Cell therapy involving treatment of diseases with the body’s own cells would benefit both liver diseases and Type 1 diabetes. Liver diseases are associated with a marked reduction in hepatocytes whilst Type 1 diabetes is characterized by the loss of functional insulin-producing β-cells. Treatment is currently achieved by whole organ liver (or hepatocyte) and islet transplantation methods respectively. However the major limitation to this approach is the shortage of organ donors, thus alternative sources of cells must be found. Potential sources with enormous therapeutic potential are existing cells in the liver and pancreas involved during the regeneration process. In vivo studies have shown progenitor oval cells differentiate into hepatocytes during liver regeneration and α-cells transdifferentiate into β-cells during pancreas regeneration. However neither can be fully exploited until the molecular mechanisms governing their proliferation and trans/differentiation are fully elucidated. Herein we characterise two in vitro cell models, a mouse adult oval cell line, known as BMOL-TAT1.1, and mouse adult pancreatic α-cell line, known as α-TC19 by RT-PCR and immunofluorescent staining. We found that under proliferating culture conditions BMOL-TAT1.1 were heterogenous consisting of two distinct cell types with different β-catenin signalling pathway activation. Inducible differentiation (dexamethasone) induced hepatic and non-hepatic markers in specific cell subtypes, indicating multi-potentiality. Ectopic expression of transcription factor HNF4α in homogenous small BMOL-TAT1.1 cells revealed no hepatic differentiation but potent expression of intestinal markers (Villin, ALPi, ApoAIV). HNF4α was identified as a candidate transcriptional regulator in α- to β-cell transdifferentiation, as ectopic expression in α-TC19 cells, suppressed glucagon and induced expression of several functionally important β-cell markers (GLUT2, GCK, insulin). The contribution of chromatin histone acetylation was also assessed, due to its importance in endocrine fate regulation. In toto these results have important implications for the development of potential therapies to treat liver diseases and Type 1 diabetes.
|Date of Award||31 Oct 2012|
|Supervisor||David Tosh (Supervisor)|
- oval cells