Directing migration of human stem cells with electric fields
Great progress has been made in the last decades to derive many types of human stem cells for potential therapeutic uses. However, practical clinical use is severely limited by several challenges. One of which is the poor homing and integration of transplanted cells with the targeted host tissues - only very few transplanted stem cells integrate structurally and functionally to the damaged or diseased tissues.
We recently demonstrated that at wounds and damaged tissue sites there are naturally occurring electric fields, which may send a signal to guide cell migration. Excitingly, applied EFs guide migration and division of murine embryonic stem cells(mESCs) and nerve stem cells (mNSCs). We hypothesize that EFs are an effective signal to direct migration of human embryonic stem cells (hESCs), and nerve stem cells (hNSCs) to, as well as engagement and interaction with, sites of tissue damage.
In this proposal, we will establish EFs as a novel signalling mechanisms to guide human stem cells homing and integration. We will optimize electric stimulations to direct migration of hESCs and hNSCs. We will combine the electric stimulation with other treatment to establish a potent and novel mechanism to direct the migration of beneficial human stem cells toward the injury sites to repair and to regenerate.
This visionary endeavor of CIRM to develop stem cell therapies leads the nation and has been galvanizing stem cell researchers to California. This represents the leading role of California at the forefront of biomedical research. Joining this exciting program, we are poised to overcome one of the big hurdles in stem cell therapy - to guide stem cells to damaged and diseased tissues to repair and regenerate. Homing and integration of stem cells to the targeted tissues are critical steps in stem cell therapy. Many types of stem cell therapies have very poor results because of poor homing and integration of transplanted stem cells with the local damaged tissues.
Exploring signals to control cell migration and other behaviors, we have been developing a novel and potentially powerful signal – electric fields for better homing and integration. We propose to understand the electrical control of homing integration of stem cells. If successful, new techniques derived from this project will help to break one of the road locks in stem cell therapies. This grant proposal falls under the mission statement of the CIRM for funding innovative research to achieve effective stem cell therapies. We aim to generate innovative and effective techniques to guide migration of human stem cells. The concept and approach will benefit many types of stem cell therapies.
Techniques developed from this project are expected to significantly increase the efficiency of stem cell to integrate with the host tissues, therefore facilitate restoration of structure and function. If successful, this technique will lead to reduction in the medical and economic burden of large numbers of patients who need stem cell therapies, therefore contribute significantly to CIRM’s mission.
We aim to develop new techniques to guide human stem cells to repair diseased or damaged tissues. In the past year, we have successfully developed new techniques and are able to guide human embryonic stem cells, ips cells and progenies to migrate and integrate with host tissues.
We aim to guide human stem cells to repair diseased or damaged tissues. In the past year, we have developed new techniques to guide neuronal stem cells to migrate in vitro, and a proprietorial technique to apply electrical cues in animal. This forms a strong basis that in the third year, we are ready to prepare to move to the next stage - to translate the results from this basic biology grant to a novel technique to possible clinical use.
The aim of this project is to develop technology to stimulate and guide human neural stem cells to repair and regenerate damaged tissues. The CIRM grant provided support that move both the science and technology forward and closer to clinical use.
Specifically, we have for the first time 1) demonstrated effectiveness of using electric stimulation to enhance migration of human stem cells to migrate directionally; 2) developed new techniques to stimulate cells in 3D and in vivo; 3) demonstrated synergistic effects of chemical guidance and electric stimulation on human stem cells.
We have successfully completed all the original proposed goals for year 3. Specific Aims that have been completed are: Aim 1B (Direct hNSCs in 2D), Aim 2A (Purinergic signaling), Aim 2B (Ca++ signaling). Aim 3A (Direct SCs in 3D), and Aim 3B (Transplant SCs in vivo and direct migration of SCs) are fully started as planned, with major part of 3A finished.
Our original hypothesis is that EFs are a powerful signal to direct migration of human embryonic stem cells (hESCs) and human nerve stem cells (hNSCs) through purinergic signaling. Three specific Aims with the following time scales were set in the proposal: Aim 1. To guide migration of hESCs and hNSCs. Aim 2. To elucidate purinergic receptor/Ca2+ signaling in EF-directed stem cell migration. Aim 3. To direct migration of hESCs and hNSCs in 3D. We have finished all proposed research and are writing up for publication.
This is report on a no cost extension of six month.
We have successfully conducted the experiments proposed and published 6 papers. We would like to request 1 year no-cost extension of the CIRM grant for the following reasons.
We have extend beyond the original proposal and carried out some in vivo experiments. We have
1. Established stable human neural stem cell (hNSC) lines that stably expressing GFP for in vivo transplantation and tracking.
2. Confirmed the electrotaxis response of those transduced cells;
3. Developed proprietary techniques for stimulating and guiding transplanted cells in the brain;
4. Manufactured prototype of stimulator for in vivo use;
5. Successfully guided transplanted hNSCs in live rat brain.
We are currently analyzing those exciting data and are preparing manuscripts for high impact publication. We are preparing for early translational work. This will need to maintain active fund for use for analysis, publication purpose. We will be grateful if the CIRM grants this no-cost extension request. We have submitted three grant applications during this period of time and have published two important papers in high impact journals - one in EMBO Reports and one in Current Biology. Both papers have attracted media interview and commentary of experts.
The EMBO Reports paper proposes for the first time the existence of endogenous electric fields in the brain, which may guide migration of neural stem cells. This is a completely new mechanism no one proposed before and we have proved strong experimental evidences.
The Current Biology paper dissected the mechanisms of how cells sense and respond to a small electric fields.
We have submitted a patent application during this period of time.
- EMBO Rep (2013) Endogenous electric currents might guide rostral migration of neuroblasts. (PubMed: 23328740)
- Curr Biol (2013) Keratocyte Fragments and Cells Utilize Competing Pathways to Move in Opposite Directions in an Electric Field. (PubMed: 23541726)
- Stem Cell Res (2012) Directing migration of endothelial progenitor cells with applied DC electric fields. (PubMed: 22099019)
- J Vis Exp (2012) Electric field-controlled directed migration of neural progenitor cells in 2D and 3D environments. (PubMed: 22370927)
- Cell Mol Life Sci (2012) E-cadherin plays an essential role in collective directional migration of large epithelial sheets. (PubMed: 22410739)
- Prog Retin Eye Res (2012) Electrical signaling in control of ocular cell behaviors. (PubMed: 22020127)
- Stem Cell Rev (2011) Electrically guiding migration of human induced pluripotent stem cells. (PubMed: 21373881)
- Exp Neurol (2011) PI3K mediated electrotaxis of embryonic and adult neural progenitor cells in the presence of growth factors. (PubMed: 21092738)
- J Vis Exp (2011) Measurement of bioelectric current with a vibrating probe. (PubMed: 21248695)
- Stem Cells (2011) Guided Migration of Neural Stem Cells Derived from Human Embryonic Stem Cells by an Electric Field. (PubMed: 22076946)
- J Neurosci Res (2010) A time-lapse and quantitative modelling analysis of neural stem cell motion in the absence of directional cues and in electric fields. (PubMed: 20890991)