Stroke etiologies in patients with COVID-19: the SVIN COVID-19 multinational registry

Coronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Ictus; MortalitatCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Ictus; MortalidadCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Stroke; MortalityBackground and purpose Coronavirus disease 2019 (COVID-19) is associated with a small but clinically significant risk of stroke, the cause of which is frequently cryptogenic. In a large multinational cohort of consecutive COVID-19 patients with stroke, we evaluated clinical predictors of cryptogenic stroke, short-term functional outcomes and in-hospital mortality among patients according to stroke etiology. Methods We explored clinical characteristics and short-term outcomes of consecutively evaluated patients 18 years of age or older with acute ischemic stroke (AIS) and laboratory-confirmed COVID-19 from 31 hospitals in 4 countries (3/1/20–6/16/20). Results Of the 14.483 laboratory-confirmed patients with COVID-19, 156 (1.1%) were diagnosed with AIS. Sixty-one (39.4%) were female, 84 (67.2%) white, and 88 (61.5%) were between 60 and 79 years of age. The most frequently reported etiology of AIS was cryptogenic (55/129, 42.6%), which was associated with significantly higher white blood cell count, c-reactive protein, and D-dimer levels than non-cryptogenic AIS patients (p</=0.05 for all comparisons). In a multivariable backward stepwise regression model estimating the odds of in-hospital mortality, cryptogenic stroke mechanism was associated with a fivefold greater odds in-hospital mortality than strokes due to any other mechanism (adjusted OR 5.16, 95%CI 1.41–18.87, p = 0.01). In that model, older age (aOR 2.05 per decade, 95%CI 1.35–3.11, p < 0.01) and higher baseline NIHSS (aOR 1.12, 95%CI 1.02–1.21, p = 0.01) were also independently predictive of mortality. Conclusions Our findings suggest that cryptogenic stroke among COVID-19 patients carries a significant risk of early mortality.MER-A was funded by The Instituto de Salud Carlos III (JR19/00020), Spain

Stroke etiologies in patients with COVID-19: the SVIN COVID-19 multinational registry

Background and purpose: Coronavirus disease 2019 (COVID-19) is associated with a small but clinically significant risk of stroke, the cause of which is frequently cryptogenic. In a large multinational cohort of consecutive COVID-19 patients with stroke, we evaluated clinical predictors of cryptogenic stroke, short-term functional outcomes and inhospital mortality among patients according to stroke etiology. Methods: We explored clinical characteristics and short-term outcomes of consecutively evaluated patients 18 years of age or older with acute ischemic stroke (AIS) and laboratory-confirmed COVID-19 from 31 hospitals in 4 countries (3/1/20–6/16/20). Results:Of the 14.483 laboratory-confirmed patients with COVID-19, 156 (1.1%) were diagnosed with AIS. Sixty-one (39.4%) were female, 84 (67.2%) white, and 88 (61.5%) were between 60 and 79 years of age. The most frequently reported etiology of AIS was cryptogenic (55/129, 42.6%), which was associated with significantly higher white blood cell count, c-reactive protein, and D-dimer levels than non-cryptogenic AIS patients (p Conclusions: Our findings suggest that cryptogenic stroke among COVID-19 patients carries a significant risk of early mortality

The nucleotidohydrolases DCTPP1 and dUTPase are involved in the cellular response to decitabine

Decitabine (5-aza-2′-deoxycytidine, aza-dCyd) is an anti-cancer drug used clinically for the treatment of myelodysplastic syndromes and acute myeloid leukaemia that can act as a DNA-demethylating or genotoxic agent in a dose-dependent manner. On the other hand, DCTPP1 (dCTP pyrophosphatase 1) and dUTPase are two ‘house-cleaning’ nucleotidohydrolases involved in the elimination of non-canonical nucleotides. In the present study, we show that exposure of HeLa cells to decitabine up-regulates the expression of several pyrimidine metabolic enzymes including DCTPP1, dUTPase, dCMP deaminase and thymidylate synthase, thus suggesting their contribution to the cellular response to this anti-cancer nucleoside. We present several lines of evidence supporting that, in addition to the formation of aza-dCTP (5-aza-2′-deoxycytidine-5′-triphosphate), an alternative cytotoxic mechanism for decitabine may involve the formation of aza-dUMP, a potential thymidylate synthase inhibitor. Indeed, dUTPase or DCTPP1 down-regulation enhanced the cytotoxic effect of decitabine producing an accumulation of nucleoside triphosphates containing uracil as well as uracil misincorporation and double-strand breaks in genomic DNA. Moreover, DCTPP1 hydrolyses the triphosphate form of decitabine with similar kinetic efficiency to its natural substrate dCTP and prevents decitabine-induced global DNA demethylation. The data suggest that the nucleotidohydrolases DCTPP1 and dUTPase are factors involved in the mode of action of decitabine with potential value as enzymatic targets to improve decitabine-based chemotherapy.This work was supported by the Ministerio de Economía y Competitividad (Plan Nacional de Investigación) [grant numbers SAF2011-27860 (to A.E.V.) and SAF2013-48999-R (to D.G.-P.)], Junta de Andalucía [grant numbers BIO-199 and P12-BIO-2059 (to D.G.-P.)], Hungarian National Research, Development and Innovation Office [grant numbers NK-84008 and K-109486], and the International Centre for Genetic Engineering and Biotechnology (ICGEB) [grant number CRP HUN14-01 (to B.G.V.)].Peer reviewe

Cerebrovascular events and outcomes in hospitalized patients with COVID-19: The SVIN COVID-19 Multinational Registry

© 2020 World Stroke Organization.[Background]: Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has been associated with a significant risk of thrombotic events in critically ill patients. [Aim]: To summarize the findings of a multinational observational cohort of patients with SARS-CoV-2 and cerebrovascular disease. [Methods]: Retrospective observational cohort of consecutive adults evaluated in the emergency department and/or admitted with coronavirus disease 2019 (COVID-19) across 31 hospitals in four countries (1 February 2020–16 June 2020). The primary outcome was the incidence rate of cerebrovascular events, inclusive of acute ischemic stroke, intracranial hemorrhages (ICH), and cortical vein and/or sinus thrombosis (CVST). [Results]: Of the 14,483 patients with laboratory-confirmed SARS-CoV-2, 172 were diagnosed with an acute cerebrovascular event (1.13% of cohort; 1130/100,000 patients, 95%CI 970–1320/100,000), 68/171 (40.5%) were female and 96/172 (55.8%) were between the ages 60 and 79 years. Of these, 156 had acute ischemic stroke (1.08%; 1080/100,000 95%CI 920–1260/100,000), 28 ICH (0.19%; 190/100,000 95%CI 130–280/100,000), and 3 with CVST (0.02%; 20/100,000, 95%CI 4–60/100,000). The in-hospital mortality rate for SARS-CoV-2-associated stroke was 38.1% and for ICH 58.3%. After adjusting for clustering by site and age, baseline stroke severity, and all predictors of in-hospital mortality found in univariate regression (p < 0.1: male sex, tobacco use, arrival by emergency medical services, lower platelet and lymphocyte counts, and intracranial occlusion), cryptogenic stroke mechanism (aOR 5.01, 95%CI 1.63–15.44, p < 0.01), older age (aOR 1.78, 95%CI 1.07–2.94, p ¼ 0.03), and lower lymphocyte count on admission (aOR 0.58, 95%CI 0.34–0.98, p ¼ 0.04) were the only independent predictors of mortality among patients with stroke and COVID-19. [Conclusions]: COVID-19 is associated with a small but significant risk of clinically relevant cerebrovascular events, particularly ischemic stroke. The mortality rate is high for COVID-19-associated cerebrovascular complications; therefore, aggressive monitoring and early intervention should be pursued to mitigate poor outcomes

Protocolo de cribado, diagnóstico y tratamiento de la enfermedad de Chagas en mujeres embarazadas latinoamericanas y en sus hijos

Malaltia de Chagas; Dones embarassades llatinoamericanes; Salut maternoinfantilEnfermedad de Chagas; Mujeres embarazadas latinoamericanas; Salud maternoinfantilChagas disease; Latin american pregnant women; Maternal and child healthLa malaltia de Chagas (MCH) continua sent un problema important de salut pública. L’OMS estima que en el món hi ha 8 milions de persones infectades per Trypanosoma cruzi, la majoria a l’Amèrica Llatina. En països no endèmics, com és el cas del nostre entorn, l’MCH s’observa en persones infectades que provenen de països endèmics o en infants nascuts en països no endèmics, però la mare dels quals ha estat infectada (transmissió congènita). A Catalunya, per tal de fer el control i la vigilància de l’MCH, l’any 2010 es va posar en marxa el Programa de prevenció i control de la malaltia de Chagas congènita a Catalunya, coordinat pel Departament de Salut i que inclou el diagnòstic, el control, el seguiment i el tractament de l’MCH congènita dirigits a les dones embarassades i als seus fills. En el marc del Programa, es va elaborar el Protocol de cribratge i diagnòstic de malaltia de Chagas en dones embarassades llatinoamericanes i en els seus fills, que es va editar el 2010. Aquest document va ser fruit de l’esforç conjunt de professionals sanitaris experts en la malaltia, de diferents societats científiques i de professionals del Departament de Salut de la Generalitat de Catalunya, amb el suport del Grup de Treball de Països No Endèmics i del Departament de Control de Malalties Tropicals Oblidades de l’OMS. El Protocol que es presenta, a més d’incloure les mateixes línies que la primera edició, disposa d’actualitzacions de diferents aspectes clínics, de diagnòstic i de vigilància epidemiològica basats en l’experiència i l’evidència observades durant aquests vuit anys del Programa de prevenció i control de la malaltia de Chagas congènita a Catalunya. Durant aquests darrers anys, s’ha reforçat la perspectiva de salut pública en el Programa, en el qual han participat un gran nombre de professionals de la xarxa assistencial i agents comunitaris de salut amb l’objectiu de reduir l’efecte de la transmissió vertical de l’MCH a Catalunya. La primera part del document recull les característiques clíniques de l’MCH que, encara que és d’aparició relativament recent en el nostre entorn, gràcies a la informació facilitada tant en l’àmbit sanitari com en l’àmbit comunitari durant els últims anys, ha deixat de ser una malaltia oblidada i desconeguda a Catalunya. En els darrers anys, els avenços i l’experiència en el nostre entorn en el diagnòstic de l’MCH ens han fet arribar a un consens sobre la utilització de mètodes directes moleculars, tal com es descriu en aquest Protocol. Així mateix, la concreció de dades epidemiològiques sobre prevalença d’infecció i incidència de casos de la malaltia ha millorat molt gràcies a la vigilància i notificació de dades recollides en el marc del Programa de prevenció i control de la malaltia de Chagas congènita a Catalunya pels professionals que formen part del Grup de Treball de la Malaltia de Chagas Congènita. En aquest aspecte i per tal de millorar-ne el control s’han incorporat els metges de família i salut comunitària, ja que són uns dels professionals clau que es troben més propers als pacients. Un aspecte fonamental que es desprèn d’aquest document i del funcionament del Programa és la multidisciplinarietat. El repte del sistema de salut i de la vigilància de la salut pública és la coordinació i el treball dels professionals de diferents àmbits sanitaris, com poden ser els ginecòlegs, els microbiòlegs, els llevadors, els pediatres d’atenció primària i hospitalària, els metges de família i salut comunitària, el personal d’infermeria, els infectòlegs, els epidemiòlegs i els agents de salut comunitària que treballen de manera conjunta per a l’assoliment de l’objectiu plantejat. El present Protocol constitueix un document eminentment pràctic, mitjançant el qual els professionals sanitaris disposen dels elements essencials per a la realització del cribratge en la dona embarassada. A partir d’aquest Protocol s’espera també aconseguir la detecció i el tractament precoç dels casos d’MCH en la població pediàtrica, nadons i altres fills a Catalunya, amb l’objectiu últim de millorar la salut maternoinfantil a Catalunya.La enfermedad de Chagas (ECH) sigue siendo un problema importante de salud pública. La OMS estima que en el mundo hay 8 millones de personas infectadas por Trypanosoma cruzi, la mayoría en América Latina. En países no endémicos, como es el caso de nuestro entorno, la ECH se observa en personas infectadas que provienen de países endémicos o en niños nacidos en países no endémicos, pero cuya madre ha sido infectada (transmisión congénita). En Cataluña, para hacer el control y la vigilancia de la ECH, en 2010 se puso en marcha el Programa de prevención y control de la enfermedad de Chagas congénita en Cataluña, coordinado por el Departamento de Salud y que incluye el diagnóstico, el control, el seguimiento y el tratamiento de la ECH congénita dirigidos a las mujeres embarazadas y a sus hijos. En el marco del Programa, se elaboró el Protocolo de cribado y diagnóstico de enfermedad de Chagas en mujeres embarazadas latinoamericanas y en sus hijos, que se editó en 2010. Este documento fue fruto del esfuerzo conjunto de profesionales sanitarios expertos en la enfermedad, de diferentes sociedades científicas y de profesionales del Departamento de Salud de la Generalidad de Cataluña, con el apoyo del Grupo de Trabajo de Países No Endémicos y del Departamento de Control de Enfermedades Tropicales Olvidadas de la OMS. El Protocolo que se presenta, además de incluir las mismas líneas que la primera edición, dispone de actualizaciones de diferentes aspectos clínicos, de diagnóstico y de vigilancia epidemiológica basados en la experiencia y la evidencia observadas durante estos ocho años del Programa de prevención y control de la enfermedad de Chagas congénita en Cataluña. Durante estos últimos años, se ha reforzado la perspectiva de salud pública en el Programa, en el que han participado un gran número de profesionales de la red asistencial y agentes comunitarios de salud con el objetivo de reducir el efecto de la transmisión vertical del ECH en Cataluña. La primera parte del documento recoge las características clínicas de la ECH que, aunque es de aparición relativamente reciente en nuestro entorno, gracias a la información facilitada tanto en el ámbito sanitario como en el ámbito comunitario durante los últimos años, ha dejado de ser una enfermedad olvidada y desconocida en Cataluña. En los últimos años, los avances y la experiencia en nuestro entorno en el diagnóstico de la ECH nos han hecho llegar a un consenso sobre la utilización de métodos directos moleculares, tal como se describe en el presente Protocolo. Asimismo, la concreción de datos epidemiológicos sobre prevalencia de infección e incidencia de casos de la enfermedad ha mejorado mucho gracias a la vigilancia y notificación de datos recogidos en el marco del Programa de prevención y control de la enfermedad de Chagas congénita en Cataluña por los profesionales que forman parte del Grupo de Trabajo de la Enfermedad de Chagas Congénita. En este aspecto y para mejorar su control se han incorporado los médicos de familia y salud comunitaria, ya que son unos de los profesionales clave que se encuentran más cercanos a los pacientes. Un aspecto fundamental que se desprende de este documento y del funcionamiento del Programa es la multidisciplinariedad. El reto del sistema de salud y de la vigilancia de la salud pública es la coordinación y el trabajo de los profesionales de diferentes ámbitos sanitarios, como pueden ser ginecólogos, microbiólogos, comadrones, pediatras de atención primaria y hospitalaria, médicos de familia y salud comunitaria, personal de enfermería, infectólogos, epidemiólogos y agentes de salud comunitaria que trabajan de manera conjunta para el logro del objetivo planteado. El presente Protocolo constituye un documento eminentemente práctico, mediante el cual los profesionales sanitarios disponen de los elementos esenciales para la realización del cribado en la mujer embarazada. A partir de este Protocolo se espera también conseguir la detección y el tratamiento precoz de los casos de ECH en la población pediátrica, bebés y otros hijos en Cataluña, con el objetivo último de mejorar la salud maternoinfantil en Cataluña.Chagas disease (CHD) continues to be a major public health problem. The WHO estimates that there are 8 million people in the world infected with Trypanosoma cruzi, the majority in Latin America. In non-endemic countries, as is the case in our environment, CHD is seen in infected people who come from endemic countries or children born in non-endemic countries, but whose mother has been infected (congenital transmission). In Catalonia, in order to control and monitor the CHD, in 2010 the Program for the Prevention and Control of Congenital Chagas' Disease in Catalonia was launched, coordinated by the Department of Health and includes diagnosis, control, follow-up and treatment of congenital CHD directed at pregnant women and their children. Within the framework of the Program, the Protocol for the Screening and Diagnosis of Chagas' Disease in Latin American pregnant women and their children was prepared, which was published in 2010. This document was the result of the joint effort of health professionals who are experts in the disease, of different scientific societies and professionals of the Department of Health of the Government of Catalonia, with the support of the Working Group of Non-endemic Countries and the Department of Control of Forgotten Tropical Diseases of WHO. The Protocol that is presented, in addition to including the same lines as the first edition, has updates on different clinical, diagnostic and epidemiological surveillance aspects based on the experience and evidence observed during these eight years of the Prevention and Control Program. Congenital Chagas disease in Catalonia. During these last years, the perspective of public health in the Program has been reinforced, in which a large number of professionals of the health care network and community health agents have participated with the aim of reducing the effect of the vertical transmission of CHD in Catalonia. The first part of the document includes the clinical characteristics of the CHD that, although it is relatively recent in our environment, thanks to the information provided both in the health field and in the community in recent years, has ceased to be a disease forgotten and unknown in Catalonia. In recent years, the advances and experience in our environment in the diagnosis of CHD have led us to reach a consensus on the use of direct molecular methods, as described in this Protocol. Likewise, the specification of epidemiological data on prevalence of infection and incidence of cases of the disease has improved greatly thanks to the monitoring and reporting of data collected within the framework of the Program for the Prevention and Control of Congenital Chagas' Disease in Catalonia by professionals. that are part of the Working Group on Congenital Chagas Disease. In this aspect and to improve their control, family doctors and community health have been incorporated, since they are one of the key professionals who are closest to patients. A fundamental aspect that emerges from this document and the operation of the Program is multidisciplinarity. The challenge of the health system and public health surveillance is the coordination and work of professionals from different health areas, such as gynecologists, microbiologists, midwives, pediatricians of primary and hospital care, family physicians and community health , nurses, infectious disease specialists, epidemiologists and community health workers who work together to achieve the stated objective. This Protocol is an eminently practical document, through which health professionals have the essential elements for carrying out screening in pregnant women. Based on this Protocol, it is also expected to achieve the detection and early treatment of cases of CHD in the pediatric population, babies and other children in Catalonia, with the ultimate goal of improving maternal and child health in Catalonia

Caracterización de la NTP pirofosfatasa humana DCTPP1 y su papel en la homeostasis intracelular de nucleótidos

El mantenimiento de la integridad de la información genética contenida en el DNA es uno de los mayores retos con los que se encuentra un organismo. De su importancia proviene el hecho de que la célula disponga de complejos mecanismos que actúan tanto evitando la producción de errores durante la síntesis de DNA, como reparando cualquier tipo de lesión que pueda generarse. Una función esencial que contribuye al control de daños en el DNA es el mantenimiento de la composición y el tamaño correcto del pool de nucleótidos que será utilizado por la DNA polimerasa durante la replicación. Esto implica no solo el mantener la proporción y la concentración adecuada de los diferentes dNTPs sino al mismo tiempo, eliminar del medio nucleótidos modificados o no canónicos cuya incorporación pudiera dar lugar a mutaciones y/o daños estructurales en el DNA. Las enzimas implicadas en el metabolismo de nucleótidos y especialmente las consideradas como house-cleaning desempeñan un papel fundamental en la regulación y control del pool de nucleótidos, tanto en situaciones fisiológicas normales como patogénicas. Así mismo, estas enzimas pueden jugar un papel relevante en la activación y/o degradación de fármacos. Todo ello confiere especial interés al estudio y caracterización de nuevas enzimas implicadas en estas rutas celulares y su regulación a nivel bioquímico y celular. La proteína humana DCTPP1 es una nucleótidohidrolasa perteneciente a la superfamilia de enzimas house-cleaning conocida como NTP pirofosfatasas todo-¿. Una caracterización bioquímica y funcional de la enzima revela su capacidad para hidrolizar dCTP y varios nucleótidos de desoxicitidina con modificaciones en la posición C5 de la base, especialmente derivados 5-halogenados y 5-formil-dCTP. Además, esta enzima es inhibida de manera competitiva por uno de los productos de la reacción, el pirofosfato, y por dCDP, un intermediario de la ruta de síntesis de pirimidinas. DCTPP1 se encuentra distribuida tanto por citosol como por núcleo y mitocondria, encontrándose una mayor acumulación de enzima en este último. El análisis de la concentración de nucleótidos en células deficientes en DCTPP1 indica que esta enzima juega un papel relevante en el mantenimiento del pool intracelular de nucleótidos mediante el control de los niveles de dCTP. La supresión prolongada de esta enzima causa defectos en proliferación. Además, la expresión de DCTPP1 es activada en distintas situaciones, como debido a la incubación con desoxicitidina o a la deficiencia en alguna de las enzimas de la ruta de síntesis de pirimidina, con el fin de mantener la proporción adecuada de los diferentes nucleótidos. Por otro lado, la deficiencia en DCTPP1 confiere hipersensibilidad a análogos de desoxicitidina con potencial genotóxico como 5I-dCyd y 5me-dCyd así como al fármaco antitumoral aza-dCyd (decitabina) cuya forma activada trifosfato es hidrolizada de manera eficiente por DCTPP1. Tanto esta enzima como la dUTPasa juegan un papel relevante en la protección celular frente al efecto citotóxico y antiproliferativo de la decitabina.Tesis Univ. Granada

The NTP pyrophosphatase DCTPP1 contributes to the homoeostasis and cleansing of the dNTP pool in human cells

The size and composition of dNTP (deoxyribonucleoside triphosphate) pools influence the accuracy of DNA synthesis and consequently the genetic stability of nuclear and mitochondrial genomes. In order to keep the dNTP pool in balance, the synthesis and degradation of DNA precursors must be precisely regulated. One such mechanism involves catabolic activities that convert deoxynucleoside triphosphates into their monophosphate form. Human cells possess an all-α NTP (nucleoside triphosphate) pyrophosphatase named DCTPP1 [dCTP pyrophosphatase 1; also known as XTP3-TPA (XTP3-transactivated protein A)]. In the present study, we provide an extensive characterization of this enzyme which is ubiquitously distributed in the nucleus, cytosol and mitochondria. Interestingly, we found that in addition to dCTP, methyl-dCTP and 5-halogenated nucleotides, DCTPP1 hydrolyses 5-formyl-dCTP very efficiently and with the lowest Km value described so far. Because the biological function of mammalian all-α NTP pyrophosphatases remains uncertain, we examined the role of DCTPP1 in the maintenance of pyrimidine nucleotide pools and cellular sensitivity to pyrimidine analogues. DCTPP1-deficient cells accumulate high levels of dCTP and are hypersensitive to exposure to the nucleoside analogues 5-iodo-2′-deoxycytidine and 5-methyl-2′-deoxycytidine. The results of the present study indicate that DCTPP1 has a central role in the balance of dCTP and the metabolism of deoxycytidine analogues, thus contributing to the preservation of genome integrity.This work was supported by the Junta de Andalucía [grant numbers BIO-199 and P06-CVI-02165], the Ministerio de Economía y Competitividad (Plan Nacional de Investigación) [grant number SAF2010-20059], the Red de Investigación Cooperativa en Enfermedades Tropicales (RICET) FIS (Fondo de Investigaciones Sanitarias) Network [grant number RD06/0021 (to D.G.P.)] and the Ministerio de Economía y Competitividad (Plan Nacional de Investigación) [grant number SAF2011-27860 (to A.E.V.)].Peer reviewe

Trypanosoma brucei AP endonuclease 1 has a major role in the repair of abasic sites and protection against DNA-damaging agents

DNA repair mechanisms guarantee the maintenance of genome integrity, which is critical for cell viability and proliferation in all organisms. As part of the cellular defenses to DNA damage, apurinic/apyrimidinic (AP) endonucleases repair the abasic sites produced by spontaneous hydrolysis, oxidative or alkylation base damage and during base excision repair (BER). Trypanosoma brucei, the protozoan pathogen responsible of human sleeping sickness, has a class II AP endonuclease (TBAPE1) with a high degree of homology to human APE1 and bacterial exonuclease III. The purified recombinant enzyme cleaves AP sites and removes 3′-phosphoglycolate groups from 3′-ends. To study its cellular function, we have established TBAPE1-deficient cell lines derived from bloodstream stage trypanosomes, thus confirming that the AP endonuclease is not essential for viability in this cell type under in vitro culture conditions. The role of TBAPE1 in the removal of AP sites is supported by the inverse correlation between the level of AP endonuclease in the cell and the number of endogenously generated abasic sites in its genomic DNA. Furthermore, depletion of TBAPE1 renders cells hypersensitive to AP site and strand break-inducing agents such as methotrexate and phleomycin respectively but not to alkylating agents. Finally, the increased susceptibility that TBAPE1-depleted cells show to nitric oxide suggests an essential role for this DNA repair enzyme in protection against the immune defenses of the mammalian host.K.S.C. was supported by a fellowship from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (Ministério da Ciência e Tecnologia, Brazil). A.E.V. was supported by funds of the Programa Ramon & Cajal (Ministerio Ciencia e Innovación, Spain). This work was funded by the Plan Nacional de Investigación (SAF2008-03953, SAF2010-20059) (Ministerio Ciencia e Innovación, Spain), the RICET FIS Network (RD06/0021) and the Junta de Andalucía (BIO-199, CVI 05367). We wish to acknowledge C. Clayton for providing the T. brucei strains 449 and pHD887 vector and G. Cross for the T. brucei strain S16. We are also grateful to Aurora Constan for her technical assistance.Peer reviewe

The nucleotidohydrolases DCTPP1 and dUTPase are involved in the cellular response to decitabine

Decitabine (5-aza-2′-deoxycytidine, aza-dCyd) is an anti-cancer drug used clinically for the treatment of myelodysplastic syndromes and acute myeloid leukaemia that can act as a DNA-demethylating or genotoxic agent in a dose-dependent manner. On the other hand, DCTPP1 (dCTP pyrophosphatase 1) and dUTPase are two ‘house-cleaning’ nucleotidohydrolases involved in the elimination of non-canonical nucleotides. In the present study, we show that exposure of HeLa cells to decitabine up-regulates the expression of several pyrimidine metabolic enzymes including DCTPP1, dUTPase, dCMP deaminase and thymidylate synthase, thus suggesting their contribution to the cellular response to this anti-cancer nucleoside. We present several lines of evidence supporting that, in addition to the formation of aza-dCTP (5-aza-2′-deoxycytidine-5′-triphosphate), an alternative cytotoxic mechanism for decitabine may involve the formation of aza-dUMP, a potential thymidylate synthase inhibitor. Indeed, dUTPase or DCTPP1 down-regulation enhanced the cytotoxic effect of decitabine producing an accumulation of nucleoside triphosphates containing uracil as well as uracil misincorporation and double-strand breaks in genomic DNA. Moreover, DCTPP1 hydrolyses the triphosphate form of decitabine with similar kinetic efficiency to its natural substrate dCTP and prevents decitabine-induced global DNA demethylation. The data suggest that the nucleotidohydrolases DCTPP1 and dUTPase are factors involved in the mode of action of decitabine with potential value as enzymatic targets to improve decitabine-based chemotherapy.This work was supported by the Ministerio de Economía y Competitividad (Plan Nacional de Investigación) [grant numbers SAF2011-27860 (to A.E.V.) and SAF2013-48999-R (to D.G.-P.)], Junta de Andalucía [grant numbers BIO-199 and P12-BIO-2059 (to D.G.-P.)], Hungarian National Research, Development and Innovation Office [grant numbers NK-84008 and K-109486], and the International Centre for Genetic Engineering and Biotechnology (ICGEB) [grant number CRP HUN14-01 (to B.G.V.)].Peer reviewe