Genomic neighborhoods and inherited disease: the case for SIOD

While completing medical training in clinical genetics, Dr. Cornelius Boerkoel was consulted on two patients with a rare disease called Schimke immuno-osseous dysplasia (SIOD). At the time, there was little known about the disease, other than that it involved kidney failure and abnormal bone growth causing short height. Dr. Boerkoel’s early research in this area highlighted several previously unknown features of this disease, including the cause of SIOD: mutations (alterations) in both copies of a gene named SMARCAL1. He has also shown that SIOD arises from abnormal activity across most genes. Working with fly and mouse models that he developed to study SIOD, Dr. Boerkoel has created a model for studying how many small alterations in gene expression can cause disease.

Since common diseases such as atherosclerosis, stroke, endocrine dysfunction, immunodeficiency, and poor growth are all features of SIOD, this research is relevant to a better understanding of various unstudied mechanisms underlying these common diseases in the general population. To continue this work, Dr. Boerkoel will complete characterization of the function of SMARCAL1 using biochemical, fruit fly and mouse studies. He will test whether hormone supplementation might be an effective treatment for SIOD. Dr. Boerkoel will also determine whether the gene expression changes observed in SIOD are a feature in other patient populations affected with diseases also found in SIOD. This research will develop a new and unique model for understanding how changes in gene expression can predispose individuals to disease.

Stimulation of Brain Activity and Recovery of Function after Stroke

Stroke is the third leading cause of death and the most common cause of adult disability in Canada and worldwide. Nearly half of all people with stroke do not have full use of their arms for daily tasks and seek rehabilitation to help restore their function. Recent discoveries have targeted effective treatments for individuals who are still able to move their wrist and fingers after stroke, but there are currently few therapies for individuals with poorer hand movement ability.

Dr. Lara Boyd is exploring whether learning and recovery of function can be enhanced by pairing direct stimulation of the brain with practice of a new motor task. Her research focuses on two areas: testing whether exciting the brain using transcranial magnetic stimulation (TMS) before practicing a new motor skill will promote faster learning and recovery of former motor function; and determining the effect of stroke severity on motor learning. Boyd expects that pairing brain stimulation and practice will help people with stroke learn new motor skills faster and more effectively than when brain stimulation is not delivered. This research may lead to new therapies to help people with stroke return to their regular activities of daily life. Brain stimulation using TMS may specifically offer an effective treatment for people with poor hand and arm function after stroke.

Partnership for Ongoing Impact Assessment of Academic Detailing

The Canadian Academic Detailing collaboration (CADC) includes academic detailing (AD) programs that routinely reach over 1,000 physicians in six provinces. They deliver evidence-based, independent information on optimal prescribing practices to physicians through one-on-one or small group visits. As the health system continues to face drug safety controversies and escalating costs of chronic disease, AD holds promise for providing physicians timely access to information and tools for better prescribing and case management. While there is evidence of AD effectiveness in special research projects, rigorous evidence is lacking of real-world impacts of ongoing AD programs.

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OGC as a link between mitochondrial function, aging and diabetes

Marco Gallo is using Caenorhabditis elegans (a small worm) as a model organism to determine how mitochondrial 2-oxoglutarate carrier (OGC) affects aging and insulin signalling. He is studying how this protein interacts with the insulin pathway, and how it affects the development and function of mitochondria, which serve as the cell’s energy source. The proposed mechanism by which OGC is involved in the occurrence of diabetes is by modulating insulin signalling (the cascade of molecular events that result in insulin production). A related version of this protein (B0432.4) is also found in C. elegans. In worms, suppression of this protein resulted in a 20 per cent increase in their average and maximum life-span & in changes in the levels of insulin secretion. Gallo’s research aims to identify the mechanisms that mediate the interaction between OGC and insulin signalling. He is addressing this question with work on C. elegans, mouse & human cell lines. This work could shed more light on the changes that occur in the mitochondria and lead to metabolic diseases, with an emphasis on diabetes.

The role of arachidonic acid metabolism in the pathogenesis of atherosclerosis

Cardiovascular disease, and in particular, the atherosclerotic disorders, are the chief cause of illness, disability and death in many regions of the developed world, where they inflict very high personal, community and health care costs on society. Atherosclerosis, commonly referred to as hardening of the arteries, is an inflammatory disease and is the primary cause of heart attacks, strokes, lower limb loss in diabetics, aneurysms and chronic transplant rejection. Atherosclerosis results in the narrowing of arteries which leads to reduced blood supply, oxygen and nutrients to the affected tissues. Occasionally these plaques can rupture causing a complete blockage of blood supply which can be fatal if it occurs in the heart (eg. heart attack) or brain (eg. stroke). Damage to the inner lining of the blood vessel wall is believed to be the initiating event of this disorder but the mechanism(s) responsible for this injury remain unclear. In the current project, we are interested in how long term use of certain pain relief medications, referred to as anti-inflammatories, contributes to the generation of deleterious oxidative stress which can trigger the onset and progression of atherosclerosis. In recent years there has been much attention given towards this topic as certain pain remedies such as VioxxTM have been pulled off the shelves due to their association with increased cardiovascular events that occur with their chronic use. Based on our previous research, we believe we have identified an oxidative stress pathway that may be induced indirectly as a consequence of the chronic administration of these drugs. We have previously shown that a group of enzymes (CYP2C) can produce reactive oxygen during heart attacks which leads to the abnormal functioning of blood vessels. This dysfunctioning of blood vessels, which is also an early event in atherosclerosis, can be blocked with inhibitors, but it is not known whether CYP2C inhibition prevents atherosclerosis. The current proposal will investigate whether we can prevent atherosclerosis if we inhibit the activation of the CYP2C enzyme. We will also examine whether the administration of certain anti-inflammatories, known to increase cardiovascular events, increase the activity of CYP and reactive oxygen production. Finally, as many people depend on chronic administration of pain relievers such as these, we will investigate the effects of combined administration of CYP2C inhibitors and anti-inflammatory agents towards atherosclerosis pathogenesis. Results from these studies will help us to establish the role CYP2C in atherosclerosis and whether CYP2C inhibitors could be used as pre-emptive treatment for patients identified to be at a high risk for atherosclerotic disease

Integrated microfluidic technologies for optimization of hematopoietic stem cell expansion

Blood contains different types of specialized cells. Red cells are responsible for oxygen transport, white cells ensure body’s defense against infections, and platelets initiate clotting to limit the loss of blood after an injury. These cells are constantly renewed, and are manufactured in the centre of the bones in a sponge-like tissue called bone marrow. Hematopoietic stem cells are a small subset of cells found in bone marrow that have the astounding ability to self-renew and divide, and to differentiate into a variety of mature blood cells. They are often used to treat blood-related diseases or given after cancer treatment. Although stem cells have great potential for regenerative medicine, they are extremely rare and they are difficult to expand in the lab, because they very readily differentiate into other cell types. The multiple factors that influence their self-renewal are poorly understood. Véronique Lecault is exploiting the potential of microfluidic technology, an engineering advance that allows thousands of different experiments to be performed in tandem upon a device the size of a microscope slide. Across rows and rows of miniature cell culture chambers, individual hematopoietic stem cells can each be exposed to different chemical conditions and tracked over time. This makes determining the specific environments that will allow the cells to be expanded much more efficient. This technology could lead to the ability to produce more hematopoietic stem cells for use in disease therapies. It could also help researchers gain a better understanding of stem cell biology, perhaps leading to the discovery of new ways to identify and purify these rare cells.

Structural characterization of Propionibacterium acnes virulence factors

Acne is the most common skin disorder worldwide, affecting approximately 80 per cent of individuals at some point in their lives. How the skin develops this inflammatory condition is not entirely understood, nor is there a cure for severe, persistent cases of acne that often result in permanent scarring. Antibiotics are often prescribed as a first-line treatment, but the most effective antibiotic (Accutane) is known to have serious side effects, including birth defects and depression. In addition, antibiotic resistance is a growing problem. Propionibacterium acnes is present on most people’s skin and is the principal microorganism associated with acne. It can behave as an opportunistic pathogen under certain circumstances, expressing genes that lead to symptoms of acne. The genome of the bacterium has been sequenced and research has shown several genes that can generate enzymes for degrading skin, and proteins that may activate the immune system, leading to the initiation of acne, its development into inflammatory lesions and scarring. Angel Yu is focusing on O-sialoglycoprotein endopeptidase, a skin tissue-degrading enzyme. In order to understand how this protease works and how it recognizes its protein targets, she is growing crystals of the enzyme and using X-ray crystallography to study its structure at the atomic level. She will conduct studies that confirm the enzyme’s biological function and identify associated amino acid residues. Ultimately, Yu hopes her findings will provide insight into the molecular mechanism of this inflammatory skin disorder and identify new leads for the treatment of acne.

CD-based ELISA for point-of-care diagnostics

Current methods of medical diagnostics, such as imaging and laboratory tests, tend to be time-consuming, labour intensive, and often limited to biomedical laboratories or hospital settings that have specialized equipment. In contrast, point-of-care diagnostic tools allow testing and diagnosis to be performed in a doctor’s office, at a significantly reduced cost and in a shorter time to obtain test results. This contributes to faster treatment decisions and better follow-up post treatment. The enzyme-linked immunosorbent assay (ELISA) is a popular tool for analyzing environmental or biomedical samples. The ELISA method uses a number of biochemical steps to detect the presence of a specific protein (such as an antigen or antibody) in a sample on a microscope slide, which is read by a robotic spotter or microplate reader. Preliminary research has suggested that these bioassays could be prepared on the surface of a compact disc (CD), and the results could be read by a standard computer drive equipped with special software. With commercialization, this method would undoubtedly reduce the cost of biomedical screening. Miao-Ling Ou is developing a diagnostic assay for detecting thrombin using this CD technology. Thrombin is a blood clotting factor that is the focus of many research studies on anticoagulation and cardiovascular disease therapy. Once fully developed, this CD-based ELISA method could be extended to other types of biomolecular interactions, such as those used in the screening of gene mutations or antibody-antigen interactions.

Epigenetic mechanisms regulating the acquisition and extinction of conditioned fear: exploring the neurobiology of relapse

A major obstacle in the treatment of fear-related anxiety disorders is their likelihood for relapse. Fear-related behaviour can be inhibited with extinction therapy (repeated exposure to specific fear-inducing cues). This is, however, a temporary fix because fear often returns after exposure to cues associated with the original learning. In the case of post-traumatic stress disorder, fear can also “incubate” or sensitize over time and further exacerbating symptoms of the disorder. These phenomena likely reflect long-term neural adaptation that occurs during learning – changes that may be based on lasting epigenetic modification of genes responsible for maintaining fear memories. Epigenetic modifications influence the way a gene functions without altering the underlying DNA sequence- processes now recognized to participate in the regulation of gene expression in the adult brain. Rapidly emerging evidence suggests that epigenetic mechanisms play an important role in psychiatric disease and in disorders of learning and memory. Dr. Timothy Bredy is employing state-of-the-art technologies to investigate the fundamental epigenetic mechanisms of associative fear memory. He is using a genome-wide approach to examine epigenetic machinery involved in regulating critical gene targets during the acquisition and extinction of conditioned fear. Dr. Bredy hopes his findings will provide insight into the molecular basis of relapse and its prevention and that this research will ultimately contribute to the design of novel pharmacotherapeutic treatment approaches for fear-related anxiety disorders.

Assembly of the type III secretion system in enteropathogenic E. coli and C. rodentium

Pathogenic E. coli bacteria cause severe intestinal infection and diarrhea in humans, leading to millions of cases of infection every year. The virulence of pathogenic E. coli and many other gram-negative bacterial pathogens (a bacteria type characterized by its membrane structure) is determined by the type III secretion systems (TTSS). TTSS are multi-protein macromolecular “machines” that mediate the secretion and translocation of bacterial proteins into the cytoplasm of eukaryotic cells – a key step in causing infection. Most of the 20 unique structural components constituting this secretion system are highly conserved among animal and plant pathogens and are also evolutionarily related to proteins in the flagellar-specific export system, another protein secretion system that has been extensively studied. However, real hard biochemical analysis of TTSS has not been done. Dr. Hendrikje Oldehinkel is investigating how the TTSS is built and how it works. She is dissecting protein to protein interactions and assembly of the type III secretion apparatus in enteropathogenic E.coli and in a mouse pathogen, Citrobacter rodentium. Her work employs a combination of biochemical techniques: electroforesis, immunoblotting, stable isotope labelling, mass spectrometry and electron microscopy. Oldehinkel’s research will contribute to the understanding of the structure of TTSS and the role the components of the type III secretion system play in the architecture and function of the system. Understanding TTSS is important for finding new therapeutic options against not only gram-negative bacterial pathogens, but also against many other disease-causing pathogens.