Dokument: Employing patient-derived iPSC-technology and hepatocyte-like cells to investigate liver diseases
| Titel: | Employing patient-derived iPSC-technology and hepatocyte-like cells to investigate liver diseases | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=71144 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20251103-083422-9 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Lörch, Christiane [Autor] | |||||||
| Dateien: |
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| Beitragende: | PD Dr. rer. nat. Graffmann, Nina [Gutachter] Prof. Dr. Heise, Henrike [Gutachter] | |||||||
| Stichwörter: | induced pluripotent stem cells (iPSCs), hepatocyte-like cells, liver diseases, MAFLD | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 570 Biowissenschaften; Biologie | |||||||
| Beschreibung: | Liver diseases contribute extensively to the global health burden. Multifactorial and monogenic liver diseases such as metabolism dysfunction-associated fatty liver disease (MAFLD) and alpha1-antitrypsin deficiency (AATD) can cause liver fibrosis, cirrhosis and hepatocellular carcinoma. Despite extensive pre-clinical research, progress in understanding liver diseases and drug development remains limited by the inability of conventional models to adequately recapitulate physiologically relevant hepatocytes. Hence, the underlying pathomechanisms and additional driving factors causing the distinct onset and variable symptoms of MAFLD or AATD remain uncertain. iPSC-derived hepatocyte-like cells (HLCs) can be reproduced indefinitely while providing the genetic background of interest. In the first study, urine-derived somatic cells from adult and pediatric AATD patients carrying the most severe genotype were successfully reprogrammed into iPSCs, providing a platform to help close the knowledge gap regarding AATD onset in children. To overcome the well-known limitation of restricted maturation and functionality of HLCs, several aspects of an established protocol were re-evaluated and optimized in the second study. A key finding of this study was that forskolin induced the expression of farnesoid X receptor, an essential regulator of hepatic functions in vivo. Forskolin significantly enhanced hepatic gene and protein expression as well as the inducibility and activity of the cytochrome P450 3A4, a clinically relevant metabolizer of xenobiotics. The establishment of this optimized, time- and cost-efficient differentiation protocol contributes to the scientific understanding of hepatic differentiation and provides relevant platforms for liver disease modeling and toxicological assessment of liver safety. In the third study, MAFLD was modeled in functional HLCs, derived from diseased and healthy individuals, by induction of intrahepatic lipid accumulation (steatosis) for seven days. Steatotic HLCs successfully recapitulated relevant hits on the progressive axis from steatosis to steatohepatitis. Dysregulation of genes involved in AMP activated protein kinase (AMPK)- and peroxisome proliferator-activated receptor (PPAR)-signaling as well as insulin resistance and glutathione metabolism indicated metabolic alterations and cell stress. Furthermore, inflammatory signaling was detected by elevated expression of genes involved in NFkB-, TNF-, and cytokine-cytokine signaling pathways. Key findings included the elevated secretion of dipeptidyl peptidase 4 (DPP4) and corresponding activity upon steatosis. DPP4 is a ubiquitously expressed protease, involved in a plethora of inflammatory and metabolic pathways and is associated with MAFLD, however its concrete role in steatotic hepatocytes remains elusive. Inhibition of DPP4 resulted in the downregulation of inflammatory pathways such as inflammatory bowel disease and type 1 diabetes mellitus. Simultaneously, expression of genes involved in metabolism associated pathways were upregulated. The presented study is the first in this format and confirms pre- and clinical data, proposing a modulating role of DPP4 at the interface between metabolism and inflammation. The novel perspective based on a relevant human in vitro hepatic steatosis model reveals potential pathomechanisms of the hepatocyte-specific contribution mediated by hepatic DPP4 activity in the context of MAFLD. | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät | |||||||
| Dokument erstellt am: | 03.11.2025 | |||||||
| Dateien geändert am: | 03.11.2025 | |||||||
| Promotionsantrag am: | 04.08.2025 | |||||||
| Datum der Promotion: | 23.10.2025 |
