The Cross-Border Biotech Blog

Biotechnology, Health and Business in Canada, the United States and Worldwide

Tag Archives: Embryonic Stem Cells

Friday Science Review: May 28, 2010

A Map to Better Beer? The key signaling protein-protein interactions in yeast have been mapped.  Mass spectrometry was used to discover the global network between protein kinases and phosphatases to generate the “kinome” map, which contains 1844 interactions.  Since yeasts are model organisms with similar signaling pathways as in human cells, this information is relevant for human disease research and drug design.  The data set in this study was so large that the research team created software to store and analyze the data (ProHits) and perform statistical analysis (SAINT).  Dr. Mike Tyers (Samuel Luenefeld Research Institute) is the lead author of the project described in Science magazine.  The entire data set is available at the yeastkinome.org resource website.

Shhhh… Improving Gene Silencing: Micro RNAs (miRNA) control gene expression by interfering with specific RNA transcripts and this requires the Argonaute proteins (AGOs) to perform this function.  Researchers isolated the specific key region in AGO and solved the crystal structure of this segment.  From this, they discovered that there are intricate and specific molecular interactions between the miRNA and AGO that can dictate specificity.  As RNA interference techniques are gaining traction in the therapeutic arena, this discovery may lead to modifications to enhance the effectiveness of these therapies.  Dr. Bhushan Nagar led the McGill University research team and published the findings in Nature or check out this video podcast.

E. coli Survival Switch: The AceK protein in some bacteria acts as a switch responding to stressful environmental cues, allowing the bacteria to bypass the energy-producing Krebs cycle and go into a conservation mode.  Bacteria such as E. coli and Salmonella can survive in low-nutrient environments such as water.  Therefore, the discovery of how AceK works provides a potential target to prevent bacterial contamination in drinking water by inhibiting the ability of the bacteria to go into survival mode.  Dr. Zongchao Jia and postdoctoral fellow Dr. Jimin Zheng at Queen’s University solved the structure of the protein that led to understanding the unique properties of the enzyme in having both phosphorylation and de-phosphorylation activities on the same protein.  This breakthrough is described in the latest edition of Nature.

Little Buggers All Over Us: The Human Microbiome Jumpstart Reference Strains Consortium is trying to catalog all the microbes in the human body.  We are covered by millions and millions of these little critters – as many as 10x more microbes than the number of cells in our body, but they’re not necessarily bad for us.  They actually play important roles in protecting against infection, aid with digestion, developing our immune system and keeping us healthy.  So far, 178 genomes have been sequenced with the goal to sequence around 900 genomes.  The NIH initiated the project and Dr. Michael Surette and his team at the University of Calgary is a major contributor to the study.  The first phase of this initiative is published in Science.

Genomic Modifications in Stem Cells: To further understand stem cells and embryonic development, scientists took a closer look at how the structural organization of genomic DNA (chromatin and histones) plays a role in determining what tissue they become.  They identified and compared specific modifications across the genome that either activates or represses gene expression in different stem cells.  The value of this information is that it suggests differential regulatory mechanisms controlling development and depends on the specific stem cell lineage.  The safety of regenerative medicine lies in these types of studies in basic stem cell biology.  Developmental biologist Dr. Janet Rossant at The Hospital for Sick Children led the study, which appears in the Proceedings of the National Academy of Sciences.  Also, congratulations to Dr. Rossant as a recent recipient of the 2010 Premier’s Summit Award for Medical Research.

Improving Alzheimer Immunotherapy: Delivering antibodies against amyloid-beta peptide (Abeta) directly into the brain is more effective than systemic delivery in reducing amyloid plaques, as demonstrated in a mouse model.  In this novel approach, transcranial focused ultrasound (FUS) was applied to improve permeability of the blood brain barrier without the need for high doses of the antibody.  The researchers administered the therapeutic antibody intravenously along with a contrast agent to follow the progress via MRI imaging.  Using this MRI guided FUS method, they could see the contrast agent enter the brain within minutes and amyloid pathology was improved in the mouse model after four days.  Drs. Kullervo Hynynen and Isabelle Aubert at Sunnybrook Research Institute published their study on-line in PLoS One.

Friday Science Review: May 14, 2010

A Cure for Brain Cancer: An aggressive type of brain cancer called glioblastoma may be cured using the small molecule dichloracetate (DCA), a cheap and safe generic compound.  The drug works by altering the metabolism of the cancer cells, which is an emerging concept that exploits the different (higher) energy demand of cancer cells.  DCA’s target in the cells is the metabolic enzyme pyruvate dehydrogenase kinase II and it also promotes cell death in glioblastoma cancer cells and cancer stem cells.  In an 18-month study, some of the five patients’ tumours either regressed in size or did not grow any more.  Drs. Kenn Petruk and Evangelos Michelakis at the University of Alberta describe their study showing efficacy of DCA in humans for the first time in the journal Science Translational Medicine.  It is interesting to note that these and future studies are funded by government grants and private donations since the pharmaceutical industry is not interested in a compound that is readily available and without intellectual property protection (ie. no $cha-ching$).

Embryonic Cells Can Stop Viruses: Embryonic cells have a natural defence mechanism to limit the ability of viruses to express their genes and thereby prevent infection and further spread of the virus.  Researchers also determined that the different layers of cells in the developing embryo have different capacities to silence viral activation.  This “graphical abstract” published in Cell Stem Cell shows the outer layer of extraembryonic endoderm stem cells as the first line of defence with the strongest abilities to extinguish viral gene expression.  Several proteins including chromatin remodelling and repressor complex proteins were also identified to play key roles in this process.  The study was lead by Dr. Mellissa Mann at the University of Western Ontario.

If Only Mice Could Talk: This one is a bit strange.  It looks like mice express pain through facial expressions similar to the way humans do.  McGill University researchers developed the Mouse Grimace Scale to aid scientists working with lab animals to better ‘communicate’ with the animals.  Not only will this help to minimize and manage the stress that is inflicted on the animals but they can read the facial responses to determine whether a drug treatment is working or as an indicator of negative side effects.  Check out the study by Dr. Jeffrey Mogil in the issue of Nature Methods.

Pathogens Are Our Friends: Diphtheria Toxin (DT) is a potent cytotoxin that kills the cells that it binds to.  The DT385 is a recombinant version that is truncated and can be targeted to cancer cells to be used as a therapeutic agent.  In the present study, 15 of the18 human cancer lines tested were inhibited by DT385 as a result of increased apoptosis and decreased protein synthesis.  Dr. David Waisman at Dalhousie University published his study online in PLoS One.  Using pathogen proteins as therapeutic agents is not a new concept.  Oncolytics Biotech’s REOLYSIN® is derived from the Reovirus and Advaxis, Inc. exploits the Listeria bacterium to activate the immune system in an immunotherapy approach.

Studying Herpes Infection: Dr. Karen Mossman (McMaster University) investigated Herpes Simplex Virus-1 infection and how a viral protein, ICP0, is localized properly in the cell to block Interferon Regulatory Factor 3 (IRF3), the cell’s innate antiviral mechanism.  The study is described in PLoS One journal.

States Step in to Ban Stem Cell Research

For those in Canada and the UK who were worried that Obama’s move to restore U.S. federal funding for stem cell research would create a 50-state mecca, I have good news:

Reuters reported yesterday that several U.S. states — Oklahoma, Georgia, Mississippi, Texas, Arizona and Louisiana — have passed or are considering legislation to outlaw some forms of embryonic stem cell research. 

For legislators in those states who voted for the bans, I have a short educational video to recommend to you:

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