Thyroid hormone metabolism and environmental chemical exposure

Cultured human peripheral blood mononuclear cells alter their gene expression when challenged with endocrine-disrupting chemicals

Endocrine disrupting chemicals (EDCs) have the potential to interfere with the hormonal system and may negatively influence human health. Microarray analysis was used in this study to investigate differential gene expression in human peripheral blood cells (PBMCs) after in vitro exposure to EDCs. PBMCs, isolated from blood samples of four male and four female healthy individuals, were exposed in vitro for 18h to either a dioxin-like polychlorinated biphenyl (PCB126, 1μM), a non-dioxin-like polychlorinated biphenyl (PCB153, 10μM), a brominated flame retardant (BDE47, 10μM), a perfluorinated alkyl acid (PFOA, 10μM) or bisphenol (BPA, 10μM). ANOVA analysis revealed a significant change in the expression of 862 genes as a result of EDC exposure. The gender of the donors did not affect gene expression. Hierarchical cluster analysis created three groups and clustered: (1) PCB126-exposed samples, (2) PCB153 and BDE47, (3) PFOA and BPA. The number of differentially expressed genes varied per compound and ranged from 60 to 192 when using fold change and multiplicity corrected p-value as filtering criteria. Exposure to PCB126 induced the AhR signaling pathway. BDE47 and PCB153 are known to disrupt thyroid metabolism and exposure influenced the expression of the nuclear receptors PPARγ and ESR2, respectively. BPA and PFOA did not induce significant changes in the expression of known nuclear receptors. Overall, each compound produced a unique gene expression signature affecting pathways and GO processes linked to metabolism and inflammation. Twenty-nine genes were significantly altered in expression under all experimental conditions. Six of these genes (HSD11B2, MMP11, ADIPOQ, CEL, DUSP9 and TUB) could be associated with obesity and metabolic syndrome. In conclusion, microarray analysis identified that PBMCs altered their gene expression response in vitro when challenged with EDCs. Our screening approach has identified a number of gene candidates that warrant further study.

How can scientists bring research to use: the HENVINET experience

BACKGROUND

Health concerns have driven the European environmental policies of the last 25 years, with issues becoming more complex. Addressing these concerns requires an approach that is both interdisciplinary and engages scientists with society. In response to this requirement, the FP6 coordination action "Health and Environment Network" HENVINET was set up to create a permanent inter-disciplinary network of professionals in the field of health and environment tasked to bridge the communication gap between science and society. In this paper we describe how HENVINET delivered on this task.

METHODS

The HENVINET project approached the issue of inter-disciplinary collaboration in four ways. (1) The Drivers-Pressures-State-Exposure-Effect-Action framework was used to structure information gathering, collaboration and communication between scientists in the field of health and the environment. (2) Interactive web-based tools were developed to enhance methods for knowledge evaluation, and use these methods to formulate policy advice. (3) Quantification methods were adapted to measure scientific agreement. And (4) Open architecture web technology was used to develop an information repository and a web portal to facilitate collaboration and communication among scientists.

RESULTS

Twenty-five organizations from Europe and five from outside Europe participated in the Health and Environment Network HENVINET, which lasted for 3.5 years. The consortium included partners in environmental research, public health and veterinary medicine; included medical practitioners and representatives of local administrations; and had access to national policy making and EEA and WHO expertise. Dedicated web-based tools for visualisation of environmental health issues and knowledge evaluation allowed remote expert elicitation, and were used as a basis for developing policy advice in five health areas (asthma and allergies; cancer; neurodevelopmental disorders; endocrine disruption; and engineered nanoparticles in the environment). An open searchable database of decision support tools was established and populated. A web based social networking tool was developed to enhance collaboration and communication between scientists and society.

CONCLUSIONS

HENVINET addressed key issues that arise in inter-disciplinary research on health and environment and in communicating research results to policy makers and society. HENVINET went beyond traditional scientific tools and methods to bridge the communication gap between science and policy makers. The project identified the need for a common framework and delivered it. It developed and implemented a variety of novel methods and tools and, using several representative examples, demonstrated the process of producing politically relevant scientific advice based on an open participation of experts. It highlighted the need for, and benefits of, a liaison between health and environment professionals and professionals in the social sciences and liberal arts. By adopting critical complexity thinking, HENVINET extended the traditional approach to environment and health research, and set the standard for current approaches to bridge the gap between science and society.