DiMeN Doctoral Training Partnership: Evaluating idiosyncratic metabolism using a flow based tissue engineering and proteomics approach for drug induced toxicity

Adverse drug reactions (ADRs) are a major cause of global hospitalisation. These can be caused by a wide range of drugs that include common over the counter medication such as paracetamol, non-steroidal anti-inflammatory such as ibuprofen as well as drugs given to patients for cancer, diabetes and cardiac arrhythmias. In our aging population where a growing concern of chronic illness can mean prolonged exposure to certain drugs, ADRs can have life threatening consequences either as a direct cause of drug reactions or as a need for drug withdrawal for patient safety concerns.

The two major organs affected by ADRs are the liver and the heart. Drug metabolism occurs predominantly in the liver and it has been hypothesised that inter-individual variation in drug metabolising enzymes coupled with mitochondrial genetics may play a large role in the yet undetermined mechanisms involved in idiosyncratic drug induced liver injury. These two factors in turn then affect the metabolism of drugs that then maybe converted more or less readily into metabolites that can lead to cardiotoxic events.

In this project we aim to use human cell culture systems under continuous flow of media to emulate the sheer stress seen by blood flow in order to develop directly translational research. To incorporate mitochondria variation we have generated HEPG2 cells with transmitochondrial cybrids as an in vitro model of personalised mitochondrial function for haplogroups H, T, J, U which represent the major evolutionary deviations in global mitochondria genetic allowing us to delineate the influence of mitochondrial haplogroup on any drug-specific adverse reaction. We further will use induced pluripotent stem cell derived (iPSC) hepatocytes to monitor inter-individual variation in metabolism. In culmination we aim to shed light on DILI mechanisms caused by mitochondrial genetic or variations in metabolising enzymes. This project utilises the QV900 flow system from Kirkstall, which allows the connection of organ specific modules allowing us to connect a liver module directly to a cardiac module by flow, which further allows us to determine the effects of varied backgrounds of liver metabolism in the progression of cardiotoxic events.

The research outlined will be carried out at the MRC Centre for Drug Safety Science (CDSS) at the University of Liverpool, which houses state-of-the art equipment, laboratories and renowned scientists conducting fundamental research into the mechanistic basis of adverse drug reactions. This is a multi-disciplinary project in which you will be trained to culture a multitude of liver and cardiac cells and to operate and dose cells in the QV900 system. We will then examine how drug-induced changes affect both liver and cardiac cell health by assessing key phenotypes such as viability, morphology, beat rates and assessment of known biomarkers of cell damage. We will asses pathways at the gene (qPCR and microarray) and protein (Western blot) level using molecular techniques. Immunofluorescence will be performed to determine morphological changes and mass spectroscopy will be used to quantify the levels of metabolites as well as global protein changes in protein levels.

This novel model set-up will allow us to be on the forefront of personalised medicine and to directly evaluate patient specific variation on the effect of treatments at a multi-organ level and reduce the number of animals in the initial phases of research. Your research will gain mechanistic and translational insight into idiosyncratic drug induced organ injury in order to assess the effect on liver and cardiovascular pathophysiology and ascertain how these regimes may vary in genetically variable patients paving the way to a more personalised approach to global drug safety.