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
The Role Of The Mammalian Grainyhead-like Gene Family In Neural Tube Closure
Funder
National Health and Medical Research Council
Funding Amount
$569,541.00
Summary
Failure of the skin to close over the brain and spinal cord during human development results in the devastating congenital birth defects anencephaly and spina bifida, known collectively as the neural tube defects. These are the second most common congenital birth defects affecting 1:1000 pregnancies. Anencephaly is not compatible with life and affected babies die at birth. In contrast children with spina bifida survive, but suffer from limb paralysis, bowel and bladder dysfunction, learning diff ....Failure of the skin to close over the brain and spinal cord during human development results in the devastating congenital birth defects anencephaly and spina bifida, known collectively as the neural tube defects. These are the second most common congenital birth defects affecting 1:1000 pregnancies. Anencephaly is not compatible with life and affected babies die at birth. In contrast children with spina bifida survive, but suffer from limb paralysis, bowel and bladder dysfunction, learning difficulties and psycho-social disturbances. Our laboratories have identified a family of genes essential for the colsure of the neural tube in mammals. The aim of this proposal is to understand the mechanisms of action with a view to developing new therapeutics that mey be used preventatively in these conditions. We also hope that these studies may facilitate the development of a genetic test to screen couples at risk.Read moreRead less
UTILITY OF NOVEL BIOMARKERS IN THE PREDICTION OF MAJOR COMPLICATIONS OF TYPE II DIABETES MELLITUS
Funder
National Health and Medical Research Council
Funding Amount
$510,639.00
Summary
Diabetes is increasingly common. It can cause a variety of complications, the most serious being heart and kidney disease. The reasons why some patients develop such complications are not fully understood so it is difficult to predict who will be affected. The current project will use samples from a large international study of patients with diabetes to assess whether levels of specific markers in the blood help to predict major complications and clarify why they occur.
Restoration Of The Nigrostriatal Pathway In The Parkinsonian Brain
Funder
National Health and Medical Research Council
Funding Amount
$299,431.00
Summary
Many obstacles exist for cell transplantation in Parkinson's disease; namely poor restoration of the host brain circuitry due to incorrect graft placement. This results in incomplete motor function and unwanted side effects. Through iterative studies we endeavor to restore this circuitry by placing grafts in the appropriate location and promoting their survival and growth-integrations. This will require: optimizing the donor tissue and exposure of the graft to growth stimulating factors.
Wnt Signaling In Dopaminergic Neuronal Connectivity
Funder
National Health and Medical Research Council
Funding Amount
$564,721.00
Summary
A major obstacle in repairing the injured or diseased brain is inducing axons (nerve cell processes) to make the appropriate connections. This is especially true following cell replacement therapy (CRT) in Parkinson's disease (PD). We will examine the processes inducing axons in the dopamine pathways to grow. We hypothesize that Wnt signaling plays and important role and that therapeutic introduction of Wnt is required to repair the dopamine pathways following CRT in PD.
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
An Examination Of Motor Functioning In Autism And Asperger's Disorder: An Analysis Of Gait & Cortical Brain Activity.
Funder
National Health and Medical Research Council
Funding Amount
$120,220.00
Summary
Autism is a developmental disorder characterised by a triad of deficits: delayed and atypical language development, impaired development of social skills, and ritualistic and stereotypic behaviour. Although not part of the standard diagnosis, movement disorders and gait abnormalities have been clinically observed in autism similar to those seen in Parkinson's disease. In addition, individuals with Asperger's disorder may appear more clumsy, have a stiff or awkward way of walking, and exhibit poo ....Autism is a developmental disorder characterised by a triad of deficits: delayed and atypical language development, impaired development of social skills, and ritualistic and stereotypic behaviour. Although not part of the standard diagnosis, movement disorders and gait abnormalities have been clinically observed in autism similar to those seen in Parkinson's disease. In addition, individuals with Asperger's disorder may appear more clumsy, have a stiff or awkward way of walking, and exhibit poor coordination in posture and gesture. It has been suggested that there is disruption within the basal-ganglia-thalamocortical circuitry (the region connecting the frontal and sub-cortical structures), which may cause the motor dysfunction seen in autism and Asperger's disorder. Few studies have attempted to isolate particular stages of motor functioning which may account for the coordination and motor delay observed clinically in autism and Asperger's disorder. A recent study of ours found evidence to suggest that motor planning deficiencies may account for the 'clumsy' movement patterns frequently reported in the autism - Asperger's disorder literature. Therefore, the aim of this research is to provide a comprehensive neurobehavioural and neurophysiological analysis of motor functioning in young people with autism and Asperger's disorder to further examine the exact stages of motor processing which are deficient in these disorder groups. Recent retrospective studies have shown that even as infants children with autism exhibit clear features of motor disturbance, which, if detected and clearly defined, could advance early diagnosis. In addition to advancing the clinical definition of autism and Asperger's disorder, a careful examination of motor disturbance may also illuminate the neurobiological underpinnings of these disorders.Read moreRead less
Understanding The Metabolic Consequences Of Impaired AMPKa2 And NNOS� In Skeletal Muscle: Implications For The Metabolic Syndrome
Funder
National Health and Medical Research Council
Funding Amount
$575,527.00
Summary
The inability of muscle to utilise sugar from the blood is a major problem that contributes to obesity and Type 2 diabetes. Since the number of people with these diseases will at least double by 2030, we need to find out what causes this problem. We will examine whether two muscle proteins that are impaired in obesity and Type 2 diabetes are also responsible for impaired sugar utilisation. We think that increasing these muscle proteins will fix the _sugar problem�, and remedy these diseases.