PI: Pawel Swietach, Professor of Physiology, Department of Physiology, Anatomy & Genetics, University of Oxford, England
“Aberrant protein propionylation and distinct histone marks in propionic acidemia: new disease mechanisms and risk factors for cardiac disease”
The challenge placed on our hearts – to contract and relax in a correct sequence and with adequate strength – is formidable. The elegant biological solution to this mechanical problem is an organ that pumps millions of liters of blood to support life for many decades. However, the quality and span of a person’s life is strongly linked to cardiac health. Thanks to scientific breakthroughs, better treatments are now available for cardiac disease, allowing patients to live longer and happier lives. Our goal at Oxford University’s British Heart Foundation Centre of Research Excellence is to ensure that scientific progress addresses a wide spectrum of disorders, irrespective of their incidence.
Cardiac problems are common in propionic acidemia (PA). Sadly, dilated cardiomyopathy and long-QT syndrome are often the cause of childhood death. In order to treat and prevent these cardiac problems, we must first understand the underlying mechanisms. Once these processes are described, our aimis to identify targets for drugs or interventions. We believe that this ambition is achievable thanks to the wealth of knowledge about the heart and the vast repertoire of drugs approved for therapy in various other cardiac conditions. Many of these drugs could be “repurposed” for PA-associated disorders, giving hope to many families for a timely treatment.
For this PAF-funded project, we have assembled a consortium of scientists who are eager to devote their expertise to studying PA. My laboratory’s expertise is in cardiac cellular physiology in the context of acid-base disorders. We are joined by Tom Milne who is Associate Professor in Epigenetics at Oxford, Holger Kramer, an expert on proteomics, and Steve Krywawych, principal biochemist at Great Ormond Street Hospital in London. Resources and facilities made available to this project include a mouse model of PA, courtesy of Michael Barry and Lourdes Desviat, methods to characterise cardiac function from the cell to organ level, as well as measurements of changes at the protein and gene level. This interdisciplinary but focused approach allows us to identify potential targets for PA treatment. Indeed, our preliminary findings point to one such enzyme, and the aim of this project is to test and validate our hypothesis.
PA is associated with major metabolic changes, and many of these substances are not merely intermediates in a chain of events, but can have strong biological actions that are not always intuitive to predict. Our project will investigate how the build-up of propionate affects cardiac genes through a chemical reaction that causes DNA scaffolds (called histones) to “open up” genes that should not normally be expressed in a healthy heart. Many genes will be affected by this, but some are more closely linked to the cardiac disorder. After identifying these lead genes, we will test the extent to which blocking these could be curative. In parallel, we will investigate if propionate can also react with other targets in the cell, such as proteins underpinning contraction. Indeed, our work suggests that a promising avenue for research relates to so-called excitation-contraction coupling, a process that converts cardiac electricity to a mechanical response.
We are excited to be part of the PA research family and wish to take this opportunity to invite patients, carers, and supporters to our lab for a visit.