Axis 2, Team 1 | Interaction of chemical environmental contaminants with membrane transport proteins

Axis 2 undertaken by IRSET Team 1 aims to understand the toxicokinetic behaviour of environmental contaminants, in particular in the pulmonary tract and to characterize their interaction with membrane transport proteins responsible for dangerous effects on health.

  1. Objective
  2. In vitro cellular and molecular approaches
  3. In silico approach
Schéma de recherche. - Axe 2, Equipe 1 | Interactions des contaminants environnementaux chimiques avec les transporteurs membranaires  - © Irset

Objective

Influx and efflux membrane transporters play an important role in the cellular and tissular pharmacokinetics of drugs , in particular with regard to absorption (in the gut), distribution (passage through the hemato-tissular barriers) and elimination in the liver and kidneys. They also potentially play a part in the absorption of drugs through the pulmonary tract and in placental transfer.
Moreover, the regulation of their expression and activity by many drugs can cause medication interaction, which has prompted drugs agencies to request that the potential interaction of new drugs with membrane transporters should be systematically characterized.
Like drugs, chemical environmental contaminants may potentially interact with xenobiotics membrane transporters. Such interactions and the effects of environmental contaminants in toxicokinetic and cellular toxicity terms, remain relatively unexplored. Our program therefore aims to define the nature of such interactions and characterize their potential contribution to the detrimental effects of environmental contaminants via an in vitro cellular/molecular approach and an in silico modelling approach, particularly at the pulmonary barrier level.

 

In vitro cellular and molecular approaches

Approches cellulaire/moléculaire in vitro - Etude in vitro des interactions transporteurs-contaminants chimiques.  - © Irset

Interaction between chemical environmental contaminants(pesticides, endocrine disruptors, petrol-like aromas, heavy metals, etc.) either alone or in combination, and membrane transporters (inhibition, uptake) are analysed using cellular models that over-express the transporters (transfected clones) or represent various biological barriers such as pulmonary epithelial cells, hepatocytes, intestinal cells; placental cells, etc.
The techniques used involve fluorescent, radiometric or HPLC tandem mass spectrometry quantification methods. In parallel, we study the role of the passive diffusion of contaminants in their cellular pharmaco-kinetics. The regulation of membrane transporter expression by environmental contaminants in various cellular models (pulmonary cells, hepatocytes, placental cells, etc.) is also studied by reverse transcription (RT-qPCR), Western-blot protein visualisation and functional analysis.
The potential implication of transporter-contaminant interaction in causing toxic effects is analyzed via general cellular toxicity techniques (viability, apostosis, barrier integrity) or specific techniques such as cellular endocrine disruption measurement.

In silico approach

Approches in silico  - Etude in silico des interactions transporteurs-contaminants chimiques. - © Irset

The in silico approach is mainly based on environmental contaminant molecular descriptor analysis and their role in predicting membrane transporter interaction, membrane passage and toxico-kinetics in the contaminants under study. It is partly based on the analysis of the data generated by our in vitro cellular/molecular approach. The bioinformatics approach is implemented using  on line  or off-the-shelf pharmaco-kinetic prediction software. We also carry out a modelling and docking approach on the active transporter sites. We should eventually be able to incorporate these results in PBTK and TDTK models, which will enable us to predict the contamination of exposed subjects and the detrimental effects expected, according to the actual exposure level, in particular with regard to pulmonary exposure.