Molecular dissection of adult liver regeneration to guide the generation of hepatocytes from pluripotent stem cells

Molecular dissection of adult liver regeneration to guide the generation of hepatocytes from pluripotent stem cells

Funding Type: 
New Faculty II
Grant Number: 
RN2-00950
Award Value: 
$2,832,008
Disease Focus: 
Liver Disease
Stem Cell Use: 
Adult Stem Cell
Embryonic Stem Cell
Status: 
Active
Public Abstract: 
Statement of Benefit to California: 
Progress Report: 

Year 1

The overall goal of this project is to establish new strategies for liver regeneration. For this purpose, we aim at identifying molecular mechanisms regulating liver regeneration that could be exploited for therapeutic purposes. Along these lines, we have identified small RNAs that either promote or inhibit the proliferation of hepatocytes, the cells in the liver that provide its manifold functions. We are now working on developing tools to modify the levels of these small RNAs in the liver with the goal to enhance liver regeneration. In addition, we aim at developing hepatocyte replacement strategies for liver diseases that cause irreparable hepatocyte damage. We focus on immune-compatible pluripotent stem cells because they can in principle generate the large numbers of hepatocytes required for therapeutically effective cell therapy and would not require life-long immune suppression. We have established proof-of-principle for the therapeutic efficacy of hepatocytes derived from mouse pluripotent stem cells, and are now working towards recapitulating these results in human cells.

Year 2

In the past year we have made several discoveries that move us closer to our goal to improve the proliferation and function and thus therapeutic efficacy of hepatocytes derived from pluripotent stem cells. Some of these discoveries have elucidated the role of microRNAs, a class of non-coding small RNAs, in liver regeneration and function. For example, we found that miR-21 acts as a promoter of hepatocyte proliferation during liver regeneration. In addition, we identified several other microRNAs that establish differentiated function in hepatocytes. Other discoveries of ours have revealed which type of pluripotent stem cell is best for liver cell therapy that does not require chronic immune suppression. Our results show that induced pluripotent stem cells derived from fibroblasts are as effective in reversing liver failure as normal hepatocytes.

Year 3

In the last year we have made significant progress towards our goal of "Molecular dissection of adult liver regeneration to guide the generation of hepatocytes from pluripotent stem cells". We have identified the mechanism of how microRNA-21 promotes liver regeneration. We are currently working on translating this understanding into a therapeutic strategy for liver failure. We have also gained in-depth insight into the molecular regulation of differentiation of liver progenitor cells into hepatocytes. We have begun to use this insight to direct the differentiation of pluripotent stem cells into hepatocytes that are effective in liver cell therapy.

Year 4

Being able to generate hepatocytes from human pluripotent stem cells would advance many important research efforts, including studies of the pathobiology of liver diseases and the development of liver cell therapies. Unfortunately, realizing this potential has been hampered by shortcomings of human hepatocyte-like cells (HLCs) generated with current in vitro-differentiation protocols, not only as it pertains to replicating the function of primary human hepatocytes, but also their ability to proliferate in vivo. We have made significant progress toward our goal of identifying regulators of hepatocyte differentiation. In addition, we have established the feasibility of liver repopulation of immune-deficient mice with HLCs generated in vitro, thereby proving their ability to mature and proliferate after transplantation

Year 5

We have made significant progress toward our goal of generating in the laboratory human liver cells that are therapeutically effective in mouse models of human liver failure. Because these surrogate human liver cells can be derived from readily accessible cell types like skin cells, they have potential for autologous liver cell therapies requiring nor or little immune suppression. Much of this progress was afforded by insight into mouse liver development and regeneration obtained from the investigations performed under this grant.

© 2013 California Institute for Regenerative Medicine