Mineralocorticoid Receptors - Mechanisms Of Ligand- And Tissue- Specific Activation
Funder
National Health and Medical Research Council
Funding Amount
$126,848.00
Summary
Heart disease is a major cause of death and economic burden in Australia and throughout the world. The steroid hormone aldosterone controls salt and water balance, blood pressure and has a significant role in heart failure. Although drugs that block the aldosterone receptor significantly help patients with heart failure, their use is limited by side effects. This work will identify the profile of proteins that promote aldosterone effects and enable the development of heart-specific blockers.
Steroid hormones, such as estrogen and androgens, act in the body by locking onto 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 exerts its effects as an RNA, rather than as a protein. SRA is aberrantly expressed in breast cancer, raising the possibility t ....Steroid hormones, such as estrogen and androgens, act in the body by locking onto 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 exerts its effects as an RNA, rather than as a protein. SRA is aberrantly expressed in breast cancer, raising the possibility that it plays an important role in breast cancer cell proliferation. To better understand how estrogen signals in breast cancer and identify proteins that bind to SRA in cancer cells, we established a collaboration with the O'Malley group at Baylor College of Medicine in Texas (who discovered SRA). We have identified several novel SRA-binding proteins, each of which plays an important role to regulate estrogen and androgen action. Up to this point, we have used a model that has enabled proof of principle studies in the same cancer cells from which SRA was discovered (non-breast or prostate cancer). However, we now need to carefully study the role of these proteins in cancer cells relevant to breast and prostate cancer. Thus, we plan to investigate how these proteins interact with SRA, how they influence nuclear receptor activity and breast and prostate cancer cell proliferation, examine their role in activating other pathways of cell growth in cancer cells, assay the levels of each protein in a series of human breast cancer specimens and solve the physcial 3-D structure of these proteins complexed to the SRA RNA. This work will provide novel insight into several key areas of hormone action in breast and prostate cancer. We hope to identify new markers that can be used for improved diagnosis and for prognosis, and provide structural information for the development of novel therapeutics.Read moreRead less
Functional Role Of A Novel Coregulator In Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$563,146.00
Summary
Australia is facing a massive epidemic of diabetes and obesity (diabesity). These disorders afflict all age groups, including teenagers, and are a major burden to the health and wealth of Australia. The nuclear receptors and their coregulators are excellent targets for developing new therapeutics to combat these disorders. This grant will evaluate the functional role of SLIRP, a novel nuclear receptor coregulator, in metabolism and could provide new avenues for drug target development.
Structure-function Analysis Of Nuclear Receptor And Cofactor Action: Evidence For A Role In Muscle.
Funder
National Health and Medical Research Council
Funding Amount
$692,040.00
Summary
Hormone receptors have critical roles in almost all aspects of physiology by transducing the effects of hormones into metabolic responses. There are ~45 orphan hormone receptors encoded by distinct genes in humans, since all receptors are important in the treatment of human disease, the plethora of orphan receptors has been the catalyst for the development of a new paradigm, reverse endocrinology. Reverse endocrinology is the process whereby the orphan hormone receptor is used to search for a pr ....Hormone receptors have critical roles in almost all aspects of physiology by transducing the effects of hormones into metabolic responses. There are ~45 orphan hormone receptors encoded by distinct genes in humans, since all receptors are important in the treatment of human disease, the plethora of orphan receptors has been the catalyst for the development of a new paradigm, reverse endocrinology. Reverse endocrinology is the process whereby the orphan hormone receptor is used to search for a previously unknown hormone, and metabolic pathway. We are interested in the orphan hormone receptors, Rev-erbA and RVR, orphan members of the receptor superfamily. Rev-erb alpha expression is regulated by fibrates, widely used hypolipidemic drugs, and the circadian cycle. Rev-erbs mediate the regulation of lipid metabolism and peroxisomal beta oxidation. Furthermore, Rev-erbs are acutely induced during brain seizures, postulated to regulate cerebellar plasticity, and involved in growth control. In view of these critical regulatory roles, and the success of reverse endocrinology to date, we intend to complete the structural analysis of the Rev-erb and RVR as a tool to identify the hormone that binds this receptor. Hormone receptors recruit proteins called nuclear receptor cofactors, that function as regulators of gene expression. The cofactors regulate gene expression and development. Furthermore these cofactors, when misregulated result in the onset of disease and carcinogenesis, which underscores the need for achieving a high resolution view of their function in many tissues. Along these lines, we are interested in exmining the function of these cofactors in muscle. Understanding the molecular role of the NR cofactors during muscle differentiation will be a critical step toward elucidating the dysregulation-function of these proteins in muscle diseases, such as rhabdomyosarcoma and inflammatory myopathy that have cofactor deficiency.Read moreRead less