bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Mono- and Mixed-Culture Campylobacter jejuni Biofilms
Authors: Ica Tuba , Caner Vildan , Istanbullu Ozlem , Nguyen Hung Duc , Ahmed Bulbul , Call Douglas R. , Beyenal Haluk
Published: December 2011

Campylobacter jejuni
, one of the most common causes of human gastroenteritis, is a thermophilic and microaerophilic bacterium. These characteristics make it a fastidious organism, which limits its ability to survive outside animal hosts. Nevertheless,
C. jejuni
can be transmitted to both humans and animals via environmental pathways, especially through contaminated water. Biofilms may play a crucial role in the survival of the bacterium under unfavorable environmental conditions. The goal of this study was to investigate survival strategies of
C. jejuni
in mono- and mixed-culture biofilms. We grew monoculture biofilms of
C. jejuni
and mixed-culture biofilms of
C. jejuni
with
Pseudomonas aeruginosa
. We found that mono- and mixed-culture biofilms had significantly different structures and activities. Monoculture
C. jejuni
biofilms did not consume a measurable quantity of oxygen. Using a confocal laser scanning microscope (CLSM), we found that cells from monoculture biofilms were alive according to live/dead staining but that these cells were not culturable. In contrast, in mixed-culture biofilms,
C. jejuni
remained in a culturable physiological state. Monoculture
C. jejuni
biofilms could persist under lower flow rates (0.75 ml/min) but were unable to persist at higher flow rates (1 to 2.5 ml/min). In sharp contrast, mixed-culture biofilms were more robust and were unaffected by higher flow rates (2.5 ml/min). Our results indicate that biofilms provide an environmental refuge that is conducive to the survival of
C. jejuni
.
Phylogenetic Diversities and Community Structure of Members of the Extremely Halophilic Archaea (Order Halobacteriales) in Multiple Saline Sediment Habitats
Authors: Youssef Noha H. , Ashlock-Savage Kristen N. , Elshahed Mostafa S.
Published: December 2011

We investigated the phylogenetic diversity and community structure of members of the halophilic
Archaea
(order
Halobacteriales
) in five distinct sediment habitats that experience various levels of salinity and salinity fluctuations (sediments from Great Salt Plains and Zodletone Spring in Oklahoma, mangrove tree sediments in Puerto Rico, sediment underneath salt heaps in a salt-processing plant, and sediments from the Great Salt Lake northern arm) using
Halobacteriales
-specific 16S rRNA gene primers. Extremely diverse
Halobacteriales
communities were encountered in all habitats, with 27 (Zodletone) to 37 (mangrove) different genera identified per sample, out of the currently described 38
Halobacteriales
genera. With the exception of Zodletone Spring, where the prevalent geochemical conditions are extremely inhospitable to
Halobacteriales
survival, habitats with fluctuating salinity levels were more diverse than permanently saline habitats. Sequences affiliated with the recently described genera
Halogranum
,
Halolamina
,
Haloplanus
,
Halosarcina
, and
Halorientalis
, in addition to the genera
Halorubrum
,
Haloferax
, and
Halobacterium
, were among the most abundant and ubiquitous genera, suggesting a wide distribution of these poorly studied genera in saline sediments. The
Halobacteriales
sediment communities analyzed in this study were more diverse than and completely distinct from communities from typical hypersaline water bodies. Finally, sequences unaffiliated with currently described genera represented a small fraction of the total
Halobacteriales
communities, ranging between 2.5% (Zodletone) to 7.0% (mangrove and Great Salt Lake). However, these novel sequences were characterized by remarkably high levels of alpha and beta diversities, suggesting the presence of an enormous, yet-untapped supply of novel
Halobacteriales
genera within the rare biosphere of various saline ecosystems.
Nature and Intensity of Selection Pressure on CRISPR-Associated Genes
Authors: Takeuchi Nobuto , Wolf Yuri I. , Makarova Kira S. , Koonin Eugene V.
Published: December 2011

The recently discovered CRISPR-Cas adaptive immune system is present in almost all archaea and many bacteria. It consists of cassettes of CRISPR repeats that incorporate spacers homologous to fragments of viral or plasmid genomes that are employed as guide RNAs in the immune response, along with numerous CRISPR-associated (cas) genes that encode proteins possessing diverse, only partially characterized activities required for the action of the system. Here, we investigate the evolution of thecasgenes and show that they evolve under purifying selection that is typically much weaker than the median strength of purifying selection affecting genes in the respective genomes. The exceptions are thecas1andcas2genes that typically evolve at levels of purifying selection close to the genomic median. Thus, although these genes are implicated in the acquisition of spacers from alien genomes, they do not appear to be directly involved in an arms race between bacterial and archaeal hosts and infectious agents. These genes might possess functions distinct from and additional to their role in the CRISPR-Cas-mediated immune response. Taken together with evidence of the frequent horizontal transfer ofcasgenes reported previously and with the wide-spread microscale recombination within these genes detected in this work, these findings reveal the highly dynamic evolution ofcasgenes. This conclusion is in line with the involvement of CRISPR-Cas in antiviral immunity that is likely to entail a coevolutionary arms race with rapidly evolving viruses. However, we failed to detect evidence of strong positive selection in any of thecasgenes.
Rapid Detection of the Marek's Disease Viral Genome in Chicken Feathers by Loop-Mediated Isothermal Amplification
Authors: Angamuthu Raja , Baskaran Subasty , Gopal Dhinakar Raj , Devarajan Jeyanthi , Kathaperumal Kumanan
Published: December 2011

A loop-mediated isothermal amplification (LAMP) method for the rapid detection of serotype 1 Marek's disease virus (MDV) was developed. The method used a set of three pairs of primers to amplify the MEQ gene for detecting serotype 1 MDV. The MDV LAMP method did not cross-react with serotype 2 and serotype 3, nor did the LAMP primers have binding sites for the common avian DNA viruses (reticuloendotheliosis virus, chicken anemia virus, subgroup J of the avian leukosis virus). Additionally, the assay could detect up to 10 copies of the MEQ gene in the MD viral genome, and it had 10 times higher sensitivity than the traditional PCR methods. The LAMP master mix was stable for 90 days at −20°C. Furthermore, the efficiency of LAMP for detection of serotype 1 MDV in clinical samples was comparable to those of PCR and viral isolation. The LAMP procedure is simple and does not rely on any special equipment. The detection of serotype 1 MDV by LAMP will be useful for detecting and controlling oncogenic Marek's disease.
Detection of Yeasts in Blood Cultures by the Luminex xTAG Fungal Assay
Authors: Balada-Llasat Joan-Miquel , LaRue Heidi , Kamboj Kamal , Rigali Lisa , Smith Debra , Thomas Keelie , Pancholi Preeti
Published: December 2011

A multiplex-PCR Luminex xMAP bead probe fluid array using xTAG analyte-specific reagents (multiplex xTAG fungal ASR assay) was employed for detection of clinically significant
Candida
species,
Cryptococcus neoformans
,
Histoplasma capsulatum
, and
Blastomyces dermatitidis
from blood cultures. We tested 132 blood cultures negative (
n
= 10) or positive (
n
= 97) for yeasts and/or bacteria (
n
= 25). The assay showed sensitivity and specificity of 100% and 99%, respectively. The xTAG fungal ASR assay is a rapid assay that allows simultaneous identification of multiple yeast species.
BLACK HOLE AREA SPECTRUM AND ENTROPY SPECTRUM VIA QUASINORMAL MODES IN A QUANTUM CORRECTED SPACETIME
Authors: LIU CHENG-ZHOU
Published: December 2011

The area spectrum and entropy spectrum of the modified Schwarzschild black hole in gravity's rainbow are investigated via the quasinormal modes of the black hole. Using the modified Hod's method and Kunstatter's method that employ the proper frequency from the imaginary part other than the real part of the quasinormal modes, the area and entropy spacing of the black hole are calculated. The results obtained from these two methods agree with each other and the equally spaced area and entropy spectrum are derived. The obtained area and entropy spectrum are independent of the energies of test particles and are the same as from the usual Schwarzschild black hole.
Evolution of activation patterns during long-duration ventricular fibrillation in pigs
Authors: Cheng Kang-An , Dosdall Derek J. , Li Li , Rogers Jack M. , Ideker Raymond E. , Huang Jian
Published: December 2011

Quantitative analysis has demonstrated five temporal stages of activation during the first 10 min of ventricular fibrillation (VF) in dogs. To determine whether these stages exist in another species, we applied the same analysis to the first 10 min of VF recorded in vivo from two 504-electrode arrays, one each on left anterior and posterior ventricular epicardium in six anesthetized pigs. The following descriptors were continuously quantified: 1) number of wavefronts, 2) wavefront fractionations, 3) wavefront collisions, 4) repeatability, 5) multiplicity index, 6) wavefront conduction velocity, 7) activation rate, 8) mean area activated by the wavefronts, 9) negative peak rate of voltage change, 10) incidence of breakthrough/foci, 11) incidence of block, and 12) incidence of reentry. Cluster analysis of these descriptors divided VF into four stages ( stages i-iv). The values of most descriptors increased during stage i (1–22 s after VF induction), changed quickly to values indicating greater organization during stage ii (23–39 s), decreased steadily during stage iii (40–187 s), and remained relatively unchanged during stage iv (188–600 s). The epicardium still activated during stage iv instead of becoming silent as in dogs. In conclusion, during the first 10 min, VF activation can be divided into four stages in pigs instead of five stages as in dogs. Following a 16-s period during the first minute of VF when activation became more organized, all parameters exhibited progressive decreased organization. Further studies are warranted to determine whether these changes, particularly the increased organization of stage ii, have clinical consequences, such as alteration in defibrillation efficacy.
Overexpression of angiopoietin-2 impairs myocardial angiogenesis and exacerbates cardiac fibrosis in the diabetic db/db mouse model
Authors: Chen Jian-Xiong , Zeng Heng , Reese Jeff , Aschner Judy L. , Meyrick Barbara
Published: December 2011

The angiopoietins/Tie-2 system is essential for the maintenance of vascular integrity and angiogenesis. The functional role of angiopoietin-2 (Ang-2) in the regulation of angiogenesis is dependent on other growth factors such as VEGF and a given physiopathological conditions. This study investigates the potential role of Ang-2 in myocardial angiogenesis and fibrosis formation in the diabetic db/db mouse. Diabetic db/db mice received intramyocardial administration of either adenovirus Ang-2 (Ad-CMV-Ang-2) or Ad-β-gal. The levels of Tie-2, VEGF, caspase-3, Wnt7b, fibroblast-specific protein-1 (FSP-1), and adhesion molecules (ICAM-1 and VCAM-1) expression were measured. Apoptosis, capillary density, and cardiac fibrosis were also analyzed in the db/db mouse hearts. Overexpression of Ang-2 suppressed Tie-2 and VEGF expression in db/db mouse hearts together with significant upregulation of Wnt7b expression. Overexpression of Ang-2 also sensitizes ICAM-1 and VCAM-1 expression in db/db mouse hearts. Immunohistochemical analysis revealed that overexpression of Ang-2 resulted in a gradual apoptosis as well as interstitial fibrosis formation, these leading to a significant loss of capillary density. Data from these studies were confirmed in cultured mouse heart microvascular endothelial cells (MHMEC) exposed to excessive Ang-2. Exposure of MHMEC to Ang-2 resulted in increased caspase-3 activity and endothelial apoptosis. Knockdown of Ang-2 attenuated high glucose-induced endothelial cell apoptosis. Further, counterbalance of Ang-2 by overexpression of Ang-1 reversed loss of capillary density and fibrosis formation in db/db mouse hearts. Our data demonstrate that Ang-2 increases endothelial apoptosis, sensitizes myocardial microvascular inflammation, and promotes cardiac fibrosis and thus contributes to loss of capillary density in diabetic diseases.
Tail-anchored membrane protein SLMAP is a novel regulator of cardiac function at the sarcoplasmic reticulum
Authors: Nader Moni , Westendorp Bart , Hawari Omar , Salih Maysoon , Stewart Alexandre F. R. , Leenen Frans H. H. , Tuana Balwant S.
Published: December 2011

Sarcolemmal membrane-associated proteins (SLMAPs) are components of cardiac membranes involved in excitation-contraction (E-C) coupling. Here, we assessed the role of SLMAP in cardiac structure and function. We generated transgenic (Tg) mice with cardiac-restricted overexpression of SLMAP1 bearing the transmembrane domain 2 (TM2) to potentially interfere with endogenous SLMAP through homodimerization and subcellular targeting. Histological examination revealed vacuolated myocardium; the severity of which correlated with the expression level of SLMAP1-TM2. High resolution microscopy showed dilation of the sarcoplasmic reticulum/endoplasmic reticulum (SR/ER) and confocal imaging combined with biochemical analysis indicated targeting of SLMAP1-TM2 to the SR/ER membranes and inappropriate homodimerization. Older (28 wk of age) Tg mice exhibited reduced contractility with impaired relaxation as assessed by left ventricle pressure monitoring. The ventricular dysfunction was associated with electrophysiological abnormalities (elongated QT interval). Younger (5 wk of age) Tg mice also exhibited an elongated QT interval with minimal functional disturbances associated with the activation of the fetal gene program. They were less responsive to isoproterenol challenge (ΔdP/d tmax) and developed electrical and left ventricular pressure alternans. The altered electrophysiological and functional disturbances in Tg mice were associated with diminished expression level of calcium cycling proteins of the sarcoplasmic reticulum such as the ryanodine receptor, Ca2+-ATPase, calsequestrin, and triadin (but not phospholamban), as well as significantly reduced calcium uptake in microsomal fractions. These data demonstrate that SLMAP is a regulator of E-C coupling at the level of the SR and its perturbation results in progressive deterioration of cardiac electrophysiology and function.
Dantrolene prevents arrhythmogenic Ca2+release in heart failure
Authors: Maxwell Joshua T. , Domeier Timothy L. , Blatter Lothar A.
Published: December 2011

In heart failure (HF), arrhythmogenic Ca2+release and chronic Ca2+depletion of the sarcoplasmic reticulum (SR) arise due to altered function of the ryanodine receptor (RyR) SR Ca2+-release channel. Dantrolene, a therapeutic agent used to treat malignant hyperthermia associated with mutations of the skeletal muscle type 1 RyR (RyR1), has recently been suggested to have effects on the cardiac type 2 RyR (RyR2). In this investigation, we tested the hypothesis that dantrolene exerts antiarrhythmic and inotropic effects on HF ventricular myocytes by examining multiple aspects of intracellular Ca2+handling. In normal rabbit myocytes, dantrolene (1 μM) had no effect on SR Ca2+load, postrest decay of SR Ca2+content, the threshold for spontaneous Ca2+wave initiation (i.e., the SR Ca2+content at which spontaneous waves initiate) and Ca2+spark frequency. In cardiomyocytes from failing rabbit hearts, SR Ca2+load and the wave initiation threshold were decreased compared with normal myocytes, Ca2+spark frequency was increased, and the postrest decay was potentiated. Using a novel approach of measuring cytosolic and intra-SR Ca2+concentration (using the low-affinity Ca2+indicator fluo-5N entrapped within the SR), we showed that treatment of HF cardiomyocytes with dantrolene rescued postrest decay and increased the wave initiation threshold. Additionally, dantrolene decreased Ca2+spark frequency while increasing the SR Ca2+content in HF myocytes. These data suggest that dantrolene exerts antiarrhythmic effects and preserves inotropy in HF cardiomyocytes by decreasing the incidence of diastolic Ca2+sparks, increasing the intra-SR Ca2+threshold at which spontaneous Ca2+waves occur, and decreasing the loss of Ca2+from the SR. Furthermore, the observation that dantrolene reduces arrhythmogenicity while at the same time preserves inotropy suggests that dantrolene is a potentially useful drug in the treatment of arrhythmia associated with HF.
Triiodothyronine increases myocardial function and pyruvate entry into the citric acid cycle after reperfusion in a model of infant cardiopulmonary bypass
Authors: Olson Aaron K. , Bouchard Bertrand , Ning Xue-Han , Isern Nancy , Rosiers Christine Des , Portman Michael A.
Published: December 2011

Triiodothyronine (T3) supplementation improves clinical outcomes in infants after cardiac surgery using cardiopulmonary bypass by unknown mechanisms. We utilized a translational model of infant cardiopulmonary bypass to test the hypothesis that T3 modulates pyruvate entry into the citric acid cycle (CAC), thereby providing the energy support for improved cardiac function after ischemia-reperfusion (I/R). Neonatal piglets received intracoronary [2-13Carbon(13C)]pyruvate for 40 min (8 mM) during control aerobic conditions (control) or immediately after reperfusion (I/R) from global hypothermic ischemia. A third group (I/R-Tr) received T3 (1.2 μg/kg) during reperfusion. We assessed absolute CAC intermediate levels and flux parameters into the CAC through oxidative pyruvate decarboxylation (PDC) and anaplerotic carboxylation (PC) using [2-13C]pyruvate and isotopomer analysis by gas and liquid chromatography-mass spectrometry and13C-nuclear magnetic resonance spectroscopy. When compared with I/R, T3 (group I/R-Tr) increased cardiac power and oxygen consumption after I/R while elevating flux of both PDC and PC (∼4-fold). Although neither I/R nor I/R-Tr modified absolute CAC levels, T3 inhibited I/R-induced reductions in their molar percent enrichment. Furthermore,13C-labeling of CAC intermediates suggests that T3 may decrease entry of unlabeled carbons at the level of oxaloacetate through anaplerosis or exchange reaction with asparate. T3 markedly enhances PC and PDC fluxes, thereby providing potential substrate for elevated cardiac function after reperfusion. This T3-induced increase in pyruvate fluxes occurs with preservation of the CAC intermediate pool. Our labeling data raise the possibility that T3 reduces reliance on amino acids for anaplerosis after reperfusion.
Postural neurocognitive and neuronal activated cerebral blood flow deficits in young chronic fatigue syndrome patients with postural tachycardia syndrome
Authors: Stewart Julian M. , Medow Marvin S. , Messer Zachary R. , Baugham Ila L. , Terilli Courtney , Ocon Anthony J.
Published: December 2011

Neurocognition is impaired in chronic fatigue syndrome (CFS). We propose that the impairment relates to postural cerebral hemodynamics. Twenty-five CFS subjects and twenty control subjects underwent incremental upright tilt at 0, 15, 30, 45, 60, and 75° with continuous measurement of arterial blood pressure and cerebral blood flow velocity (CBFV). We used an n-back task with n ranging from 0 to 4 (increased n = increased task difficulty) to test working memory and information processing. We measured n-back outcomes by the number of correct answers and by reaction time. We measured CBFV, critical closing pressure (CCP), and CBFV altered by neuronal activity (activated CBFV) during each n value and every tilt angle using transcranial Doppler ultrasound. N-back outcome in control subjects decreased with n valve but was independent of tilt angle. N-back outcome in CFS subjects decreased with n value but deteriorated as orthostasis progressed. Absolute mean CBFV was slightly less than in control subjects in CFS subject at each angle. Activated CBFV in control subjects was independent of tilt angle and increased with n value. In contrast, activated CBFV averaged 0 in CFS subjects, decreased with angle, and was less than in control subjects. CCP was increased in CFS subjects, suggesting increased vasomotor tone and decreased metabolic control of CBFV. CCP did not change with orthostasis in CFS subjects but decreased monotonically in control subjects, consistent with vasodilation as compensation for the orthostatic reduction of cerebral perfusion pressure. Increasing orthostatic stress impairs neurocognition in CFS subjects. CBFV activation, normally tightly linked to cognitive neuronal activity, is unrelated to cognitive performance in CFS subjects; the increased CCP and vasomotor tone may indicate an uncoupling of the neurovascular unit during orthostasis.
Neonatal epithelial hypoxia inducible factor-1α expression regulates the response of the lung to experimental asthma
Authors: Greenwood Krista K. , Proper Steven P. , Saini Yogesh , Bramble Lori A. , Jackson-Humbles Daven N. , Wagner James G. , Harkema Jack R. , LaPres John J.
Published: December 2011

Allergic airway disease is characterized by a T helper type 2 cell-mediated airway inflammation and airway hyperresponsiveness. Little is known about the role of hypoxia-mediated signaling in the progression of the disease. To address this knowledge gap, a mouse model was created in which doxycycline exposure induces the functional deletion of hypoxia inducible factor-1α from alveolar type II and Clara cells of the lung. When hypoxia inducible factor-1α deletion was induced during the early postnatal development period of the lung, the mice displayed an enhanced response to the ovalbumin model of allergic airway disease. These hypoxia inducible factor-1α-deficient mice exhibit increased cellular infiltrates, eosinophilia in the lavage fluid and parenchyma, and T helper type 2 cytokines, as compared with ovalbumin-treated control mice. Moreover, these hypoxia inducible factor-1α-deficient mice display increased airway resistance when compared with their control counterparts. Interestingly, if the loss of hypoxia inducible factor-1α was induced in early adulthood, the exacerbated phenotype was not observed. Taken together, these results suggest that epithelial hypoxia inducible factor-1α plays an important role in establishing the innate immunity of the lung and epithelial-specific deficiency in the transcription factor, during early postnatal development, increases the severity of inflammation and functional airway resistance, following ovalbumin challenge. Finally, these results might explain some of the chronic respiratory pathology observed in premature infants, especially those that receive supplemental oxygen. This early hyperoxic exposure, from normal ambient and supplemental oxygen, would presumably inhibit normal hypoxia inducible factor-1α signaling, mimicking the functional deletion described.
Cytoskeletal defects in Bmpr2-associated pulmonary arterial hypertension
Authors: Johnson Jennifer A. , Hemnes Anna R. , Perrien Daniel S. , Schuster Manfred , Robinson Linda J. , Gladson Santhi , Loibner Hans , Bai Susan , Blackwell Tom R. , Tada Yuji , Harral Julie W. , Talati Megha , Lane Kirk B. , Fagan Karen A. , West James
Published: December 2011

The heritable form of pulmonary arterial hypertension (PAH) is typically caused by a mutation in bone morphogenic protein receptor type 2 ( BMPR2), and mice expressing Bmpr2 mutations develop PAH with features similar to human disease. BMPR2 is known to interact with the cytoskeleton, and human array studies in PAH patients confirm alterations in cytoskeletal pathways. The goal of this study was to evaluate cytoskeletal defects in BMPR2-associated PAH. Expression arrays on our Bmpr2 mutant mouse lungs revealed cytoskeletal defects as a prominent molecular consequence of universal expression of a Bmpr2 mutation (Rosa26-Bmpr2R899X). Pulmonary microvascular endothelial cells cultured from these mice have histological and functional cytoskeletal defects. Stable transfection of different BMPR2 mutations into pulmonary microvascular endothelial cells revealed that cytoskeletal defects are common to multiple BMPR2 mutations and are associated with activation of the Rho GTPase, Rac1. Rac1 defects are corrected in cell culture and in vivo through administration of exogenous recombinant human angiotensin-converting enzyme 2 (rhACE2). rhACE2 reverses 77% of gene expression changes in Rosa26-Bmpr2R899Xtransgenic mice, in particular, correcting defects in cytoskeletal function. Administration of rhACE2 to Rosa26-Bmpr2R899Xmice with established PAH normalizes pulmonary pressures. Together, these findings suggest that cytoskeletal function is central to the development of BMPR2-associated PAH and that intervention against cytoskeletal defects may reverse established disease.
IL-33 induces Th17-mediated airway inflammation via mast cells in ovalbumin-challenged mice
Authors: Cho Kyung-Ah , Suh Jee Won , Sohn Jung Ho , Park Jung Won , Lee Hyejin , Kang JiHee Lee , Woo So-Youn , Cho Young Joo
Published: December 2011

Allergic asthma is characterized by infiltration of eosinophils, elevated Th2 cytokine levels, airway hyperresponsiveness, and IgE. In addition to eosinophils, mast cells, and basophils, a variety of cytokines are also involved in the development of allergic asthma. The pivotal role of eosinophils in the progression of the disease has been a subject of controversy. To determine the role of eosinophils in the progression of airway inflammation, we sensitized and challenged BALB/c wild-type (WT) mice and eosinophil-deficient ΔdblGATA mice with ovalbumin (OVA) and analyzed different aspects of inflammation. We observed increased eosinophil levels and a Th2-dominant response in OVA-challenged WT mice. In contrast, eosinophil-deficient ΔdblGATA mice displayed an increased proportion of mast cells and a Th17-biased response following OVA inhalation. Notably, the levels of IL-33, an important cytokine responsible for Th2 immune deviation, were not different between WT and eosinophil-deficient mice. We also demonstrated that mast cells induced Th17-differentiation via IL-33/ST2 stimulation in vitro. These results indicate that eosinophils are not essential for the development of allergic asthma and that mast cells can skew the immune reaction predominantly toward Th17 responses via IL-33 stimulation.
Tumor Suppressor Function of CYLD in Nonmelanoma Skin Cancer
Authors: Masoumi K. C. , Shaw-Hallgren Gina , Massoumi Ramin
Published: December 2011

Ubiquitin and ubiquitin-related proteins posttranslationally modify substrates, and thereby alter the functions of their targets. The ubiquitination process is involved in various physiological responses, and dysregulation of components of the ubiquitin system has been linked to many diseases including skin cancer. The ubiquitin pathways activated among skin cancers are highly diverse and may reflect the various characteristics of the cancer type. Basal cell carcinoma and squamous cell carcinoma, the most common types of human skin cancer, are instances where the involvement of the deubiquitination enzyme CYLD has been recently highlighted. In basal cell carcinoma, the tumor suppressor protein CYLD is repressed at the transcriptional levels through hedgehog signaling pathway. Downregulation of CYLD in basal cell carcinoma was also shown to interfere with TrkC expression and signaling, thereby promoting cancer progression. By contrast, the level of CYLD is unchanged in squamous cell carcinoma, instead, catalytic inactivation of CYLD in the skin has been linked to the development of squamous cell carcinoma. This paper will focus on the current knowledge that links CYLD to nonmelanoma skin cancers and will explore recent insights regarding CYLD regulation of NF-κB and hedgehog signaling during the development and progression of these types of human tumors.
Transcriptional and Nontranscriptional Functions of E2F1 in Response to DNA Damage
Authors: Biswas Anup K. , Johnson David G.
Published: December 2011

E2F is a family of transcription factors that regulate the expression of genes involved in a wide range of cellular processes, including cell-cycle progression, DNA replication, DNA repair, differentiation, and apoptosis. E2F1, the founding member of the family, undergoes posttranslational modifications in response to DNA damage, resulting in E2F1 stabilization. In some cases, E2F1 is important for DNA damage–induced apoptosis through the transcriptional activation of p73 and perhaps other proapoptotic target genes. However, in other contexts, E2F1 can stimulate DNA repair and promote survival in response to DNA damage. The E2F1 protein accumulates at sites of both DNA double-strand breaks and UV radiation–induced damage, indicating that E2F1 has a nontranscriptional function at sites of damage. This review summarizes recent progress made in understanding the role of E2F1 in the DNA damage response, including transcription-independent activities that facilitate DNA repair in the context of chromatin. Cancer Res; 72(1); 13–7. ©2011 AACR.
Antitumor Activity of BRAF Inhibitor Vemurafenib in Preclinical Models of BRAF-Mutant Colorectal Cancer
Authors: Yang Hong , Higgins Brian , Kolinsky Kenneth , Packman Kathryn , Bradley William D. , Lee Richard J. , Schostack Kathleen , Simcox Mary Ellen , Kopetz Scott , Heimbrook David , Lestini Brian , Bollag Gideon , Su Fei
Published: December 2011

The protein kinase BRAF is a key component of the RAS–RAF signaling pathway which plays an important role in regulating cell proliferation, differentiation, and survival. Mutations in BRAF at codon 600 promote catalytic activity and are associated with 8% of all human (solid) tumors, including 8% to 10% of colorectal cancers (CRC). Here, we report the preclinical characterization of vemurafenib (RG7204; PLX4032; RO5185426), a first-in-class, specific small molecule inhibitor of BRAFV600E in BRAF-mutated CRC cell lines and tumor xenograft models. As a single agent, vemurafenib shows dose-dependent inhibition of ERK and MEK phosphorylation, thereby arresting cell proliferation in BRAFV600-expressing cell lines and inhibiting tumor growth in BRAFV600E bearing xenograft models. Because vemurafenib has shown limited single-agent clinical activity in BRAFV600E-mutant metastatic CRC, we therefore explored a range of combination therapies, with both standard agents and targeted inhibitors in preclinical xenograft models. In a BRAF-mutant CRC xenograft model with de novo resistance to vemurafenib (RKO), tumor growth inhibition by vemurafenib was enhanced by combining with an AKT inhibitor (MK-2206). The addition of vemurafenib to capecitabine and/or bevacizumab, cetuximab and/or irinotecan, or erlotinib resulted in increased antitumor activity and improved survival in xenograft models. Together, our findings suggest that the administration of vemurafenib in combination with standard-of-care or novel targeted therapies may lead to enhanced and sustained clinical antitumor efficacy in CRCs harboring the BRAFV600E mutation. Cancer Res; 72(3); 779–89. ©2011 AACR.
Monofunctional Platinum–DNA Adducts Are Strong Inhibitors of Transcription and Substrates for Nucleotide Excision Repair in Live Mammalian Cells
Authors: Zhu Guangyu , Myint MyatNoeZin , Ang Wee Han , Song Lina , Lippard Stephen J.
Published: December 2011

To overcome drug resistance and reduce the side effects of cisplatin, a widely used antineoplastic agent, major efforts have been made to develop next generation platinum-based anticancer drugs. Because cisplatin–DNA adducts block RNA polymerase II unless removed by transcription-coupled excision repair, compounds that react similarly but elude repair are desirable. The monofunctional platinum agent pyriplatin displays antitumor activity in mice, a cytotoxicity profile in cell cultures distinct from that of cisplatin, and a unique in vitro transcription inhibition mechanism. In this study, we incorporated pyriplatin globally or site specifically into luciferase reporter vectors to examine its transcription inhibition profiles in live mammalian cells. Monofunctional pyriplatin reacted with plasmid DNA as efficiently as bifunctional cisplatin and inhibited transcription as strongly as cisplatin in various mammalian cells. Using repair-defective nucleotide excision repair (NER)-, mismatch repair-, and single-strand break repair–deficient cells, we show that NER is mainly responsible for removal of pyriplatin–DNA adducts. These findings reveal that the mechanism by which pyriplatin generates its antitumor activity is very similar to that of cisplatin, despite the chemically different nature of their DNA adducts, further supporting a role for monofunctional platinum anticancer agents in human cancer therapy. This information also provides support for the validity of the proposed mechanism of action of cisplatin and provides a rational basis for the design of more potent platinum anticancer drug candidates using a monofunctional DNA-damaging strategy. Cancer Res; 72(3); 790–800. ©2011 AACR.
Phase I Study of Bosutinib, a Src/Abl Tyrosine Kinase Inhibitor, Administered to Patients with Advanced Solid Tumors
Authors: Daud Adil I. , Krishnamurthi Smitha S. , Saleh Mansoor N. , Gitlitz Barbara J. , Borad Mitesh J. , Gold Philip J. , Chiorean Elena G. , Springett Gregory M. , Abbas Richat , Agarwal Shefali , Bardy-Bouxin Nathalie , Hsyu Poe-Hirr , Leip Eric , Turnbull Kathleen , Zacharchuk Charles , Messersmith Wells A.
Published: December 2011

Purpose: Bosutinib, a potent ATP-competitive, quinolinecarbonitrile Src/Abl kinase inhibitor, was tested in this first-in-human phase I trial in patients with advanced solid tumor malignancies.

Patients and Methods: This trial was conducted in 2 parts. In part 1 (dose escalation), increasing oral bosutinib doses were administered using a 3 + 3 design. In part 2 (dose expansion), approximately 30 patients each with refractory colorectal, pancreas, or non–small cell lung cancer were treated at the recommended phase II dose (RP2D). Primary efficacy endpoints for part 2 were median progression-free survival (colorectal and non–small cell lung) and median overall survival (pancreas).

Results: In part 1, dose-limiting toxicities of grade 3 diarrhea (two patients) and grade 3 rash occurred with bosutinib 600 mg/day and the maximum tolerated dose identified was 500 mg/day. However, the majority of patients treated with 500 mg/day had grade 2 or greater gastrointestinal toxicity, and 400 mg/day was identified as the RP2D. The most common bosutinib-related adverse events were nausea (60% patients), diarrhea (47%), vomiting (40%), fatigue (38%), and anorexia (36%). Bosutinib had a mean half-life of 19 to 20 hours at the RP2D. A partial response (breast) and unconfirmed complete response (pancreas) were observed; 8 of 112 evaluable patients had stable disease for 22 to 101 weeks. However, the primary efficacy endpoints for part 2 were not met.

Conclusions: Bosutinib was generally well tolerated in patients with solid tumors, with the main toxicity being gastrointestinal. The RP2D was 400 mg/day orally. Further study of bosutinib is planned in combination regimens. Clin Cancer Res; 18(4); 1092–100. ©2011 AACR.
Does PTEN Loss Impair DNA Double-Strand Break Repair by Homologous Recombination?
Authors: Hunt Clayton R. , Gupta Arun , Horikoshi Nobuo , Pandita Tej K.
Published: December 2011

The tumor suppressor PTEN is frequently lost in cancer cells, resulting in altered radiation and drug sensitivity. However, the role of PTEN in DNA repair is controversial. Detailed studies in prostate cancer cells now indicate PTEN does not regulate RAD51 expression or homologous recombination and is not a biomarker for PARP inhibitor sensitivity. Clin Cancer Res; 18(4); 920–2. ©2011 AACR.
Contractile Dysfunction Irrespective of the Mutant Protein in Human Hypertrophic Cardiomyopathy With Normal Systolic Function
Authors: van Dijk Sabine J. , Paalberends E. Rosalie , Najafi Aref , Michels Michelle , Sadayappan Sakthivel , Carrier Lucie , Boontje Nicky M. , Kuster Diederik W.D. , van Slegtenhorst Marjon , Dooijes Dennis , dos Remedios Cris , ten Cate Folkert J. , Stienen Ger J.M. , van der Velden Jolanda
Published: December 2011

Background—

Hypertrophic cardiomyopathy (HCM), typically characterized by asymmetrical left ventricular hypertrophy, frequently is caused by mutations in sarcomeric proteins. We studied if changes in sarcomeric properties in HCM depend on the underlying protein mutation.

Methods and Results—

Comparisons were made between cardiac samples from patients carrying a
MYBPC3
mutation (MYBPC3
mut
; n=17), mutation negative HCM patients without an identified sarcomere mutation (HCM
mn
; n=11), and nonfailing donors (n=12). All patients had normal systolic function, but impaired diastolic function. Protein expression of myosin binding protein C (cMyBP-C) was significantly lower in MYBPC3
mut
by 33±5%, and similar in HCM
mn
compared with donor. cMyBP-C phosphorylation in MYBPC3
mut
was similar to donor, whereas it was significantly lower in HCM
mn
. Troponin I phosphorylation was lower in both patient groups compared with donor. Force measurements in single permeabilized cardiomyocytes demonstrated comparable sarcomeric dysfunction in both patient groups characterized by lower maximal force generating capacity in MYBPC3
mut
and HCM
mn,
compared with donor (26.4±2.9, 28.0±3.7, and 37.2±2.3 kN/m
2
, respectively), and higher myofilament Ca
2+
-sensitivity (EC
50
=2.5±0.2, 2.4±0.2, and 3.0±0.2 μmol/L, respectively). The sarcomere length-dependent increase in Ca
2+
-sensitivity was significantly smaller in both patient groups compared with donor (ΔEC
50
: 0.46±0.04, 0.37±0.05, and 0.75±0.07 μmol/L, respectively). Protein kinase A treatment restored myofilament Ca
2+
-sensitivity and length-dependent activation in both patient groups to donor values.

Conclusions—

Changes in sarcomere function reflect the clinical HCM phenotype rather than the specific
MYBPC3
mutation. Hypocontractile sarcomeres are a common deficit in human HCM with normal systolic left ventricular function and may contribute to HCM disease progression.
Reference Values for Normal Pulmonary Artery Dimensions by Noncontrast Cardiac Computed Tomography
Authors: Truong Quynh A. , Massaro Joseph M. , Rogers Ian S. , Mahabadi Amir A. , Kriegel Matthias F. , Fox Caroline S. , O'Donnell Christopher J. , Hoffmann Udo
Published: December 2011

Background—

Main pulmonary artery diameter (mPA) and ratio of mPA to ascending aorta diameter (ratio PA) derived from chest CT are commonly reported in clinical practice. We determined the age- and sex-specific distribution and normal reference values for mPA and ratio PA by CT in an asymptomatic community-based population.

Methods and Results—

In 3171 men and women (mean age, 51±10 years; 51% men) from the Framingham Heart Study, a noncontrast, ECG-gated, 8-slice cardiac multidetector CT was performed. We measured the mPA and transverse axial diameter of the ascending aorta at the level of the bifurcation of the right pulmonary artery and calculated the ratio PA. We defined the healthy referent cohort (n=706) as those without obesity, hypertension, current and past smokers, chronic obstructive pulmonary disease, history of pulmonary embolism, diabetics, cardiovascular disease, and heart valve surgery. The mean mPA diameter in the overall cohort was 25.1±2.8 mm and mean ratio PA was 0.77±0.09. The sex-specific 90th percentile cutoff value for mPA diameter was 28.9 mm in men and 26.9 mm in women and was associated with increase risk for self-reported dyspnea (adjusted odds ratio, 1.31;
P
=0.02). The 90th percentile cutoff value for ratio PA of the healthy referent group was 0.91, similar between sexes but decreased with increasing age (range, 0.82–0.94), though not associated with dyspnea.

Conclusions—

For simplicity, we established 29 mm in men and 27 mm in women as sex-specific normative reference values for mPA and 0.9 for ratio PA.
Short-Term Outcomes of Acute Myocardial Infarction in Patients With Acute Kidney Injury
Authors: Fox Caroline S. , Muntner Paul , Chen Anita Y. , Alexander Karen P. , Roe Matthew T. , Wiviott Stephen D.
Published: December 2011

Background—

Acute kidney injury (AKI) is a risk factor for long-term adverse outcomes, including acute myocardial infarction and death. However, the relationship between severity of AKI and in-hospital outcomes in the setting of acute myocardial infarction has not been well documented.

Methods and Results—

The study population (n=59 970) was drawn from the Acute Coronary Treatment and Intervention Outcomes Network (ACTION) Registry–Get With the Guidelines (GWTG), a nationwide sample of myocardial infarction patients admitted to 383 hospitals in the United States between July 2008 and September 2009. AKI was defined using absolute changes in serum creatinine (SCr; peak SCr minus admission SCr) and categorized as no AKI (SCr change, <0.3 mg/dL), mild AKI (SCr change, 0.3–<0.5 mg/dL), moderate AKI (SCr change, 0.5–<1.0 mg/dL), and severe AKI (SCr change, ≥1.0 mg/dL). Overall, 16.1% had AKI, including 6.5% with mild AKI, 5.6% with moderate AKI, and 4.0% with severe AKI. In-hospital mortality rates for those with mild, moderate, and severe AKI were 6.6%, 14.2%, and 31.8% compared with 2.1% in those without AKI. The odds ratios for in-hospital death were 2.4 (95% confidence interval, 2.0–2.7), 4.5 (95% confidence interval, 3.9–5.1), and 12.6 (95% confidence interval, 11.1–14.3) for mild, moderate, and severe AKI compared with those without AKI. Although patients with AKI were less likely to undergo early invasive care or to receive antiplatelet therapies, rates of major bleeding ranged from 8.4% (no AKI) to 32.7% (severe AKI).

Conclusion—

AKI is common and associated with mortality and bleeding, underscoring the importance of efforts to identify risk factors and to prevent AKI in acute myocardial infarction care.
ST-Elevation Acute Coronary Syndromes in the Platelet Inhibition and Patient Outcomes (PLATO) Trial
Authors: Armstrong Paul W. , Siha Hany , Fu Yuling , Westerhout Cynthia M. , Steg Ph. Gabriel , James Stefan K. , Storey Robert F. , Horrow Jay , Katus Hugo , Clemmensen Peter , Harrington Robert A. , Wallentin Lars
Published: December 2011

Background—

Ticagrelor, when compared with clopidogrel, reduced the 12-month risk of vascular death/myocardial infarction and stroke in patients with ST-elevation acute coronary syndromes intended to undergo primary percutaneous coronary intervention in the PLATelet inhibition and patient Outcomes (PLATO) trial. This prespecified ECG substudy explored whether ticagrelor's association with vascular death and myocardial infarction within 1 year would be amplified by (1) the extent of baseline ST shift and (2) subsequently associated with fewer residual ST changes at hospital discharge.

Methods and Results—

ECGs were evaluated centrally in a core laboratory in 3122 ticagrelor- and 3084 clopidogrel-assigned patients having at least 1 mm ST-elevation in 2 contiguous leads as identified by site investigators on the qualifying ECG. Patients with greater ST-segment shift at baseline had higher rates of vascular death/myocardial infarction within 1 year. Among those who also had an ECG at hospital discharge (n=4798), patients with ≥50% ΣST-deviation (ΣST-dev) resolution had higher event-free survival than those with incomplete resolution (6.4% versus 8.8%, adjusted hazard ratio 0.69 (0.54–0.88),
P
=0.003). The extent of ΣST-dev resolution was similar irrespective of treatment assignment. The benefit of ticagrelor versus clopidogrel on clinical events was consistent irrespective of the extent of baseline ΣST-dev (
P
(interaction)=0.728). When stratified according to conventional times from symptom onset, ie, ≤3 hours, 3 to 6 hours, >6 hours, the extent of baseline ΣST-dev declined progressively over time. As time from symptom onset increased beyond 3 hours, the benefit of ticagrelor appeared to be more pronounced; however, the interaction between time and treatment was not significant (
P
=0.175).

Conclusions—

Ticagrelor did not modify ΣST-dev resolution at discharge nor was its benefit affected by the extent of baseline ΣST-dev. These hypothesis-generating observations suggest that the main effects of ticagrelor may not relate to the rapidity or the completeness of acute reperfusion, but rather the prevention of recurrent vascular events by more powerful platelet inhibition or other mechanisms.

Clinical Trial Registration—

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT00391872.
Functional Variant in Methionine Synthase Reductase Intron-1 Significantly Increases the Risk of Congenital Heart Disease in the Han Chinese Population
Authors: Zhao Jian-Yuan , Yang Xue-Yan , Gong Xiao-Hong , Gu Zhuo-Ya , Duan Wen-Yuan , Wang Jue , Ye Zhi-Zhou , Shen Hong-Bing , Shi Kai-Hu , Hou Jia , Huang Guo-Ying , Jin Li , Qiao Bin , Wang Hong-Yan
Published: December 2011

Background—

Homocysteine is known to be an independent risk factor for congenital heart disease (CHD). Methionine synthase reductase (
MTRR
) is essential for the adequate remethylation of homocysteine, which is the dominant pathway for homocysteine removal during early embryonic development.

Methods and Results—

Here, we report that the c.56+781 A>C (rs326119) variant of intron-1 of
MTRR
significantly increases the risk of CHD in the Han Chinese population. In 3 independent case-control studies involving a total of 2340 CHD patients and 2270 healthy control participants from different geographic areas, we observed that patients carrying the heterozygous AC and homozygous CC genotype had a 1.40-fold (odds ratio=1.40;
P
=2.32×10
−7
) and 1.84-fold (odds ratio=1.84;
P
=2.3×10
−11
) increased risk, respectively, of developing CHD than those carrying the wild-type AA genotype. Both in vivo quantitative real-time polymerase chain reaction analysis of
MTRR
mRNA in cardiac tissue samples from CHD patients and in vitro luciferase assays in transfected cells demonstrated that the c.56+781 C allele profoundly decreased
MTRR
transcription. Further analysis demonstrated that the c.56+781 C allele manifested reduced CCAAT/enhancer binding protein-α binding affinity. In addition, healthy individuals with the homozygous CC genotype had significantly elevated levels of plasma homocysteine compared with the wild-type AA carriers.

Conclusions—

We have demonstrated that the
MTRR
c.56+781 A>C variant is an important genetic marker for increased CHD risk because this variant results in functionally reduced
MTRR
expression at the transcriptional level. Our results accentuate the significance of functional single-nucleotide polymorphisms in noncoding regions of the homocysteine/folate metabolism pathway core genes for their potential contributions to the origin of CHD.