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
Mechanisms Guiding Pathfinding And Positioning Of Cortical Interneurons
Funder
National Health and Medical Research Council
Funding Amount
$621,606.00
Summary
Brain disorders place an economic and social burden on Australia and the personal costs of these illnesses are immeasurable. Several brain abnormalities are caused from the failure of neurons to position themselves in the correct location when the brain develops. Our study aims to discover how neurons move and what factors influence this process. It provides an understanding of normal brain development, as well as providing insight into what may go wrong in the formation of brain diseases.
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.
NPY Suppresses Seizures And Modulates Thalamocortical Activity In Animal Models Of Generalized Epilepsy
Funder
National Health and Medical Research Council
Funding Amount
$386,020.00
Summary
Epilepsy is the most common serious chronic neurological disease in the community, affecting up to 3% of the population in a lifetime and 0.5-1% at any one time. Absence epilepsy is one of the most common types of epilepsy, most frequently seen in childhood and teenage years that may persist into adulthood. Anti-epileptic drugs are effective in controlling absence seizures in most patients, however there is an important group (20-40%) of patients in whom the absence seizures remain uncontrolled ....Epilepsy is the most common serious chronic neurological disease in the community, affecting up to 3% of the population in a lifetime and 0.5-1% at any one time. Absence epilepsy is one of the most common types of epilepsy, most frequently seen in childhood and teenage years that may persist into adulthood. Anti-epileptic drugs are effective in controlling absence seizures in most patients, however there is an important group (20-40%) of patients in whom the absence seizures remain uncontrolled with current medications. Recently there has been considerable interest in the role that chemical in the brain, such as neuropeptide Y (NPY), may play in epilepsy. The research proposed will examine the role of NPY in several animal models of absence epilepsy. We have recently shown that NPY suppresses absence seizures in a rat genetic model of generalised epilepsy, and that this appears to be mediated by Y2 receptors. This work will build on these novel findings, and determine the localisation of the effect within the brain, and the underlying mechanism. We will check NPY effects across several models in different species, a genetic rat model with spontaneous seizures, and in mice treated with a chemical to induce seizures. This will determine its broad applicability. We will also determine the effects of removal of NPY or NPY receptors on the effects of NPY on seizure expression. Finally, brain recording techniques will be applied to determine the mechanism and site within the brain underlying the protective actions of NPY. The project has the potential to provide novel insights into the role of NPY in the expression and modulation of absence seizures. NPY related mechanisms might represent targets for the development of a new class of therapeutic agents for the treatment of absence epilepsy. Targets that are identified as being important in the expression of absence seizures may also prove to be relevant in other types of generalised epilepsy syndromes.Read moreRead less
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
Understanding How Language And Reading Problems Develop: A Population-based Longitudinal Study From Infancy To Age 7
Funder
National Health and Medical Research Council
Funding Amount
$667,507.00
Summary
Early language and reading problems are common and therefore significant public health problems. They are disabling and have life-long implications for oral and written communication skills, social and emotional well-being, cognition, behaviour, academic achievement and employment. This study will address the following three problems: 1. To date no study has documented how language and reading problems develop from infancy (8 months) through to school age (7 years). 2. Little is known about risk ....Early language and reading problems are common and therefore significant public health problems. They are disabling and have life-long implications for oral and written communication skills, social and emotional well-being, cognition, behaviour, academic achievement and employment. This study will address the following three problems: 1. To date no study has documented how language and reading problems develop from infancy (8 months) through to school age (7 years). 2. Little is known about risk factors, identified early in infancy and childhood, that can be reliably used to predict language and reading problems later in childhood. 3. The relationships between language difficulties and reading problems are poorly understood. Therefore, we currently have no satisfactory methods for reliably detecting which children at much younger ages are at risk of later language disorders or reading problems. Without this information it is impossible to develop effective prevention and early intervention programs. These programs are critical if we are to: a) Prevent language and reading problems from occurring, thereby reducing the prevalence of the problem b) Intervene early in childhood, thereby reducing in the longer term the burden and cost associated with language and reading problems. The proposed study builds on an existing substantial investment by the NHMRC in the Early Language in Victoria Study (ELVS). It will provide a world-first description of the evolution of language difficulties and reading problems from infancy through to school age within a single population cohort.Read moreRead less
The Role Of GRHL-3, A Mammalian Homologue Of Drosophila Grainyhead, In Neural Tube Development
Funder
National Health and Medical Research Council
Funding Amount
$496,500.00
Summary
Spina bifida and anencephaly are two common human congenital malformations that form part of a wide spectrum of mutations known collectively as neural tube defects (NTDs). Patients with the most severe form of spina bifida have a failure of the vertebral column and skin to close over the spinal cord and therefore suffer from limb paralysis and marked bladder and bowel dysfunction. Infants with anencephaly have an open cranial vault and failure of normal brain development and die within the first ....Spina bifida and anencephaly are two common human congenital malformations that form part of a wide spectrum of mutations known collectively as neural tube defects (NTDs). Patients with the most severe form of spina bifida have a failure of the vertebral column and skin to close over the spinal cord and therefore suffer from limb paralysis and marked bladder and bowel dysfunction. Infants with anencephaly have an open cranial vault and failure of normal brain development and die within the first few hours of life. These abnormalities occur frequently (1-1000 live births) and are a direct result of failure of the neural tube to close during embryogenesis. NTDs are influenced by both environmental and genetic factors. The best characterised environmental factor is the dietary supplement folate, which when administered before conception results in a reduction in the incidence of spina bifida. The genetic complexity is evidenced by the array of mouse genetic mutations that give rise to NTDs. One of these mouse mutations, known as Curly tail (ct), has served as the major animal model of human NTDs. This is because the ct mice are resistant to folate administration (like most of the cases of spina bifida currently seen in patients) and because the mice seem to have normal development in virtually all other organ systems. Ironically, the genetic mutation that causes the curly tail phenotype has remained undiscovered for over 50 years. We have now identified the gene mutated in the curly tail mice. This gene is highly conserved in humans suggesting that it will play a similar role in neural tube development in man. The gene, known as GRHL-3, is a descendant of a fly gene critical for development of the nervous system in that organism. The studies we propose here will examine the developmental pathways involved in normal neural tube closure in mice and humans and will impact on our understanding of these devastating congenital malformations.Read moreRead less
Defining Genetic And Epigenetic Variation During Early Development
Funder
National Health and Medical Research Council
Funding Amount
$996,075.00
Summary
We all began life with a set of genes inherited from our parents. However, it's now known that from the time we were in the womb onwards that genes can be turned off and on by the environment or even completely lost or gained. Even what your mother ate or how she behaved while she was pregnant could have influenced your future health. Because people are so different, we are studying the subtle differences between twins to tease out the factors that may influence our genes and our health.
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.