Plasmodium Knowlesi As A Genetic Model For Plasmodium Vivax Drug Resistance
Funder
National Health and Medical Research Council
Funding Amount
$417,193.00
Summary
Two different Plasmodium parasites cause the majority of malaria worldwide. However, one type, P. vivax, is unable to be cultured in the laboratory and therefore has been poorly studied. Drug resistance has been observed but the underlying causes are poorly understood. We propose to use a closely related parasite, P. knowlesi, as a model to understand drug resistance mechanisms. This knowledge will be used to follow resistance in the field and direct policy of the most appropriate treatment.
Chloroquine Resistance And The Physiology Of The Malaria Parasite S Digestive Vacuole
Funder
National Health and Medical Research Council
Funding Amount
$287,921.00
Summary
Malaria is an infectious disease, caused by a single-celled parasite which invades the red blood cells of its human host. Each year, malaria causes the death of up to 3 million people, mostly children under the age of 5 The parasite has become resistant to most, if not all, of the antimalarial drugs presently available, and there is no vaccine. There is therefore an urgent need to develop new antimalarial drugs, and-or to devise strategies for overcoming the parasite s drug resistance mechanisms ....Malaria is an infectious disease, caused by a single-celled parasite which invades the red blood cells of its human host. Each year, malaria causes the death of up to 3 million people, mostly children under the age of 5 The parasite has become resistant to most, if not all, of the antimalarial drugs presently available, and there is no vaccine. There is therefore an urgent need to develop new antimalarial drugs, and-or to devise strategies for overcoming the parasite s drug resistance mechanisms. Chloroquine was, for many years, the mainstay of antimalarial chemotherapy and was, in many senses, a 'wonder-drug' cheap, safe and effective. However the emergence and spread of parasites that are resistant to chloroquine has meant that the drug is now largely useless as an antimalarial. Chloroquine kills (sensitive) parasite through an effect on the parasite s digestive vacuole an internal acidic compartment in which the parasite breaks down protein taken up from its host red blood cell. This compartment plays a crucial role in the growth and proliferation of the parasite. Yet we understand very little about its basic physiology, and nor do we understand the mechanism by which chloroquine-resistant parasites are able to survive exposure to the drug. The aim of the work proposed here is to gain an increased understanding of some of the mechanisms underlying the physiology of the parasite s digestive vacuole, as well as some of the factors influencing the accumulation of chloroquine within this compartment. The former part of the work may well reveal new antimalarial drug targets. The latter part of the work will increase our understanding of the mechanism of chloroquine resistance, thereby laying the groundwork for strategies by which these mechanisms might be circumvented and chloroquine-related drugs thereby restored to the front-line of our ongoing and increasingly desperate fight against malaria.Read moreRead less
The Na+-H+ Exchanger And H+-pumping Pyrophosphatases Of The Malaria Parasite
Funder
National Health and Medical Research Council
Funding Amount
$664,604.00
Summary
Malaria is an infectious disease caused by a single-celled parasite. The disease kills up to 2 million people each year and the parasite is becoming increasingly resistant to available drugs. This work focuses on the mechanisms by which the parasite controls its internal ion concentrations. These mechanisms may be new drug targets, and they may also play a role in antimalarial drug resistance. For both of these reasons it is important that we understand them.
Interactions Between The Malaria Parasite's Chloroquine Resistance Transporter And Antimalarial Drugs
Funder
National Health and Medical Research Council
Funding Amount
$485,641.00
Summary
The malaria parasite is a single-celled organism which invades the red blood cells of its host. The aim of this project is to characterize the parasite protein responsible for conferring resistance to chloroquine, and to study its interaction with other antimalarial drugs. The parasite's susceptibility to chloroquine, and other drugs, is altered by small changes in this protein. This work will advance our understanding of the increasingly widespread phenomenon of antimalarial drug resistance.
Developing Synergisers Of The Antimalarial Drug, Chloroquine, For The Treatment Of Chloroquine-resistant P. Falciparum.
Funder
National Health and Medical Research Council
Funding Amount
$243,000.00
Summary
Malaria is a debilitating parasitic disease that is responsible for the deaths of about two million children each year. As drugs, such as chloroquine, become increasingly useless due to the development of parasite resistance, there is an urgent need to understand the mode of action of and the molecular basis of resistance to existing antimalarials and to design affordable treatments that can replace chloroquine. It is known that some compounds, that have only poor antimalarial activity themselve ....Malaria is a debilitating parasitic disease that is responsible for the deaths of about two million children each year. As drugs, such as chloroquine, become increasingly useless due to the development of parasite resistance, there is an urgent need to understand the mode of action of and the molecular basis of resistance to existing antimalarials and to design affordable treatments that can replace chloroquine. It is known that some compounds, that have only poor antimalarial activity themselves, can synergise the action of chloroquine. This may involve the inhibition of the activity of proteins that directly or indirectly extrude chloroquine from its site of action in the parasite's digestive apparatus. Unfortunately, thechloroquine synergisers examined to date have been too toxic to be useful in vivo. In preliminary studies we have identified some compounds that would be suitable for use in malaria patients, including a widely used antimalarial drug, primaquine, that can synergise the activity of chloroquine against chloroquine-resistant parasites. We will attempt to understand the molecular basis of this interaction. This will allow us to define optimal combinations of chloroquine and a resistance-reversing quinoline for use treating malaria. This could extend the clinical life of this important antimalarial drug. The information obtained may also help to design novel antimalarial drugs.Read moreRead less
Metabolomic Analysis And Membrane Transport Proteins In The Malaria Parasite
Funder
National Health and Medical Research Council
Funding Amount
$368,875.00
Summary
The malaria parasite is a single celled organism which invades the red blood cells of those it infects. There is no vaccine and the parasite is becoming increasingly resistant to the drugs that we have available. There is therefore an urgent need for new antimalarial strategies. Research in this area has been helped by the sequencing of the genome of the parasite. However we still don t know what most of the genes in the parasite do, and it is not a straightforward matter to find out. One of the ....The malaria parasite is a single celled organism which invades the red blood cells of those it infects. There is no vaccine and the parasite is becoming increasingly resistant to the drugs that we have available. There is therefore an urgent need for new antimalarial strategies. Research in this area has been helped by the sequencing of the genome of the parasite. However we still don t know what most of the genes in the parasite do, and it is not a straightforward matter to find out. One of the things hampering us in our efforts to develop new antimalarial drugs is our relatively poor understanding of the sorts of biochemical pathways that the parasite relies on to support its high rate of growth and replication inside the red blood cell, as well the biochemical mechanisms that enable it to becomes drug-resistant. In this study we will use a range of modern analytical techniques to carry out the first detailed survey of the biochemical composition - the so-called metabolome - of the parasite. We will investigate how this changes in response to nutrient deprivation, in response to mutations in genes which play a key role in antimalarial drug resistance and in response to changes in the expression of genes encoding proteins which we believe to be involved in the uptake of nutrients by the parasite. This project will provide us with a wealth of new information about the biochemical make-up of the parasite, and it will provide new insights into the biochemical pathways that are operating and which might be targeted with new drugs. The work is likely to provide new insights into mechanisms of antimalarial drug resistance. It will also form the basis for a strategy that is likely to be extremely useful in helping us to ascribe function to the many genes involved in the biochemistry of this important human pathogen.Read moreRead less
Protecting The Efficacy Of Antimalarial Therapies With Novel Approaches To Suppress The Emergence Of Drug Resistance
Funder
National Health and Medical Research Council
Funding Amount
$408,768.00
Summary
The global campaign to eliminate malaria is under serious threat from the continuing emergence and spread of Plasmodium falciparum parasites resistant to antimalarial drugs. However in acquiring resistance to one drug, the parasite can become more susceptible to other antimalarials. This project aims to 1) test the ability of drug pairs with opposing selection forces to suppress resistance in vitro and 2) define the physiological and molecular basis of these opposing evolutionary forces.
Exported Epoxide Hydrolases Of The Malaria Parasite, Plasmodium Falciparum, And Their Role In Modulation Of Host Vasoregulation
Funder
National Health and Medical Research Council
Funding Amount
$342,054.00
Summary
The major aim of this study is to define the physiological role of the parasite EHs, and to establish whether they modulate levels of EETs within infected erythrocytes. I will examine if infected erythrocytes have impaired vasoactive properties and also determine if this pathway has therapeutic potential
Human Malarial Immunity And Assessment Of Emerging Artemisinin Resistance
Funder
National Health and Medical Research Council
Funding Amount
$312,570.00
Summary
Resistance to antimalarial drugs is a major global threat for malaria treatment, control and elimination. Assessment of the spread of resistance is severely impeded by the presence of host immunity. This project will identify population biomarkers of immunity during antimalarial treatment to include in studies of antimalarial resistance. These findings will facilitate the correct assessment of the global spread of antimalarial resistance.