Early Translational IV
$4 221 065
Over 8 million people in the US suffer from peripheral arterial disease (PAD). PAD causes leg pain, ulcers, and gangrene formation due to narrowing of the vessels in the arms and legs. PAD is associated with diseased endothelial cells that occupy the inner lining of blood vessels. Cell therapy approaches to restore blood flow to the leg by generating new vessels is promising. We propose to improve the generation of functional endothelial cells by direct reprogramming using chemical compounds in a safe and efficacious manner. These “induced endothelial cells” (iECs) will be evaluated for their ability to function like native endothelial cells. After optimization of iEC generation, we will develop reproducible scale-up method of the cells using standards that meet the requirements of clinical trials. We anticipate our proposed studies will have tremendous impact on cardiovascular health and regenerative medicine.
Statement of Benefit to California:
Over 8 million people in the US suffer from peripheral arterial disease (PAD). PAD causes leg ischemia due to atherosclerotic occlusive disease, and may cause intermittent claudication, ulceration and gangrene. A feature of PAD is dysfunction or damage to the vascular endothelium, a layer of endothelial cells (ECs) that exerts control over vascular reactivity, remodeling and angiogenesis. Cell-based approaches to restore or regenerate the endothelium so as to enhance the formation of neovessels hold promise for the treatment of PAD. In order to obviate the possibility of teratoma formation associated with pluripotent stem cells, an emerging paradigm is direct reprogramming of somatic cells into induced ECs (iECs) without genetic modification. Therefore, the broad objective of this work is to utilize small molecule-based approaches to develop a highly efficient and reproducible approach to generate iECs with high fidelity to endothelial phenotype and genotype. A high yield, high speed direct reprogramming protocol will enhance the clinical feasibility of an autologous iEC therapy. Accordingly, California will be the main beneficiaries in the treatment of PAD using safe and autologous iECs. Furthermore, this research will stimulate the development of businesses interested in developing iEC therapy for other ischemic diseases, thus providing important economic revenue and resources to California.
The goal of this Development Candidate (DC) proposal is to generate and characterize autologous induced endothelial cells (iEC) to be administered for relief of pain and for limb salvage in patients with Peripheral Arterial Disease (PAD). PAD typically results from atherosclerotic or inflammation-induced obstruction of large arteries supplying the limbs, organs and head and is most commonly manifest in the legs, where it leads to pain, ulcers, and in severe cases, gangrene formation. The applicants propose first to screen for small molecules (or combinations thereof) that efficiently reprogram fibroblasts to iEC, and then to characterize those iECs phenotypically and functionally, both in vitro and in vivo in a PAD disease model. They will then develop methods for scaled up Good Manufacturing Practice-compatible production of the iECs and will perform efficacy studies using cells generated under those conditions. Objective and Milestones - Reviewers considered the milestones to be disproportionately focused on screening and subsequent compound optimization, with insufficient attention afforded to the cells that are the intended product. - The Target Product Profile and milestones are clear and well defined. Rationale and Significance - Reviewers were not convinced that the need for new therapies was as great for PAD as for other diseases, noting that other stem cells have been used clinically and have had some efficacy for PAD. Hence, they did not consider the approach to be transformative. - The proposed mechanism of action of the iEC cells is not clearly articulated, leaving reviewers to question whether that specific cell type is really required for a beneficial effect. Furthermore, reviewers were not sure whether bona fide primary EC can significantly alleviate PAD, calling into question the underlying premise of the proposal. Feasibility and Design - The preliminary data provided were fairly minimal, with only one figure documenting in vivo effects of iEC on peripheral blood flow. Reviewers did not find the evidence that iECs can impact PAD to be compelling. - Reviewers felt that this project was not yet ready for a DC award as there were doubts that all the necessary activities could be achieved within three years. Qualification of the PI (Co-PI, Partner PI, if applicable) and Research Team - The team members are excellent research scientists with relevant expertise in stem cell biology and high throughput screening but relatively little experience with translational research. - The PI has been working in this area for approximately 10 years and intends to build upon successful ongoing research. However, he/she lacks product development experience. Collaborations, Assets, Resources and Environment - The PI has access to the necessary resources including the chemical libraries for the high throughput screening. - The budget of just under $1M for the 3 years seems realistic given the amount of screening necessary for identifying the right conditions for cell treatment. Responsiveness to the RFA - This proposal is responsive to the RFA in that it proposes to carry out direct reprogramming from skin fibroblasts to iEC for treatment of a defined disease indication.