Regulatory network control of neural stem cells for endogenous repair
Project PI: Gary Bader
Donnelly Centre for Cellular and Biomolecular Research and Department of Molecular Genetics and Department of Computer Science, University of Toronto
Co-PIs: Freda Miller, David Kaplan, Derek van der Kooy, Michael Moran, Aaron Wheeler, Cindi Morshead, Quaid Morris, Michael Hoffman, Lincoln Stein, Sidhartha Goyal, Trevor Pugh, Michael Wilson
Project Description: The brain is built from many different types of cells and their interconnections, forming an amazingly complex “computer” that controls all aspects of our lives. Better understanding the development of this complex system will lead to improved treatments of nervous system injuries, such as stroke, and neurodevelopmental disorders, such as cerebral palsy. These treatments will have important benefits to Canada, and internationally, in terms of improved quality of life for patients and reduced health-care costs for society. All cells in the brain originate from stem cells, which also maintain and repair brain tissue in adulthood. This project proposes a transformative approach to discovering the circuits that control brain tissue growth that will provide new insights into normal and pathological development and aging, help develop drugs that activate stem cells for tissue repair, and enable the growth of pure populations of specific cell types potentially useful for replacing damaged tissue. This project will measure millions of data points about gene expression in these cells and computationally mine this data to identify cell states, state transitions and critical points that will be targeted with the aim of controlling stem cell fate for therapeutic use.
Pathways to enhance the clinical utility of hematopoietic stem cell transplantation
Project PI: John Dick
Princess Margaret Cancer Centre, University Health Network
Department of Molecular Genetics, University of Toronto
Co-PIs: Norman Iscove, Mathieu Lupien, Gary Bader, Quaid Morris, Igor Jurisica, Shana Kelley
Project Description: Worldwide, 50,000 hematopoietic stem cell transplant (HSCT) procedures are undertaken annually to replace a person’s blood-forming cells — hematopoietic stem cells (HSCs) — to treat blood disorders and cancers, yet two-thirds of patients who need HSCT lack matched donor tissue. If more donors where available and the efficacy and safety of HSCT improved, HSCT could benefit more patients with blood diseases. Cord blood (CB) biobanking is being developed worldwide to increase the probability of finding matched donor HSC. However, HSC number in CB is usually limiting and methods for large-scale expansion remain to be developed. In addition to limiting HSC numbers, HSCT is inefficient, as many HSC do not get to the relevant areas in the body and/or die following transplantation. This project will generate methods to increase HSC number and/or overcome transplant inefficiencies from adult and CB sources. It will combine functional data with bioinformatics analyses to identify regulators of stemness and HSC survival pathways and then use this information to develop therapeutic targets for preclinical testing. It will also prioritize up to five candidates for the translational pipeline, with one candidate ready to move forward. With the Centre for Commercialization of Regenerative Medicine (CCRM), this project will test top candidates for batch-fed pre-clinical HSC expansion. With CCRM and UHN Technology Development and Commercialization assistance, potential licensees for this innovation have been identified and the formation of a company will be explored. The model selected will depend on the patent portfolio developed at study completion.
Modelling functional hepatocytes and liver tissue from pluripotent stem cells
Project PI: Gordon Keller
McEwen Centre for Regenerative Medicine and Princess Margaret Cancer Centre, University Health Network
Department of Medical Biophysics, University of Toronto
Co-PIs: Ian McGilvray, Molly Shoichet, Axel Guenther, Christine Bear
Projects Description: The goal of this project is to generate functional liver cells and engineered liver tissues from human pluripotent stem cells (hPSCs) to 1) study human liver disease, 2) test new therapeutic approaches to treat liver disease, and 3) assess new drugs in a predictable and reproducible manner. To achieve this goal, five principal investigators with complementary expertise have been brought together. The Keller lab, leaders in stem cell biology, will derive the complete spectrum of cell types found in the human liver from hPSCs. The McGilvray lab has access to high quality primary human tissue from livers used for transplantation at the Toronto General Hospital. They will isolate and characterize primary liver cell populations, compare them to hPSC-derived cells, and use this information to predict which cells are best for transplant. The Shoichet lab, with their expertise in materials chemistry and tissue engineering, will use these cells to engineer 3D tissues in hydrogels that have been designed to mimic critical aspects of the liver environment. As a complementary engineering approach, the Guenther lab will use these cells to 3D print tissue constructs designed to imitate the liver bile ducts. These ducts can be used to recapitulate cystic fibrosis (CF), allowing the Bear lab to test emerging CF therapies. Finally, these engineered cells and tissues will be evaluated for their ability to rescue liver failure in mice. Collectively, this project aims to determine the most effective new therapies to treat Canadians with liver disease.
Improving the function, integration and safety of stem cell-derived cardiomyocyte transplantation
Project PI: Michael Laflamme
Toronto General Research Institute, University Health Network
Department of Laboratory Medicine and Pathobiology, University of Toronto
Co-PIs: Gordon Keller, Hai-Ling Margaret Cheng, Andras Nagy
Project Description: Heart disease remains the leading cause of death in Canada and worldwide. After a heart attack (also known as myocardial infarction, or an MI), the heart muscle lost is replaced by non-contractile scar tissue, often initiating progressive heart failure. Current options for treating post-MI heart failure are limited, and this remains a disease with high morbidity, mortality and societal costs. The ability to “remuscularize” the injured heart by transplanting cardiomyocytes (heart muscle cells) derived from human embryonic stem cells (hESCs) represents a potentially revolutionary new therapy for patients suffering from this disease. In past work, this team has developed efficient methods for generating large quantities of human embryonic stem cell-derived cardiomyocytes (hESC-CMs), and shown that the transplantation of these cells mediates beneficial effects on contractile function in models of post-MI heart failure. This project is aimed at overcoming critical remaining barriers to the successful development of hESC-based cardiac therapies. First, the team will develop improved populations of hESC-CMs that have the appropriate functional properties for cardiac repair. Second, to address important safety concerns, it will engineer hESC-CMs to reduce the risk of both graft cell-related arrhythmias and tumour formation. Third, it will develop novel imaging methods to non-invasively track the size and location of hESC-CM graft cells in vivo. The successful completion of this work will bring closer the goal of a Canada-based, first-in-humans clinical trial with hESC-CMs in post-MI heart failure.
Synthetic biology approaches to regenerative medicine in the human intestine
Project PI: David McMillen
Department of Chemical and Physical Sciences, University of Toronto Mississauga
Co-PIs: Keith Pardee, Radhakrishnan Mahadevan, Dana Philpott, Tae-Hee Kim, John Parkinson
Project Description: Inflammatory bowel diseases (IBDs) affect 1 in 200 people in Ontario, and while various factors have been identified, the ultimate cause of these diseases is currently unknown. One major contributor has been identified, however: a defect in a particular protein that affects the gut lining’s ability to renew itself properly. This protein is stimulated by molecules that come from the bacteria living in the intestines (the “gut microbiome”), and the details of that connection have only recently been discovered (by a member of our team). The plan for this project is to create a new probiotic bacterium that can sense the level of these molecules and produce more of them when needed, providing extra stimulation to the cells in the gut lining and helping improve or cure the disease for people whose protein detectors need more of the stimulatory molecule in order to respond properly. This team combines expertise in synthetic biology, biological engineering, gut stem cell research, and advanced genetic analysis to address the challenges of designing this brand-new approach to IBD therapy. The gut microbiome is emerging as a key player in a wide range of human health issues, including bowel diseases but extending to metabolic, immunological and even neural diseases. The overall goal is to establish ways of systematically sensing and manipulating the environment inside the intestine, laying the groundwork for a wide range of bacteria-mediated therapies that improve human health by the repairing the conditions in the intestine.
Preparing the ground for endogenous repair
Project PI: Michael Sefton
Department of Chemical Engineering and Applied Chemistry, University of Toronto
Co-PIs: Penney Gilbert, Alison McGuigan, Clint Robbins, Philip Marsden, Christoph Licht
Project Description: Skeletal muscle loss caused by surgery, trauma or increased pressure within a limb (compartment syndrome) results in loss in function. As an alternative to tissue grafting, which is limited by graft availability and immunological issues, we propose to use a synthetic, regeneration-inducing biomaterial scaffold (without cells) to “prepare the ground” for endogenous repair by the resident stem cells, known as satellite cells (SC). In order to mobilize and direct SC-mediated endogenous repair with purpose-built biomaterials (“biomaterials by design”), this project will build a comprehensive view of SC interactions with their surroundings (the “niche”) and how the niche, modulated by custom designed biomaterials, affects, if not also controls, the life cycle of SC and their progeny. It will focus on the intimate relationship between the muscles, the blood vessels and the innate inflammatory response that provide instructive cues to guide tissue regeneration. Poor revascularization and acute inflammation are features of critical-sized tissue defects from traumatic insult. This team will aim to convert this degenerative niche into a regenerative niche, primarily with a new suite of biomaterials, such as one that promotes vascularization or one that targets a particular cell pathway to activate and restore the endogenous repair process in situ for a wide range of muscle conditions. Designing biomaterials to modify specific aspects of the muscle “niche” to support and synergize with innate repair mechanisms will be a unique and effective off-the-shelf regenerative medicine solution. This collaborative effort will address a global unmet clinical need to restore tissue integrity and strength following skeletal muscle trauma.
Overcoming blindness: Differentiation, purification and transplantation of photoreceptors
Project PI: Molly Shoichet
Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, Department of Chemistry & Institute of Medical Science, University of Toronto
Co-PIs: Derek van der Kooy, Gary Bader, Shana Kelley, Ted Sargent, Valerie Wallace, Robert Devenyi
Project Description: Age-related macular degeneration (AMD) is one of the leading causes of blindness in developed countries. AMD is characterized by the degeneration of cone photoreceptors in the retina, the cells responsible for central pattern (e.g. reading) and colour vision. This degeneration is due to pathological changes in the cone photoreceptors themselves, the retinal pigment epithelial (RPE) cells, and/or the rod photoreceptors. Current therapies for AMD are effective in slowing degeneration and the onset of blindness, but cannot restore lost vision. The goal of this project is to use cell therapy to restore vision loss in AMD patients. The team proposes that cone transplantation, either alone or in combination with rods and/or RPE cells, will restore central vision, and proposes to study this first in mice and ultimately in patients with AMD. To achieve this goal, a team of clinical and basic researchers has been assembled with the expertise required for success. This internationally renowned team brings their expertise to achieve success in rod and cone photoreceptor derivation, computational biology, cell purification, bioengineering, rodent models of disease and the clinic. The team will develop procedures for the efficient identification of rod and cone photoreceptor specific progenitors from stem cells and their differentiation and purification into human rod and cone photoreceptors. Simultaneously, it will determine the optimal conditions for cone engraftment into blind hosts and measure visual improvement in rodents. Ultimately, it will require a vitreous substitute that will improve retinal re-attachment after transplant surgery and thus will pursue an innovative biomaterial strategy to this end.
Cells to tissues in 4D: Understanding how single cell behaviour drives tissue generation, degeneration and regeneration
Project PI: Jeff Wrana
Lunenfeld-Tanenbaum Research Institute, Sinai Health System
Department of Molecular Genetics, University of Toronto
Co-PIs: Laurence Pelletier, Christopher Yip, Sevan Hopyan, Anna Goldenberg, John Parkinson, Liliana Attisano, Daniel Schramek, Luca Scardovi, Daniel Durocher
Project Description: Research on organ development, their response to injury and their regenerative capacity has historically been studied whole tissue or groups of cells. However, organs require millions of individual cells to act as a collective that is responsible for the unique functions of each organ. Studies at the tissue level provide an exquisite understanding of how organs function, but we know almost nothing about how the activity of individual cells is corralled to support the overall structure and function of organs. Understanding individual cell behaviour is also critical to understanding how regeneration of functional tissue could be stimulated. For example, when the intestinal lining is damaged, individual stem cells get tasked with the job of repairing the tissue. The research in this proposal focuses on illuminating how individual cells are instructed to drive tissue repair. This multidisciplinary team is developing and applying new imaging technologies, gene editing strategies and next-generation sequencing to map individual cell behaviour in a tissue and will be linked to mathematical models that predict how perturbing individual cells might ultimately affect organ function. These discoveries can then be applied to the development of new drugs for the regenerative medicine clinic, for example, by making the growth of human replacement tissues more efficient, or by illuminating how to get replacement tissue to functionally integrate into the recipient organ. This research will also enable the design of therapies aimed at awakening dormant regenerative programs in damaged organs, thereby stimulating our own tissue to repair itself.