Determining The Impacts Of Epigenetic Modifying Drugs On Germline Programming And Offspring Health
Funder
National Health and Medical Research Council
Funding Amount
$863,918.00
Summary
New drugs have been developed that inhibit specific enzymes that regulate epigenetic pathways in cells. These pathways significantly affect growth and development in offspring and may represent a risk to future children of patients taking the drug. This project will determine these risks and provide data for developing clinical guidelines for safe use of the drugs.
Cohesin: Role In Germ Cell Chromosomal Segregation
Funder
National Health and Medical Research Council
Funding Amount
$435,526.00
Summary
At least 10 to 25% of all human fetuses have the wrong number of chromosomes (aneuploidy). Most of these abormal fetuses perish in utero, making it the leading known cause of early pregnancy loss. Aneuploidy is the leading genetic cause of developmental disabilities and mental retardation. Abundant evidence suggests that most of these chromosome abnormalities originate during unequal partitioning of genetic material (chromosomes) in eggs and sperm. The proposed project focuses on two related gen ....At least 10 to 25% of all human fetuses have the wrong number of chromosomes (aneuploidy). Most of these abormal fetuses perish in utero, making it the leading known cause of early pregnancy loss. Aneuploidy is the leading genetic cause of developmental disabilities and mental retardation. Abundant evidence suggests that most of these chromosome abnormalities originate during unequal partitioning of genetic material (chromosomes) in eggs and sperm. The proposed project focuses on two related genes, called Rec8 and Rad21, which we recently discovered in humans and mice. Due to that these genes are essential for chromosome separation in other species and they exists in species as diverse as yeast and humans, they may be responsible for accurate separation of chromosomes in germ cells in mammals. In this proposal, we will determine the role(s) of these molecules in controlling proper chromosome segregation by loss-of-function studies in genetically engineered mice lacking Rec8 and Rad21 genes. By analyzing the chromosomal abnormalities of the cells from these animals, we will gain critical information about the nature of chromosome partitioning disorders in humans.Read moreRead less
Metabolic And Molecular Determinants Of Embryo Viability
Funder
National Health and Medical Research Council
Funding Amount
$551,321.00
Summary
We know that our health as adults is influenced by the lifestyle of our mothers during pregnancy. In particular, increased risk of adult-onset diseases such as diabetes and cardiovascular disease occurs when small and lean infants at birth are raised in conditions where nutrient intake is not restricted and obesity occurs. This concept of fetal programming is now widely accepted. Our laboratory is leading research in a new concept, that of embryonic programming. We have extensive animal data dem ....We know that our health as adults is influenced by the lifestyle of our mothers during pregnancy. In particular, increased risk of adult-onset diseases such as diabetes and cardiovascular disease occurs when small and lean infants at birth are raised in conditions where nutrient intake is not restricted and obesity occurs. This concept of fetal programming is now widely accepted. Our laboratory is leading research in a new concept, that of embryonic programming. We have extensive animal data demonstrating that exposure of embryos to physiological perturbations alters fetal development, similarly to that occurring in nutrient restriction during pregnancy. Furthermore, there is data from IVF-derived children that their birth-weight is lower than expected, possibly due to the conditions used for conception in the laboratory. How does the response by eggs and embryos, at the time of conception, affect subsequent development? There has been some focus on changes to DNA that are not related to mutations, but structural changes in the DNA that alters gene expression. We call this epigenetics and epigenetic changes are found in embryos, including human embryos following IVF. However, no one knows how such epigenetic changes occur as a result of this stress response by the egg or embryo. Our proposal is to determine the mechanism of how epigenetic alterations take place in eggs and embryos. Our theory is that the mitochondria, the energy producing packages within all cells, are sending signals to the embryo's nucleus. When the egg or embryo finds itself in adverse conditions, the signals change as a result of changes in the energy balance. This in turn changes the activity of enzymes in the nucleus that regulates DNA structure. If we can prove that this relationship occurs, then we can assess these changes in human embryos that are excess to a patient's requirements and learn if programming takes place in human embryos.Read moreRead less
Neuroendocrine Mechanisms By Which Leptin Regulates Reproduction
Funder
National Health and Medical Research Council
Funding Amount
$447,750.00
Summary
The reproductive system is sensitive to alterations in body weight. In particular, low body weight causes the reproductive system to cease functioning. This is because the brain 'senses' metabolic status and responds by ceasing to secrete the brain hormone that drives the reproductive process. This hormone is gonadotropin releasing hormone that acts on the pituitary gland to control the release of gonadotropins. These, in turn, act on the gonads. How the brain perceives metabolic status is not k ....The reproductive system is sensitive to alterations in body weight. In particular, low body weight causes the reproductive system to cease functioning. This is because the brain 'senses' metabolic status and responds by ceasing to secrete the brain hormone that drives the reproductive process. This hormone is gonadotropin releasing hormone that acts on the pituitary gland to control the release of gonadotropins. These, in turn, act on the gonads. How the brain perceives metabolic status is not known. Leptin is a hormone that is produced by fat and acts on the brain. This appears to be one of the means by which the reproductive system is regulated. Leptin also regulates food intake and other brain processes. Leptin acts on specific cell types in the brain. Some of these may have dual function to regulated appetite as well as reproduction. The present proposal is for work to determine mechanisms within the brain that are altered by leptin. We will also determine which specific mechanisms relate to the regulation of gonadotropin releasing hormone. The work will provide information on how putative appetite regulators might affect the reproductive axis. Such work will provide a platform for design of pharmaceutical means to manipulate the reproductive axis and will impact on the design of drugs that regulate obesity. It is possible that drugs that developed to control obesity may affect the reproductive axis and the project will identify these.Read moreRead less
Role Of Tumour Suppressor Genes In Early Embryopathy
Funder
National Health and Medical Research Council
Funding Amount
$408,000.00
Summary
Assisted reproductive technologies (ART, such as IVF and related techniques) are successful treatments for most forms of infertility. Much of this is due to the high mortality of the resulting embryos. Typically, 45-80% of embryos produced by ART do not survive the first week. The high mortality of the early embryo seems to be a general feature of ART but its causes and effectors are incompletely defined. It has been established that this high mortality is largely due to a marked retardation in ....Assisted reproductive technologies (ART, such as IVF and related techniques) are successful treatments for most forms of infertility. Much of this is due to the high mortality of the resulting embryos. Typically, 45-80% of embryos produced by ART do not survive the first week. The high mortality of the early embryo seems to be a general feature of ART but its causes and effectors are incompletely defined. It has been established that this high mortality is largely due to a marked retardation in the rate of cell cycle progression by embryo cells, and commonly is associated with a form of cell 'suicide', known as apoptosis. In non-embryonic cells a group of genes known as the tumour suppressor genes (TSGs) are responsible for slowing cell-cycle progression and are commonly involved in inducing apoptosis following cell stress. The role of TSGs in the early embryo is not well studied. We have recently shown that the most important of the TSGs, P53, is normally kept at very low levels in the early embryo but that ART causes up-regulation of its expression. This upregulation is a major cause of the embryopathy associated with ART in an animal model but that genetic mutations that prevent P53 expression favours increased embryo development and viability. This project will examine whether ART also causes up-regulation other important TSGs and whether this occurs in human embryos. We will examine the hypothesis that ART increases the survival of embryos with mutations to the P53 gene (creating a postive genetic selection pressure in favour of these mutations); and which aspects of ART cause this positive selection. The project will demonstarte whether changes in the ART procedures have the potential to mitigate against selection of embryos bearing deletrious mutations.Read moreRead less
Characterisation Of The Pathways Leading To DNA Demethylation In The Embryo.
Funder
National Health and Medical Research Council
Funding Amount
$634,573.00
Summary
Complex living creatures like humans have specialised cells that co-operate to form important organs like brains and reproductive organs. Specialised cells have specific genes locked on or off. When a sperm fertilises an egg, all the switches of the genes that are locked on or off get reset to neutral so that the fertilised egg can divide and grow into all cell types in the body. We do not know how this resetting happens in the egg. This project seeks to discover the mechanism involved.