Presenting Author: Prof Jos Kleinjans, Maastricht University
AUTHORS: Jos Kleinjans, Linda Rieswijk,Theo de Kok, Simone van Breda. Department of Toxicogenomics, Maastricht University, the Netherlands
DETECTIVE is part of an integrated research strategy towards the replacement of animal testing set up by the European Commission (EC) within the FP7 Health Programme and supported by the Cosmetics Europe – The Personal Care Association. The project’s main focus refers to the systematic exploitation of a battery of complementary functional and ‘omics readouts to identify in relevant human cellular models in vitro predictive biomarkers for repeated dose toxicity in humans. Endpoints of toxicity under investigation are liver toxicity, heart toxicity and kidney toxicity. Importantly, DETECTIVE performs for the first time an in-depth investigation of repeated dose effects on epigenetics and microRNA expression thus exploring whether such analyses deepen our understanding of toxic modes of action. Check http://www.detect-iv-e.eu/.
Within this context, we investigated cross-omics and functional responses to several well-known human liver toxicants in primary human hepatocytes taken from three donors. Liver cells were pooled in order to bypass the issue of large inter-individual differences in toxic responses. Liver toxicants were administered daily over a 5 day period, at sub-cytotoxic incubation concentrations. Sub-types of liver injury evaluated till date, refer to necrosis and steatosis. Relevant functional tests were applied in order to ascertain that these particular toxic phenotypes were actually induced. After 5 days of treatment, samples were taken and subjected to analyses by multiple ‘omics platforms enabling the capturing of responses to liver toxicants on the gene expression, microRNA and epigenetics level. Advanced bioinformatics approaches were applied for combining and visualizing cross-omics results into integrated response networks. This could successfully be linked to the observed functional characteristics of induced toxicity, thus enabling the discovery of new molecular biomarkers for these types of liver toxicity.
In order to evaluate whether repeated dosing of liver toxicants is capable of inducing toxic responses also on longer term, e.g. after exposure has stopped, some hepatocyte cultures were maintained only in incubation medium for a further 3 days. Samples were subjected to the same cross-omics analyses as described above. Persistent molecular response networks were identified which indeed are still indicative for these particular endpoints of liver toxicity despite the earlier termination of the toxic challenge. It is thus suggested that genes involved in these persistent modifications, represent most promising biomarkers for assessing repeated dose toxicity in the human liver in vitro.
Prof Jos Kleinjans
Prof. Kleinjans studied biology at the Catholic University of Nijmegen and took a training in general biology and further trainings in physiological psychology, pharmacology, neuro-anatomy, and chemical cytology. Immediately after his graduation in 1979, he started working as a PhD student at the Department of Pharmacology of the Faculty of Medicine of Maastricht University.
In 1983, he obtained his PhD degree for his thesis 'Stimulation of renal adrenergic mechanisms as a model for the development of hypertension'. A few months before, he had started to work as a Postdoctoral Research Fellow at the Department of Biological Health Science of the Faculty of Health Sciences of the same University. His research interests were project development in relation to human nutrition and project development and project management concerning nutritional toxicology. In addition, he was involved in the development of curricula and training courses in biological health.
In 1986, he was appointed Associate Professor at the Department of Biological Health Science, where he performed research tasks of programme management in nutritional toxicology and programme development regarding environmental health sciences as well as educational tasks described earlierextended with the development of curricula concerning environmental health sciences.
In 1991, he was appointed Full Professor of Environmental Health Science, head of the Department of Health Risk Analysis and Toxicology, and director of the interfaculty research programme Health and Environment of the Faculties of Health Sciences and Medicine.
Prof. Kleinjans was acknowledged as a pharmacologist by the Concilium Pharmacologicum on behalf of the Foundation for the training of Medical-Biological Scientific Researchers (SMBWO) in 1985 and as a toxicologist in 1988. He is a member of the Netherlands Society of Toxicology (Genetic Toxicology Section and In Vitro Toxicology Section), the Netherlands Society of Environmental Medicine, the Netherlands Society of Environmental Sciences, the Belgian Society of Toxicology, the European Environmental Mutagen Society, the Interuniversity Commission for Environmental Sciences of the Society of Cooperating Dutch Universities, and the Commission on Criteria Documents of the Dutch Health Council. Prof. Kleinjans, furthermore, is a consultant for governmental and non-governmental organizations on an incidental basis and author of national and international training courses in toxicology.