The Role Of Cell Adhesion Molecules In Regulation Of Axon Advance
Funder
National Health and Medical Research Council
Funding Amount
$426,006.00
Summary
All cells contain on their surface a class of molecules, cell adhesion molecules, that enable them to adhere to other cells in tissues. Cell adhesion molecules have long been known to be involved in the guidance of axons to their targets during development. However the molecular mechanisms by which these molecules act are largely unknown. We propose to use the powerful genetic tools available in the fruitfly to dissect the mechanisms by which two cell adhesion molecules promote axon growth.
Cellular Mechanisms Controlling Neural Crest Cell Migration Along The Developing Gut
Funder
National Health and Medical Research Council
Funding Amount
$368,895.00
Summary
Within the wall of the gut, there are a large number of neurons, probably more than are in the spinal cord. These enteric neurons play an essential role in controlling a number of gut functions including peristalsis (the propulsion of contents along the gut). Most of the neurons in the gut, including those in the large intestine, arise from precursors that emigrate from the hindbrain, and then migrate into and along the gastrointestinal tract during development. The colonization of the gut by ne ....Within the wall of the gut, there are a large number of neurons, probably more than are in the spinal cord. These enteric neurons play an essential role in controlling a number of gut functions including peristalsis (the propulsion of contents along the gut). Most of the neurons in the gut, including those in the large intestine, arise from precursors that emigrate from the hindbrain, and then migrate into and along the gastrointestinal tract during development. The colonization of the gut by neuron precursors takes 5 days in mice and 6 weeks in humans. Studies of the mechanisms controlling the migration of neuron precursors along the gut have provided fundamental information about cell migration in general. Genetic studies in humans and mice have identified some of the genes that are necessary for the migration of neuron precursors along the gastrointestinal tract, but for some of the key genes, their precise role is unknown. We have recently developed a method for imaging living neuron precursors migrating through explants of embryonic mouse gut. In the current proposal we will meld imaging and genetic studies to understand how mutations in particular genes lead to migration defects. In particular, how do particular mutations affect the migratory behaviour of enteric neural precursors? We have also previously shown that neuron precursors migrate along the gut in close association with axons. We will examine the nature of these interactions - in particular, who is following whom, and what happens when cell migration and axon growth are uncoupled? These studies, which will investigate a number of critical aspects of the migration of neural precursors into and along the developing gut, are central to understanding how the enteric nervous system is established along the gastrointestinal tract.Read moreRead less
Migration And Differentiation Of Enteric Neuron Precursors
Funder
National Health and Medical Research Council
Funding Amount
$385,116.00
Summary
There are many millions of nerve cells within the wall of the intestine, and they control many intestinal functions, including motility. During development, these nerve cells arise from cells which migrate away from the developing brain and first enter the stomach. The migratory cells are called neural crest cells. After entering the stomach, neural crest cells migrate within the wall of the gastrointestinal tract, until they reach the far (anal) end. In embryonic mice, this colonisation of the ....There are many millions of nerve cells within the wall of the intestine, and they control many intestinal functions, including motility. During development, these nerve cells arise from cells which migrate away from the developing brain and first enter the stomach. The migratory cells are called neural crest cells. After entering the stomach, neural crest cells migrate within the wall of the gastrointestinal tract, until they reach the far (anal) end. In embryonic mice, this colonisation of the entire small and large intestines by neural crest cells takes over 4 days, and in humans the process probably takes at least one week. It is essential that the neural crest cells colonise the entire gastrointestinal tract, since regions of intestine lacking neural crest cells (and hence nerve cells) cannot function and intestinal contents build up in front of the region lacking nerve cells. This condition is found in some babies (Hirschsprung's disease), and it can only be treated by surgically removing the region lacking nerve cells. It is therefore essential that migratory neural crest cells colonise the entire gastrointestinal tract. Currently, little is known about the mechanisms controlling the migration of neural crest cells, and whether a) particular molecules within the gut wall are important for migration, and-or b) the migratory behaviour of the neural crest cells is regulated mostly by the neural crest cells themselves. In this study we will take time-lapse images of neural crest cells migrating through the gut of embryonic mice to identify the factors that are important for the migration. After the neural crest cells have colonised the entire intestine, they develop into different types of nerve cells. We will also examine some of the factors affecting the development of different types of nerve cells.Read moreRead less
Throughout our lives cells must die and be replenished. One way multicellular organisms remove unwanted cells is through a process called programmed cell death. This process eliminates redundant, damaged or infected cells by a program of cell suicide. We are studying the underlying molecular mechanisms of this cell suicide in order to design new pharmaceuticals to treat illnesses caused by a disruption in programmed cell death. The fine balance between living and dying cells must be maintained a ....Throughout our lives cells must die and be replenished. One way multicellular organisms remove unwanted cells is through a process called programmed cell death. This process eliminates redundant, damaged or infected cells by a program of cell suicide. We are studying the underlying molecular mechanisms of this cell suicide in order to design new pharmaceuticals to treat illnesses caused by a disruption in programmed cell death. The fine balance between living and dying cells must be maintained and if this balance is lost then disease may result. A reduced level of cell death may result in cancers while too many dying can contribute to degenerative diseases such as Alzheimer's disease and stroke. Currently many of these diseases do not have effective treatments. We will determine the three-dimensional structures of key proteins involved in programmed cell death and use this information to design drugs that can interfere with the molecular processes involved in signalling cell death. Such drugs may prove useful new therapies in a wide range of diseases caused by a breakdown in the biochemical paths to cell death.Read moreRead less
The Molecular Basis For Target Selection In The Central Nervous System By Sensory Axons
Funder
National Health and Medical Research Council
Funding Amount
$251,325.00
Summary
The normal function of the brain depends upon the specific connections that nerve cells make with each other. These connections are set up in the developing embryo when nerve cells send out long processes - axons - which grow towards their synaptic targets. How axons select their correct targets from amongst the millions of alternatives in the developing brain is unknown. A better understanding of this problem will help us develop therapies to assist regenerating axons re-establish correct conne ....The normal function of the brain depends upon the specific connections that nerve cells make with each other. These connections are set up in the developing embryo when nerve cells send out long processes - axons - which grow towards their synaptic targets. How axons select their correct targets from amongst the millions of alternatives in the developing brain is unknown. A better understanding of this problem will help us develop therapies to assist regenerating axons re-establish correct connections following injury to the brain or spinal cord. We propose to use a simple model system, the embryo of the fruitfly Drosophila, to find molecules that are involved in this process of neuron target recognition - ' axon targeting' molecules - and to study how they work. Drosophila can be genetically manipulated in ways not possible in higher animals. Furthermore the simplicity of its nervous system means that we can determine the connections of individual nerve cells with a high degree of precision. In the first part of our project, we will examine Drosophila embryos that carry mutations in genes suspected to code for targeting molecules. We will stain individual sensory nerve cells in these embryos with dyes to reveal the anatomy of their axons in the brain. If sensory axons terminate abnormally in the brain of a given mutant, the affected gene is likely to code for an axon targeting molecule. In the second part of the study, we will investigate the functions of candidate axon targeting molecules using two approaches. Firstly, we will seek to determine whether the molecule acts in the sensory axons or in their target cells. Secondly, we will use time-lapse microscopy to study how the homing behaviour of the sensory axons is affected in mutant embryos. The results of these studies will lead us closer to an answer to the question: How do axons recognise their specific target cells in the brain?Read moreRead less
The Role Of Rnd Genes During Cortical Neurogenesis And Cell Migration
Funder
National Health and Medical Research Council
Funding Amount
$410,384.00
Summary
In order for the brain to function properly, tens of billions of neurons within it first have to be born, then find their proper location before connecting with other neurons in a highly ordered fashion. Failure of these key processes heavily impacts on subsequent brain function, and have been shown to underlie several disorders including epilepsy. This study will investigate how members of the Rnd gene family control cell production and positioning within the developing brain.
The Role Of Interferon Signalling In The Regulation Of Stroke
Funder
National Health and Medical Research Council
Funding Amount
$620,381.00
Summary
This project focuses on the role that inflammation plays in the progression of the type of neural injury seen in stroke victims. This project targets a specific pathway that is thought to be involved in the regulation of general inflammation but has not been greatly investigated in terms of the neural injury seen in stroke. Understanding the actions of this pathway may lead to future therapies that can be used to prime the brain to react in a positive way to stroke.
Brain Protection: A new therapeutic approach for Multiple Sclerosis In Multiple Sclerosis (MS), the immune system mistakenly attacks the brain. The immune attacks destroy myelin, the protective coat around electrical cables in the brain (demyelination). Current treatments for MS are only partially effective, and work by reducing the number and severity of these attacks. However, MS-related permanent disability in the majority of sufferers is due to the development of progressive MS, and current ....Brain Protection: A new therapeutic approach for Multiple Sclerosis In Multiple Sclerosis (MS), the immune system mistakenly attacks the brain. The immune attacks destroy myelin, the protective coat around electrical cables in the brain (demyelination). Current treatments for MS are only partially effective, and work by reducing the number and severity of these attacks. However, MS-related permanent disability in the majority of sufferers is due to the development of progressive MS, and current therapies do not reduce this progression. It is believed that one major cause of this permanent disability is permanent myelin loss. Interestingly, we have already shown that the growth factor LIF is made by the body during MS-like inflammation, and that it limits damage by directly protecting myelin-producing cells. However, the bodies own LIF production during inflammation is sub-maximal, because myelin protection can be enhanced by giving additional therapeutic LIF. This suggests that (1) The brain produces a defence response to harmful inflammation and that (2) This defence response can be enhanced therapeutically. We therefore want to define exactly how LIF enhances myelin survival. We have measured the response to LIF in myelin-producing cells, and have discovered that it strongly stimulates the production of the small protein galanin. We will now assess if galanin itself protects myelin and myelin-producing cells, and we will test this both in isolated cells and whole animal models. If galanin production is a major mechanism by which the body tries to limit the damage from abnormal inflammation during MS, then medications that mimic the action of galanin (which are already under development for different reasons) could become a major new therapy for Multiple Sclerosis.Read moreRead less
Identification Of Novel Mechanisms Governing Stage-specific Regulation Of The Human Globin Genes
Funder
National Health and Medical Research Council
Funding Amount
$481,826.00
Summary
Hemoglobin is the major protein in red blood cells and is essential for the transport of oxygen from the lungs to the tissues. The disorders of hemoglobin production are the commonest genetic diseases worldwide. These diseases can be markedly improved with elevation of the form of hemoglobin produced by the developing embryo, fetal hemoglobin. We have identified key factors important for fetal gene expression. Our goal is to translate these findings into therapies for the hemoglobin disorders.
How Does Fra-1 Regulate The Invasive Properties Of Tumour Cells?
Funder
National Health and Medical Research Council
Funding Amount
$468,119.00
Summary
Most cancer deaths occur when tumours spread and destroy vital body functions. The invasion of tumour cells into surrounding tissue is a critical step during the spread of cancer. This project aims to unravel the molecular mechanisms that control the ability of tumour cells to invade into surrounding tissue and subsequently spread to other sites in the body. We expect to identify potential targets to better diagnose and treat the spread of cancer.