Desmetilación activa del ADN: un mecanismo epigenético para la reactivación de genes silenciados

Los mecanismos de control epigenético son esenciales para una regulación estable de los patrones de expresión génica y desempeñan un papel central en los ciclos de vida de animales y plantas. La metilación de la citosina en el carbono 5 del anillo de pirimidina (5-meC) es una marca epigenética estable, pero reversible, que promueve el silenciamiento génico transcripcional. Comprender cómo se regula el estado de metilación del genoma a nivel global o local requiere una definición de los procesos enzimáticos que metilan y desmetilan el ADN. Sin embargo, aunque las enzimas responsables del establecimiento y mantenimiento de la metilación de ADN han sido bien caracterizadas, los mecanismos de desmetilación no se conocen con exactitud. Nuestro grupo, junto con otros, ha obtenido datos genéticos y bioquímicos que sugieren que dos proteínas de Arabidopsis con dominio ADN glicosilasa (ROS1 y DME) actúan como ADN desmetilasas capaces de activar la expresión de genes previamente silenciados. Nuestros resultados previos indican que ROS1 y DME catalizan la liberación de 5-meC del ADN mediante un mecanismo ADN glicosilasa. Estos resultados sugieren que una de las funciones de ROS1 y DME es iniciar el borrado de 5-meC mediante un proceso de escisión de bases y proporcionan una importante evidencia bioquímica a favor de la existencia de una ruta de desmetilación activa en plantas. En la actualidad, nuestro grupo de investigación se concentra en caracterizar funcionalmente este novedoso mecanismo de control epigenético mediante una aproximación multidisciplinar que combina metodologías del campo de la bioquímica, la genética y la biofísica. Este estudio suministrará una información esencial para entender los mecanismos responsables de la reprogramación epigenética en el núcleo celular, con aplicaciones potenciales en biotecnología y biomedicin

Pro-environmental behaviors: Determinants and obstacles among italian university students

none31The awareness of citizens concerning the health risks caused by environmental pollution is growing, but studies on determinants of pro-environmental behaviors have rarely examined health-related aspects. In this study, we investigated these determinants using data from a large survey among Italian university students (15 Universities: 4778 filled questionnaires). Besides the health-related aspects, represented by environmental health risk perception and functional health literacy, we considered social and demographic characteristics (gender, area of residence, sources of information, trust in institutional and non-institutional subjects, and students’ capacity of positive actions, indicated as internal locus of control). The attitudes towards pro-environmental behaviors were positive for more than 70% of students and positively related with health risk perception, internal locus of control, and health literacy. The correspondence between the positive attitudes towards pro-environmental behaviors and the real adoption of such behaviors was approximately 20% for most behaviors, except for the separate collection of waste (60%). Such a discrepancy can be attributable to external obstacles (i.e., lack of time, costs, lack of support). The health-related aspects were linked to the pro-environmental attitudes, but to a lesser extent to pro-environmental behaviors, owing to the complexity of their determinants. However, they should be taken in account in planning education interventions.openCarducci A.; Fiore M.; Azara A.; Bonaccorsi G.; Bortoletto M.; Caggiano G.; Calamusa A.; De Donno A.; De Giglio O.; Dettori M.; Di Giovanni P.; Di Pietro A.; Facciola A.; Federigi I.; Grappasonni I.; Izzotti A.; Libralato G.; Lorini C.; Montagna M.T.; Nicolosi L.K.; Paladino G.; Palomba G.; Petrelli F.; Schiliro T.; Scuri S.; Serio F.; Tesauro M.; Verani M.; Vinceti M.; Violi F.; Ferrante M.Carducci, A.; Fiore, M.; Azara, A.; Bonaccorsi, G.; Bortoletto, M.; Caggiano, G.; Calamusa, A.; De Donno, A.; De Giglio, O.; Dettori, M.; Di Giovanni, P.; Di Pietro, A.; Facciola, A.; Federigi, I.; Grappasonni, I.; Izzotti, A.; Libralato, G.; Lorini, C.; Montagna, M. T.; Nicolosi, L. K.; Paladino, G.; Palomba, G.; Petrelli, F.; Schiliro, T.; Scuri, S.; Serio, F.; Tesauro, M.; Verani, M.; Vinceti, M.; Violi, F.; Ferrante, M

Results from the European Union MAPEC_LIFE cohort study on air pollution and chromosomal damage in children: are public health policies sufficiently protective?

Background: Children are at high risk of suffering health consequences of air pollution and childhood exposure can increase the risk of developing chronic diseases in adulthood. This study, part of the MAPEC_LIFE project (LIFE12 ENV/IT/000614), aimed to investigate the associations between exposure to urban air pollutants and micronucleus (MN) frequency, as a biomarker of chromosomal damage, in buccal cells of children for supporting implementation and updating of environmental policy and legislation. Methods: This prospective epidemiological cohort study was carried out on 6- to 8-year-old children living in five Italian towns with different levels and features of air pollution. Exfoliated buccal cells of the children were sampled twice, in winter and spring, obtaining 2139 biological samples for genotoxicological investigation. Micronucleus (MN) frequency was investigated in buccal cells of children and its association with air pollution exposure was assessed applying multiple Poisson regression mixed models, including socio-demographic and lifestyle factors as confounders. We also dichotomize air pollutants\u2019 concentration according to the EU Ambient Air Quality Directives and WHO Air Quality Guidelines in all Poisson regression models to assess their risk predictive capacity. Results: Positive and statistically significant associations were found between MN frequency and PM10, PM2.5, benzene, SO2 and ozone. The increment of the risk of having MN in buccal cells for each \u3bcg/m3 increase of pollutant concentration was maximum for benzene (18.9%, 95% CIs 2.2\u201338.4%) and modest for the other pollutants (between 0.2 and 1.4%). An increased risk (between 17.9% and 59.8%) was found also for exposure to PM10, benzene and benzo(a)pyrene levels higher than the threshold limits. Conclusions: Some air pollutants are able to induce chromosomal damage in buccal cells of children even at concentrations below present EU/WHO limits. This type of biological effects may be indicative of the environmental pressure which populations are exposed to in urban areas

Cabbage butterfly as bioindicator species to investigate the genotoxic effects of PM10

Atmospheric pollution poses a serious threat to environment and human health, and particulate matter (PM) is one of the major contributors. Biological effects induced by PM are investigated through in vitro assays using cells and by in vivo tests with laboratory model animals. However, also the estimation of adverse effects of pollutants, including airborne ones, on wild animals, such as insects, is an essential component of environmental risk assessment. Among insects, butterflies are sensitive to environmental changes and are important wild pollinators, so they might be suitable as environmental bioindicator species. The aim of this study was to evaluate the suitability of a wild cabbage butterfly species (Pieris brassicae) as a bioindicator organism to assess the genotoxic effects of PM10 collected in different sites. PM10 was collected from April to September in urban, suburban, and rural sites. P. brassicae larvae were reared in laboratory under controlled conditions on cabbage plants and exposed to PM10 organic extracts or dimethyl sulfoxide (controls) through vaporization. After exposure, larvae were dissected, and cells were used for comet assay. All PM extracts induced significant DNA damage in exposed larvae compared to controls and the extract collected in the most polluted site caused the highest genotoxic effect. In conclusion, the study suggested that butterflies, such as P. brassicae, could be applied as sensitive and promising bioindicators to investigate air quality and PM genotoxicity. Indeed, the use of these organisms allows the detection of genotoxic effects induced by PM sampled also in low-polluted areas

PM10 in a background urban site: Chemical characteristics and biological effects

PM10 was sampled in a background urban site in Torino, a northern Italian city. PM10 extracts were tested with THP-1 and A-549 cells to evaluate their effects on cell proliferation, LDH activity, TNFα, IL8 and CYP1A1 expression, and genotoxic damage induction (Comet assay). Through Principal Component Analysis (PCA), it was observed that (1) the aqueous extracts induced the inhibition of cell proliferation in the warm season that clustered together to total ions, (2) organic extracts determined a winter cell viability reduction and (3) there was a genotoxic effect associated with PAH and metal concentrations. The analysed low PAH levels were unable to induce significant CYP1A1 expression. The results obtained confirmed that PM composition and seasonality play an important role in particle-induced toxicity. The presence of PM10-induced biological effects at a low polluted site suggested that a reduction of PM10 mass did not seem to be sufficient to reduce its toxicity