Anywhere from infectious diseases to splicing and dicing RNA | 083

Welcome to another episode of Biotechnology Focus radio! I am your host, Michelle Currie, here to give you the rundown on Canada’s biotech scene. This week we have stories about a possible Ebola treatment, how there may be a link between an increase in cholinergic system activity and parkinson’s disease, CRISPR makes its move on RNA, and according to a u of t study, rheumatoid arthritis patients have a higher risk of earlier mortality. So, keep listening to hear what’s going on from coast to coast! +++++ In the wake of the 2014 Ebola outbreak, with more than 11,000 known deaths, researchers are attempting to come up with innovative ways to prevent and cure the disease. Due to the dire nature of the virus, it sheds light on the limitations of the medication currently in circulation. Now, University of Guelph researchers have shown that an innovative antibody delivery method could offer an effective way to prevent and treat Ebola infection. Their goal is to make an antibody-based therapy that can protect against all strains of Ebola, and potentially the Marburg virus as well. It would be used to stop the spread of the virus in outbreak situations. The researchers say monoclonal antibody therapies (mAbs) hold promise for the treatment of the Ebola virus, but monoclonal antibody therapies are a costly operation and provide only short-term immunity. That could change though thanks to a recent discovery by lead researchers Sarah Wootton and Laura van Lieshout. Their findings were published in the Journal of Infectious Diseases. The approach technique that the researchers are using has been seen in studies with the human immunodeficiency virus (HIV). It delivers a monoclonal antibody gene through a viral vector to bypass the need to generate a natural immune response – something that can take the body weeks to occur and quite frankly, time is of the essence with this particular disease. Wootton found that using the adeno-associated virus (AAV) to deliver antibodies was remarkably effective at keeping the Ebola virus infection at bay in mice. Other researchers have used the adeno-associated virus extensively to treat a variety of genetic disorders. The goal is to use the adeno-associated virus gene therapy vector to deliver the DNA blueprint to a cell, and that cell will produce a protective antibody against the Ebola virus, which is then secreted into the bloodstream and protects mice from infection. The approach provided 100 per cent protection against an Ebola infection in mice using two separate types of monoclonal antibodies, and 83 per cent protection with a third. A “cocktail” of two antibodies provided sustained protection against Ebola for up to five months. Once the antibody gene is delivered, antibodies will be continually reproduced in the bloodstream. Mice in the laboratory expressed the antibody for more than 300 days. Researchers are hoping to utilize this technology in a post-exposure scenario. +++++ There is a particular gene mutation that happens in the brain that could be linked to an inherited form of Parkinson’s disease (PD) that might shed some light on a controversial theory about where PD begins in the brain. Idiopathic PD, a sporadic form of the disease, affects the dopamine system and is treated with replacement therapy to restore the brain’s natural chemical balance and alleviate physical symptoms. Frequently, other neurotransmitter systems are involved, but it is not yet clear whether this happens pre- or post the dopamine loss characteristic. By studying people with the inherited form of the disease, researchers hope that they will be able to determine brain involvement prior to the development of symptoms. The results of an international collaboration, led by Dr. Jon Stoessl, published in The Lancet Neurology shows that mutations in the LRRK2 – a gene associated with an inherited form of PD – can cause imbalances in the cholinergic system of the brain, but not in the way they thought. The cholinergic system is responsible for learning and memory. An imbalanced cholinergic system has been witnessed in other neurodegenerative disorders, including Alzheimer’s. While the investigators expected to find evidence of reduced cholinergic activity in the brain, positron emission tomography (PET) scans revealed widespread increases not only in people with the LRRK2 mutation-related form of PD, but also in unaffected individuals who carry the mutation but do not yet have manifestations of disease. Changes in the cholinergic system are thought to contribute to PD complications including cognitive difficulties, postural instability and sleep disturbances. It is possible that an increase in activity may reflect the brain’s attempt to compensate for dysfunction related to the mutated gene, and may also explain why patients with LRRK2 mutations have fewer problems with certain complications of disease, even though their PD is in most ways similar to the usual sporadic form of the disease. This provides a tremendous opportunity to study people with Parkinson-causing genetic mutations before they develop. The findings of this study have considerable implications for understanding how the disease begins to manifest in the years before diagnosis, and builds on research previously published last year that demonstrated that patients with the LRRK2 mutation show an increase in serotonin nerve terminals before a formal Parkinson’s Disease diagnosis, possibly reflecting the brain’s attempts to compensate for the decrease in dopamine associated with onset of physical symptoms. According to Statistics Canada, PD is the second most common neurodegenerative disease in Canada with an estimated 55,000 people suffering from it. It is a progressive disorder of the nervous system that affects movement. It develops gradually, sometimes starting with a barely noticeable tremor in just one hand. But while a tremor may be the most well-known sign of Parkinson’s disease, the disorder also commonly causes stiffness or slowing of movement that worsens as it progresses. The majority of new diagnoses are in adults over the age of 64. +++++ CRISPR/Cas9, the “scissors” of life sciences, is now not only targeting DNA, but RNA as well. Scientists from the Salk Institute in the U.S. have created this new tool, CasRx, to correct protein imbalances in cells. This provides researchers with a powerful way to develop new gene therapies, as well as investigate fundamental biological functions. Bioengineers are like nature’s detectives, searching for clues in patterns of DNA to help solve the mysteries of genetic diseases. CRISPR has revolutionized genome engineering, and the researchers wanted to expand the toolbox from DNA to RNA. CRISPR technology was adapted from the natural defense mechanisms of bacteria and archaea (the domain of single-celled microorganisms). These organisms use CRISPR-derived RNA and various Cas proteins, including Cas9, to foil attacks by viruses and other foreign bodies. They do so primarily by chopping up and destroying the DNA of a foreign invader. When these components are transferred into other, more complex, organisms, it allows for the manipulation of genes, or “editing.” The Salk team decided to search bacterial genomes for new CRISPR enzymes that could target RNA, which could then be engineered to address problems with RNA and resulting proteins. A given RNA message, for example, can be expressed at varying levels and its balance relative to other RNAs is critical for healthy function. Furthermore, RNA can be spliced in various ways to make different proteins, but problems with splicing can lead to diseases such as spinal muscular atrophy, atypical cystic fibrosis and frontotemporal dementia (FTD). So, a drug that targets toxic RNAs or RNAs resulting from improper splicing could have a life-changing impact for people with these types of devastating diseases. The researchers began the project with the hypothesis that different CRISPR systems may have been specialized throughout an evolutionary arms race between bacteria and their viruses, potentially giving them the ability to target viral RNA. They developed a computational program to search bacterial DNA databases for particular repeating DNA sequences. Whilst this was happening, they discovered a family of CRISPR enzymes that targets RNA. They called it Cas13. The name is derived from the gut bacterium Ruminococcus flaveflacians XPD3002 due to it being the best version for use in human cells, because just like Cas9, Cas13 enzymes originate from different bacterial species and vary in activity. The scientists tried out this new method in a dementia patient, attempting to replace the damaged cells with healthy ones. CasRx was 80 per cent effective. The team genetically engineered CasRx to target RNA sequences for the version of the tau protein that is overabundant. They did this by packaging CasRx into a virus and delivering it to neurons grown from a frontotemporal degeneration patient’s stem cells. Compared to other technologies that target RNA, CasRx is unique due to its small size – making it easier to package into therapeutically relevant viral vectors – its high degree of effectiveness, and that it creates no discernible off-target effects compared to RNA interference. The Salk team is excited about the possibilities their tool opens up for exploring new biological questions about RNA and protein function, as well as therapies to tackle RNA and protein-based diseases. To quote one of the authors of the study, “Nature is full of so many secrets. It’s really a rich, untapped resource for inventing new technologies.” +++++ According to a study done by the University of Toronto, sufferers of rheumatoid arthritis are more likely to have further complications and die at a younger age than the general population. The study was examining causes of death of Ontarians over a 14-year period. Everyone deserves to live the same length and quality of life. Mortality is also one of the strongest markers to evaluate inadequate care. The excess mortality related to rheumatoid arthritis that the researchers observed may suggest inadequate attention to control of the disease and its related morbidity. The study is one of the largest of its kind to comprehensively look at causes of death over an extended period. More than 87,000 patients with rheumatoid arthritis in Ontario were included in the study and compared with more than 340,000 members of the general population over a span of 14 years. Causes of death were found to be quite similar between the general population and those with rheumatoid arthritis, but the notable difference was that those with the disease were dying at a much younger age – which is something that concerns the researchers. Rheumatoid arthritis is a chronic condition that can affect two to three per cent of older adults. As an inflammatory disease, rheumatoid arthritis can affect more than just the joints in the body – ongoing inflammation often leads to further complications and multimorbidity in patients. This means that individuals will likely have multiple chronic conditions occurring simultaneously, such as diabetes and high blood pressure, or heart disease and a respiratory illness. The study also found that among arthritis sufferers, one in three were dying of complications attributed to heart disease. The head researcher wants to underscore the importance of improving preventative measures to slow down the progression of some of these co-morbid conditions in order to improve a patients’ overall life expectancy. The hope through this research is that it will shed light and awareness on the disease and inspire patients to play a more active and vigilant role when it comes to their health. The study was published in Arthritis Care & Research and was supported by the Catherine and Fredrik Eaton Charitable Foundation, the Canadian Institutes of Health Research, and the Arthritis Society Post Doctoral Fellowship. +++++ Well, that wraps up another episode of Biotechnology Focus radio! I hope you enjoyed it! Next week I’ll have Vatche Bartekian on the show to tell me about his event coming up in May! Stay tuned and have a great week! From my desk to yours – this is Michelle Currie.