Formation of Personalized Embryonic Stem-Like Cells by In Vitro Epigenetic Cell Reprogramming
Embryonic stem (ES) cells have great promise for treating many human diseases and it is believed that this cell therapy someday will revolutionize medicine. However, the rejection of the introduced ES cells by the patient’s immune system is a big challenge lying ahead when applying the currently available human ES cell lines to clinical trials. The recent breakthrough of creating human embryonic stem cells (ESCs) from human embryos by therapeutic cloning has offered a resolution and highlights the possibility of making so called “autologous” cell lines specific to individual patients. However, this technique is not without problems because the successful rate of cloning is extremely low. Furthermore, the technical difficulties make it hard to be broadly employed in common research and clinical facilities.
We thus propose to develop a simple and efficient method to replace therapeutic cloning in creating personalized stem cells. We will achieve this goal by using a two-step “cell reprogramming” procedure. Specifically, cells are collected from the skin of the patient and are converted into embryonic stem-like (ESL) cells using defined ES factors, which will induce a complete cell reprogramming in skin cells by activating a panel of ES-specific genes and silence genes specifically expressed in skin cells. These ESL cells have the same features as ES cells and are capable of self-renewing and differentiating into all the adult cell types for clinical cell therapy. Most importantly, they are stem cells derived from the patient and will not cause any side-effects related to immune rejection by the patient’s defense system. As a result, these patient-derived stem cells may function better when implanted in diseased organs in cell therapy than currently available ES cell lines that are cloned from early embryos. Thus, there is every reason to hope that this revolutionary new approach will result in radically improved ways to create human stem cells for treatment of disease.
This project proposes to develop an efficient cell rejuvenating method to create patient-specific pluripotent cells used in cell regeneration therapy. We believe this project will make the following contributions to the stem cell research for the state of California.
1. The project will provide a simple and useful complement, rather than human therapeutic cloning, to reprogram somatic nuclei in creating customized stem cells. This approach is cost-effective and time-saving, and it may eventually lead to an alternative approach for creating genetically tailored human embryonic stem (ES) cell lines for use in stem cell research and treatment of human diseases.
2. These pluripotent cell lines are patient-specific and are unlikely to be rejected by the patient’s immune system when transplanted into the body. Thus, they may be much safer than ES cells that are derived the embryo when applied to clinical cell therapy.
3. Identification and characterization of reprogramming factors in ES cell extracts will benefit biomedical and genetic studies aimed at understanding how to reprogram differentiated cells to an embryonic state and thereby increase their developmental potential.
4. With this powerful in vitro cell reprogramming technique, it is highly possible to create a stem cell bank in California that holds thousands of ES cell Lines with varied HLA types. These stem cell lines will be immediately available for basic research and clinical studies.