ADAMTS-5 Activity And The Effect Of A Dominant-negative Mutant
Funder
National Health and Medical Research Council
Funding Amount
$540,235.00
Summary
Cartilage loss is a feature of arthritis and is caused by enzymes. We discovered that loss of a critical cartilage component is caused by the enzyme ADAMTS-5. We also discovered that a mutant form of ADAMTS-5 blocks the normal emzyme, possibly by a novel binding interaction. If we can understand how this interaction works, we can exploit it for the design of new arthritis therapies. This project aims to identify the novel interaction and improve out understanding of cartilage destruction.
Cartilage Destruction In Joint Disease: Studies With ADAMTS-4 And ADAMTS-5 Deficient Mice
Funder
National Health and Medical Research Council
Funding Amount
$540,600.00
Summary
In healthy joints the proteoglycan, aggrecan, gives cartilage compressive resilience to permit weight bearing, but in disease aggrecan is degraded by ADAMTS enzymes. The challenges to the field are to determine which ADAMTS is involved, when these enzymes are active and precisely where they come from. We hypothesise that ADAMTS-4 and-or ADAMTS-5 is involved in cartilage pathology. To test this hypothesis we aim to [1] Generate mice containing mutant ADAMTS-4 and-or -5 in all cells, or [2] in car ....In healthy joints the proteoglycan, aggrecan, gives cartilage compressive resilience to permit weight bearing, but in disease aggrecan is degraded by ADAMTS enzymes. The challenges to the field are to determine which ADAMTS is involved, when these enzymes are active and precisely where they come from. We hypothesise that ADAMTS-4 and-or ADAMTS-5 is involved in cartilage pathology. To test this hypothesis we aim to [1] Generate mice containing mutant ADAMTS-4 and-or -5 in all cells, or [2] in cartilage cells only. [3] Analyse mutant mice for changes in skeletal architecture, changes in ADAMTS mRNA and protein, and changes in aggrecan breakdown products. [4] Assess disease severity in mutant mice in in vivo models of joint disease. We already have mice with ADAMTS-4, or -5, mutated in all tissues and we are generating the double mutants now. We will also generate single and double mutants with dysfunctional enzymes in cartilage only. We will examine skeletal structure by histology and X-ray at all ages and monitor for expression of ADAMTS-1 and -9 to detect any compensatory over-production of other potential 'aggrecanases'. We will also do co-culture experiments in which cartilage and synovial cells from combinations of mutant and control mice will be incubated together to determine whether synovial ADAMTS can penetrate and degrade aggrecan in cartilage. Finally we will induce arthritis in mutant and control mice and monitor them to detect differences in the time of disease onset, the rate of disease progression and overall disease severity. A comparison of whole-mouse with cartilage only mutants in the in vivo models will complement the in vitro co-culture studies and determine whether other joint tissues such as synovium and joint capsule can also produce ADAMTS enzymes that destroy cartilage. This is not known. Together these experiments will reveal if, where and when ADAMTS-4 and-or -5 are active, and whether indeed they are the best targets for drug development.Read moreRead less