Regulation Of Bone Resorption And Formation In Health And Disease
Funder
National Health and Medical Research Council
Funding Amount
$5,596,183.00
Summary
Bone is continually being formed and broken down, and these two processes are critical forthe maintenance of a normal skeleton. These processes are dependent upon communication between the bone building and degrading cells, and the hormones growth factors and cytokines that are present in the circulation or produced in bone. The tightly regulated processes of bone formation and degradation need to remain equal, and are essential for the achievement and maintenance of skeletal strength and form. ....Bone is continually being formed and broken down, and these two processes are critical forthe maintenance of a normal skeleton. These processes are dependent upon communication between the bone building and degrading cells, and the hormones growth factors and cytokines that are present in the circulation or produced in bone. The tightly regulated processes of bone formation and degradation need to remain equal, and are essential for the achievement and maintenance of skeletal strength and form. Osteoporosis results from an excess of bone breakdown over formation, and our Program aims to identify the factors that regulate these processes, and develop new therapies that can modify them. We will also determine what it is about bone cell properties that make some cancers, especially those of breast and prostate, particularly prone to spread to bone.Read moreRead less
Overweight and obesity are at epidemic proportions in Australia, reflecting the pattern in the developed and developing world. The main cause appears to be an energy mismatch, with excessive caloric consumption. One response of the body to excessive nutrient supply is energy storage in fat tissue and to aid in this the body also generates new fat tissue, termed adipogenesis (also known in cells as fat cell differentiation). In many people who gain excess body weight, fat tissue is abnormal and d ....Overweight and obesity are at epidemic proportions in Australia, reflecting the pattern in the developed and developing world. The main cause appears to be an energy mismatch, with excessive caloric consumption. One response of the body to excessive nutrient supply is energy storage in fat tissue and to aid in this the body also generates new fat tissue, termed adipogenesis (also known in cells as fat cell differentiation). In many people who gain excess body weight, fat tissue is abnormal and does not respond well to the chemical insulin, thus causing insulin resistance. This insulin resistant fat tissue is especially present in a central body (visceral) site. Insulin resistance related to this visceral fat predisposes to both diabetes and premature death from cardiovascular disease. Understanding how fat tissue develops and how it might cause insulin resistance is thus important in human health. One of the factors in fat that prevents normal development of fat tissue and which induces insulin resistance is transforming growth factor- (TGF- ). We have generated new data showing that two proteins which are increased by TGF- , termed connective tissue growth factor (CTGF) and insulin like growth factor binding protein-3, (IGFBP-3), prevent adipogenesis. We have shown this in cultured cells, and have found that CTGF and IGFBP-3 are increased in visceral fat in animal models of obesity and insulin resistance. Our preliminary work has further indicated how CTGF and IGFBP-3 might each work in the fat cell to prevent adipogenesis. This proposal will determine if TGF- works through CTGF and IGFBP-3 to block adipogenesis, and it will define how CTGF and IGFBP-3 have their inhibitory effects on fat cell differentiation. Cells in culture will be utilised and an animal model of dietary induced obesity and insulin resistance will help to define whether CTGF and IGFBP-3 prevent adipogenesis in vivo, furthering our understanding in how abnormal fat tissue may develop.Read moreRead less
Inosine-5' Monophosphate Dehydrogenase (IMPDH) is an enzyme responsible for providing a form of energy to cells, so that they may undertake their correct functions. Recently, we have demonstrated that IMPDH also has a role in the formation of fat droplets within cells, when they are exposed to excessive nutrients. In mammals, excess consumed energy is stored as fat droplets within all cells. In fat cells, the energy is stored in very large droplets, and we see this as extra body fat. This is som ....Inosine-5' Monophosphate Dehydrogenase (IMPDH) is an enzyme responsible for providing a form of energy to cells, so that they may undertake their correct functions. Recently, we have demonstrated that IMPDH also has a role in the formation of fat droplets within cells, when they are exposed to excessive nutrients. In mammals, excess consumed energy is stored as fat droplets within all cells. In fat cells, the energy is stored in very large droplets, and we see this as extra body fat. This is sometimes associated with an alteration in the hormone production of the cells, leading to problems such as diabetes. In other cells, the excess energy is stored as tiny fat droplets (lipid bodies) that can adversely affect the function of the cell. We have shown that blocking the action of IMPDH can interfere with the accumulation of fat in both fat cells and other types of cell. This suggests that IMPDH has an important role in the development of obesity and associated problems such as diabetes. In this study we aim to investigate in detail the role of IMPDH in the accumulation of fat droplets in cells. We will do this by looking at the effects of different forms of IMPDH in different cell types, including human fat cells. We will also study cells and animals with increased or decreased amounts of IMPDH, and investigate the effects of this on the development of increased fat stores and insulin resistance. These studies will increase our understanding of the role of IMPDH in the development of obesity, and may lead to identification of new avenues of treatment for obesity and type 2 diabetes.Read moreRead less