careful electron microscopy of nanoparticle-prostate cancer cells interactions, we elucidated that there exists a dynamic equilibrium between "free" cytosolic diffusion of the nanoparticles and endocytosis through vesicle formation - and trehalose tilts the scale in favor of the latter to mask the toxic effects of the nanoparticles. The precise molecular interpretation of this behavior was further probed through SERS, which directly points towards the protein stabilization properties of trehalose mediation during interaction of the nanoparticles with the plasma membrane components.

Plasma spectrum peak extraction algorithm of laser film damage

NASA Astrophysics Data System (ADS)

Zhao, Dan; Su, Jun-hong; Xu, Jun-qi

2012-10-01

The plasma spectrometry is an emerging method to distinguish the thin-film laser damage. Laser irradiation film surface occurrence of flash, using the spectrometer receives the flash spectrum, extracting the spectral peak, and by means of the spectra of the thin-film materials and the atmosphere has determine the difference, as a standard to determine the film damage. Plasma spectrometry can eliminate the miscarriage of justice which caused by atmospheric flashes, and distinguish high accuracy. Plasma spectra extraction algorithm is the key technology of Plasma spectrometry. Firstly, data de noising and smoothing filter is introduced in this paper, and then during the peak is detecting, the data packet is proposed, and this method can increase the stability and accuracy of the spectral peak recognition. Such algorithm makes simultaneous measurement of Plasma spectrometry to detect thin film laser damage, and greatly improves work efficiency.

Stem Cell Hydrogel, Jump-Starting Zika Drug Discovery, and Engineering RNA Recognition.

PubMed

Kostic, Milka

2016-08-18

Every month the editors of Cell Chemical Biology bring you highlights of the most recent chemical biology literature that impressed them with creativity and potential for follow up work. Our August 2016 selection includes a description of hydrogels with self-tunable stiffness that are used to profile lipid metabolites during stems cell differentiation, a look at whether we can find a drug repurposing solution to Zika virus infection, and an engineered RNA recognition motif (RRM). Copyright © 2016. Published by Elsevier Ltd.

Automatic classification of fish germ cells through optimum-path forest.

PubMed

Papa, João P; Gutierrez, Mario E M; Nakamura, Rodrigo Y M; Papa, Luciene P; Vicentini, Irene B F; Vicentini, Carlos A

2011-01-01

The spermatogenesis is crucial to the species reproduction, and its monitoring may shed light over some important information of such process. Thus, the germ cells quantification can provide useful tools to improve the reproduction cycle. In this paper, we present the first work that address this problem in fishes with machine learning techniques. We show here how to obtain high recognition accuracies in order to identify fish germ cells with several state-of-the-art supervised pattern recognition techniques.

Investigating biomolecular recognition at the cell surface using atomic force microscopy.

PubMed

Wang, Congzhou; Yadavalli, Vamsi K

2014-05-01

Probing the interaction forces that drive biomolecular recognition on cell surfaces is essential for understanding diverse biological processes. Force spectroscopy has been a widely used dynamic analytical technique, allowing measurement of such interactions at the molecular and cellular level. The capabilities of working under near physiological environments, combined with excellent force and lateral resolution make atomic force microscopy (AFM)-based force spectroscopy a powerful approach to measure biomolecular interaction forces not only on non-biological substrates, but also on soft, dynamic cell surfaces. Over the last few years, AFM-based force spectroscopy has provided biophysical insight into how biomolecules on cell surfaces interact with each other and induce relevant biological processes. In this review, we focus on describing the technique of force spectroscopy using the AFM, specifically in the context of probing cell surfaces. We summarize recent progress in understanding the recognition and interactions between macromolecules that may be found at cell surfaces from a force spectroscopy perspective. We further discuss the challenges and future prospects of the application of this versatile technique. Copyright © 2014 Elsevier Ltd. All rights reserved.

Genotoxicity profiles in exfoliated human mammary cells recovered from lactating mothers in Istanbul; relationship with demographic and dietary factors.

PubMed

Yilmaz, Bayram; Sandal, Suleyman; Ayvaci, Habibe; Tug, Niyazi; Vitrinel, Ayca

2012-12-12

We have investigated the presence of DNA damage in human mammary epithelial cells collected from healthy lactating mothers (age, 20-35 years) who were resident in the Istanbul area. Breast milk (10ml) was collected from 30 women between one and two weeks post-partum. Demographic information (parity, breast cancer, occupation, duration of residency in Istanbul, consumption of fish, beef and poultry) was also obtained. Milk samples were diluted 1:1 with RPMI 1640 medium and centrifuged to collect cells. The cells were re-suspended and cell viability was determined by use of 0.4% trypan blue. DNA damage was assessed by use of the comet assay (alkaline single-cell gel electrophoresis). Fifty cells per slide and two slides per sample were scored to evaluate DNA damage. The cells were visually classified into four categories on the basis of extent of migration: undamaged (UD), lightly damaged (LD), moderately damaged (MD) and highly damaged (HD). Total comet scores (TCS) were calculated as: 1× UD+2× LD+3× MD+4× HD. Exfoliated mammary cells of the donors showed high (TCS≥150a.u.), moderate and low DNA damage in 10 (33.3%), 8 (26.7%) and 12 (40%) mothers, respectively. There was no significant correlation between TCS for DNA damage and the duration of previous breastfeeding, parity or age. None of the mothers was vegetarian, smoker or on any medication. Meat and chicken consumption did not significantly correlate with the TCS values. Fish consumption was significantly correlated with TCS results (Spearman's rho=0.39, p<0.05). No significant correlation was found between the DNA-damage scores and the period of residency in Istanbul, but fish consumption increased as the duration of stay was longer (Spearman's rho=0.53, p<0.01). These findings suggest that the primary causes of differences in genotoxicity detected in lactating mothers in Istanbul may be of dietary origin. Our experience also confirms that sampling breast milk from lactating mothers provides a valuable and non-invasive tool to study DNA damage in mammary cells. Copyright © 2012 Elsevier B.V. All rights reserved.

Different subsets of natural killer T cells may vary in their roles in health and disease

PubMed Central

Kumar, Vipin; Delovitch, Terry L

2014-01-01

Natural killer T cells (NKT) can regulate innate and adaptive immune responses. Type I and type II NKT cell subsets recognize different lipid antigens presented by CD1d, an MHC class-I-like molecule. Most type I NKT cells express a semi-invariant T-cell receptor (TCR), but a major subset of type II NKT cells reactive to a self antigen sulphatide use an oligoclonal TCR. Whereas TCR-α dominates CD1d-lipid recognition by type I NKT cells, TCR-α and TCR-β contribute equally to CD1d-lipid recognition by type II NKT cells. These variable modes of NKT cell recognition of lipid–CD1d complexes activate a host of cytokine-dependent responses that can either exacerbate or protect from disease. Recent studies of chronic inflammatory and autoimmune diseases have led to a hypothesis that: (i) although type I NKT cells can promote pathogenic and regulatory responses, they are more frequently pathogenic, and (ii) type II NKT cells are predominantly inhibitory and protective from such responses and diseases. This review focuses on a further test of this hypothesis by the use of recently developed techniques, intravital imaging and mass cytometry, to analyse the molecular and cellular dynamics of type I and type II NKT cell antigen-presenting cell motility, interaction, activation and immunoregulation that promote immune responses leading to health versus disease outcomes. PMID:24428389

CD1d-restricted immunoglobulin G formation to GPI-anchored antigens mediated by NKT cells.

PubMed

Schofield, L; McConville, M J; Hansen, D; Campbell, A S; Fraser-Reid, B; Grusby, M J; Tachado, S D

1999-01-08

Immunoglobulin G (IgG) responses require major histocompatibility complex (MHC)-restricted recognition of peptide fragments by conventional CD4(+) helper T cells. Immunoglobulin G responses to glycosylphosphatidylinositol (GPI)- anchored protein antigens, however, were found to be regulated in part through CD1d-restricted recognition of the GPI moiety by thymus-dependent, interleukin-4-producing CD4(+), natural killer cell antigen 1.1 [(NK1.1)+] helper T cells. The CD1-NKT cell pathway regulated immunogobulin G responses to the GPI-anchored surface antigens of Plasmodium and Trypanosoma and may be a general mechanism for rapid, MHC-unrestricted antibody responses to diverse pathogens.

An early history of T cell-mediated cytotoxicity.

PubMed

Golstein, Pierre; Griffiths, Gillian M

2018-04-16

After 60 years of intense fundamental research into T cell-mediated cytotoxicity, we have gained a detailed knowledge of the cells involved, specific recognition mechanisms and post-recognition perforin-granzyme-based and FAS-based molecular mechanisms. What could not be anticipated at the outset was how discovery of the mechanisms regulating the activation and function of cytotoxic T cells would lead to new developments in cancer immunotherapy. Given the profound recent interest in therapeutic manipulation of cytotoxic T cell responses, it is an opportune time to look back on the early history of the field. This Timeline describes how the early findings occurred and eventually led to current therapeutic applications.

Sox2 and Jagged1 Expression in Normal and Drug-Damaged Adult Mouse Inner Ear

PubMed Central

Campbell, Sean; Taylor, Ruth R.; Forge, Andrew; Hume, Clifford R.

2007-01-01

Inner ear hair cells detect environmental signals associated with hearing, balance, and body orientation. In humans and other mammals, significant hair cell loss leads to irreversible hearing and balance deficits, whereas hair cell loss in nonmammalian vertebrates is repaired by the spontaneous generation of replacement hair cells. Research in mammalian hair cell regeneration is hampered by the lack of in vivo damage models for the adult mouse inner ear and the paucity of cell-type-specific markers for non-sensory cells within the sensory receptor epithelia. The present study delineates a protocol to drug damage the adult mouse auditory epithelium (organ of Corti) in situ and uses this protocol to investigate Sox2 and Jagged1 expression in damaged inner ear sensory epithelia. In other tissues, the transcription factor Sox2 and a ligand member of the Notch signaling pathway, Jagged1, are involved in regenerative processes. Both are involved in early inner ear development and are expressed in developing support cells, but little is known about their expressions in the adult. We describe a nonsurgical technique for inducing hair cell damage in adult mouse organ of Corti by a single high-dose injection of the aminoglycoside kanamycin followed by a single injection of the loop diuretic furosemide. This drug combination causes the rapid death of outer hair cells throughout the cochlea. Using immunocytochemical techniques, Sox2 is shown to be expressed specifically in support cells in normal adult mouse inner ear and is not affected by drug damage. Sox2 is absent from auditory hair cells, but is expressed in a subset of vestibular hair cells. Double-labeling experiments with Sox2 and calbindin suggest Sox2-positive hair cells are Type II. Jagged1 is also expressed in support cells in the adult ear and is not affected by drug damage. Sox2 and Jagged1 may be involved in the maintenance of support cells in adult mouse inner ear. PMID:18157569

U2AF1 mutations alter splice site recognition in hematological malignancies.

PubMed

Ilagan, Janine O; Ramakrishnan, Aravind; Hayes, Brian; Murphy, Michele E; Zebari, Ahmad S; Bradley, Philip; Bradley, Robert K

2015-01-01

Whole-exome sequencing studies have identified common mutations affecting genes encoding components of the RNA splicing machinery in hematological malignancies. Here, we sought to determine how mutations affecting the 3' splice site recognition factor U2AF1 alter its normal role in RNA splicing. We find that U2AF1 mutations influence the similarity of splicing programs in leukemias, but do not give rise to widespread splicing failure. U2AF1 mutations cause differential splicing of hundreds of genes, affecting biological pathways such as DNA methylation (DNMT3B), X chromosome inactivation (H2AFY), the DNA damage response (ATR, FANCA), and apoptosis (CASP8). We show that U2AF1 mutations alter the preferred 3' splice site motif in patients, in cell culture, and in vitro. Mutations affecting the first and second zinc fingers give rise to different alterations in splice site preference and largely distinct downstream splicing programs. These allele-specific effects are consistent with a computationally predicted model of U2AF1 in complex with RNA. Our findings suggest that U2AF1 mutations contribute to pathogenesis by causing quantitative changes in splicing that affect diverse cellular pathways, and give insight into the normal function of U2AF1's zinc finger domains. © 2015 Ilagan et al.; Published by Cold Spring Harbor Laboratory Press.

The Fanconi Anemia DNA Repair Pathway Is Regulated by an Interaction between Ubiquitin and the E2-like Fold Domain of FANCL.

PubMed

Miles, Jennifer A; Frost, Mark G; Carroll, Eilis; Rowe, Michelle L; Howard, Mark J; Sidhu, Ateesh; Chaugule, Viduth K; Alpi, Arno F; Walden, Helen

2015-08-21

The Fanconi Anemia (FA) DNA repair pathway is essential for the recognition and repair of DNA interstrand crosslinks (ICL). Inefficient repair of these ICL can lead to leukemia and bone marrow failure. A critical step in the pathway is the monoubiquitination of FANCD2 by the RING E3 ligase FANCL. FANCL comprises 3 domains, a RING domain that interacts with E2 conjugating enzymes, a central domain required for substrate interaction, and an N-terminal E2-like fold (ELF) domain. The ELF domain is found in all FANCL homologues, yet the function of the domain remains unknown. We report here that the ELF domain of FANCL is required to mediate a non-covalent interaction between FANCL and ubiquitin. The interaction involves the canonical Ile44 patch on ubiquitin, and a functionally conserved patch on FANCL. We show that the interaction is not necessary for the recognition of the core complex, it does not enhance the interaction between FANCL and Ube2T, and is not required for FANCD2 monoubiquitination in vitro. However, we demonstrate that the ELF domain is required to promote efficient DNA damage-induced FANCD2 monoubiquitination in vertebrate cells, suggesting an important function of ubiquitin binding by FANCL in vivo. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Inflammasomes and Their Role in Innate Immunity of Sexually Transmitted Infections

PubMed Central

Verma, Vivek; Dhanda, Rakesh Singh; Møller, Niels Frimodt; Yadav, Manisha

2016-01-01

Inflammasomes are multiprotein complexes present in the cytosol as pattern recognition receptors or as sensors of damage-associated molecular patterns. After recognition of microbe-associated molecular patterns or host-derived danger signals, nucleotide oligomerization domain-like receptors oligomerize to form inflammasomes. The activation of inflammasomes results in an alarm, which is raised to alert adjacent cells through the processing and release of a number of other substrates present in the cytosol. A wide array of inflammasomes and their adapter molecules have been identified in the host’s innate immune system in response to various pathogens. Components of specific pathogens activate different inflammasomes, which once activated in response to pathogen-induced infection, induce the activation of caspases, and the release of mature forms of interleukin-1β (IL-1β) and IL-18. Identifying the mechanisms underlying pathogen-induced inflammasome activation is important if we are to develop novel therapeutic strategies to target sexually transmitted infections (STIs) related pathogens. This information is currently lacking in literature. In this review, we have discussed the role of various inflammasomes in sensing different STIs, as well as the beneficial or detrimental effects of inflammasome signaling in host resistance. Additionally, we have discussed both canonical and non-canonical processing of IL-1β induced with respect to particular infections. Overall, these findings transform our understanding of both the basic biology and clinical relevance of inflammasomes. PMID:27994587

ClpXP protease targets long-lived DNA translocation states of a helicase-like motor to cause restriction alleviation

PubMed Central

Simons, Michelle; Diffin, Fiona M.; Szczelkun, Mark D.

2014-01-01

We investigated how Escherichia coli ClpXP targets the helicase-nuclease (HsdR) subunit of the bacterial Type I restriction–modification enzyme EcoKI during restriction alleviation (RA). RA is a temporary reduction in endonuclease activity that occurs when Type I enzymes bind unmodified recognition sites on the host genome. These conditions arise upon acquisition of a new system by a naïve host, upon generation of new sites by genome rearrangement/mutation or during homologous recombination between hemimethylated DNA. Using recombinant DNA and proteins in vitro, we demonstrate that ClpXP targets EcoKI HsdR during dsDNA translocation on circular DNA but not on linear DNA. Protein roadblocks did not activate HsdR proteolysis. We suggest that DNA translocation lifetime, which is elevated on circular DNA relative to linear DNA, is important to RA. To identify the ClpX degradation tag (degron) in HsdR, we used bioinformatics and biochemical assays to design N- and C-terminal mutations that were analysed in vitro and in vivo. None of the mutants produced a phenotype consistent with loss of the degron, suggesting an as-yet-unidentified recognition pathway. We note that an EcoKI nuclease mutant still produces cell death in a clpx− strain, consistent with DNA damage induced by unregulated motor activity. PMID:25260590

MHC class I immune proteins are critical for hippocampus-dependent memory and gate NMDAR-dependent hippocampal long-term depression

PubMed Central

Nelson, P. Austin; Sage, Jennifer R.; Wood, Suzanne C.; Davenport, Christopher M.; Anagnostaras, Stephan G.; Boulanger, Lisa M.

2013-01-01

Memory impairment is a common feature of conditions that involve changes in inflammatory signaling in the brain, including traumatic brain injury, infection, neurodegenerative disorders, and normal aging. However, the causal importance of inflammatory mediators in cognitive impairments in these conditions remains unclear. Here we show that specific immune proteins, members of the major histocompatibility complex class I (MHC class I), are essential for normal hippocampus-dependent memory, and are specifically required for NMDAR-dependent forms of long-term depression (LTD) in the healthy adult hippocampus. In β2m−/−TAP−/−mice, which lack stable cell-surface expression of most MHC class I proteins, NMDAR-dependent LTD in area CA1 of adult hippocampus is abolished, while NMDAR-independent forms of potentiation, facilitation, and depression are unaffected. Altered NMDAR-dependent synaptic plasticity in the hippocampus of β2m−/−TAP−/−mice is accompanied by pervasive deficits in hippocampus-dependent memory, including contextual fear memory, object recognition memory, and social recognition memory. Thus normal MHC class I expression is essential for NMDAR-dependent hippocampal synaptic depression and hippocampus-dependent memory. These results suggest that changes in MHC class I expression could be an unexpected cause of disrupted synaptic plasticity and cognitive deficits in the aging, damaged, and diseased brain. PMID:23959708

Genotoxicity of waterpipe smoke in buccal cells and peripheral blood leukocytes as determined by comet assay.

PubMed

Al-Amrah, Hadba Jar-Allah; Aboznada, Osama Abdullah; Alam, Mohammad Zubair; ElAssouli, M-Zaki Mustafa; Mujallid, Mohammad Ibrahim; ElAssouli, Sufian Mohamad

2014-12-01

Waterpipe smoke causes DNA damage in peripheral blood leukocytes and in buccal cells of smokers. To determine the exposure effect of waterpipe smoke on buccal cells and peripheral blood leukocytes in regard to DNA damage using comet assay. The waterpipe smoke condensates were analyzed by gas chromatography-mass spectrometry (GC-MS). The study was performed on 20 waterpipe smokers. To perform comet assay on bucaal cells of smokers, 10 µl of cell suspension was mixed with 85 µl of pre-warmed 1% low melting agarose, applied to comet slide and electrophoresed. To analyze the effect of smoke condensate in vitro, 1 ml of peripheral blood was mixed with 10 µl of smoke condensate and subjected for comet assay. The GC-MS analysis revealed the presence of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4on, nicotine, hydroxymethyl furancarboxaldehyde and 3-ethoxy-4-hydroxybenzaldehyde in the smoke condensates. Waterpipe smoking caused DNA damage in vivo in buccal cells of smokers. The tail moment and tail length in buccal cells of smokers were 186 ± 26 and 456 ± 71, respectively, which are higher than control. The jurak and moassel smoke condensates were found to cause DNA damage in peripheral blood leukocytes. The moassel smoke condensate was more damaging. There is wide misconception that waterpipe smoking is not as harmful as cigarette smoking. This study demonstrated that waterpipe smoke induced DNA damage in exposed cells. Waterpipe smokes cause DNA damage in buccal cells. The smoke condensate of both jurak and moassel caused comet formation suggesting DNA damage in peripheral blood leukocytes.

Alteration/deficiency in activation-3 (Ada3) plays a critical role in maintaining genomic stability

PubMed Central

Mirza, Sameer; Katafiasz, Bryan J.; Kumar, Rakesh; Wang, Jun; Mohibi, Shakur; Jain, Smrati; Gurumurthy, Channabasavaiah Basavaraju; Pandita, Tej K.; Dave, Bhavana J.; Band, Hamid; Band, Vimla

2012-01-01

Cell cycle regulation and DNA repair following damage are essential for maintaining genome integrity. DNA damage activates checkpoints in order to repair damaged DNA prior to exit to the next phase of cell cycle. Recently, we have shown the role of Ada3, a component of various histone acetyltransferase complexes, in cell cycle regulation, and loss of Ada3 results in mouse embryonic lethality. Here, we used adenovirus-Cre-mediated Ada3 deletion in Ada3fl/fl mouse embryonic fibroblasts (MEFs) to assess the role of Ada3 in DNA damage response following exposure to ionizing radiation (IR). We report that Ada3 depletion was associated with increased levels of phospho-ATM (pATM), γH2AX, phospho-53BP1 (p53BP1) and phospho-RAD51 (pRAD51) in untreated cells; however, radiation response was intact in Ada3−/− cells. Notably, Ada3−/− cells exhibited a significant delay in disappearance of DNA damage foci for several critical proteins involved in the DNA repair process. Significantly, loss of Ada3 led to enhanced chromosomal aberrations, such as chromosome breaks, fragments, deletions and translocations, which further increased upon DNA damage. Notably, the total numbers of aberrations were more clearly observed in S-phase, as compared with G₁ or G₂ phases of cell cycle with IR. Lastly, comparison of DNA damage in Ada3fl/fl and Ada3−/− cells confirmed higher residual DNA damage in Ada3−/− cells, underscoring a critical role of Ada3 in the DNA repair process. Taken together, these findings provide evidence for a novel role for Ada3 in maintenance of the DNA repair process and genomic stability. PMID:23095635

Tissue repair in myxobacteria: A cooperative strategy to heal cellular damage.

PubMed

Vassallo, Christopher N; Wall, Daniel

2016-04-01

Damage repair is a fundamental requirement of all life as organisms find themselves in challenging and fluctuating environments. In particular, damage to the barrier between an organism and its environment (e.g. skin, plasma membrane, bacterial cell envelope) is frequent because these organs/organelles directly interact with the external world. Here, we discuss the general strategies that bacteria use to cope with damage to their cell envelope and their repair limits. We then describe a novel damage-coping mechanism used by multicellular myxobacteria. We propose that cell-cell transfer of membrane material within a population serves as a wound-healing strategy and provide evidence for its utility. We suggest that--similar to how tissues in eukaryotes have evolved cooperative methods of damage repair--so too have some bacteria that live a multicellular lifestyle. © 2016 WILEY Periodicals, Inc.

Protective mechanisms of p53-p21-pRb proteins against DNA damage-induced cell death.

PubMed

Garner, Elizabeth; Raj, Kenneth

2008-02-01

There have been innumerate demonstrations of p53's activity as a tumour suppressor protein with the ability to stimulate cell signalling that can lead to cell cycle arrest and cell death in the event of DNA damage. Despite the solid body of evidence to support these properties of p53, reports have emerged that suggest a role for p53 in protecting cells from cell death. Our recent report highlighted a mechanism by which p53 activity can promote cell survival in the event of DNA damage. Here we present the various mechanisms that are activated by p53 signalling that can confer protection to cells with damaged DNA and emphasise the practical and clinical implications of a more balanced and context-dependent understanding of p53's pro-apoptotic and pro-survival activities.

Long-Time Plasma Membrane Imaging Based on a Two-Step Synergistic Cell Surface Modification Strategy.

PubMed

Jia, Hao-Ran; Wang, Hong-Yin; Yu, Zhi-Wu; Chen, Zhan; Wu, Fu-Gen

2016-03-16

Long-time stable plasma membrane imaging is difficult due to the fast cellular internalization of fluorescent dyes and the quick detachment of the dyes from the membrane. In this study, we developed a two-step synergistic cell surface modification and labeling strategy to realize long-time plasma membrane imaging. Initially, a multisite plasma membrane anchoring reagent, glycol chitosan-10% PEG2000 cholesterol-10% biotin (abbreviated as "GC-Chol-Biotin"), was incubated with cells to modify the plasma membranes with biotin groups with the assistance of the membrane anchoring ability of cholesterol moieties. Fluorescein isothiocyanate (FITC)-conjugated avidin was then introduced to achieve the fluorescence-labeled plasma membranes based on the supramolecular recognition between biotin and avidin. This strategy achieved stable plasma membrane imaging for up to 8 h without substantial internalization of the dyes, and avoided the quick fluorescence loss caused by the detachment of dyes from plasma membranes. We have also demonstrated that the imaging performance of our staining strategy far surpassed that of current commercial plasma membrane imaging reagents such as DiD and CellMask. Furthermore, the photodynamic damage of plasma membranes caused by a photosensitizer, Chlorin e6 (Ce6), was tracked in real time for 5 h during continuous laser irradiation. Plasma membrane behaviors including cell shrinkage, membrane blebbing, and plasma membrane vesiculation could be dynamically recorded. Therefore, the imaging strategy developed in this work may provide a novel platform to investigate plasma membrane behaviors over a relatively long time period.

AtMMS21, an SMC5/6 complex subunit, is involved in stem cell niche maintenance and DNA damage responses in Arabidopsis roots.

PubMed

Xu, Panglian; Yuan, Dongke; Liu, Ming; Li, Chunxin; Liu, Yiyang; Zhang, Shengchun; Yao, Nan; Yang, Chengwei

2013-04-01

Plants maintain stem cells in meristems to sustain lifelong growth; these stem cells must have effective DNA damage responses to prevent mutations that can propagate to large parts of the plant. However, the molecular links between stem cell functions and DNA damage responses remain largely unexplored. Here, we report that the small ubiquitin-related modifier E3 ligase AtMMS21 (for methyl methanesulfonate sensitivity gene21) acts to maintain the root stem cell niche by mediating DNA damage responses in Arabidopsis (Arabidopsis thaliana). Mutation of AtMMS21 causes defects in the root stem cell niche during embryogenesis and postembryonic stages. AtMMS21 is essential for the proper expression of stem cell niche-defining transcription factors. Moreover, mms21-1 mutants are hypersensitive to DNA-damaging agents, have a constitutively increased DNA damage response, and have more DNA double-strand breaks (DSBs) in the roots. Also, mms21-1 mutants exhibit spontaneous cell death within the root stem cell niche, and treatment with DSB-inducing agents increases this cell death, suggesting that AtMMS21 is required to prevent DSB-induced stem cell death. We further show that AtMMS21 functions as a subunit of the STRUCTURAL MAINTENANCE OF CHROMOSOMES5/6 complex, an evolutionarily conserved chromosomal ATPase required for DNA repair. These data reveal that AtMMS21 acts in DSB amelioration and stem cell niche maintenance during Arabidopsis root development.

A Novel ATM/TP53/p21-Mediated Checkpoint Only Activated by Chronic γ-Irradiation

PubMed Central

Sasatani, Megumi; Iizuka, Daisuke; Masuda, Yuji; Inaba, Toshiya; Suzuki, Keiji; Ootsuyama, Akira; Umata, Toshiyuki; Kamiya, Kenji; Suzuki, Fumio

2014-01-01

Different levels or types of DNA damage activate distinct signaling pathways that elicit various cellular responses, including cell-cycle arrest, DNA repair, senescence, and apoptosis. Whereas a range of DNA-damage responses have been characterized, mechanisms underlying subsequent cell-fate decision remain elusive. Here we exposed cultured cells and mice to different doses and dose rates of γ-irradiation, which revealed cell-type-specific sensitivities to chronic, but not acute, γ-irradiation. Among tested cell types, human fibroblasts were associated with the highest levels of growth inhibition in response to chronic γ-irradiation. In this context, fibroblasts exhibited a reversible G1 cell-cycle arrest or an irreversible senescence-like growth arrest, depending on the irradiation dose rate or the rate of DNA damage. Remarkably, when the same dose of γ-irradiation was delivered chronically or acutely, chronic delivery induced considerably more cellular senescence. A similar effect was observed with primary cells isolated from irradiated mice. We demonstrate a critical role for the ataxia telangiectasia mutated (ATM)/tumor protein p53 (TP53)/p21 pathway in regulating DNA-damage-associated cell fate. Indeed, blocking the ATM/TP53/p21 pathway deregulated DNA damage responses, leading to micronucleus formation in chronically irradiated cells. Together these results provide insights into the mechanisms governing cell-fate determination in response to different rates of DNA damage. PMID:25093836

Predictions of cell damage rates for Lifesat missions

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Atwell, William; Hardy, Alva C.; Golightly, Michael J.; Wilson, John W.; Townsend, Lawrence W.; Shinn, Judy; Nealy, John E.; Katz, Robert

1990-01-01

The track model of Katz is used to make predictions of cell damage rates for possible Lifesat experiments. Contributions from trapped protons and electrons and galactic cosmic rays are considered for several orbits. Damage rates for survival and transformation of C3HT10-1/2 cells are predicted for various spacecraft shields.

Ceramide-1-phosphate regulates migration of multipotent stromal cells (MSCs) and endothelial progenitor cells (EPCs) – implications for tissue regeneration

PubMed Central

Kim, ChiHwa; Schneider, Gabriela; Abdel-Latif, Ahmed; Mierzejewska, Kasia; Sunkara, Manjula; Borkowska, Sylwia; Ratajczak, Janina; Morris, Andrew J.; Kucia, Magda; Ratajczak, Mariusz Z.

2012-01-01

Ceramide-1-phosphate (C1P) is a bioactive lipid that, in contrast to ceramide, is an anti-apoptotic molecule released from cells that are damaged and “leaky”. As reported recently, C1P promotes migration of hematopoietic cells. In the current paper, we tested the hypothesis that C1P released upon tissue damage may play an underappreciated role in chemoattraction of various types of stem cells and endothelial cells involved in tissue/organ regeneration. We show for a first time that C1P is upregulated in damaged tissues and chemoattracts BM-derived multipotent stroma cells (MSCs), endothelial progenitor cells (EPCs), and very small embryonic-like stem cells (VSELs). Furthermore, compared to other bioactive lipids, C1P more potently chemoattracted human umbilical vein endothelial cells (HUVECs) and stimulated tube formation by these cells. C1P also promoted in vivo vascularization of Matrigel implants and stimulated secretion of stromal derived factor-1 (SDF-1) from BM-derived fibroblasts. Thus, our data demonstrate, for the first time, that C1P is a potent bioactive lipid released from damaged cells that potentially plays an important and novel role in recruitment of stem/progenitor cells to damaged organs and may promote their vascularization. PMID:23193025

Identification of liver cancer-specific aptamers using whole live cells.

PubMed

Shangguan, Dihua; Meng, Ling; Cao, Zehui Charles; Xiao, Zeyu; Fang, Xiaohong; Li, Ying; Cardona, Diana; Witek, Rafal P; Liu, Chen; Tan, Weihong

2008-02-01

Liver cancer is the third most deadly cancers in the world. Unfortunately, there is no effective treatment. One of the major problems is that most cancers are diagnosed in the later stage, when surgical resection is not feasible. Thus, accurate early diagnosis would significantly improve the clinical outcome of liver cancer. Currently, there are no effective molecular probes to recognize biomarkers that are specific for liver cancer. The objective of our current study is to identify liver cancer cell-specific molecular probes that could be used for liver cancer recognition and diagnosis. We applied a newly developed cell-SELEX (Systematic Evolution of Ligands by EXponential enrichment) method for the generation of molecular probes for specific recognition of liver cancer cells. The cell-SELEX uses whole live cells as targets to select aptamers (designed DNA/RNA) for cell recognition. In generating aptamers for liver cancer recognition, two liver cell lines were used: a liver cancer cell line BNL 1ME A.7R.1 (MEAR) and a noncancer cell line, BNL CL.2 (BNL). Both cell lines were originally derived from Balb/cJ mice. Through multiple rounds of selection using BNL as a control, we have identified a panel of aptamers that specifically recognize the cancer cell line MEAR with Kd in the nanomolar range. We have also demonstrated that some of the selective aptamers could specifically bind liver cancer cells in a mouse model. There are two major new results (compared with our reported cell-SELEX methodology) in addition to the generation of aptamers specifically for liver cancer. The first one is that our current study demonstrates that cell-based aptamer selection can select specific aptamers for multiple cell lines, even for two cell lines with minor differences (MEAR cell is derived from BNL by chemical inducement); and the second result is that cell-SELEX can be used for adhesive cells and thus open the door for solid tumor selection and investigation. The newly generated cancer-specific aptamers hold great promise as molecular probes for cancer early diagnosis and basic mechanism studies.

Cell damage caused by vaginal Candida albicans isolates from women with different symptomatologies.

PubMed

Faria, Daniella Renata; Sakita, Karina Mayumi; Akimoto-Gunther, Luciene Setsuko; Kioshima, Érika Seki; Svidzinski, Terezinha Inez Estivalet; Bonfim-Mendonça, Patrícia de Souza

2017-08-01

The present study aimed to characterize cell damage caused by vaginal Candida albicans isolates from women with different symptomatologies. It was evaluated 12 clinical isolates of C. albicans from vaginal samples: 4 from asymptomatic women (AS), 4 from women with a single episode of vulvovaginal candidiasis (VVC) and 4 from women with recurrent vulvovaginal candidiasis (RVVC). We evaluated the ability of C. albicans to adhere to human cervical cancer cells (SiHa), the yeast-SiHa cell interactions and cell damage. All of the clinical isolates presented a high adhesion capacity on SiHa cells. However, clinical isolates from symptomatic women (VVC and RVVC) had higher filamentation after contact (24 h) with SiHa cells and a greater capacity to cause cell damage (>80 %). Clinical isolates from symptomatic women had greater potential to invade SiHa cells, suggesting that they are more pathogenic than AS isolates.

Senescence, apoptosis or autophagy? When a damaged cell must decide its path--a mini-review.

PubMed

Vicencio, José Miguel; Galluzzi, Lorenzo; Tajeddine, Nicolas; Ortiz, Carla; Criollo, Alfredo; Tasdemir, Ezgi; Morselli, Eugenia; Ben Younes, Amena; Maiuri, Maria Chiara; Lavandero, Sergio; Kroemer, Guido

2008-01-01

Many features of aging result from the incapacity of cells to adapt to stress conditions. When damage accumulates irreversibly, mitotic cells from renewable tissues rely on either of two mechanisms to avoid replication. They can permanently arrest the cell cycle (cellular senescence) or trigger cell death programs. Apoptosis (self-killing) is the best-described form of programmed cell death, but autophagy (self-eating), which is a lysosomal degradation pathway essential for homeostasis, reportedly contributes to cell death as well. Unlike mitotic cells, postmitotic cells like neurons or cardiomyocytes cannot become senescent since they are already terminally differentiated. The fate of these cells entirely depends on their ability to cope with stress. Autophagy then operates as a major homeostatic mechanism to eliminate damaged organelles, long-lived or aberrant proteins and superfluous portions of the cytoplasm. In this mini-review, we briefly summarize the molecular networks that allow damaged cells either to adapt to stress or to engage in programmed-cell-death pathways. (c) 2008 S. Karger AG, Basel.

Behavioral pattern identification for structural health monitoring in complex systems

NASA Astrophysics Data System (ADS)

Gupta, Shalabh

Estimation of structural damage and quantification of structural integrity are critical for safe and reliable operation of human-engineered complex systems, such as electromechanical, thermofluid, and petrochemical systems. Damage due to fatigue crack is one of the most commonly encountered sources of structural degradation in mechanical systems. Early detection of fatigue damage is essential because the resulting structural degradation could potentially cause catastrophic failures, leading to loss of expensive equipment and human life. Therefore, for reliable operation and enhanced availability, it is necessary to develop capabilities for prognosis and estimation of impending failures, such as the onset of wide-spread fatigue crack damage in mechanical structures. This dissertation presents information-based online sensing of fatigue damage using the analytical tools of symbolic time series analysis ( STSA). Anomaly detection using STSA is a pattern recognition method that has been recently developed based upon a fixed-structure, fixed-order Markov chain. The analysis procedure is built upon the principles of Symbolic Dynamics, Information Theory and Statistical Pattern Recognition. The dissertation demonstrates real-time fatigue damage monitoring based on time series data of ultrasonic signals. Statistical pattern changes are measured using STSA to monitor the evolution of fatigue damage. Real-time anomaly detection is presented as a solution to the forward (analysis) problem and the inverse (synthesis) problem. (1) the forward problem - The primary objective of the forward problem is identification of the statistical changes in the time series data of ultrasonic signals due to gradual evolution of fatigue damage. (2) the inverse problem - The objective of the inverse problem is to infer the anomalies from the observed time series data in real time based on the statistical information generated during the forward problem. A computer-controlled special-purpose fatigue test apparatus, equipped with multiple sensing devices (e.g., ultrasonics and optical microscope) for damage analysis, has been used to experimentally validate the STSA method for early detection of anomalous behavior. The sensor information is integrated with a software module consisting of the STSA algorithm for real-time monitoring of fatigue damage. Experiments have been conducted under different loading conditions on specimens constructed from the ductile aluminium alloy 7075 - T6. The dissertation has also investigated the application of the STSA method for early detection of anomalies in other engineering disciplines. Two primary applications include combustion instability in a generic thermal pulse combustor model and whirling phenomenon in a typical misaligned shaft.

Phagocytic response of astrocytes to damaged neighboring cells

PubMed Central

Cruz, Gladys Mae S.; Ro, Clarissa C.; Moncada, Emmanuel G.; Khatibzadeh, Nima; Flanagan, Lisa A.; Berns, Michael W.

2018-01-01

This study aims to understand the phagocytic response of astrocytes to the injury of neurons or other astrocytes at the single cell level. Laser nanosurgery was used to damage individual cells in both primary mouse cortical astrocytes and an established astrocyte cell line. In both cases, the release of material/substances from laser-irradiated astrocytes or neurons induced a phagocytic response in near-by astrocytes. Propidium iodide stained DNA originating from irradiated cells was visible in vesicles of neighboring cells, confirming phagocytosis of material from damaged cortical cells. In the presence of an intracellular pH indicator dye, newly formed vesicles correspond to acidic pH fluorescence, thus suggesting lysosome bound degradation of cellular debris. Cells with shared membrane connections prior to laser damage had a significantly higher frequency of induced phagocytosis compared to isolated cells with no shared membrane. The increase in phagocytic response of cells with a shared membrane occurred regardless of the extent of shared membrane (a thin filopodial connection vs. a cell cluster with significant shared membrane). In addition to the presence (or lack) of a membrane connection, variation in phagocytic ability was also observed with differences in injury location within the cell and distance separating isolated astrocytes. These results demonstrate the ability of an astrocyte to respond to the damage of a single cell, be it another astrocyte, or a neuron. This single-cell level of analysis results in a better understanding of the role of astrocytes to maintain homeostasis in the CNS, particularly in the sensing and removal of debris in damaged or pathologic nervous tissue. PMID:29708987

Investigation of an expert health monitoring system for aeronautical structures based on pattern recognition and acousto-ultrasonics

NASA Astrophysics Data System (ADS)

Tibaduiza-Burgos, Diego Alexander; Torres-Arredondo, Miguel Angel

2015-08-01

Aeronautical structures are subjected to damage during their service raising the necessity for periodic inspection and maintenance of their components so that structural integrity and safe operation can be guaranteed. Cost reduction related to minimizing the out-of-service time of the aircraft, together with the advantages offered by real-time and safe-life service monitoring, have led to a boom in the design of inexpensive and structurally integrated transducer networks comprising actuators, sensors, signal processing units and controllers. These kinds of automated systems are normally referred to as smart structures and offer a multitude of new solutions to engineering problems and multi-functional capabilities. It is thus expected that structural health monitoring (SHM) systems will become one of the leading technologies for assessing and assuring the structural integrity of future aircraft. This study is devoted to the development and experimental investigation of an SHM methodology for the detection of damage in real scale complex aeronautical structures. The work focuses on each aspect of the SHM system and highlights the potentialities of the health monitoring technique based on acousto-ultrasonics and data-driven modelling within the concepts of sensor data fusion, feature extraction and pattern recognition. The methodology is experimentally demonstrated on an aircraft skin panel and fuselage panel for which several damage scenarios are analysed. The detection performance in both structures is quantified and presented.

Emotional memory and perception in temporal lobectomy patients with amygdala damage.

PubMed

Brierley, B; Medford, N; Shaw, P; David, A S

2004-04-01

The human amygdala is implicated in the formation of emotional memories and the perception of emotional stimuli--particularly fear--across various modalities. To discern the extent to which these functions are related. 28 patients who had anterior temporal lobectomy (13 left and 15 right) for intractable epilepsy were recruited. Structural magnetic resonance imaging showed that three of them had atrophy of their remaining amygdala. All participants were given tests of affect perception from facial and vocal expressions and of emotional memory, using a standard narrative test and a novel test of word recognition. The results were standardised against matched healthy controls. Performance on all emotion tasks in patients with unilateral lobectomy ranged from unimpaired to moderately impaired. Perception of emotions in faces and voices was (with exceptions) significantly positively correlated, indicating multimodal emotional processing. However, there was no correlation between the subjects' performance on tests of emotional memory and perception. Several subjects showed strong emotional memory enhancement but poor fear perception. Patients with bilateral amygdala damage had greater impairment, particularly on the narrative test of emotional memory, one showing superior fear recognition but absent memory enhancement. Bilateral amygdala damage is particularly disruptive of emotional memory processes in comparison with unilateral temporal lobectomy. On a cognitive level, the pattern of results implies that perception of emotional expressions and emotional memory are supported by separate processing systems or streams.

Radiation damage of gallium arsenide production cells

NASA Technical Reports Server (NTRS)

Mardesich, N.; Garlick, G. F. J.

1987-01-01

High-efficiency gallium arsenide cells, made by the liquid epitaxy method (LPE), have been irradiated with 1-MeV electrons up to fluences of 10 to the 16th e/sq cm. Measurements have been made of cell spectral response and dark and light-excited current-voltage characteristics and analyzed using computer-based models to determine underlying parameters such as damage coefficients. It is possible to use spectral response to sort out damage effects in the different cell component layers. Damage coefficients are similar to other reported in the literature for the emitter and buffer (base). However, there is also a damage effect in the window layer and possibly at the window emitter interface similar to that found for proton-irradiated liquid-phase epitaxy-grown cells. Depletion layer recombination is found to be less than theoretically expected at high fluence.

[Neurological disease and facial recognition].

PubMed

Kawamura, Mitsuru; Sugimoto, Azusa; Kobayakawa, Mutsutaka; Tsuruya, Natsuko

2012-07-01

To discuss the neurological basis of facial recognition, we present our case reports of impaired recognition and a review of previous literature. First, we present a case of infarction and discuss prosopagnosia, which has had a large impact on face recognition research. From a study of patient symptoms, we assume that prosopagnosia may be caused by unilateral right occipitotemporal lesion and right cerebral dominance of facial recognition. Further, circumscribed lesion and degenerative disease may also cause progressive prosopagnosia. Apperceptive prosopagnosia is observed in patients with posterior cortical atrophy (PCA), pathologically considered as Alzheimer's disease, and associative prosopagnosia in frontotemporal lobar degeneration (FTLD). Second, we discuss face recognition as part of communication. Patients with Parkinson disease show social cognitive impairments, such as difficulty in facial expression recognition and deficits in theory of mind as detected by the reading the mind in the eyes test. Pathological and functional imaging studies indicate that social cognitive impairment in Parkinson disease is possibly related to damages in the amygdalae and surrounding limbic system. The social cognitive deficits can be observed in the early stages of Parkinson disease, and even in the prodromal stage, for example, patients with rapid eye movement (REM) sleep behavior disorder (RBD) show impairment in facial expression recognition. Further, patients with myotonic dystrophy type 1 (DM 1), which is a multisystem disease that mainly affects the muscles, show social cognitive impairment similar to that of Parkinson disease. Our previous study showed that facial expression recognition impairment of DM 1 patients is associated with lesion in the amygdalae and insulae. Our study results indicate that behaviors and personality traits in DM 1 patients, which are revealed by social cognitive impairment, are attributable to dysfunction of the limbic system.

A Recombinant Antibody with the Antigen-Specific, Major Histocompatibility Complex-Restricted Specificity of T Cells

NASA Astrophysics Data System (ADS)

Andersen, Peter S.; Stryhn, Anette; Hansen, Bjarke E.; Fugger, Lars; Engberg, Jan; Buus, Soren

1996-03-01

Specific recognition of peptide/major histocompatibility complex (MHC) molecule complexes by the T-cell receptor is a key reaction in the specific immune response. Antibodies against peptide/MHC complexes would therefore be valuable tools in studying MHC function and T-cell recognition and might lead to novel approaches in immunotherapy. However, it has proven difficult to generate antibodies with the specificity of T cells by conventional hybridoma techniques. Here we report that the phage display technology is a feasible alternative to generate antibodies recognizing specific, predetermined peptide/MHC complexes.

Rapid communications: antiperspirant induced DNA damage in canine cells by comet assay.

PubMed

Yiu, Gloria

2004-01-01

Abstract Millions of people around the world use antiperspirants to decrease or eliminate body odors. Most antiperspirants contain aluminum zirconium or another form of aluminum as its active ingredient. The present investigation applied Comet assay to detect if Secret Platinum for women, Old Spice for men, or Crystal Natural produced DNA damage in Madin-Darby canine kidney cells (MDCKII). This study has shown that antiperspirants cause DNA damage on a single-cell level. Additionally, our data showed us that in general, Secret Platinum for women and Old Spice for men, produced equivalent damage. Crystal Natural, marketed as being safer or less damaging, induced the most extensive damage of all three antiperspirants tested.

Goblet cell mucins as the selective barrier for the intestinal helminths: T-cell-independent alteration of goblet cell mucins by immunologically 'damaged' Nippostrongylus brasiliensis worms and its significance on the challenge infection with homologous and heterologous parasites.

PubMed Central

Ishikawa, N; Horii, Y; Oinuma, T; Suganuma, T; Nawa, Y

1994-01-01

The aim of this study was to examine the role of T cells on the alteration of terminal sugars of goblet cell mucins in the small intestinal mucosa of parasitized rats and to clarify the biological significance of the altered mucins in the mucosal defence against intestinal helminths. For this purpose, Nippostrongylus brasiliensis adult worms obtained from donor rats at 7 ('normal' worms) or 13 days ('damaged' worms) post-infection were implanted intraduodenally into euthymic and hypothymic (rnu/rnu) rats. Expulsion of implanted normal worms and associated goblet cell changes were extremely delayed in hypothymic recipients compared with euthymic recipients. In contrast, intraduodenally implanted damaged worms were expelled by day 5 regardless of the strains. Around the time of expulsion of implanted damaged worms, euthymic recipients showed both goblet cell hyperplasia and alteration of mucins, whereas hypothymic rats showed only the latter. Dexamethasone treatment completely abolished goblet cell changes of both strains of recipients. To clarify the importance of the constitutional changes of goblet cell mucins in mucosal defence, euthymic rats were primed by implantation of damaged worms to induce goblet cell changes, and then 3 or 5 days later they were challenged by implantation with normal worms. The results show that when goblet cell changes were induced by priming with damaged worms, recipient rats could completely prevent the establishment of normal worms. When hypothymic rats were primed and challenged in the same manner, a similar but slightly less preventive effect was observed. Such a protective effect of altered mucins seems to be selective because priming of euthymic rats with damaged N. brasiliensis did not affect the establishment of Strongyloides venezuelensis. These results suggest that: (1) once N. brasiliensis adult worms are 'damaged' by the host's T-cell-dependent immune mechanisms, they can induce alteration of sugar residues of goblet cell mucins via host-mediated, T-cell-independent processes; (2) the expression of such altered mucins is highly effective not only in causing expulsion of established damaged worms but also in preventing establishment of normal worms; and (3) the preventive effect of altered mucins is selective against parasite species. Images Figure 2 Figure 4 PMID:8206520

Slp-76 is a critical determinant of NK-cell mediated recognition of missing-self targets.

PubMed

Lampe, Kristin; Endale, Mehari; Cashman, Siobhan; Fang, Hao; Mattner, Jochen; Hildeman, David; Hoebe, Kasper

2015-07-01

Absence of MHC class I expression is an important mechanism by which NK cells recognize a variety of target cells, yet the pathways underlying "missing-self" recognition, including the involvement of activating receptors, remain poorly understood. Using ethyl-N-nitrosourea mutagenesis in mice, we identified a germline mutant, designated Ace, with a marked defect in NK cell mediated recognition and elimination of "missing-self" targets. The causative mutation was linked to chromosome 11 and identified as a missense mutation (Thr428Ile) in the SH2 domain of Slp-76-a critical adapter molecule downstream of ITAM-containing surface receptors. The Slp-76 Ace mutation behaved as a hypomorphic allele-while no major defects were observed in conventional T-cell development/function, a marked defect in NK cell mediated elimination of β2-microglobulin (β2M) deficient target cells was observed. Further studies revealed Slp-76 to control NK-cell receptor expression and maturation; however, activation of Slp-76(ace/ace) NK cells through ITAM-containing NK-cell receptors or allogeneic/tumor target cells appeared largely unaffected. Imagestream analysis of the NK-β2M(-/-) target cell synapse revealed a specific defect in actin recruitment to the conjugate synapse in Slp-76(ace/ace) NK cells. Overall these studies establish Slp-76 as a critical determinant of NK-cell development and NK cell mediated elimination of missing-self target cells in mice. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Slp-76 is a critical determinant of NK cell-mediated recognition of missing-self targets

PubMed Central

Lampe, Kristin; Endale, Mehari; Cashman, Siobhan; Fang, Hao; Mattner, Jochen; Hildeman, David; Hoebe, Kasper

2015-01-01

Absence of MHC class I expression is an important mechanism by which NK cells recognize a variety of target cells, yet the pathways underlying “missing-self” recognition, including the involvement of activating receptors, remain poorly understood. Using ENU mutagenesis in mice, we identified a germline mutant, designated Ace, with a marked defect in NK cell-mediated recognition and elimination of “missing-self” targets. The causative mutation was linked to chromosome 11 and identified as a missense mutation [Thr428Ile] in the SH2 domain of Slp-76—a critical adapter molecule downstream of ITAM-containing surface receptors. The Slp-76 Ace mutation behaved as a hypomorphic allele—while no major defects were observed in conventional T cell development/function, a marked defect in NK cell-mediated elimination of β2-Microglobulin (β2M)-deficient target cells was observed. Further studies revealed Slp-76 to control NK cell receptor expression and maturation, however, activation of Slp-76ace/ace NK cells through ITAM-containing NK cell receptors or allogeneic/tumor target cells appeared largely unaffected. Imagestream analysis of the NK-β2M−/− target cell synapse, revealed a specific defect in actin recruitment to the conjugate synapse in Slp-76ace/ace NK cells. Overall these studies establish Slp-76 as a critical determinant of NK cell development and NK cell-mediated elimination of missing-self target cells. PMID:25929249

Multiple view image analysis of freefalling U.S. wheat grains for damage assessment

USDA-ARS?s Scientific Manuscript database

Currently, inspection of wheat in the United States for grade and class is performed by human visual analysis. This is a time consuming operation typically taking several minutes for each sample. Digital imaging research has addressed this issue over the past two decades, with success in recognition...

Identification and Targeting of Tyrosine Kinase Activity in Prostate Cancer Initiation, Progression, and Metastasis

DTIC Science & Technology

2013-12-01

University) "Effectors of the DNA damage and radiotherapy response in cancer" 9:20 pm - 9:30 pm Discussion TUESDAY 7:30 am - 8:30 am Breakfast 9:00...M. Morris , Hideki Onagi, Timothy M. Altamore, Allan B. Gamble, Christopher J. Easton Prohormone-substrate peptide sequence recognition by

A newly identified tomato peptide induces cytosolic calcium and may correspond to pathogen defense-related endogenous peptides in Arabidopsis

USDA-ARS?s Scientific Manuscript database

Plants recognize a variety of stimuli that invoke defenses against attacking pathogens and herbivores. This recognition primes the plant to mount defenses against herbivory and disease. These stimuli include molecules called damage-associated molecular patterns or DAMPs, among them signaling peptide...

Consuming Conventions: Sustainable Consumption, Ecological Citizenship and the Worlds of Worth

ERIC Educational Resources Information Center

Evans, David

2011-01-01

In light of the recognition that current patterns of consumption in the developed world are environmentally damaging, the question of sustainable consumption has become increasingly prominent in public and policy discourse. This paper joins an emerging body of work that critiques the behaviorist perspectives that currently dominate the field and…

Track structure model of cell damage in space flight

NASA Technical Reports Server (NTRS)

Katz, Robert; Cucinotta, Francis A.; Wilson, John W.; Shinn, Judy L.; Ngo, Duc M.

1992-01-01

The phenomenological track-structure model of cell damage is discussed. A description of the application of the track-structure model with the NASA Langley transport code for laboratory and space radiation is given. Comparisons to experimental results for cell survival during exposure to monoenergetic, heavy-ion beams are made. The model is also applied to predict cell damage rates and relative biological effectiveness for deep-space exposures.

Tool use in left brain damage and Alzheimer's disease: What about function and manipulation knowledge?

PubMed

Jarry, Christophe; Osiurak, François; Besnard, Jérémy; Baumard, Josselin; Lesourd, Mathieu; Croisile, Bernard; Etcharry-Bouyx, Frédérique; Chauviré, Valérie; Le Gall, Didier

2016-03-01

Tool use disorders are usually associated with difficulties in retrieving function and manipulation knowledge. Here, we investigate tool use (Real Tool Use, RTU), function (Functional Association, FA) and manipulation knowledge (Gesture Recognition, GR) in 17 left-brain-damaged (LBD) patients and 14 AD patients (Alzheimer disease). LBD group exhibited predicted deficit on RTU but not on FA and GR while AD patients showed deficits on GR and FA with preserved tool use skills. These findings question the role played by function and manipulation knowledge in actual tool use. © 2016 The British Psychological Society.

Hippocampal amnesia.

PubMed

Spiers, H J; Maguire, E A; Burgess, N

2001-01-01

This article reviews 147 cases of amnesia following damage including the hippocampus or fornix as reported in 179 publications. The aetiology, mnestic abilities and reference(s) are tabulated for each case. Consistent findings across cases include the association of bilateral hippocampal damage with a deficit in anterograde episodic memory combined with spared procedural and working memory. The limited nature of retrograde amnesia following lesions to the fornix is also noted. Less consistent and thus more controversial findings, include effects of lesion size or laterality, deficits in semantic memory or familiarity-based recognition and the extent of retrograde amnesia. The evidence concerning these issues is reviewed across cases.

Paradoxical false memory for objects after brain damage.

PubMed

McTighe, Stephanie M; Cowell, Rosemary A; Winters, Boyer D; Bussey, Timothy J; Saksida, Lisa M

2010-12-03

Poor memory after brain damage is usually considered to be a result of information being lost or rendered inaccessible. It is assumed that such memory impairment must be due to the incorrect interpretation of previously encountered information as being novel. In object recognition memory experiments with rats, we found that memory impairment can take the opposite form: a tendency to treat novel experiences as familiar. This impairment could be rescued with the use of a visual-restriction procedure that reduces interference. Such a pattern of data can be explained in terms of a recent representational-hierarchical view of cognition.

Automatic building identification under bomb damage conditions

NASA Astrophysics Data System (ADS)

Woodley, Robert; Noll, Warren; Barker, Joseph; Wunsch, Donald C., II

2009-05-01

Given the vast amount of image intelligence utilized in support of planning and executing military operations, a passive automated image processing capability for target identification is urgently required. Furthermore, transmitting large image streams from remote locations would quickly use available band width (BW) precipitating the need for processing to occur at the sensor location. This paper addresses the problem of automatic target recognition for battle damage assessment (BDA). We utilize an Adaptive Resonance Theory approach to cluster templates of target buildings. The results show that the network successfully classifies targets from non-targets in a virtual test bed environment.

A computer vision system for the recognition of trees in aerial photographs

NASA Technical Reports Server (NTRS)

Pinz, Axel J.

1991-01-01

Increasing problems of forest damage in Central Europe set the demand for an appropriate forest damage assessment tool. The Vision Expert System (VES) is presented which is capable of finding trees in color infrared aerial photographs. Concept and architecture of VES are discussed briefly. The system is applied to a multisource test data set. The processing of this multisource data set leads to a multiple interpretation result for one scene. An integration of these results will provide a better scene description by the vision system. This is achieved by an implementation of Steven's correlation algorithm.

PINK1 is degraded through the N-end rule pathway

PubMed Central

Yamano, Koji; Youle, Richard J

2013-01-01

PINK1, a mitochondrial serine/threonine kinase, is the product of a gene mutated in an autosomal recessive form of Parkinson disease. PINK1 is constitutively degraded by an unknown mechanism and stabilized selectively on damaged mitochondria where it can recruit the E3 ligase PARK2/PARKIN to induce mitophagy. Here, we show that, under steady-state conditions, endogenous PINK1 is constitutively and rapidly degraded by E3 ubiquitin ligases UBR1, UBR2 and UBR4 through the N-end rule pathway. Following precursor import into mitochondria, PINK1 is cleaved in the transmembrane segment by a mitochondrial intramembrane protease PARL generating an N-terminal destabilizing amino acid and then retrotranslocates from mitochondria to the cytosol for N-end recognition and proteasomal degradation. Thus, sequential actions of mitochondrial import, PARL-processing, retrotranslocation and recognition by N-end rule E3 enzymes for the ubiquitin proteosomal degradation defines the rapid PINK1 turnover. PINK1 steady-state elimination by the N-end rule identifies a novel organelle to cytoplasm turnover pathway that yields a mechanism to flag damaged mitochondria for autophagic elimination. PMID:24121706

The von Restorff effect in amnesia: the contribution of the hippocampal system to novelty-related memory enhancements.

PubMed

Kishiyama, M M; Yonelinas, A P; Lazzara, M M

2004-01-01

The ability to detect novelty is a characteristic of all mammalian nervous systems (Sokolov, 1963), and it plays a critical role in memory in the sense that items that are novel, or distinctive, are remembered better than those that are less distinct (von Restorff, 1933). Although several brain areas are sensitive to stimulus novelty, it is not yet known which regions play a role in producing novelty-related effects on memory. In the current study, we investigated novelty effects on recognition memory in amnesic patients and healthy control subjects. The control subjects demonstrated better recognition for items that were novel (i.e., presented in an infrequent color), and this effect was found for both recollection and familiarity-based responses. However, the novelty advantage was effectively eliminated in patients with extensive medial temporal lobe damage, mild hypoxic patients expected to have relatively selective hippocampal damage, and in a patient with thalamic lesions. The results indicate that the human medial temporal lobes play a critical role in producing normal novelty effects in memory.

Predicted molecular signaling guiding photoreceptor cell migration following transplantation into damaged retina

NASA Astrophysics Data System (ADS)

Unachukwu, Uchenna John; Warren, Alice; Li, Ze; Mishra, Shawn; Zhou, Jing; Sauane, Moira; Lim, Hyungsik; Vazquez, Maribel; Redenti, Stephen

2016-03-01

To replace photoreceptors lost to disease or trauma and restore vision, laboratories around the world are investigating photoreceptor replacement strategies using subretinal transplantation of photoreceptor precursor cells (PPCs) and retinal progenitor cells (RPCs). Significant obstacles to advancement of photoreceptor cell-replacement include low migration rates of transplanted cells into host retina and an absence of data describing chemotactic signaling guiding migration of transplanted cells in the damaged retinal microenvironment. To elucidate chemotactic signaling guiding transplanted cell migration, bioinformatics modeling of PPC transplantation into light-damaged retina was performed. The bioinformatics modeling analyzed whole-genome expression data and matched PPC chemotactic cell-surface receptors to cognate ligands expressed in the light-damaged retinal microenvironment. A library of significantly predicted chemotactic ligand-receptor pairs, as well as downstream signaling networks was generated. PPC and RPC migration in microfluidic ligand gradients were analyzed using a highly predicted ligand-receptor pair, SDF-1α - CXCR4, and both PPCs and RPCs exhibited significant chemotaxis. This work present a systems level model and begins to elucidate molecular mechanisms involved in PPC and RPC migration within the damaged retinal microenvironment.

Relationship Between Hair Cell Loss and Hearing Loss in Fishes.

PubMed

Smith, Michael E

2016-01-01

Exposure to intense sound or ototoxic chemicals can damage the auditory hair cells of vertebrates, resulting in hearing loss. Although the relationship between such hair cell damage and auditory function is fairly established for terrestrial vertebrates, there are limited data available to understand this relationship in fishes. Although investigators have measured either the morphological damage of the inner ear or the functional deficits in the hearing of fishes, very few have directly measured both in an attempt to find a relationship between the two. Those studies that have examined both auditory hair cell damage in the inner ear and the resulting hearing loss in fishes are reviewed here. In general, there is a significant linear relationship between the number of hair cells lost and the severity of hearing threshold shifts, although this varies between species and different hair cell-damaging stimuli. After trauma to the fish ear, auditory hair cells are able to regenerate to control level densities. With this regeneration also comes a restoration of hearing. Thus there is also a significant relationship between hair cell recovery and hearing recovery in fishes.

Hyaluronan functionalizing QDs as turn-on fluorescent probe for targeted recognition CD44 receptor

NASA Astrophysics Data System (ADS)

Zhou, Shang; Huo, Danqun; Hou, Changjun; Yang, Mei; Fa, Huanbao

2017-09-01

The recognition of tumor markers in living cancer cells has attracted increasing interest. In the present study, the turn-on fluorescence probe was designed based on the fluorescence of thiolated chitosan-coated CdTe QDs (CdTe/TCS QDs) quenched by hyaluronan, which could provide the low background signal for sensitive cellular imaging. This system is expected to offer specific recognition of CD44 receptor over other substances owing to the specific affinity of hyaluronan and CD44 receptor ( 8-9 kcal/mol). The probe is stable in aqueous and has little toxicity to living cells; thus, it can be utilized for targeted cancer cell imaging. The living lung cancer cell imaging experiments further demonstrate its value in recognizing cell-surface CD44 receptor with turn-on mode. In addition, the probe can be used to recognize and differentiate the subtypes of lung cancer cells based on the difference of CD44 expression on the surface of lung cancer cells. And, the western blot test further confirmed that the expression level of the CD44 receptor in lung cancer cells is different. Therefore, this probe may be potentially applied in recognizing lung cancer cells with higher contrast and sensitivity and provide new tools for cancer prognosis and therapy. [Figure not available: see fulltext.

A bio-recognition device developed onto nano-crystals of carbonate apatite for cell-targeted gene delivery.

PubMed

Chowdhury, E H; Akaike, Toshihiro

2005-05-20

The DNA delivery to mammalian cells is an essential tool for analyzing gene structure, regulation, and function. The approach holds great promise for the further development of gene therapy techniques and DNA vaccination strategies to treat and control diseases. Here, we report on the establishment of a cell-specific gene delivery and expression system by physical adsorption of a cell-recognition molecule on the nano-crystal surface of carbonate apatite. As a model, DNA/nano-particles were successfully coated with asialofetuin to facilitate uptake by hepatocyte-derived cell lines through the asialoglycoprotein receptor (ASGPr) and albumin to prevent non-specific interactions of the particles with cell-surface. The resulting composite particles with dual surface properties could accelerate DNA uptake and enhance expression to a notable extent. Nano-particles coated with transferrin in the same manner dramatically enhanced transgene expression in the corresponding receptor-bearing cells and thus our newly developed strategy represents a universal phenomenon for anchoring a bio-recognition macromolecule on the apatite crystal surface for targeted gene delivery, having immediate applications in basic research laboratories and great promise for gene therapy. (c) 2005 Wiley Periodicals, Inc.

Crystal structure of a gammadelta T-cell receptor specific for the human MHC class I homolog MICA.

PubMed

Xu, Bin; Pizarro, Juan C; Holmes, Margaret A; McBeth, Christine; Groh, Veronika; Spies, Thomas; Strong, Roland K

2011-02-08

γδ T cells play important roles in bridging innate and adaptive immunity, but their recognition mechanisms remain poorly understood. Human γδ T cells of the V(δ)1 subset predominate in intestinal epithelia and respond to MICA and MICB (MHC class I chain-related, A and B; MIC) self-antigens, mediating responses to tumorigenesis or viral infection. The crystal structure of an MIC-reactive V(δ)1 γδ T-cell receptor (TCR) showed expected overall structural homology to antibodies, αβ, and other γδ TCRs, but complementary determining region conformations and conservation of V(δ)1 use revealed an uncharacteristically flat potential binding surface. MIC, likewise, serves as a ligand for the activating immunoreceptor natural killer group 2, D (NKG2D), also expressed on γδ T cells. Although MIC recognition drives both the TCR-dependent stimulatory and NKG2D-dependent costimulatory signals necessary for activation, interaction analyses showed that MIC binding by the two receptors was mutually exclusive. Analysis of relative binding kinetics suggested sequential recognition, defining constraints for the temporal organization of γδ T-cell/target cell interfaces.

Optimal Battery Charging for Damage Mitigation

NASA Technical Reports Server (NTRS)

Hartley, Tom T.; Lorenzo, Carl F.

2003-01-01

Our control philosophy is to charge the NiH2 cell in such a way that the damage incurred during the charging period is minimized, thus extending its cycle life. This requires nonlinear dynamic model of NiH2 cell and a damage rate model. We must do this first. This control philosophy is generally considered damage mitigating control or life-extending control. This presentation covers how NiH2 cells function, electrode behavior, an essentialized model, damage mechanisms for NiH2 batteries, battery continuum damage modeling, and battery life models. The presentation includes graphs and a chart illustrating how charging a NiH2 battery with different voltages and currents affects damages the battery and affects its life. The presentation concludes with diagrams of control system architectures for tracking battery recharging.

Alkylation Damage by Lipid Electrophiles Targets Functional Protein Systems*

PubMed Central

Codreanu, Simona G.; Ullery, Jody C.; Zhu, Jing; Tallman, Keri A.; Beavers, William N.; Porter, Ned A.; Marnett, Lawrence J.; Zhang, Bing; Liebler, Daniel C.

2014-01-01

Protein alkylation by reactive electrophiles contributes to chemical toxicities and oxidative stress, but the functional impact of alkylation damage across proteomes is poorly understood. We used Click chemistry and shotgun proteomics to profile the accumulation of proteome damage in human cells treated with lipid electrophile probes. Protein target profiles revealed three damage susceptibility classes, as well as proteins that were highly resistant to alkylation. Damage occurred selectively across functional protein interaction networks, with the most highly alkylation-susceptible proteins mapping to networks involved in cytoskeletal regulation. Proteins with lower damage susceptibility mapped to networks involved in protein synthesis and turnover and were alkylated only at electrophile concentrations that caused significant toxicity. Hierarchical susceptibility of proteome systems to alkylation may allow cells to survive sublethal damage while protecting critical cell functions. PMID:24429493

4β-Hydroxywithanolide E selectively induces oxidative DNA damage for selective killing of oral cancer cells.

PubMed

Tang, Jen-Yang; Huang, Hurng-Wern; Wang, Hui-Ru; Chan, Ya-Ching; Haung, Jo-Wen; Shu, Chih-Wen; Wu, Yang-Chang; Chang, Hsueh-Wei

2018-03-01

Reactive oxygen species (ROS) induction had been previously reported in 4β-hydroxywithanolide (4βHWE)-induced selective killing of oral cancer cells, but the mechanism involving ROS and the DNA damage effect remain unclear. This study explores the role of ROS and oxidative DNA damage of 4βHWE in the selective killing of oral cancer cells. Changes in cell viability, morphology, ROS, DNA double strand break (DSB) signaling (γH2AX foci in immunofluorescence and DSB signaling in western blotting), and oxidative DNA damage (8-oxo-2'deoxyguanosine [8-oxodG]) were detected in 4βHWE-treated oral cancer (Ca9-22) and/or normal (HGF-1) cells. 4βHWE decreased cell viability, changed cell morphology and induced ROS generation in oral cancer cells rather than oral normal cells, which were recovered by a free radical scavenger N-acetylcysteine (NAC). For immunofluorescence, 4βHWE also accumulated more of the DSB marker, γH2AX foci, in oral cancer cells than in oral normal cells. For western blotting, DSB signaling proteins such as γH2AX and MRN complex (MRE11, RAD50, and NBS1) were overexpressed in 4βHWE-treated oral cancer cells in different concentrations and treatment time. In the formamidopyrimidine-DNA glycolyase (Fpg)-based comet assay and 8-oxodG-based flow cytometry, the 8-oxodG expressions were higher in 4βHWE-treated oral cancer cells than in oral normal cells. All the 4βHWE-induced DSB and oxidative DNA damage to oral cancer cells were recovered by NAC pretreatment. Taken together, the 4βHWE selectively induced DSB and oxidative DNA damage for the ROS-mediated selective killing of oral cancer cells. © 2017 Wiley Periodicals, Inc.