Premature birth is a major cause of neonatal death and intellectual and other handicaps among the survivors. While neonatal intensive care has improved the survival of premature babies, there has been no reduction in the number of premature babies born, in fact the numbers are increasing. Our inability to reduce premature birth is partly related to our lack of knowledge of the physiological processes that lead to normal labour. As a result many of our drugs for women in premature labour are not ....Premature birth is a major cause of neonatal death and intellectual and other handicaps among the survivors. While neonatal intensive care has improved the survival of premature babies, there has been no reduction in the number of premature babies born, in fact the numbers are increasing. Our inability to reduce premature birth is partly related to our lack of knowledge of the physiological processes that lead to normal labour. As a result many of our drugs for women in premature labour are not very effective. We have recently identified a novel pathway that regulates the activity of the muscle cells that form the uterus. This project seeks to understand the biochemical processes that change a muscle cell so that it begins to contract actively at the end of pregnancy. Specifically the project will examine two proteins called HSP20 and HSP27. These proteins have recently been reported to play a critical role in the contraction and relaxation of smooth muscle cells in the heart and blood vessels. We have identified for the first time that these proteins are also present in the muscle of the human uterus. It is likely that they play a critical role in regulating the contractions of the uterus. By understanding this process better we may be able to design better treatments to prevent premature birth.Read moreRead less
Premature birth is a major cause of neonatal death and intellectual and other handicaps among the survivors. While neonatal intensive care has improved the survival of premature babies, there has been no reduction in the number of premature babies born, in fact the numbers are increasing. Our inability to reduce premature birth is partly related to our lack of knowledge of the physiological processes that lead to normal labour. As a result many of our drugs for women in premature labour are not ....Premature birth is a major cause of neonatal death and intellectual and other handicaps among the survivors. While neonatal intensive care has improved the survival of premature babies, there has been no reduction in the number of premature babies born, in fact the numbers are increasing. Our inability to reduce premature birth is partly related to our lack of knowledge of the physiological processes that lead to normal labour. As a result many of our drugs for women in premature labour are not very effective. Our work has shown that a hormone called corticotrophin releasing hormone (CRH) made in the placenta plays a critical role in determining the length of a pregnancy. We have measured the levels of this hormone in the blood of pregnant women and shown that it increases more rapidly than normal in women who deliver prematurely and more slowly than normal in women who deliver late. It acts as a kind of clock to determine the length of pregnancy. What is not known is how this hormone acts to bring on labour. What is particularly puzzling is that some of the actions of the CRH seem likely to cause the uterus to relax rather than to contract. We wish to test the idea that the rapidly rising levels of this hormone in late pregnancy cause changes in the uterus that stop the pathways to relaxation and lead to contraction. To perform these studies we will use small pieces of uterus donated with informed consent from women undergoing caesarean section. The results of these studies may allow us to design better ways of preventing premature birth and prevent many cases of cerebral palsy and intellectual handicap.Read moreRead less
This project will test if the ratio of the two different estrogens found in the blood of pregnant women is the critical factor in determining the onset of contractions in the uterus at labour. The studies will also determine the role of a newly discovered receptor for estrogens in allowing powerful contractions at labour. Results will allow development of new treatments to prevent premature birth that block the actions of estrogen at this new receptor or change the ratio of the two estrogens.
Molecular Mechanisms Of Receptor Activation And Signalling
Funder
National Health and Medical Research Council
Funding Amount
$571,980.00
Summary
Fundamental to our ability to respond to both immediate and long-term environmental changes and stresses is the coordinated regulation of cellular functions by hormonal and neurotransmitter stimuli. The great majority of such stimuli are sensed by G-protein coupled receptors (GPCR), complex glycoprotein molecules on the surface of most cells that selectively bind and are activated by various hormones and neurotransmitters. Although GPCRs are a superfamily of proteins that now compromise several ....Fundamental to our ability to respond to both immediate and long-term environmental changes and stresses is the coordinated regulation of cellular functions by hormonal and neurotransmitter stimuli. The great majority of such stimuli are sensed by G-protein coupled receptors (GPCR), complex glycoprotein molecules on the surface of most cells that selectively bind and are activated by various hormones and neurotransmitters. Although GPCRs are a superfamily of proteins that now compromise several hundred distinct but structurally-related members, the molecular mechanisms involved in their activation and, thus, their regulation of vital cellular functions, remains unclear. Based on insights that we have gained from the development and characterisation of several alpha1-adrenergic receptor mutants, we have developed a model of receptor activation. In this application we are proposing to further test and to extend the hypotheses underlying this model. Importantly, the functions regulated by GPCR include vital responses, such as the maintenance of circulatory homeostasis by augmenting heart pump function and by constricting vascular smooth muscle to maintain blood pressure. In addition, disordered cellular regulation by GPCR has been implicated in a wide variety of diseases, including hypertension, congestive heart failure and cardiac hypertrophy. Thus, the studies detailed here to further understand the molecular mechanisms of receptor activation have broad implications for our knowledge of critical physiological control systems, and may lead to novel therapeutic approaches to treat a variety of diseases.Read moreRead less