Development of Blood and Liver Stem Cells from Embryonic Stem Cells

Funding Type: 
SEED Grant
Grant Number: 
ICOC Funds Committed: 
Disease Focus: 
Blood Disorders
Stem Cell Use: 
Embryonic Stem Cell
Public Abstract: 
The aim of this research project is to develop a new supply of transplantable blood and liver cells from embryonic stem cells. These cells would have wide application in treating birth defects, cancer and viral diseases by cellular transplantation. To achieve this goal, efficient methods of generating blood and liver cells from embryonic stem cells must be devised. The approach used in this proposal is to apply knowledge gained from the study of how stem cells normally develop to devise methods that can be used for the production of stem cells for human transplantation. The hypothesis being pursued is that tissue stem cells generated from embryonic stem cells are more similar to fetal stem cells than adult stem cells. The implications, if true, is that knowledge of the growth properties of fetal stem cells can be used to devise the best technology for growing tissue stem cells from embryonic stem cells. This project proposes to determine the best conditions for growing blood and liver stem cells from human embryonic stem cells. Various protein growth agents known to play a role in the early stages of development of blood and liver tissues will be tested. A number of different embryonic stem cell lines will be tested under the best growth conditions for their ability to form blood and liver cells. Understanding the variability in the growth of stem cell lines is important in determining the feasibility of using different cell lines to treat patients. Lastly, another goal is to compare how similar tissue stem-cells grown from embryonic stem cells are to normal blood and liver stem cells. Gene expression and other changes can occur to cells grown outside the body and it is important to understand these differences and if they pose any danger to patients treated with cultured cells.
Statement of Benefit to California: 
This research project is aimed at developing a new supply of blood and liver cells from embryonic stem cells that can be transfused or transplanted into patients for a variety of disorders. Blood diseases such as sickle cell anemia and thalassemia as well as liver diseases caused by viral infection, drugs or inherited disease affect many thousands of Californians. Often, transplanting healthy cells offers treatment or a cure for many of these diseases, but a lack of available or suitable donor tissue prevents such therapy in many cases. Embryonic stem cells offer the hope of generating a sufficient supply of tissues for cellular therapy. To achieve this goal we are studying the factors involved in growing embryonic stem cells and turning them into stem cells that form blood or liver tissues. The successful outcome of this work will offer new hope to many Californians suffering from blood or liver diseases. This will improve lives and save money on long-term health care costs associated with these diseases. Development of the technologies and expertise to bring these novel forms of therapy from the laboratory bench to hospital bedside will also keep California in the forefront of the biotechnology industry, will attract talented scientists and clinicians to California and will create high-paying jobs.
Progress Report: 
  • Our goal has been to improve the microenvironment where human embryonic stem cells (hESC) differentiate in order to generate functional hematopoietic stem/progenitor cells (HS/PC) in culture, with the ultimate goal to use these HS/PCs for the treatment of leukemias and other blood diseases. We have tested various human and mouse stroma lines for their ability to support expansion of multipotential human HS/PCs as well as hematopoietic specification from hESCs. So far mouse mesenchymal stem cells (MSC) have proven to provide the best supportive ability for human hematopoiesis. By combining embryoid body differentiation and co-culture on mouse MSC stroma, we have succesfully generated HS/PCs that phenotypically resemble bona fide human HSCs (CD34+CD38-CD90+CD45+). However, so far their differentiation ability has been biased toward myeloerythroid cells, with poor ability to generate B-cells in culture. Based on microarray data that we obtained from a related project supported by the CIRM New Faculty Award, we have identified molecular programs that are defective in hES derived HS/PCs. Future efforts will be directed in modifying the culture microenvironment as well as the cell intrinsic regulatory machinery in hES derived HS/PCs in order to improve their differentiation and self-renewal potential.
  • Our goal has been to improve the microenvironment where human embryonic stem cells (hESC) differentiate in order to generate functional hematopoietic stem/progenitor cells (HS/PC) in culture, with the ultimate goal to use these HS/PCs for the treatment of leukemias and other blood diseases. We have optimized a two step differentiation protocol that combines embryoid body differentiation and subsequent stroma co-culture to generate HS/PCs that exhibit the same phenotype as HSCs obtained from human hematopoietic tissues (CD34+CD38-CD90+CD45+). However, our findings indicate that the hESC derived HS/PCs have restricted developmental potential as compared to fetal liver or cord blood derived HS/PCs, and they senesce prematurely in culture, and are unable to generate B-cells . Our functional and molecular studies suggest that hES-derived HS/PCs resemble closely lineage-restricted progenitors found early in development in human hematopoietic tissues. Our recent studies have focused on exploring the possibility that another precursor that develops in the embryoid bodies could have lymphoid potential when placed in an appropriate microenvironment. Our preliminary data suggests that development of T-lymphocytes from hESCs in vitro may be feasible. Our future work will continue to focus on generating fully functional HSCs by improving the in vitro microenvironment where HS/PCs develop, and/or programming HSC transcriptional program using inducible lentiviral vectors.

© 2013 California Institute for Regenerative Medicine