The role of the CD34 family of Sialomucins in Development and Disease

Dr. Kelly McNagny studies the CD34 family of molecules: CD34, Podocalyxin, and Endoglycan. First identified solely as markers of blood stem cells and blood vessels, McNagny’s research has shown that they are also present on a variety of other cell types in the body. In particular, they are found on cells that play an important role in inflammatory diseases like asthma, allergies, arthritis, multiple sclerosis, intestinal infections and cancer.

Previously supported by MSFHR as a Scholar, McNagny’s current focus is to determine whether these molecules are important in the development or progression of inflammatory disease. Developing mice that lack each of these molecules, then testing their susceptibility to disease, has shown that mice that that lack CD34 are strikingly resistant to asthma, allergies and other lung inflammatory diseases. McNagny has also shown that these mice are more resistant to colon cancer and to bacterial infections.

Inhibiting CD34 expression may be beneficial in preventing or treating these diseases. In studies of Podocalyxin, the second member of this family, it appears that this molecule is essential for normal kidney development and for regulating normal blood pressure. McNagny has also found that this protein is ‘turned on’ in a number of high-risk cancers (those with very poor outcomes). This molecule may be a particularly good diagnostic tool for identifying those high-risk cancers. He will further clarify how these molecules work under normal and disease conditions. The research could lead to new treatments for a variety of conditions and diseases.

Viral host interactions of the Dicistroviridae family

All successful viruses have evolved strategies to infect host cells and disrupt normal cell functions. However, the host can counteract these strategies by using its natural antiviral responses to detect and defend against viruses. Revealing the molecular mechanisms between the battle of the virus and host is vital in the fight against many of today’s viruses. Some viruses use an internal ribosome entry site (IRES) to infect cells. Molecular machines in cells called ribosomes translate genes into proteins, but viruses with an IRES can hijack the ribosome to replicate their viral proteins instead. IRESs are found in a number of human viruses, including polio, hepatitis C, herpes and HIV, but there is limited understanding of how these mechanisms work. Understanding the ways in which a virus hijacks the ribosome function is the focus of Dr. Eric Jan’s laboratory. He uses a unique IRES found in an insect virus called the cricket paralysis virus (CrPV). Jan’s previous work was critical in delineating important CrPV IRES functions. Building on this work, he plans to map the specific IRES elements that interact with the ribosome. He will also determine how CrPV disrupts cellular function that leads to IRES activity in Drosophila (fruit fly) cells, and elucidate the host antiviral response in these cells. The study of Drosophila antiviral responses will contribute to knowledge about fundamental virus-host interactions in humans. The research could lead to new drug targets for inhibiting viral IRESs and therapies that can augment antiviral responses. An exciting future goal will be to exploit viral IRESs to prompt the destruction of virus-infected cells – taking advantage of a viral mechanism against itself.

Development of a screening strategy for community-based adverse drug related events in the emergency department

Adverse Drug Related Events (ADREs) are the most common type of preventable non-surgical adverse event related to medical care, and represent a leading cause of death. Each year, in BC alone, Emergency Departments treat an estimated 130,000 patients for ADREs, most of which are caused by medications prescribed in community settings. Unfortunately, community-based programs aimed at detecting and reducing drug-related problems have not led to a significant decline in morbidity, mortality or health services utilization. Emergency Department practitioners are well situated to play a pivotal role in the timely recognition and treatment of community-based ADREs. Unfortunately, Emergency Physicians currently detect only 50% of ADREs, missing opportunities to intervene.

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Novel characterization of a G-protein coupled receptor, Autocrine Motility Factor Receptor (AMFR): an endoplasmic reticulum-localized E3 ubiquitin ligase

The endoplasmic reticulum is a membrane network within cells involved in the synthesis, modification, and transport of cellular materials. Endoplasmic Reticulum Associated Protein Degradation (ERAD) is a cellular process that identifies unneeded or misfolded proteins of the endoplasmic reticulum and modifies the protein by attaching to it a ubiquitin protein. This ubiquitination process serves to mark the protein for destruction – a key process that helps prevent a range of diseases. Autocrine motility factor receptor (AMFR) is a transmembrane protein expressed on the cell surface and in a smooth subdomain of the endoplasmic reticulum (SER). AMFR has a critical function in the ubiquitination process, binding to the regulatory protein autocrine motility factor (AMF). Overexpression of AMF and AMFR occurs in a number of malignancies and participates in cancer cell migration during cancer progression and metastasis. It has been observed that AMF is secreted by tumour cells and acts as a protein messenger to other cells. However, its mechanisms remain unknown. Maria Abramow-Newerly is determining the signalling pathways used by AFMR following its binding to AMF, working to identify critical proteins and factors that may all tightly regulate AMFR expression and distribution within normal and cancer cell lines. In particular, she is focusing on characterizing AMFR as a G-protein coupled receptor, a family of proteins that serve as important drug targets for a number of diseases. Abramow-Newerly’s studies may contribute to the future design of drugs that specifically target components in the AMFR-signalling pathway to reduce cancer cell migration and metastasis

Development of an Integrated Risk Assessment and Risk Management Tool for Health Care in BC, Phase 1 – assessment of chemical exposure hazards encountered by health care workers in BC

There are more than 80,000 health care providers working in BC. They work in complex and demanding environments where they may be exposed to numerous potential health hazards, including those that are chemical (e.g. drugs or cleaning agents), biological (e.g. bacteria or viruses) and physical (e.g. noise or radiation) in nature. Dr. George Astrakianakis focuses on understanding the many factors that determine the potential for exposure to health hazards among health care workers, and how to best mitigate their associated risks. In the initial phase of his research, he is identifying the specific chemical exposures commonly encountered in the healthcare workplace, assessing the risk to health for healthcare providers, and defining appropriate exposure control measures. In subsequent phases, he will assess biological and physical hazards, and implement and evaluate control strategies. Much of Astrakianakis’ data will be drawn from surveillance information collected by the Occupational Health and Safety Agency for Healthcare, which supports BC’s health care industry in part by monitoring information on occupations, exposure incidents and injuries among the Province’s health care professionals This information will form the basis for creating a job exposure matrix (JEM), which will be used to map exposure levels to occupations and eventually to provide risk estimates. The ultimate goal of this project is to design and implement appropriate exposure control strategies — such as technology, policy and training — in health care settings and to evaluate their effectiveness in mitigating risk to health care providers.

Global view of pre-mRNA splicing in Saccharomyces cerevisiae

Proteins, the molecules that carry out most cellular functions, are synthesized according to information contained in DNA sequences. Converting information from DNA into a protein requires an intermediate step in which the DNA sequence is copied into a molecule called mRNA. In humans, there is an essential biochemical process called pre-mRNA splicing, in which certain (non-coding) portions of the sequence are removed and the remaining protein-coding portions are joined together to form a template for protein synthesis. This is a complex process with multiple steps, and even small errors can be dangerous. Many diseases, such as some cancers, Alzheimer’s disease, and Parkinson’s syndrome, can be attributed to defects in the pre-mRNA splicing machinery. Perhaps due to the complexity and requirement for absolute precision in splicing, the molecular machine that carries out splicing – termed the spliceosome – is enormous. For both humans and yeast, its components number well over 100. However, several splicing proteins likely remain unidentified. A thorough understanding of splicing will require a complete inventory of its parts. Paul Kahlke is identifying novel splicing factors in yeast, which serves as a laboratory model for human splicing. His objective is to uncover previously unknown splicing factors and to determine whether existing candidate proteins are indeed integral to splicing. His studies take a whole genome approach, testing many genes one by one to see which ones are involved in splicing. By screening a large number of genes, Kahlke hopes to identify several new splicing factors and gain insight into the function of known pre-mRNA splicing factors.

The immunomodulatory effects of host defence peptides on dendritic cells

Modern day vaccines are effective at preventing infections such as tetanus, influenza, polio and many others. To ensure full protection from illness, some vaccines require more than one immunization. This is commonly known as a booster shot. In developed countries, getting vaccinated usually means nothing more than going to the clinic. In developing countries the process is not so straight forward. Limited access to, and availability of vaccines makes widespread immunization a difficult process. The fact that people may have to return for a booster shot only compounds the problem. For all of the above reasons, there is clearly a need for improved vaccines in developing countries. Our laboratory is studying ways to create effective single-dose neonatal vaccines for developing countries. This means the vaccine would be given shortly after birth, and there is no need for a booster shot to ensure complete protection. Such a vaccine would alleviate the previously described difficulties. Specifically, our lab is developing more effective vaccine adjuvants. An adjuvant is simply any component added to a vaccine that will interact with the immune system to improve protection. We believe that a class of proteins known as host defence peptides (HDPs) will act as effective vaccine adjuvants. HDPs are short proteins, found almost ubiquitously in nature (microorganisms, insects, plants and mammals for example). Historically, the function of HDPs has been primarily to kill invading bacteria and viruses. Recent research conclusively shows that some HDPs are capable of altering the way in which immune system responds to an infection. My research will focus on how HDPs interact with and important type of immune cell known as a dendritic cell. Dendritic cells (DCs) circulate in the body in an “”immature”” form. When they encounter anything foreign (for example, bacteria or viruses), they become “”activated,”” capture the invader, and alert the immune system so it can mount a full response. They are now said to be “”mature.”” For this reason, DCs are a very unique type of cell. They are part of the front line of defence, yet they are also critical in generating the full immune response, which develops shortly after. We believe that HDPs will influence DCs in such a way that they will promote an efficient immune response in the context of vaccination. I hypothesize that HDPs impact DC function, activation, and maturation by altering specific genes and proteins important to DCs. This hypothesis has lead me to develop five goals to guide my research. I will provide an overview of these goals: 1) Bioinformatics. My preliminary experiments have tracked how HDPs influence the expression of 16,000 genes in mouse DCs. Such a large amount of data needs to be handled by a computer. Using specially designed programs, I am able to sort through the vast amounts of data and determine the broad trends occurring in response to HDPs. Furthermore, I am able to look at how small groups of genes behave in the context of their larger gene families; 2) IRAK-4. Results show that one peptide altered the behaviour of an important protein called IRAK-4. IRAK-4 is known to be important for specific immune responses. I will further analyze how this protein functions in the presence and absence of HDPs and other immune stimuli in DCs. I will also determine how proteins related to, and dependent on IRAK-4 will behave in response to HDPs; 3) Lyn Kinase. Another interesting finding was the altered production of Lyn, another protein important for proper DC function. I will continue analyzing the behaviour of Lyn in DCs in response to HDPs. I will also study the consequences of Lyn deficiency and determine its effects on HDP function. 4) DC Type. There are different types of DCs depending on where in the body you look, each performing similar, yet distinct functions. Currently it is not known how different types of DCs respond to HDPs. A lot of DC research is done with mouse DCs because they are relatively easy to generate compared to their human counterparts. The comparative responses of human and mouse DCs to HDPs are not well understood. For these reasons, I will be experimenting in multiple DC types, and in both human and mouse DCs. 5) In vivo peptide effects. Using the previously described experiments as a guide, I will examine how HDPs affect whole mice. We have access to mice deficient in all of the genes listed above, and this will be useful in determining the role of specific genes on the scale of a whole animal. At the completion of this project, I will have gained a comprehensive understanding of how HDPs influence DCs, with the goal of using this information to provide better vaccine adjuvant candidates aimed at developing countries.

Modeling Dynamical Neural Activity of Magnetoencephalography Measurements using a Real Time Hardware Phantom

The acts of perceiving, thinking, doing or feeling are marked by complex patterns of electrical activity in the brain. Dysfunction in neuronal activity is observed in many diseases and conditions, including epilepsy, dyslexia and Down syndrome. Magnetoencephalography (MEG) is a leading edge technology that images functional brain activity in the human cerebral cortex. The MEG installed in the Vancouver/Burnaby (V/B) MEG laboratory contains an array of 151 sensors configured to record minute magnetic fields that are generated when neurons depolarize in the brain. MEG is used to study neural patterns and pathways using human subjects. However, creating a phantom model to artificially activate sequences of simulated neurons in realistic patterns could help researchers explore dynamic neural networks in more detail. Using a phantom model would allow for more complex studies of brain activity and would also allow researchers to test what happens when pathways are “virtually” altered or severed. Using neuroscience, physics and engineering, Teresa Cheung is developing a phantom model of the cerebral cortex. She will use a series of magnetic dipoles to simulate the brain’s magnetic fields and write the software to control the activation of these fields. By creating a model that accurately simulates brain activity in healthy and dysfunctional states, Cheung’s research will help researchers better understand the complex workings of the brain.

Development of a pipeline for the analysis of flow cytometry data

Flow cytometry (FCM) is a method of sorting and measuring types of cells by fluorescent labelling of markers on the surface of the cells. It plays a critical role in basic research and clinical therapy in the areas of cancer, HIV and stem cell manipulation. For example, it can be used to diagnose some types of cancer, based on which labelled antibodies bind to a particular cell’s surface. It is widely recognized that one of the main stumbling blocks for FCM analysis is in data processing and interpretation, which heavily relies on manual processes to identify particular cell populations and to find correlations between these cell populations and their clinical diagnosis and outcome (e.g. survival). Manual analysis of FCM data is a process that is highly tedious, time-consuming (to the level of impracticality for some datasets), subjective and based on intuition rather than standardized statistical inference. Dr. Ali Bashashati has developed a “pipeline” for automatic analysis of FCM data – a computational platform that can identify cell populations, find biomarkers that correlate with clinical outcomes, and label the samples as normal or diseased. Preliminary evaluations of this pipeline have shown accuracy levels of more than 90 per cent in identifying some sub-types of lymphoma. Moreover, a biomarker that contributes to a more aggressive behaviour of a specific sub-type of lymphoma has been discovered. Bashashati is now testing and refining the platform to improve its analytical power and applicability to a range of FCM data, testing its performance across a number of ongoing FCM studies in BC. Ultimately, he hopes to provide an accurate, powerful computational platform to increase the efficiency of using FCM for research and clinical purposes.

Determining the rhythm of post stroke activity-dependent neural repair

Stroke is the fourth leading cause of death and the main source of adult disability in Canada, costing our health system $2.7 billion annually. It is caused by the interruption of flow of blood or the rupture of blood vessels in the brain, which leads to brain cell death. Depending on the area of the brain that is affected, people experience loss of different abilities including speech, movement and memory. The effects of a stroke depend on where the brain has been injured, as well as how much damage has occurred. Recovery after stroke may be related to changes in the structure and activity of brain cells. Previous studies suggested that new regions of the brain can adopt the function of damaged regions after stroke – effectively rewiring the brain for function. However, the way that brain cells change their activity after stroke, and how these changes affect recovery, is still poorly understood. Dr. Majid Mohaherani is studying the basic mechanisms that lead to the recovery of the affected area in the brain. He is examining how brain cells that survive after stroke change their activity during the weeks and months after the initial injury, rebuilding the lost connections. This research aims to provide a better understanding of the link between previously reported structural changes that occur in the brain after stroke, and changes in the activity of individual cells and large neuronal networks. This work could lead to the development of new therapeutic tools that help the brain rewire itself, which could contribute to a reduction in disabilities in stroke patients.