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
Many infants and children suffer from bowel motility disorders, for example, chronic constipation affects up to 1 in 10 children. However, the cause of many of these paediatric motility disorders remains unknown. In this project, we will examine the development of wiring of the nervous system that controls bowel motility. This is the first study to investigate the development of cell-cell communication during early stages of nervous system development.
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 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 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
A New Function For An Old Enzyme: Src Protein Kinase Directs Excitotoxic Neuronal Death In Stroke
Funder
National Health and Medical Research Council
Funding Amount
$513,975.00
Summary
In our previous investigation of how brain cells die in patients suffering from stroke, we found that stroke causes aberrant activation of an enzyme called Src in the affected brain cells. Furthermore, this aberrantly activated Src directs the brain cells to undergo cell death. Our proposal, which aims to decipher this neurotoxic mechanism of the aberrantly activated Src will benefit development of new therapeutic strategies to reduce brain damage in stroke patients.
Promoting Regrowth Of Nerve Fibres Into The Epidermis During Diabetic Neuropathy By LRP Agonists
Funder
National Health and Medical Research Council
Funding Amount
$427,102.00
Summary
Nerve damage can develop post injury or disease and is often very debilitating, slow to heal and can cause increased pain. Our work aims to examine a new class of molecules that we show can activate selected fat-receptors on nerve cells to guide the growth of regenerating nerves. We will determine how these receptors function with the aim of developing a novel class of therapeutics directed at healing nerve damage.
Aurora Kinase: Molecular, Cellular And Functional Studies Deciphering Its Role In Stroke Injury
Funder
National Health and Medical Research Council
Funding Amount
$580,993.00
Summary
In stroke patients, oxygen deprivation indirectly induces massive nerve cell death by activating an enzyme called aurora kinase A (AURKA). We aim at unravelling (i) how AURKA is activated by oxygen deprivation, (ii) where the activated AURKA is localised in cells, and (iii) how the activated AURKA induces nerve cell death.The study will benefit development of therapeutic strategies to protect against brain damage in stroke since this is novel and different target for drug targeting.
Characterisation Of Eurl, A Novel Gene Implicated In The Etiology Of Abnormal Brain Development And Intellectual Disability
Funder
National Health and Medical Research Council
Funding Amount
$597,541.00
Summary
Intellectual disability affects around one per cent of Australians, and can arise from genetic abnormalities during fetal life, such as through abnormal regulation of gene expression. We have identified a novel gene, known as eurl, which controls brain assembly as well as the ability of neurons to form functional connections within the brain. We will investigate how this novel gene controls brain development, and characterise eurl as a potential therapeutic target for learning and memory.