Somatic cell age and memory in the generation of iPS cells

Somatic cell age and memory in the generation of iPS cells

Funding Type: 
New Cell Lines
Grant Number: 
RL1-00669
Award Value: 
$1,307,201
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
Status: 
Closed
Public Abstract: 
Statement of Benefit to California: 
Progress Report: 

Year 1

It is of great interest to derive pluripotent stem cells from non-embryonic cells. In this way, one could potentially model in vitro genetic diseases that afflict patients. In addition, cells derived from patient-specific stem cells would not be rejected upon transplantation back into the patient. A methodology for generating induced pluripotent stem (iPS) cells from adult human cells was reported in 2007, and involves the forced activation of specific genes in the adult cells. A central goal of our proposal is to compare human iPS cells derived from different types of starting cells. This analysis will allow us to determine whether the type or state of the starting cells affects the quality of the resulting iPS cells. In the first year of this grant we have successfully generated and validated 14 different iPS cells from fibroblasts, and have underway experiments aimed at generating iPS cells from other cell types, with promising preliminary results. This progress puts on track to accomplishing the proposed research in the 2nd and 3rd years. Our laboratory also has extensive experience with studies of the basic biology of pluripotent stem cells, and we are making use of that expertise in the proposed work. The proposed research is expected to provide the community of stem cell researchers with new pluripotent stem cells from diverse cell types, and to make important contributions towards the development of safe clinical applications of iPS cells.

Year 2

Adult specialized cells can be converted to pluripotent stem cells by activation of specific genes. This process, called induction of pluripotency, opens exciting novel opportunities in Regenerative Medicine. Our goal is to derive and compare new human induced pluripotent stem (iPS) cell lines, in particular to address the question of whether the type of the starting specialized cell affects the properties of the resulting human iPS cells. Beyond this fundamental biological question, our proposed research is also expected to lead to the generation of a significant number of new human iPS cells that will be made available to the scientific community, thus accelerating the pace of research in this field. We have made significant progress in our proposed goals during the past year. We generated several new human iPS cells fully validated for pluripotency. Importantly, we have generated iPS cells from different human specialized cell types using the same method and have began to compare them at the cellular and molecular level. The results to date already prove to be quite insightful. Relative to human ES cells, all iPS cells analyzed have significant differences in gene activity that represent a “memory” of original differentiated cell. We are beginning to understand how this memory is preserved at the level of the organization of the genome. These results may help optimize methods for derivation and differentiation of human iPS cells. Overall, the progress to date and the planned experiments keep us on track to successfully achieve the goals proposed.

Year 3

Adult specialized cells can be converted to pluripotent stem cells by activation of specific genes. This process, called induction of pluripotency, opens exciting novel opportunities in Regenerative Medicine. Our goal is to derive and compare new human induced pluripotent stem (iPS) cell lines, in particular to address the question of whether the type of the starting specialized cell affects the properties of the resulting human iPS cells. Beyond this fundamental biological question, our proposed research is also expected to lead to the generation of a significant number of new human iPS cells that will be made available to the scientific community, thus accelerating the pace of research in this field. We have made significant progress in our proposed goals during the past year. We generated several new human iPS cells from different human specialized cell types and compared them at the cellular and molecular level. Relative to human ES cells, all iPS cells analyzed have significant differences in gene activity that represent a “memory” of original differentiated cell, and we now have a detailed understanding of how this memory is preserved at the level of the organization of the genome. Specifically, it involves the chemical modification (methylation) of DNA at a set of memory genes. We are studying what the significance of this memory is and how much is present in different types of human iPS cells. These results may help optimize methods for derivation and differentiation of human iPS cells. Overall, the progress to date and the planned experiments keep us on track to successfully achieve the goals proposed.

Year 4

Adult specialized cells can be converted to pluripotent stem cells by activation of specific genes. This process, called induction of pluripotency, opens exciting novel opportunities in Regenerative Medicine. Our goal is to derive and compare new human induced pluripotent stem (iPS) cell lines, in particular to address the question of whether the type of the starting specialized cell affects the properties of the resulting human iPS cells. Beyond this fundamental biological question, our proposed research is also expected to lead to the generation of a significant number of new human iPS cells that will be made available to the scientific community, thus accelerating the pace of research in this field. This no cost extension closes our grant. During this period we made further inroads into the derivation of human pluripotent stem cells, using different methodologies, so as to be in a position of comparing them with regards to somatic cell memory. Therefore, during the course of the grant we have successfully achieved the aims proposed, and gained additional insights into the mechanisms that underlie human cellular reprogramming to pluripotency.

© 2013 California Institute for Regenerative Medicine