Tools and Technologies I
Human pluripotent stem cells have already been shown to be capable of long-term self-renewal in culture and have remarkable potential to develop into many different cell types in the body (known as “pluripotency”). ). Many diseases, such as Parkinson’s disease and juvenile-onset diabetes mellitus, result from the death or dysfunction of just one or a few cell types. The replacement of those cells could offer lifelong treatment. Before the therapeutic potential of hESCs can be realized, obstacles such as the controls of their fate decisions and technical complexity to cultivate these cells must be overcome. This requires improved tools and technologies of manipulating the signaling pathways that govern hESC fate determination. Thus, it is essential to define and control these molecular mechanisms to improve conditions for synchronized hESCs for therapeutical applications. Despite recent identification of the transcriptional regulatory circuitry comprised of Sox-2, Nanog and Oct-4, the intracellular signaling networks that control pluripotency of human embryonic stem cells (hESCs) remains largely undefined. We recently discovered a known drug from a screening of chemical inhibitor collection, which can disrupt hESC pluripotency (Patent was filed). Our results have provided novel insights into the signaling mechanism by which hESCs safeguard pluripotency. To develop this drug as powerful pharmacological tool for hESC differentiation and other stem cells, we need to evaluate it further for its irreversibility of stem cell differentiation-inducing effects and its effects for other approach-derived stem cells, such as inducible pluripotent stem cells(iPS). This discovery has provided us a powerful tool to facilitate synchronized hESC and set the stage for the induction and study of directed hESC differentiation in vivo and in vitro. Safety and immune compatibility are two critical considerations in the development of any clinical product derived from hES cells in clinics. iPS approach offers same genetic background as patients. We therefore propose to characterize the activities of this drug for its irreversibility of pluripotency blockage, its disruption of teratomas in animal implantation of hESCs and its pluripotency blockage effects in iPS. Due to small molecule properties, this drug can penetrate all hESC cells to disrupt its pluripotency in a synchronized manner, and therefore it can be used as very useful reagent to disrupt hESC teratomas in clinical transplantation therapies, and to provide large scale of synchronized human stem cells from different resources. Because this drug is currently in clinical use, our proposed experiments would allow us to verify this drug as a very useful tool for scientific research community to study signaling pathways for human stem cell pluripotency and assess the therapeutic potential in hESC preclinical models. Our research will provide a critical tool for clinical drug development for stem cell therapies.
Statement of Benefit to California:
Human stem cells (hSCs), initially derived from embryos or recently derived from somatic nuclear transfer and combinatorial gene expression, represent a inexhaustible source of precursor cells to treat degenerative, malignant, or genetic diseases, or injury due to inflammation, infection, and trauma. This pluripotent cell has been hailed as a possible means for treating Parkinson’s disease, Alzheimer’s, diabetes, spinal cord injury, heart failure, and bone marrow failure. Meanwhile, hSCs are an invaluable research tool to study human development, both normal and abnormal, and can serve as a platform to develop and test new drugs. The drug that can disrupt pluripotency of human stem cells will unlock whole new techniques for working with these valuable but sophisticated resources. The proposed project, when successful and scaled up, eventually will serve to disrupt pluripotency of a variety of stem cell types as used in many downstream medical, biotechnology and pharmaceutical projects. A ready source of conveniently available stem cells of all types, in turn, will act as a catalyst for new fundamental discoveries in stem cell biology, and will provide enabling reagents for many future products and methods. These discoveries, products, and methods will improve the tax base, create many new jobs, and save billions in healthcare costs in California. Product resulting from this project will lead to a quick development of powerful scientific tool and drug for stem research and clinic application for stem cell therapy. Improved function in patients afflicted with these diseases will greatly promote the public health and result in tremendous savings to California in healthcare costs, particularly in the areas of long-term care. Federal constraints on stem cell research create a critical need for non-federal funds to achieve these goals. Funding by the California Institute for Regenerative Medicine improve California’s stem cell infrastructure and speed the translation of basic university research into medical products that change lives in the nearly future. Stem cell technology is currently a very strong research area where rapid advances are possible and the research in developing new products and unlocking basic understanding of how human cells function is of very high value. California has initiated the largest efforts in stem cell research in the world. Therefore, California is viewed as a world leader in stem cell research, biotechnology and pharmaceutical research and development, and the advances in the field made here will contribute to the California’s leading position in these fields immediately.
This proposal focuses on the evaluation of a known drug as a pharmacological tool for controlling stem cell pluripotency and preventing teratoma formation. The Principal Investigator (PI) presents preliminary data demonstrating that this drug induces human embryonic stem cell (hESC) differentiation towards mesoderm and endoderm fates, and reduces expression of markers of pluripotency (Oct-4, Sox-2 and Nanog). The PI proposes to further characterize the effects of this drug on both hESC and induced pluripotent stem cells (iPSCs) and determine its effects in an in vivo model to assess the drug’s possible clinical utility. Overall, the reviewers found this proposal to be too narrow in focus, which would limit its potential impact on the field. Preliminary data was supportive of the effects of this drug on hESCs but one reviewer noted that this effect may also be seen with many other compounds including currently used chemotherapy agents, which are also approved for clinical use. Reviewers also expressed concern about the PI’s lack of experience with iPSCs and therefore the feasibility of experiments proposed with these cells. While the reviewers noted the presence of qualified collaborators, they still weren’t convinced of the project’s overall feasibility given the minimal contribution by these out-of-state collaborators. The reviewers agreed that the goals of this proposal are important ones but felt that the chosen approach could only provide incremental gains. If successful, the project would identify the drug as a tool for enhancing the differentiation of hESCs and iPSCs and reducing the possibility of teratoma formation following transplantation. But one reviewer doubted that such a simple treatment would be able to control a biological process as complex as teratoma formation to the level required for safe clinical use. The reviewers found the specific aims to be logically organized. The first aim of the proposal was found to be mostly feasible but doubts were raised about the second. The second aim requires the generation of iPSCs de novo, an area in which the applicants have no demonstrated experience. The reviewers found the preliminary data compelling but one reviewer noted that it wasn’t clear whether the data were generated by the PI’s lab or by the collaborator who made the initial observation. One reviewer felt that the proposed experiments should generate unambiguous conclusions but also noted that it lacks clear milestones for assessing success. A reviewer also noted that the investigators propose to follow well-established protocols from murine immune regulation studies for in vivo use of the drug under study. But this reviewer cautioned that the optimal dosing regimens for regulation of hESC and iPSC differentiation in vivo may be quite different from those in immune regulation studies and should be explored carefully. The reviewers raised concerns about the PI’s lack of experience working with stem cells but otherwise s/he was qualified to carry out the proposed studies. They noted the inclusion of two collaborators to help overcome this limitation but noted that both are out-of state. The reviewers had mixed responses to the budget. One reviewer found it appropriate and modest while another found it excessive given the scope of the proposed experiments. Overall, the reviewers found the proposal to be too narrowly focused and the approach to be limited in its usefulness. The proposal is an extension of an observation made by a collaborator but reviewers felt that the substance of the proposal was not significant enough to merit funding.