Malaria is a very important disease worldwide, causing hundreds of millions of cases and about two million deaths per year. Severe malaria including cerebral malaria is a major cause of death. It is caused by red blood cells which contain malaria parasites sticking to the lining of microscopic veins and clogging them; what happens after this is complex. The process of sticking is called cytoadherence. We have discovered a gene which is important in this process of sticking. We have called it by ....Malaria is a very important disease worldwide, causing hundreds of millions of cases and about two million deaths per year. Severe malaria including cerebral malaria is a major cause of death. It is caused by red blood cells which contain malaria parasites sticking to the lining of microscopic veins and clogging them; what happens after this is complex. The process of sticking is called cytoadherence. We have discovered a gene which is important in this process of sticking. We have called it by the acronym clag, for cytoadherence-linked asexual gene; most Australians know of Clag as a glue. Our evidence for this has been accepted for publication by the prestigious USA journal Proceedings of the National Academy of Sciences of the USA. Recent work overseas aimed at determining the entire DNA sequence of the malaria parasite has shown that clag is not alone; there are at least 9 slightly different clag genes in the malaria parasite. What do the others do? We propose two possibilities. The first is that all of them act in cytoadherence but that different clags enable the parasitised cells to stick to different things on the lining of veins. The second is that they enable the parasitised cells, or perhaps the parasites alone, to stick to other things at different stages of the complex life cycle of the parasite. The experiments that we propose should show whether either of these proposals is true.Read moreRead less
The Clag Gene Family Of P. Falciparum; Examining Roles In Cytoadherence, Rheological Properties Or Tissue Trophism.
Funder
National Health and Medical Research Council
Funding Amount
$451,980.00
Summary
There are approximately 500 million of cases of malaria per year worldwide and about two million deaths per year. Severe malaria including cerebral malaria is a major cause of death. It is caused by the sticking of red blood cells which contain malaria parasites to the lining of microscopic veins and blocking them; what happens after this is complex. The process of sticking is called cytoadherence. We have discovered a gene which is important in this process of sticking. We have called it by the ....There are approximately 500 million of cases of malaria per year worldwide and about two million deaths per year. Severe malaria including cerebral malaria is a major cause of death. It is caused by the sticking of red blood cells which contain malaria parasites to the lining of microscopic veins and blocking them; what happens after this is complex. The process of sticking is called cytoadherence. We have discovered a gene which is important in this process of sticking. We have called it by the acronym clag, for cytoadherence-linked asexual gene. Most Australians know of clag as a glue, and our data provides evidence that it sticks the parasitised red cells to veins via a protein called CD36 on the internal surface of veins. Our evidence for this has been published in two prestigious international journals. We propose here to examine the same gene in a mouse malaria model as it should be highly informative to see what effect destoying clag has on the disease in a living animal. Obviously this cannot be tested in people. It has now become clear that there are a number of slightly different clag genes and we do not know what the others do. We propose here that they may enable the parasitised red cells to stick to targets other than CD36 on the surfaces of veins, or affect blood flow of infected cells, or direct the parasitised red cells to other organs. The experiments that we propose should reveal whether these ideas are true.Read moreRead less
Protein Trafficking In Malaria Parasite-infected Erythrocytes
Funder
National Health and Medical Research Council
Funding Amount
$417,750.00
Summary
Malaria kills between 1 and 3 million children each year. In addition, the disease debilitates the adult population in malaria-endemic areas, thereby contributing to the cycle of poverty in many third world countries. As resistance to existing antimalarial drugs increases, there is an urgent need to understand the workings of the parasite at a molecular level to enable the development of alternative antimalarial strategies. During part of its life cycle, the malaria parasite infects the erythroc ....Malaria kills between 1 and 3 million children each year. In addition, the disease debilitates the adult population in malaria-endemic areas, thereby contributing to the cycle of poverty in many third world countries. As resistance to existing antimalarial drugs increases, there is an urgent need to understand the workings of the parasite at a molecular level to enable the development of alternative antimalarial strategies. During part of its life cycle, the malaria parasite infects the erythrocytes of its human host. The parasite transports proteins to the erythrocyte membrane so as to modify the properties of its adopted cellular residence. The parasite proteins that are deposited at or in the erythrocyte membrane increase the leakiness and the stickiness of the parasitised erythrocytes. This allows more efficient uptake of nutrients and allows the parasitised erythrocytes to adhere to blood vessel walls, thereby avoiding passage through the spleen. Adherence of parasitised erythrocytes to capillaries in the brain is thought to lead to the development of the complication known as cerebral malaria. This complication is responsible for most of the deaths due to malaria. In order to traffic the adherence proteins to the erythrocyte surface, the parasite establishes novel transport pathways for moving proteins across the erythrocyte cytoplasm. As the uninfected erythrocyte has no means, nor requirement, for moving proteins, this novel transport mechanism may represent a target for drugs that kill the malaria parasite without being toxic to humans. The pathways for the movement of proteins around the infected erythrocyte are largely unknown. We propose to use cell biology techniques and techniques to introduce foreign genes into malaria-infected erythrocytes to unravel the details of the molecular machinery and the ticketing system that the parasite uses to traffic proteins to their correct destinations in its adopted home.Read moreRead less
Trafficking Of The Major Virulence Protein To The Host Cell Surface In Malaria Parasite-infected Erythrocytes
Funder
National Health and Medical Research Council
Funding Amount
$658,164.00
Summary
The malaria parasite infects human red blood cells and causes them to stick to blood vessels in the brain, inducing coma. This causes the deaths of ~2 million children each year. We will use cell biology techniques to manipulate malaria parasites to unravel the details of the molecular ticketing system that the parasite uses to get its adhesive proteins onto the red blood cell surface. The ability to interfere with this process would greatly decrease the impact of this major human pathogen.
Trafficking Of The Cytoadherence-mediating Protein To The Host Cell Surface In Malaria Parasite-infected Erythrocytes
Funder
National Health and Medical Research Council
Funding Amount
$547,315.00
Summary
Malaria kills between 1 and 3 million children each year. In addition, the disease debilitates the adult population in malaria-endemic areas, thereby contributing to the cycle of poverty in many third world countries. As resistance to existing antimalarial drugs increases, there is an urgent need to understand the workings of the parasite at a molecular level to enable the development of alternative antimalarial strategies. During part of its life cycle, the malaria parasite infects the red bloo ....Malaria kills between 1 and 3 million children each year. In addition, the disease debilitates the adult population in malaria-endemic areas, thereby contributing to the cycle of poverty in many third world countries. As resistance to existing antimalarial drugs increases, there is an urgent need to understand the workings of the parasite at a molecular level to enable the development of alternative antimalarial strategies. During part of its life cycle, the malaria parasite infects the red blood cells of its human host. The parasite transports proteins to the red blood cell membrane so as to modify the properties of its adopted cellular residence. The parasite proteins that are deposited at or in the red blood cell membrane increase the leakiness and the stickiness of the parasitised red blood cells. This allows more efficient uptake of nutrients and allows the parasitised red blood cells to adhere to blood vessel walls, thereby avoiding passage through the spleen. Adherence of parasitised red blood cells to capillaries in the brain and the placenta is thought to lead to the development of the complications known as 'cerebral' and 'placental' malaria. These complications are responsible for the deaths of many children and pregnant women. We propose to use cell biology techniques to introduce foreign genes into malaria parasite-infected red blood cells to unravel the details of the molecular machinery and the ticketing system that the parasite uses to traffic its virulence proteins to their correct destinations. These studies could potentially lead to the development of novel intervention strategies. For example, if it were possible to decrease the levels of surface expression of a protein known as PfEMP1, adhesion of infected red blood cells would be inhibited. This would greatly decrease the impact of this important human pathogen.Read moreRead less