Introduction to mammalian genome special issue: the combined role of genetics and environment relevant to human disease outcomes

Recent Advances in Probabilistic Dose-Response Assessment to Inform Risk-Based Decision Making

Paradoxically, risk assessments for the majority of chemicals lack any quantitative characterization as to the likelihood, incidence, or severity of the risks involved. The relatively few cases where "risk" is truly quantified are based on either epidemiologic data or extrapolation of experimental animal cancer bioassay data. The paucity of chemicals and health endpoints for which such data are available severely limits the ability of decisionmakers to account for the impacts of chemical exposures on human health. The development by the World Health Organization International Programme on Chemical Safety (WHO/IPCS) in 2014 of a comprehensive framework for probabilistic dose-response assessment has opened the door to a myriad of potential advances to better support decision making. Building on the pioneering work of Evans, Hattis, and Slob from the 1990s, the WHO/IPCS framework provides both a firm conceptual foundation as well as practical implementation tools to simultaneously assess uncertainty, variability, and severity of effect as a function of exposure. Moreover, such approaches do not depend on the availability of epidemiologic data, nor are they limited to cancer endpoints. Recent work has demonstrated the broad feasibility of such approaches in order to estimate the functional relationship between exposure level and the incidence or severity of health effects. While challenges remain, such as better characterization of the relationship between endpoints observed in experimental animal or in vitro studies and human health effects, the WHO/IPCS framework provides a strong basis for expanding the breadth of risk management decision contexts supported by chemical risk assessment.

The discovery BPD (D-BPD) program: study protocol of a prospective translational multicenter collaborative study to investigate determinants of chronic lung disease in very low birth weight infants

Background

Premature birth is a growing and serious public health problem affecting more than one of every ten infants worldwide. Bronchopulmonary dysplasia (BPD) is the most common neonatal morbidity associated with prematurity and infants with BPD suffer from increased incidence of respiratory infections, asthma, other forms of chronic lung illness, and death (Day and Ryan, Pediatr Res 81: 210–213, 2017; Isayama et la., JAMA Pediatr 171:271–279, 2017). BPD is now understood as a longitudinal disease process influenced by the intrauterine environment during gestation and modulated by gene-environment interactions throughout the neonatal and early childhood periods. Despite of this concept, there remains a paucity of multidisciplinary team-based approaches dedicated to the comprehensive study of this complex disease.

Methods

The Discovery BPD (D-BPD) Program involves a cohort of infants < 1,250 g at birth prospectively followed until 6 years of age. The program integrates analysis of detailed clinical data by machine learning, genetic susceptibility and molecular translation studies.

Discussion

The current gap in understanding BPD as a complex multi-trait spectrum of different disease endotypes will be addressed by a bedside-to-bench and bench-to-bedside approach in the D-BPD program. The D-BPD will provide enhanced understanding of mechanisms, evolution and consequences of lung diseases in preterm infants. The D-BPD program represents a unique opportunity to combine the expertise of biologists, neonatologists, pulmonologists, geneticists and biostatisticians to examine the disease process from multiple perspectives with a singular goal of improving outcomes of premature infants.

Trial registration

Does not apply for this study.

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1610-8) contains supplementary material, which is available to authorized users.

Sex-specific differences in genotoxic and epigenetic effects of 1,3-butadiene among mouse tissues

Exposure to environmental chemicals has been shown to have an impact on the epigenome. One example is a known human carcinogen 1,3-butadiene which acts primarily by a genotoxic mechanism, but also disrupts the chromatin structure by altering patterns of cytosine DNA methylation and histone modifications. Sex-specific differences in 1,3-butadiene-induced genotoxicity and carcinogenicity are well established; however, it remains unknown whether 1,3-butadiene-associated epigenetic alterations are also sex dependent. Therefore, we tested the hypothesis that inhalational exposure to 1,3-butadiene will result in sex-specific epigenetic alterations. DNA damage and epigenetic effects of 1,3-butadiene were evaluated in liver, lung, and kidney tissues of male and female mice of two inbred strains (C57BL/6J and CAST/EiJ). Mice were exposed to 0 or 425 ppm of 1,3-butadiene by inhalation (6 h/day, 5 days/week) for 2 weeks. Strain- and tissue-specific differences in 1,3-butadiene-induced DNA adducts and crosslinks were detected in the liver, lung and kidney; however, significant sex-specific differences in DNA damage were observed in the lung of C57BL/6J mice only. In addition, we assessed expression of the DNA repair genes and observed a marked upregulation of Mgmt in the kidney in female C57BL/6J mice. Sex-specific epigenetic effects of 1,3-butadiene exposure were evident in alterations of cytosine DNA methylation and histone modifications in the liver and lung in both strains. Specifically, we observed a loss of cytosine DNA methylation in the liver and lung of male and female 1,3-butadiene-exposed C57BL/6J mice, whereas hypermethylation was found in the liver and lung in 1,3-butadiene-exposed female CAST/EiJ mice. Our findings suggest that strain- and sex-specific effects of 1,3-butadiene on the epigenome may contribute to the known differences in cancer susceptibility.