Engineering Bioactive Hydrogels for Neuronal Differentiation of hESCs
Human embryonic stem cells (hESCs) have strong potential as sources of cells for the treatment for disease and injury (e.g. Parkinson’s Disease, amyotrophic lateral sclerosis, spinal cord injury, diabetes, congestive heart failure, etc.). The successful integration of hESC into such therapies will hinge upon three critical steps: their expansion without differentiation, their differentiation into a specific cell type or collection of cell types, and the promotion of their survival and functional integration at the site of disease or injury. Precisely controlling each of these steps will be essential to maximize hESC’s therapeutic efficacy, as well as to minimize potential side effects that can occur when the cells numbers and types are not properly controlled. However, hESCs are typically grown on murine or human feeder cells, in conditioned media derived from these cells, and/or within complex mixtures of animal or human proteins. Such growth conditions present major problems: there is a possibility of pathogen transmission from feeder cells or proteins, hESCs can acquire non-human antigens that will lead to immune rejection following implantation into a patient, and these growth conditions are difficult to precisely control and reproducibly scale up to a clinical process for the treatment of large patient populations.
To achieve the intended goals of regenerative medicine, methods for the precise control of the proliferation, differentiation, and survival of stem cell populations in cell culture and in the body after cell implantation are necessary. We have made significant progress in developing a novel technology platform consisting of completely synthetic polymer-based synthetic matrices to support hESC proliferation and self-renewal. We now propose to create synthetic microenvironments to support hESC differentiation into two important neuronal lineages: dopaminergic neurons with potential for Parkinson’s Disease therapy and motor neurons with potential for Lou Gehrig’s Disease. Previous protocols have been developed for controlled differentiation into these lineages; however, they have typically involved culture conditions with animal and human proteins and ECM. Furthermore, after implantation into the site of injury or disease, the majority of neurons typically die. We hypothesize that implanting neurons differentiated from hESCs along with a supporting, bioactive matrix will enhance cell survival and therefore future efforts to utilize grafts for tissue engineering and repair.
The result will be a technology platform that can be generally applied to numerous stem cell populations and used to investigate the basic biological/developmental mechanisms underlying cell differentiation. Therefore, this novel integration of stem cell biology, neurobiology, bioengineering, and materials science has the potential to overcome a major challenge in regenerative medicine.
Stem cell research in general, and this proposed research in particular, have great potential for enhancing the scientific and economic development of the state of California.
First, this project is highly integrative in that it melds expertise and investigators from a number of scientific fields including tissue engineering, materials science, chemical engineering, stem cell biology, neurobiology, electrophysiology, and genomics. It therefore represents a model project for the development of interdisciplinary research teams, since success in research increasingly relies upon taking the initiative to draw from numerous fields of science and engineering. Furthermore, this project will represent a highly valuable and unique interdisciplinary training environment. Two trainees will be able to draw from leading scientific expertise in five research groups in five departments and two institutes to make progress in this high impact work. Finally, the collaborative expertise that this group develops as a result of this funding will be in place to continue this and other research areas, with the aid of numerous additional trainees, in the future.
In addition, the field of stem cells represents a unique economic opportunity for the state of California. Both Northern and Southern California are dominant areas for biotechnology research and companies. We anticipate that the products of this research will be of interest to numerous sectors of biotech, not only for its potential in neuronal differentiation but in its generality for both embryonic and adult stem cell culture and differentiation into numerous lineages. First, the use of stem cells for in vitro pharmacology and toxicology screening will rely upon the development of scaleable and reproducible systems for stem cell expansion and differentiation, which this work can provide. Second, research product companies may be interested in providing reproducible, synthetic culture systems for stem cell experimentalists. Finally, this work potentially has its largest promise in the development of scaleable systems to support stem cell differentiation in vitro and cell transplantation in vivo for therapeutic application in tissue engineering and repair.