Can Vitamin D Prevent Diabetes By Improving Insulin Sensitivity And Secreation In Overweight Humans?
Funder
National Health and Medical Research Council
Funding Amount
$715,371.00
Summary
Vitamin D is mainly produced by the action of sunlight on skin. Low levels of vitamin D are becoming more common, as we work more indoors and avoid the sun and have been associated with type 2 diabetes. In proposed study, healthy overweight people, with low vitamin D, will be given vitamin D for 16 weeks to optimise blood levels of this vitamin. We will examine the changes in sugar metabolism. This study should provide important evidence on how vitamin D protects against diabetes and will suppor ....Vitamin D is mainly produced by the action of sunlight on skin. Low levels of vitamin D are becoming more common, as we work more indoors and avoid the sun and have been associated with type 2 diabetes. In proposed study, healthy overweight people, with low vitamin D, will be given vitamin D for 16 weeks to optimise blood levels of this vitamin. We will examine the changes in sugar metabolism. This study should provide important evidence on how vitamin D protects against diabetes and will support novel approaches to diabetes prevention.Read moreRead less
Type 2 diabetes is a health crisis in Australia. In this project, we will investigate the mechanisms whereby high glucose and fat impair pancreatic beta-cell function leading to type 2 diabetes. We will establish how endoplasmic reticulum stress and the protein Id1 are linked with loss of beta-cell gene expression and function. The information gained will further our understanding of the basic mechanisms regulating insulin secretion and provide new therapeutic targets for diabetes treatment.
Investigating The Novel Role Of SEPS1 In The Prevention Of Islet Beta Cell Failure And Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$535,804.00
Summary
SEPS1 is an important glucose-regulated protein whose function is to protect tissues from oxidative stress. Inhibition of SEPS1 by hyperglycaemia, is a mechanism for progression of Type 1 and Type 2 diabetes once hyperglycaemia supervenes. The overall aim of the project is to investigate the function of the novel SEPS1, using transgenic and knockout approaches.
New Molecular Mechanisms Of Islet Protection Against Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$673,259.00
Summary
Type 2 diabetes is an enormous health and economic burden. The mechanisms of ?-cell compensation for insulin resistance and of ?-cell failure in type 2 diabetes are unclear. This proposal will test the novel hypothesis that the adaptation of endoplasmic reticulum (ER) capacity mediates ?-cell compensation, and that the failure of ?-cell adaptation to ER stress causes diabetes. The studies will show that targeting ER capacity is an important novel strategy for type 2 diabetes therapy.
Reversal Of Diabetes In A Humanised Mouse Using A Clinically Applicable Vector System
Funder
National Health and Medical Research Council
Funding Amount
$842,173.00
Summary
Somatic gene therapy is one of the strategies that is being considered to cure Type I diabetes. Specifically, we wish to engineer liver cells to replace beta cell function. The aim of this project is to design a clinically-applicable protocol for the reversal of diabetes using a recombinant adeno-associated vector that delivers genes to human livers with high efficiency showing long term expression without pathogenicity and immunogenicity following a simple intra-peritoneal injection.
In Australia over 7% of the population have type 2 diabetes. This epidemic represents a major health problem. The majority of overweight individuals do not develop diabetes because their insulin-secreting pancreatic beta-cells adequately compensate with over-secretion. It is the failure of this so called, beta-cell compensation, that is fundamental to the development of diabetes. We propose that in susceptible individuals, a gradual rise in blood glucose levels resulting from obesity and insulin ....In Australia over 7% of the population have type 2 diabetes. This epidemic represents a major health problem. The majority of overweight individuals do not develop diabetes because their insulin-secreting pancreatic beta-cells adequately compensate with over-secretion. It is the failure of this so called, beta-cell compensation, that is fundamental to the development of diabetes. We propose that in susceptible individuals, a gradual rise in blood glucose levels resulting from obesity and insulin resistance leads to beta-cell failure and overt diabetes. This project will investigate the mechanisms responsible for beta-cell failure in a mouse model with a similar time-dependent progression to obesity and type 2 diabetes as that seen in humans. C57BL-KsJ db-db mice progress from a pre-diabetic phase of insulin over-secretion, obesity and insulin resistance to a diabetic state characterised by the appearance of high blood glucose and lipid levels and the loss of insulin secretory capacity. With age, there are also a reduced number of beta-cells because of increased cell death. db-db mice will be studied at different stages in their natural progression to diabetes to fully characterise the secretory dysfunction and the changes in beta-cell phenotype over the time-course of diabetes development. The use of laser capture microdissection will allow us to study selectively the actual beta-cells without contamination from the other cells of the pancreas. The mice will also be treated with an agent that lowers blood glucose levels without affecting lipids to test the influence of hyperglycaemia itself in the development of beta-cell dysfunction. We will also test if the changes observed in the mice are regulated independently by high glucose levels in cell culture systems. The role of one candidate protein called ID-1 will be investigated as a potential link between hyperglycaemia and the development of beta-cell dysfunction.Read moreRead less
Role Of The Adaptive Unfolded Protein Response In Beta-cell Compensation
Funder
National Health and Medical Research Council
Funding Amount
$581,715.00
Summary
Obesity is a strong risk factor for type 2 diabetes. Obese subjects with “robust” pancreatic beta-cells can sustain a compensatory response. Type 2 diabetes arises in subjects with beta-cells that are “susceptible” to dysfunction and death. We will investigate the role of the adaptive unfolded protein response in beta-cell compensation for obesity-associated insulin resistance. Findings will help explain why some individuals but not others develop type 2 diabetes.
Role Of Lysosomal Acid Lipase In Regulating Insulin Secretion
Funder
National Health and Medical Research Council
Funding Amount
$570,928.00
Summary
Type 2 diabetes (T2D) affects 7% of Australians and is a major cause of morbidity and mortality. A failure of insulin secretion contributes to T2D, and this is linked to the inability of insulin producing ?-cells to use lipids appropriately (lipotoxicity). Here we will study the role of a cellular body called the lysosome to regulate ?-cell lipid metabolism and insulin secretion. This work will greatly increase the understanding of ?-cell failure in T2D.
Role Of Islet ?-cell Failure In The Pathogenesis Of Non-alcoholic Steatohepatitis
Funder
National Health and Medical Research Council
Funding Amount
$560,111.00
Summary
Some people respond to obesity poorly developing diseases such as non-alcoholic steatohepatitis (NASH) and diabetes. Other people do not, safely storing the excess energy in non-abdominal fat. The applicants will study 2 obese strains of mice; one develops “adipose tissue restriction”, NASH and diabetes, the other does not. The hypothesis that failure of compensatory insulin secretion to over-nutrition is an upstream event causing adipose tissue restriction, followed by NASH, will be tested.