Congratulations to the successful applicants in the CIHR Fall 2022 Project Grant competition!
Listed below are the LSI-based PIs on the six funded projects. These include one bridge grant and one Priority Announcement Grant. This amounts to 21.4% of submitted applications receiving funds to a total of $3.77 million from this competition, where overall funding rate was 20% and British Columbia’s success rate was 15.5%.
Role of XIST in human X-chromosome inactivation and health
Female cells are generally XX while male cells are XY. The sex chromosomes (X and Y) were once the same size as each other, but now while the Y has critical functions in spermatogenesis, it has lost most of the genes that it once shared with the X chromosome. Therefore, there is a big imbalance in genes on the X between XX females and XY males. The XIST RNA is expressed from one X, which it then coats and recruits proteins in order to silence this chromosome. We want to understand how XIST does this silencing, and what happens in XX cells when XIST is lost. By putting the human X chromosome into mouse cells we have shown that the DNA must match the cell in order for XIST to coat the chromosome. We will look for the essential proteins and DNA allowing this coating. Separately we will take out pieces of the RNA until we have a smaller RNA that can still function. We have observed that some regions of the mouse RNA are smaller than human, so we are combining human and mouse to make a small functional XIST. In our third part of the work, we are using our knowledge to take away important parts of the RNA to see what happens to XX cells without XIST and test if they are more sensitive to drugs or changes that happen in cancer cells. Overall, these experiments will help us understand how female cells manage the different X chromosome content from male cells and how that management can be disrupted in disease.
Pieter Cullis (NPA, with Brian McVicar as PA)
Newly Optimized LNP Systems for Genetic drugs and Gene therapy in Neurological diseases
Neurological conditions affect millions of Canadians. Unfortunately, such conditions are particularly challenging to treat due to difficulty in accessing the brain and the lack of specialized tools to enable treatments. New tools for manipulation of brain tissues are desperately needed. One approach with enormous potential for enabling novel and potentially life-changing treatments is genetic drugs – the delivery of a genetic sequence encoding one or more biologically active proteins that act to resolve complex diseases processes. Lipid nanoparticles (LNP) are the current best delivery system for genetic cargo, such as mRNA, with an excellent safety profile as evidenced by the billions of administered shots of the COVID-19 mRNA vaccines. Here we propose to develop LNPs for delivery of mRNA into brain tissues. Experiments in our labs have demonstrated that mRNA can be effectively delivered to white matter in the brain after intraventricular delivery. Our objective is to further develop this LNP-mRNA formulation as a platform delivery system for genetic drugs in the brain. For proof-of-concept, we have chosen stroke as a disease indication, and aim to show the function of our system by synthetic expression of a growth factor known to be important for post-stroke recovery. We aim to both develop a platform technology for genetic drug delivery in the brain and demonstrate its functional potential in a relevant disease model.
Propagation of diet-derived immunoregulatory signals across tissues
The old adage “You are what you eat” has been gaining traction in scientific circles as we continue to discover pathways that microbes living within our intestines use to break down the food we eat and produce small compounds (metabolites) that influence the function of our own cells. It is truly remarkable how much has been learned in the last decade, including identification of some previously unknown diet-derived metabolites that appear to prevent or treat disease in mouse models of autoimmunity and inflammation. Here, we propose to build on previous research from our lab showing that a particular type of dietary fiber (guar gum) has a powerful effect on immune cell activation that delays development of a multiple sclerosis (MS)-like autoimmune disease in mice. One of the most remarkable findings of these studies is the discovery that this is not a common feature of other fibers, which suggests that the microbes lining our intestines (the microbiota) are producing a unique suite of metabolites when they feed on guar gum. Our goals are to: identify the breakdown products (ie metabolites) of this dietary fiber, determine the pathways that the identified metabolite(s) alter in immune cell activation, and test whether guar gum itself or the metabolites produced by its digestion can treat MS-like disease in mice. Given that Canada has the highest rate of MS globally, these studies have the potential to affect the well-being of a large number of Canadians who are at risk of developing or are living with MS.
Localized immuno-cloaking organ engineering approach to prevent transplant rejection without immunosuppressants
Organ transplantation is lifesaving therapy. However, its potential is diminished by the rejection. Many thousands of patients are waiting for transplantation and the waiting list is growing day by day. Organs are damaged during their and storage using current protocols, which lead to their poor performance post-transplantation and ultimately leads to rejection. Current treatments for organ protection and rejection are suboptimal; life-long immunosuppressants are required for all transplant patients to prevent the rejection. However, immunosuppressants have major side effects including infection, diabetics and cancer. The root cause of the delayed performance and rejection of the transplanted organs is the initial damage of blood vessel lining during organ procurement and preservation which is exacerbated after transplantation. This damage recruit cells and proteins in our immune system upon transplantation, and causes damage to the organs which cannot be self-repaired. Based on our recent discovery, we hypothesize that rebuilding the immunosuppressive blood vessel lining will prevent such injuries and could prevent organ rejection (both immediate and delayed). Thus, in this project, we will develop a novel organ engineering therapy based on an immunosuppressing cell surface modification. This is anticipated to inhibit the immune damage and thus will prevent organ rejection. In this proposal, we will investigate the therapeutic potential of this technology in large animal models of kidney and lung transplantation. If successful, this new immunomodulation approach will help millions of transplant patients and significantly improve their quality of life. Importantly, the new therapy can be applied during the current clinical organ procurement and preservation protocols thus have significant translational potential. The new approach may minimize or eliminate the use of immunosuppressants, thus increasing the health benefits.
Calvin Roskelley (PA with NPA Kelly McNagny)
Breast Cancer Priority Announcement
Podocalyxin’s role in tumor invasion, metastasis, and immune evasion
We have developed two promising monoclonal antibodies (mAbs) for the treatment of human cancers. These mAbs both target a protein expressed in a subset of highly aggressive tumors in ovarian, breast and pancreatic cancers (among others) called podocalyxin (PODXL). One mAb (PODO83) blocks the invasion and spread of tumors. The other mAb (PODO447) only binds tumors and can be used to target toxins to cancer cells while avoiding harm to normal tissue. We think that the place on the PODXL protein that these mAbs target (domains) have important roles in making tumor cells more aggressive and harder to treat. We propose to use these mAbs to better understand how PODXL promotes aggressive tumor behaviour. Our research will allow us to more effectively apply our mAbs for immunotherapy in patients that do not have other treatment options and also to discover new treatment approaches.
James Johnson (Link coming soon)
Bridge Grant
Beta-cell Na+ channels as therapeutic targets
Our research group established unique methods for simultaneously testing thousands of drugs to identify new chemicals that might be useful for beta-cell protection in diabetes. One of these screens was designed to identify drugs that can protect beta-cells from cytokines that the immune system uses to kill beta-cells in type 1 diabetes. The drugs we tested were specially selected from a library of FDA-approved drugs, meaning that they were already optimized for use in humans. We identified a drug called carbamazepine that reduced beta-cell death in a type 1 diabetes-like context. Carbamazepine is an interesting lead compound because it works by inhibiting a specific type of sodium channels, encoded by the Scn9a gene, but only when they are over-active. This was the first implication of sodium channels in beta-cell death and opened up a whole new area for type 1 diabetes drug discovery. Importantly, pancreatic beta-cells have a unique complement of sodium channels, meaning that this drug and its derivatives are likely to have beta-cell-selective action. We validated our cell culture data by showing that carbamazepine reduces diabetes incidence in the gold standard NOD mouse model. We also determined that carbamazepine can protect human beta-cells. In the proposed studies, we plan to continue this exciting line of investigation towards a new diabetes therapeutic and answer several key questions that arose from our previous studies. First, we must determine how carbamazepine and Scn9a protect the mice from type 1 diabetes. Second, we have to test how carbamazepine and Scn9a affect insulin secretion. Third, we plan to develop and test new analogues of carbamazepine that might have even more favorable properties for a human clinical trial. Collectively, these studies will help us determine whether beta-cell sodium channels are a viable therapeutic target in type 1 diabetes and whether use-dependent blockers related to carbamazepine represent a possible drug treatment for protecting beta-cells in new-onset type 1 diabetes or at-risk individuals.
Chris Overall (Link coming soon)
Bridge Grant
Deciphering inflammation pathways in gum disease
Impact—Our study will help unravel new complexity in inflammation control in human tissues using gingivitis as a model. Our results will identify new drug targets and, in the future, potentially new tests for earlier diagnosis of inflammatory diseases.
Significance—Inflammation is the body’s protective response to infection. Inflammation normally turns off to allow healing. Prolonged inflammation results in diseases, e.g., gingivitis, periodontitis, arthritis and fibrosis. Gingivitis (mild gum inflammation) can progress to severe periodontitis to ultimately cause jaw bone and tooth loss. Periodontal disease is common—in the US, 47% of adults >30 years have gum disease, rising to 70% at >65 years—and is associated with an increased risk of other serious conditions, e.g. diabetes, heart attack and rheumatoid arthritis. Thus, preventing periodontitis reduces the risk of associated diseases. Periodontitis develops slowly, with irreversible damage occurring during active bursts of inflammation. Affected people are often unaware of the disease as it is not yet possible to accurately predict disease fare ups.
Approach—Control of inflammation is complex and known to be fuelled by several proteins. Matrix metalloproteinases (MMPs) are enzymes that cut proteins to alter their functions, thus controlling the start and end of inflammation. With our unique methods that identify cut protein ends, we discovered that many pro-inflammatory proteins are cut by MMPs. Thus, by trimming inflammatory proteins and their regulators, MMPs orchestrate inflammation. We will study how cutting changes the actions of bioactive molecules in gingivitis, e.g., determine if trimming dampens or worsens inflammation and if males and female patients show differences that could influence treatment. We will make tools based on the cut ends to measure intact and cut molecules in healthy vs. inflamed human periodontium and will use these to assess if these cut ends can be used to monitor inflammation.
Christopher Loewen (Link Coming Soon)
Bridge Grant
Systematic characterization of membrane contact sites in budding yeast
Our knowledge of the functions for membrane contact sites within cells is extremely limited yet they are present in all eukaryotic cells, from budding yeast to humans. Hence employing models such as the budding yeast to make breakthrough fundamental discoveries will lead to a better understanding of membrane contact site function in humans and their roles in disease. A major contributing organelle to membrane contact sites is the endoplasmic reticulum, which makes contacts with all other organelles in the cell. Some well characterized contacts are with mitochondria, plasma membrane, lysosomes, peroxisomes, Golgi and endosomes. However, membrane contact sites are not restricted to the endoplasmic reticulum and have been observed between mitochondria and plasma membrane and vacuoles/lysosomes. Main functions ascribed to membrane contact sites so far are in lipid and calcium traffic, cell signaling, and organelle biogenesis/homeostasis. The work proposed in this grant will use yeast to identify new components of membrane contact sites and define their functions and organization in much more detail. This will be through the use of high-resolution microscopy, genetic and biochemical approaches. The importance of membrane contact sites in human disease is also being uncovered through defining proteins with functions at membrane contact sites and include cancer, obesity, diabetes, and neurological diseases. However, many of the disease mechanisms have yet to be defined largely due to a lack of a clear understanding of the physiological functions of MCSs. This work will expand our understanding of these mechanisms.