Novel Strategies to Generate Large-Scale Cultures of Human Hematopoietic Progenitors

Funding Type: 
Basic Biology II
Grant Number: 
RB2-01585
Investigator: 
ICOC Funds Committed: 
$0
Public Abstract: 
The goal of the proposed study is to generate large numbers of hematopoietic progenitor cells that can be manipulated in order to become red and white blood cells. This is important since large numbers of such blood cells can be provided to patients that suffer from different sets of immune-deficiency disorders. In principle, the gowth of human hematopoietic progenitor cells can be achieved using culture conditions in which human cord blood or embryonic stem cells (hESCs) are differentiated in the presence of the appropriate cytokines and stromal cells. However, the efficiency by which human progenitor cells differentiate from hESCs is currently inefficient at best. Here we propose to develop a novel strategy that would permit the generation of large numbers of progenitors (up to 109) from cord blood or hESCs. To accomplish this objective we would target a critical regulator of early hematopoiesis, named E2A. In previous studies, we have demonstrated that murine E2A-deficient hematopoietic progenitors can be grown indefinitely in culture without significant loss of multipotency. We have recently continued these studies with the ultimate aim to generate long-term cultures of human hematopoietic progenitors. Specifically, we have generated a lentiviral vector carrying Id2, an antagonist of E2A activity. Using this vector we have inactivated the E2A gene in murine hematopoietic progenitors and established a long-term culture of mouse hematopoietic progenitors that can be grown long-term in culture. These progenitors self-renew in vitro and remain pluripotent. In collaboration with {REDACTED} we have initiated studies to generate long-term cultures of human hematopoietic progenitors from human cord blood using the same approach. These studies are now in progress. Here we propose to continue these studies with the ultimate goal of generating long-term cultures of pluripotent hematopoietic progenitors from human embryonic stem cells. We would like to avoid using lentiviruses as a means to suppress E2A activity. To achieve this objective we propose to develop a cell permeable peptide approach, permitting us to inactivate E2A DNA binding activity in a transient manner.
Statement of Benefit to California: 
If successful the proposed study would directly benefit patients that are immune-deficient. These include patients that are infected with the HIV virus, patients that suffer from auto-immune disease or cancer. For example, a prominent subset of white blood cells, named CD4 helper T cells, are critical in modulating the immune response against viral and bacterial pathogens. During HIV infection, the CD4 compartment is selectively reduced, suppressing the activity and response of cytolytic CD8 T cells, needed to abolish cells infected with the virus. Pharmaceutical therapies have been developed but they are not consistently effective and multidrug resistant viral strains are increasingly prevalent. Similarly, it is important to establish large cultures of NK and dendritic cells with the ultimate goal for the treatment of auto-immune disease and malignancy. The efficiency by which human progenitor cells develop into commited lymphoid or myeloid cells is low. Here we propose to develop a novel strategy that would permit the generation of large numbers of human T cell progenitors (up to 109) from both human cord blood and human embryonic stem cells. To accomplish this objective we would target a critical regulator of early hematopoieisis, named E2A. This strategy is unconventional since it would permit the growth and isolation of large numbers of human hematopoietic progenitors, has not been achieved sofar by conventional culture conditions. If successful the approach would enable clinicians to reconstitute the hematopoietic compartments of patients that are immune-deficient, caused either by genetic abnormalities, virus infection or aging.

© 2013 California Institute for Regenerative Medicine