Endocrine And Molecular Regulation Of Placental CRH Expression
Funder
National Health and Medical Research Council
Funding Amount
$466,980.00
Summary
Approximately 70% of infant death is associated with premature birth. Preterm birth occurs in 6-10% of pregnancies, and there has been no reduction in the rates of premature birth in the last 30 years. This is largely because we remain ignorant of how normal and abnormal birth is controlled. Understanding the physiology of human pregnancy is a critical step in the development of ways to detect and prevent preterm birth. Our group has demonstrated a link between production of a hormone (corticotr ....Approximately 70% of infant death is associated with premature birth. Preterm birth occurs in 6-10% of pregnancies, and there has been no reduction in the rates of premature birth in the last 30 years. This is largely because we remain ignorant of how normal and abnormal birth is controlled. Understanding the physiology of human pregnancy is a critical step in the development of ways to detect and prevent preterm birth. Our group has demonstrated a link between production of a hormone (corticotrophin releasing hormone, CRH) in the placenta and the length of time the baby is carried in the mother. In women who will deliver prematurely a rise in CRH occurs earlier in the pregnancy and more rapidly, while in women who deliver late the rise occurs more slowly. This work has given rise to the concept of a biological clock that determines the length of time the fetus will be carried by the mother before birth, and in which production of CRH in the placenta plays a central role. We have been studying how the CRH gene is controlled in placental cells. We have discovered some regions in the DNA of the CRH gene which have important roles in controlling how much CRH is made by the placenta. The experiments described in this research project will determine the molecular mechanisms that control the production of CRH in the human placenta. This will be done in two ways: (1) by examining the DNA sequences involved in controlling expression of the CRH gene and (2) by identifying the proteins that actually perform the regulating functions that result in either increased or decreased amounts of CRH being produced by the placenta. This important information will help us better understand how normal and abnormal birth is controlled, and from that knowledge new ways to detect and prevent premature birth can be invented.Read moreRead less
Molecular Characterisation Of The Ligand-binding Domain Of The Mineralocorticoid Receptor
Funder
National Health and Medical Research Council
Funding Amount
$215,183.00
Summary
The steroid hormone aldosterone regulates blood pressure by controlling sodium retention. The important role of this hormone in blood pressure control is underlined by the fact that all known monogenetic hypertensive conditions involve aldosterone or sodium reabsorption. Aldosterone works by activating an intracellular 'receptor' protein that in turn switches on specific genes. The products of these genes act to produce sodium retention. Antagonists (blockers) of this receptor are used in the tr ....The steroid hormone aldosterone regulates blood pressure by controlling sodium retention. The important role of this hormone in blood pressure control is underlined by the fact that all known monogenetic hypertensive conditions involve aldosterone or sodium reabsorption. Aldosterone works by activating an intracellular 'receptor' protein that in turn switches on specific genes. The products of these genes act to produce sodium retention. Antagonists (blockers) of this receptor are used in the treatment of hypertension but have undesirable side effects. The design of new, more specific, antagonists has been slow because we do not understand how these drugs bind to the receptor and what effect they have on the protein. How the aldosterone receptor functions is poorly understood. This project aims to investigate the receptor in detail. We are in the process of determining regions of the receptor structure important for hormone binding. This information is vital for the design of new antagonists. The aldosterone receptor is unusual in that it is also activated by cortisol, a steroid hormone involved in stress and inflammation. By examining hormone binding it may be possible to determine if the two steroids activate the receptor in the same way. An understanding of how both natural hormones and synthetic antagonists function is impossible without thorough study of the receptor itself. We intend to examine fundamental aspects of aldosterone receptor function. In particular we wish to identify proteins that interact with the receptor. These proteins either enhance or inhibit the ability of the receptor to switch on genes and are vital to explaining the actions of both natural hormones and synthetic antagonists. Results from these experiments should advance our understanding of the basic biology of aldosterone action and its role in cardiovascular biology, and lead to the design of better receptor antagonists for use in the treatment of hypertension and cardiac fibrosis.Read moreRead less
Reversal Of Diabetes In Pigs Using Liver-directed Gene Therapy
Funder
National Health and Medical Research Council
Funding Amount
$573,807.00
Summary
Type I diabetes mellitus is caused by the autoimmune destruction of the beta cells of the pancreas that secrete insulin. We have shown that we can cure diabetes in spontaneously diabetic mice by delivery of the insulin gene to the liver using a non-pathogenic viral delivery system. The study aims to repeat this work in pigs which have similar physiology to humans. If successful this would be proof-of-principle that we could theoretically control blood glucose levels in humans.
Role Of Liver Receptor Homologue-1 (LRH-1) In Male Germ Cells
Funder
National Health and Medical Research Council
Funding Amount
$224,250.00
Summary
Historically the steroid sex hormones - oestrogens and androgens - have been regarded as female- and male- specific sex hormones, respectively. Oestrogens are produced by the ovary and regulate female-specific processes such as ovulation and development of female sexual characteristics, whereas androgens are produced by the testis and regulate male-specific functions. However it is now clear that the distinction between oestrogen and androgen is not a sharp one. For example, we now know that oes ....Historically the steroid sex hormones - oestrogens and androgens - have been regarded as female- and male- specific sex hormones, respectively. Oestrogens are produced by the ovary and regulate female-specific processes such as ovulation and development of female sexual characteristics, whereas androgens are produced by the testis and regulate male-specific functions. However it is now clear that the distinction between oestrogen and androgen is not a sharp one. For example, we now know that oestrogens are produced within the testis and play a very important role in male fertility. Human males patients who are unable to synthesise oestrogens are infertile. Similarly, mice that cannot produce oestrogens are also infertile, due to a defect in sperm production. Oestrogens are therefore critical for normal male fertility, and reduced oestrogen production within the testis may be a significant cause of infertility which would be easily treatable in the clinic. The protein LRH-1 regulates oestrogen production in other tissues. This proposal aims to identify the role of LRH-1 in testicular oestrogen production by identifiying the genes regulated by LRH-1 and the proteins that interact with it in the testis. We also aim to study the structure of these proteins in infertile men. These studies will define new genes associated with male infertility and may lead to the development of more effective treatments for this common condition.Read moreRead less
Mechanisms Of Pro-atherogenic Effects Of Androgens In Human Vascular Cells
Funder
National Health and Medical Research Council
Funding Amount
$211,320.00
Summary
Atherosclerosis is the most important cardiovascular disease and is now the leading cause of death in Western societies. A major clue to the causality of the disease is the striking gender gap in its prevalence and severity. The gender gap in atherosclerotic cardiovascular disease may be due to genetic, lifestyle or hormonal differences between males and females. Of these, hormonal differences are the most amenable to therapeutic intervention. Accordingly, there has been a lot of interest in the ....Atherosclerosis is the most important cardiovascular disease and is now the leading cause of death in Western societies. A major clue to the causality of the disease is the striking gender gap in its prevalence and severity. The gender gap in atherosclerotic cardiovascular disease may be due to genetic, lifestyle or hormonal differences between males and females. Of these, hormonal differences are the most amenable to therapeutic intervention. Accordingly, there has been a lot of interest in the potential protective effects of estrogens but few have studied the role of androgens with sophisticated approaches to androgen physiology and pharmacology. Clues from epidemiological and our recent studies suggest that androgenic influences on atherosclerosis may involve positive and negative effects on atherogenesis but the mechanisms are not understood. We now propose a comprehensive approach to studying androgenic effects on vascular biology both to enhance knowledge as well as potentially opening new therapeutic options in selective androgen receptor modulation.Read moreRead less
NR1F (ROR) Nuclear Hormone Receptors And Metabolism: Insights Into The Control Of Lipid Homeostasis.
Funder
National Health and Medical Research Council
Funding Amount
$581,892.00
Summary
ROR is a member of a gene family, that regulates reproduction, endocrine physiology, and metabolism, and are important in human health. ROR function remains illusive. However, it is expressed in liver, fat and muscle, tissues that (i) modulate blood lipids, insulin sensitivity and energy balance, and (ii) have an important role in diabetes and obesity. Understanding ROR function in metabolism provides the opportunity for the discovery of new pathways that ameliorate metabolic disease.
Steroid hormones, such as oestrogen and cortisol, act in the body by binding a family of proteins (nuclear receptors) that bind directly to the DNA to regulate genes. The mechanisms underlying this process are complex and involve recruitment of additional molecules or coactivators to improve efficiency. Recently a novel coactivator was identified termed SRA, which remarkably is never made into protein in cells, rather exerting its effects as a RNA. We have identified a novel family of proteins t ....Steroid hormones, such as oestrogen and cortisol, act in the body by binding a family of proteins (nuclear receptors) that bind directly to the DNA to regulate genes. The mechanisms underlying this process are complex and involve recruitment of additional molecules or coactivators to improve efficiency. Recently a novel coactivator was identified termed SRA, which remarkably is never made into protein in cells, rather exerting its effects as a RNA. We have identified a novel family of proteins that bind to SRA in cancer cells, and may well play a critical role in regulating how SRA modulates genes. This project seeks to understand how this family interacts with SRA, the functional effects on breast cancer cells, and the detailed 3-dimensional structure of the family members coupled with SRA. This work will provide novel insight into how SRA regulates steroid hormone action, and may create new potential avenues for developing therapeutics in breast cancer.Read moreRead less
Physiological Function Of The Novel Vitamin D Receptor Isoform
Funder
National Health and Medical Research Council
Funding Amount
$465,750.00
Summary
Vitamin D regulates a wide range of physiological systems including those involved in control of calcium blood level and bone health as well as regulation of the immune system and of cell growth. Vitamin D action is mediated through the vitamin D receptor (VDR), a member of a large family of proteins that regulate the activity of specific target genes that control numerous biological functions. A novel, larger form of the human VDR has recently been described in our laboratory. This novel form s ....Vitamin D regulates a wide range of physiological systems including those involved in control of calcium blood level and bone health as well as regulation of the immune system and of cell growth. Vitamin D action is mediated through the vitamin D receptor (VDR), a member of a large family of proteins that regulate the activity of specific target genes that control numerous biological functions. A novel, larger form of the human VDR has recently been described in our laboratory. This novel form shows differences in activity from the shorter VDR form (VDRA) and also has an unusual distribution within the nucleus of the cell that may relate to its function. The present project focuses on further analysis of the relevance of this novel VDR isoform to normal physiology. We hypothesise that the larger VDR isoform has unique characteristics that may modify how vitamin D works in different cells and tissues, on specific target genes and in response to different active forms of vitamin D. These differences depend on this novel isoform s interaction with specific nuclear proteins that regulate the actions of other hormone receptors. The specific aims of this project are to study the functions of the novel VDR isoform in comparison to VDRA: * On different target genes that are either activated or inhibited in response to vitamin D, and on different cell lines from tissues where vitamin D has important roles, like intestine, kidney and bone * In their response to natural and synthetic vitamin D compounds, because of their possible therapeutic applications * In their interactions with intranuclear regulatory proteins, to understand the underlying mechanisms The study of these two forms of the VDR will help to clarify their potentially different cellular roles and their contribution to the wide range of physiological processes regulated by the vitamin D endocrine system. This understanding may open new paths for treatments of human bone and calcium-related diseases.Read moreRead less