The research team is developing strategies to differentiate stem cells induced from patients to hepatocytes. They have described this tool that allows to asses the extent of differentiation achieved.

Differentiation of induced stem cells to hepatocytes

It is possible to produce induced pluripotent stem cells (iPSC) from a patient that are subsequently differentiated into hepatocytes by using transcription factors and specific culture media. This differentiation process, although guided by a set of general principles, is carried out with a high degree of empiricism and hit/miss by the different research groups. The objective of the paper was to be able to calculate how differentiated the cells are. This is how many hepatocytes were generated and to what extent they are comparable to the liver hepatocytes in order to guide the differentiation process.

International collaboration

The research has been carried out by researchers of the Mixed Unit UV-IIS La Fe with the CIBER of Liver and Digestive Diseases (CIBEREHD), and the University of Louvain as part of the European Project EuToxRisk. Owing to the paper’s originality it appeared on the cover of the prestigious magazine. This paper is the first one in which the metabolomics (the study of the metabolites of a cell) are used to monitor to what extent the pluripotent stem cells have differentiated to hepatocytes and what is their degree of differentiation compared to adult hepatocytes.

The metabolomics: a powerful tool

Mass spectrometry-based metabolomics (UPLC-MS) has the remarkable capacity of accurately measuring hundreds of cell metabolites to be able to compare them with those that a differentiated hepatocyte should have.

“The concept of the idea is simple”, sais Dr. José Vargas, initiator of the idea. “We analysed the metabolites present in the stem cell, as the differentiation process progresses, to compare them with those present in an adult hepatocyte. Of this comparison it can be stablished in what extent de differentiated cell express the functions and behaves as an adult hepatocyte. All of this can be represented with a representative number.”

“This work has required the development of a considerable number of highly innovative analytical and bioinformatics strategies to accurately quantify changes in the metabolome and their metabolic relevance," says Marta Moreno, first author of the paper. Guillermo Quintas, expert in mass spectrometry said: “the personal creative challenge of handling a huge amount of information and it’s elaboration to make it’s interpretation useful and intuitive.” Laia Tolosa, co-author, added: “so that from now on, the tool allows the evaluation and optimization of the differentiation strategies with quantitative criteria”.

The originality and novelty of this strategy awaken the interest of the Journal of Proteome Research editors that selected this work for the cover of a special edition about new applications of metabolomics. One of the authors of the paper, the doctorate student of the Biochemistry Department of the Universitat de València, Guillem García is the creator of the graphical composition that received the favour of the prestigious magazine. The aesthetics, simplicity and composition of the figure has received the unanimous endorsement. “For me it has been a boost of satisfaction, self-steam and incentive for my researching career”.

Hepatocytes from patients obtained by cell reprogramming

The Mixed Unit Universitat de Valéncia-IIS La Fe of Experimental Hepatology and Hepatic Transplantation has a long history and international recognition in the study of drug hepatotoxicity. Many of the toxic events are of idiosyncratic nature, hence highly dependent of the individual. Having a cellular model of the hepatocytes of the patient who suffered a hepatotoxicity event would be definitive, but the accessibility to the patient’s hepatocytes (for example through a biopsy) is neither ethically or clinically feasible in these patients. In this way in the Unit has explored different ways to generate hepatocytes from other somatic cells that are of easier access in the patient: iPSC generation and their subsequent differentiation to hepatocytes or their direct reprogramming. The tool described by the authors is an important advance to guide the differentiation process and knowing how differentiated this reprogrammed hepatocytes are.

--------------------------

Marta Moreno-Torres, Manoj Kumar, Guillem García-Llorens, Guillermo Quintás, Tine Tricot, Ruben Boon, Laia Tolosa, Burak Toprakhisar, Francois Chesnais, Catherine Verfaillie, and José V. Castell. A Novel UPLC-MS Metabolomic Analysis-Based Strategy to Monitor the Course and Extent of iPSC Differentiation to Hepatocytes. Journal of Proteome Research 2022 DOI: https://doi.org/10.1021/acs.jproteome.1c00779