Characterization and reprogramming of umbilical cord-derived mesenchymal stromal cells towards the hepatic lineage

Student thesis: Doctoral Thesis

Abstract

Drug-induced liver injury is one of the major causes for the
discontinuation of drug development and post-market drug withdrawal.
Thus, it is of utmost importance to screen out hepatotoxic compounds
during the early preclinical phases of the drug development process. For
this purpose, primary human hepatocytes are seen as the gold standard.
However, these are very scarce since human donor livers are intensively
used for transplantation purposes. Consequently, the search for
alternative sources of primary human hepatocytes is still ongoing. In this
context, stem cell technology holds great promise. Although a lot of
hurdles still need to be overcome, important advances have been made
over the last years. The current doctoral research could demonstrate that
the human umbilical cord is an important source of mesenchymal stromal
cells (MSC) that intrinsically express a set of liver-enriched transcription
factors (LETFs) and other fetal and adult hepatic markers. Consequently,
it was suggested that human umbilical cord-derived MSC (hUC-MSCs)
could represent an important source to generate human hepatocyte-like
cells. However, in order to imply these cells for in vitro hepatotoxicity
testing, hUC-MSCs need to be obtained in a standardized and
reproducible way. As such, a robust isolation protocol could be
developed, allowing the isolation of hUC-MSCs within the short period of
three hours. Using this procedure, hUC-MSCs could be obtained that
retain the typical characteristics of MSCs. These hUC-MSCs also
maintained the intrinsic expression of the aforementioned LETFs and fetal
and adult hepatic markers and therefore could qualify as a plausible cell
source to generate functional hepatocyte-like cells. However, we also
found that hUC-MSCs lack the expression of other key LETFs (e.g.
hepatocyte nuclear factor 1 alpha; Hnf1a) that are mandatory for
hepatocytes to obtain and maintain their functional properties. We
hypothesized that over-expression of these missing LETFs could support
the hepatic differentiation of hUC-MSCs. Therefore, as a proof-ofprinciple,
a lentiviral hepatic reprogramming protocol was established
over-expressing one key LETF, i.e. Hnf1a, in order to investigate this
hypothesis. It was found that over-expression of Hnf1a improves the
hepatic differentiation of hUC-MSCs compared to a standard hepatic
differentiation protocol. As such, hUC-MSC-derived hepatic cells could be
obtained that significantly express several phase I and phase II
biotransformation enzymes. Altogether, it is our firm believe that this
PhD thesis delivers an important contribution in the search for plausible
cell sources to generate functional human hepatocytes using stem cell
technology.
Date of Award28 Feb 2017
Original languageEnglish
Awarding Institution
  • Vrije Universiteit Brussel
SupervisorJoery De Kock (Promotor), Tamara Vanhaecke (Promotor), Vera Rogiers (Promotor), Dimitri De Bundel (Jury), Mathieu Vinken (Jury), Sophie Hernot (Jury), M. Najimi (Jury), Tania Roskams (Jury) & José V. Castell (Jury)

Keywords

  • liver injury
  • drug
  • hepatic

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