RoFAR awards another 1.2 million Swiss Francs to fund ground-breaking anaemia research in the USA and Australia
The award winners with institution and the description of their projects are:
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Professor Nancy C. Andrews
Duke University School of Medicine, Durham, USA
Regulation of hepcidin expression |
Genetic haemochromatosis is an iron overload disease that results from mutations in genes encoding hepcidin, ferroportin, HFE, transferrin receptor-2 (TFR2) and haemojuvelin (HJV). Hepcidin is a circulating peptide hormone that controls the activity of ferroportin, a cellular iron exporter. This control mechanism governs both dietary iron absorption and body iron distribution. HJV acts as a bone morphogenetic protein (BMP) co-receptor to stimulate hepcidin expression. However, the functions of HFE and TFR2 have remained enigmatic. Our preliminary results suggest that HJV, HFE and TFR2 interact to form a protein complex in transfected cells. HFE over-expression amplifies BMP signalling. Over-expression of TFR2 inhibits the cellular secretion of a soluble form of HJV that acts as a negative regulator of hepcidin expression. The studies proposed in this application will extend that work, and test the hypothesis that disease-associated mutations in HJV, TFR2 and HFE interfere with formation of the complex and/or its biological activities. This work will provide new insight into how hepcidin expression is regulated. This, in turn, will add to our understanding of the anaemia of chronic disease, a prevalent disorder attributable to excess hepcidin production in response to inflammation. Ultimately, a better understanding of HJV, TFR2 and HFE as potential therapeutic targets may lead to new treatments for iron overload disorders, iron deficiency disorders and the anaemia of chronic disease.
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Dr Mark D. Fleming
Children's Hospital Boston, USA
The genetics of erythroid haem and iron metabolism
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Developing red blood cells need to make large amounts of haemoglobin, the oxygen carrying substance in the blood. Haemoglobin is comprised of a protein component, globin, and the red pigment haem, which is formed from the metal iron and a chemical compound called protoporphyrin IX (PPIX). All three - globin, iron, and PPIX - must be made or acquired in the proper proportion to make haemoglobin efficiently. A deficiency of any component leads to too little haemoglobin in the blood - anaemia - in which the red blood cells are small and pale. These so-called hypochromic, microcytic anaemias are among the most common diseases in humans, and include iron deficiency anaemia and the inherited globin disorders collectively called the thalassaemias. In order to meet the demand for globin and haem, red blood cells precursors have a number of proteins dedicated to their acquisition and synthesis that are turned on by other proteins during the course of red blood cell development. My laboratory is interested in understanding the basic physiology of haemoglobin production. In particular, we have focused on how red blood cells acquire iron and make PPIX in sufficiently large amounts to make the haem required for haemoglobin. To do so, we have used a technique called positional cloning to find the mutated genes and proteins responsible for inherited hypochromic, microcytic anaemias in mice. In this proposal we describe the anaemia and the gene responsible for a new mouse hypochromic, microcytic anaemia mutant that appears to have a defect in the early stages of PPIX biosynthesis; the anaemia is due to a mutation in a completely novel gene that may control the haem biosynthetic pathway in red blood cell precursors. Here, we propose experiments to determine the specific function of this protein in haem biosynthesis.
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Prof. David Johnson
Princess Alexander Hospital, Brisbane, Australia
A randomised, placebo-controlled trial of oxpentifylline on haemoglobin levels in patients with erythropoietin-resistant anaemia
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Low red blood cell counts (anaemia) occur in the vast majority of patients with chronic kidney disease. In most cases, these low red blood cell counts respond to treatment with medications, such as erythropoietin (Eprex®) or darbepoietin alpha (Aranesp®). However, about 10-15% of patients continue to be anaemic even with appropriate treatment. Such patients are at increased risk of being hospitalised, developing complications such as heart failure and death. A number of small studies have suggested that a drug called oxpentifylline (Trental®) is very good at safely raising red blood cell counts in persistently anaemic patients. However, this drug has not yet been properly tested in a controlled trial (that is, where the drug is given to one group of patients, but not another).
Eligible patients who choose to participate will receive either the oxpentifylline treatment or a placebo. Which treatment will be determined by random chance (similar to the toss of a coin) and neither the patient nor the doctor will know whether the treatment is oxpentifylline or a placebo. Apart from receiving oxpentifylline or placebo, usual treatment will not be affected in any other way. Information about blood test results, blood pressure, weight, any drug side effects, as well as limited clinical information will be recorded. The study will involve 4 months of daily treatment.
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Dr Zvonimir Katusic
Mayo Clinic, Rochester (Minnesota), USA
Role of antioxidant enzymes in vasculoprotective effect of erythropoietin
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Erythropoietin (EPO) is widely used as a major therapeutic drug in the treatment of anaemia. The scientific community has recently recognised that EPO has beneficial effect in the prevention and treatment of diseases other than anaemia. Diseases of blood vessels are a major cause of mortality and disability. The inner lining of the blood vessel wall (endothelium) plays a key role in regulation of blood supply to the tissues. Previous studies suggest that EPO has beneficial effects on endothelial function. However, the exact mechanism of this effect is not completely understood. Experiments proposed in this project are designed to determine whether EPO stimulates repair of the injured blood vessel wall and what mechanisms are responsible for the effects of EPO. It is anticipated that the results may help to better understand the effects of EPO on the cardiovascular system in patients who are treated with this drug. Improved understanding of the effects of EPO may also help to harness the therapeutic value of EPO in the prevention and treatment of cardiovascular disease, including myocardial infarction and stroke.
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Dr Frank S. Lee
University of Pennsylvania School of Medicine, Philadelphia, USA
Prolyl hydroxylase domain protein 2, a physiologic regulator of erythropoietin
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Recombinant erythropoietin (EPO) has proven to be a remarkably effective treatment for certain types of anaemia, such as that associated with chronic kidney disease or chemotherapy. If one were to be able to increase endogenous EPO, for example by controlling the activity of factors that regulate EPO, one might be able to avoid the necessity of EPO injections and routine clinic visits. This necessitates a detailed molecular understanding of the factors that regulate endogenous EPO levels and haematocrit. A family with abnormally high haematocrit was recently identified as having a novel mutation in a protein known as PHD2. This points to PHD2 as being a physiologic regulator of EPO and haematocrit in humans. We propose examining a mouse model in which the gene encoding this protein can be inactivated to test whether this leads to increased EPO and haematocrit. This would be an independent, and indeed, critical test of the physiologic role of PHD2 in red blood cell production. Should loss of PHD2 lead to increased haematocrit, it would make targeting this pathway and this particular protein a possible means to treating anaemia.
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Dr Tonia S. Rex
University of Tennessee Health Science Center, Memphis, USA
Analysis of rhEPO processing in mouse tissue - implications for gene therapy of retinal degenerations
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Erythropoietin (EPO) is a secreted cytokine with neuroprotective activity. Injection of EPO into the vitreous of the eye protects ganglion cells from axotomy-induced cell death. However, subretinal injection of AAV-EPO does not protect the photoreceptors from cell death induced by light-damage. Surprisingly, intramuscular delivery of AAV-EPO was neuroprotective to the photoreceptors. This implies that either EPO protected the photoreceptors via an indirect mechanism (i.e. increased oxygen), or that EPO produced in the retina is non-functional, while EPO produced in the muscle is functional. The fact that the ganglion cells are protected by direct injection of EPO would imply that there is a direct neuroprotective effect of EPO on retinal neurons. In addition, a recent study demonstrated that the isoelectric focusing pattern of EPO produced in the retina is different from that produced in the muscle. Therefore, the goal of the proposed study is to determine the differences between EPO produced in the retina and that produced in the muscle after transduction with AAV-EPO and to determine the ideal form of EPO to protect retinal neurons from degeneration. The sugar moieties on EPO are altered depending on the tissue from which it is expressed, and this, in turn, alters the ability of EPO to activate its receptor. Serum and anterior chamber fluid samples will be collected from primates previously injected with AAV-EPO. The samples will be analysed biochemically for differences in sugar moieties. Then, forms of EPO containing different amounts of glycosylation will be injected into the eyes of retinal degeneration mice to assess for neuroprotection by histological and physiological analysis. Finally, gene therapy will be optimised in two models of retinal degeneration using AAV to deliver a mutant form of EPO that has been shown to be neuroprotective, but not erythropoietic.
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