Nerve cell survival is dependent on both growth-promoting factors and factors released by neurotransmission, which can promote recovery in neurodegenerative conditions by overriding cell death pathways. The molecule responsible for activating death pathways in the nervous system is called p75. This project will investigate how p75 results in cell death, how synaptic signals can prevent the activation of the p75 death pathway and whether blocking p75 function can limit neurodegeneration.
Characterisation Of Neuregulin-2 Function In The Nervous System.
Funder
National Health and Medical Research Council
Funding Amount
$183,250.00
Summary
The Neuregulins (NRG's) are a family of four structurally related growth factors expressed in the developing and adult brain. NRG-1 is essential for life and has been implicated in the development and maintenance of both neurons and glial cells, as well as being essential for normal heart formation. NRG-2 was identified by us and others as being closely related to NRG-1 and, like NRG-1, it is also expressed predominantly in neuronal populations of the brain. One striking feature of NRG-2 express ....The Neuregulins (NRG's) are a family of four structurally related growth factors expressed in the developing and adult brain. NRG-1 is essential for life and has been implicated in the development and maintenance of both neurons and glial cells, as well as being essential for normal heart formation. NRG-2 was identified by us and others as being closely related to NRG-1 and, like NRG-1, it is also expressed predominantly in neuronal populations of the brain. One striking feature of NRG-2 expression in the adult brain is its localisation to regions associated with neurogenesis (renewal of neurons from stem cell precursors). Outside the nervous system Neuregulin-2 can stimulate the proliferation and differentiation of epithelial cells. However, little is known about the activity of Neuregulin-2 in the brain. This grant proposal aims to study the biological functions of Neuregulin-2 in the developing and adult central nervous system. The experimental design is based on characterisation of mice that do not contain the Neuregulin-2 gene. We will also look specifically at the action of Neuregulin-2 on discrete populations of neuronal cells, grown in tissue culture. We expect that these studies will provide valuable insight into the role of NRG-2 in the brain and that they will be the basis for defining the mechanisms by which NRG-2 activity differs to that of the NRG family members. By studying factors that are involved in the development of the nervous system it is hoped that valuable insights will be made regarding repair and regeneration in the adult brain.Read moreRead less
How Does The P75 Neurotrophin Receptor Transmit Both Pro-survival And Pro-apoptotic Signals In Neurons?
Funder
National Health and Medical Research Council
Funding Amount
$265,500.00
Summary
Signaling by the two NGF receptors, TrkA and p75, determines the survival or death of sensory neurons and of certain brain neurons involved in memory and learning. The most baffling aspect of these receptors is that in most circumstances they cooperate with each other to maximise the survival of neurons when NGF is present, but in some situations they are opposed to each other. In the latter case, NGF treatment can lead to death, rather than rescue, of neurons. In the last three years we have de ....Signaling by the two NGF receptors, TrkA and p75, determines the survival or death of sensory neurons and of certain brain neurons involved in memory and learning. The most baffling aspect of these receptors is that in most circumstances they cooperate with each other to maximise the survival of neurons when NGF is present, but in some situations they are opposed to each other. In the latter case, NGF treatment can lead to death, rather than rescue, of neurons. In the last three years we have developed novel antisense oligonucleotides which can be used to switch off each receptor separately. These have been, and will continue to be, particularly valuable tools for our research. We have also uncovered a novel way in which the two receptors interact (via a signal transduction molecule known as SHC), which provides us with a competitive edge in this area. We have the expertise and equipment to identify and clone the missing factors that account for the paradoxical interactions between p75 and TrkA. A successful outcome from this project will have important benefits by improving our understanding of the factors controlling neuronal fate, and will help to develop treatments for neurodegenerative diseases.Read moreRead less
Roles Of Brain-derived Neurotrophic Factor In Plasticity Of Injured Sensory Neurons
Funder
National Health and Medical Research Council
Funding Amount
$461,443.00
Summary
The fundamental problem of how nerve cells respond to a nerve injury has long been studied by neuroscientists and clinicians. After a nerve injury outside the brain or spinal cord, ie, in the periphery, some sensory nerve cells die, some regenerate to reconnect to their targets, and some sprout to make abnormal connections. Recent evidence from our lab and others indicates that the nerve sprouting is linked to chronic pain experienced by nerve-injury patients. However, how these changes occur st ....The fundamental problem of how nerve cells respond to a nerve injury has long been studied by neuroscientists and clinicians. After a nerve injury outside the brain or spinal cord, ie, in the periphery, some sensory nerve cells die, some regenerate to reconnect to their targets, and some sprout to make abnormal connections. Recent evidence from our lab and others indicates that the nerve sprouting is linked to chronic pain experienced by nerve-injury patients. However, how these changes occur still remains largely unknown. Our recent studies showed that growth factors, particularly brain-derived neurotrophic factor (BDNF) which is made by the sensory nerve cells, may play important roles in mediating these changes. This proposed project, directly evolved from our recent exciting findings, aims to further examine roles and action mechanisms of BDNF and its relatives in regulating the responses of sensory nerve cells to a nerve injury. We propose that after an injury, BDNF promotes survival of some nerve cells, enhances sensory nerve regeneration in both periphery and spinal cord, and also mediates abnormal nerve sprouting and is involved in neuropathic pain. With strong expertise and powerful tools in hand, we have designed a series of experiments to investigate the roles and action mechanisms of BDNF and its related molecules in these processes. Results from this project will help us understand mechanisms underlying the responses of nerve cells to a nerve injury, and should provide much needed information which would help in designing new methods for enhancing nerve cell survival and nerve regeneration as well as for inhibiting nerve injury-induced chronic pain in nerve-injury patients.Read moreRead less
Identification And Origin Of Neuronal Precursors In The Adult Mouse Hippocampus
Funder
National Health and Medical Research Council
Funding Amount
$284,250.00
Summary
It is now clear that new neurons continue to be generated under normal conditions in at least 2 regions of the adult mammalian brain: the olfactory bulb (smell centre) and the hippocampus (organ responsible for memory and learning). These new neurons replace those lost as part of aging and, as such, are vital to normal brain function. Recently, these results have been extended to show that various insults, such as stroke, can cause the proliferation of precursor cells in the adult brain, which u ....It is now clear that new neurons continue to be generated under normal conditions in at least 2 regions of the adult mammalian brain: the olfactory bulb (smell centre) and the hippocampus (organ responsible for memory and learning). These new neurons replace those lost as part of aging and, as such, are vital to normal brain function. Recently, these results have been extended to show that various insults, such as stroke, can cause the proliferation of precursor cells in the adult brain, which ultimately results in the addition of new nerve cells that go on to repair the pathological damage. Although the production of new nerve cells under normal conditions and following damage is highly significant, we still know surprisingly little about the nature of the precursor population which produces these cells and even less about their regulation. For the most part, this has been due to our inability to identify and isolate the brain stem cell. Thus, over the last 5 years I have adapted cell sorting techniques - which are normally used to separate blood cells to isolate populations of cells from the brains of adult mice. As a result of my work, we are now in the position to sort for a population of stem cells that are known to give rise to new brain cells in the adult olfactory bulb. This work will be extended to identify and characterise the precursor population that resides in the hippocampus. The identification of this hippocampal precursor population will thus provide the foundation for developing new approaches for the treatment of diseases such as strokeRead moreRead less
A -induced Cell Death Signalling By The P75 Neurotrophin Receptor.
Funder
National Health and Medical Research Council
Funding Amount
$546,382.00
Summary
The amyloid peptide A is central to the cause of Alzheimer's disease. We have recently found that A can activate the cell death receptor p75NTR which is found in the nerve cells that die in Alzheimer's disease. This project will study whether this death pathway underpins the neuronal death associated with Alzheimer's disease. It will also determine the mechanism by which A activates p75NTR death signalling, and identify biochemical ways to prevent this from occurring.
Regulation Of Brain Development By Members Of The Fibroblast Growth Factor Family
Funder
National Health and Medical Research Council
Funding Amount
$65,685.00
Summary
The brain is the most complex organ in the body. It is made up of many different types of cells broadly classified into two classes called neurons and glia. The growth of the brain from a small population of immature neuroepithelial cells to many different types of neurons and glia is controlled by small potent proteins called growth factors. We understand that many different families of growth factors are involved in the development of the brain but not how they do what they do. We are studying ....The brain is the most complex organ in the body. It is made up of many different types of cells broadly classified into two classes called neurons and glia. The growth of the brain from a small population of immature neuroepithelial cells to many different types of neurons and glia is controlled by small potent proteins called growth factors. We understand that many different families of growth factors are involved in the development of the brain but not how they do what they do. We are studying the members of one particular family known as the Fibroblast Growth Factor family or FGFs. We want to find out how they instruct young brain cells to grow and divide and turn into mature neurons.Read moreRead less