In vivo assessment of class-specific inducible inhibitors of metalloproteinases in osteoarthritis
File(s)
Author(s)
Lo Cascio, Leandro
Type
Thesis
Abstract
The role of articular cartilage is providing a painless and attrition-free surface for
joints movements. Osteoarthritis (OA) is a debilitating multifactorial pathology
characterized by progressive articular cartilage loss, exposition of the bone
surface accompanied by pain, and final loss of joint functions. To date there is
not an effective alternative to surgical replacement of damaged joints.
Metalloproteinases (MPs) play an important role in cartilage remodelling both in
physiological and pathological conditions. Among the metalloproteinases, the
aggrecanase family was shown to be the major family responsible for aggrecan
breakdown, while matrix metalloproteinases (MMPs) target preferentially the
collagen molecules. Tissue inhibitor of metalloproteinases (TIMPs) are the
endogenous regulators of those enzymes and in particular TIMP-3 was found to
possess the broadest activity. So far all synthetic MP inhibitors failed in trials for
OA treatment, and TIMP-3 may prove to be a possible alternative. Notably
several synthetic mutants were generated to restrict its activity towards
metalloproteinases.
In order to test the potential therapeutic effects of these proteins, I decided to
employ transgenic overexpressing mice. However I appreciated that it is of
paramount importance to restrict the exogenous expression just to cartilage.
Moreover because it was previously observed that overexpression of TIMP-3 in
cartilage severely affects bone development and caused embryonic lethality, I
decided to generate tissue specific inducible transgenic mice. I focused on the
Aggrecan promoter in order to achieve specific cartilage expression and the
Cre/loxP system to obtain inducible expression.
Here I show the design and generation of a new aggrecan-driven Cre deleter
mouse line. These mice can effectively target floxed genes in cartilage. I also
show the generation of inducible TIMP-expressing mouse lines for both a
cartilage-specific and ubiquitous expression.
I aim to induce OA in those transgenic mice, after induction of TIMPs
expression, to evaluate the inhibitors role in OA treatment.
joints movements. Osteoarthritis (OA) is a debilitating multifactorial pathology
characterized by progressive articular cartilage loss, exposition of the bone
surface accompanied by pain, and final loss of joint functions. To date there is
not an effective alternative to surgical replacement of damaged joints.
Metalloproteinases (MPs) play an important role in cartilage remodelling both in
physiological and pathological conditions. Among the metalloproteinases, the
aggrecanase family was shown to be the major family responsible for aggrecan
breakdown, while matrix metalloproteinases (MMPs) target preferentially the
collagen molecules. Tissue inhibitor of metalloproteinases (TIMPs) are the
endogenous regulators of those enzymes and in particular TIMP-3 was found to
possess the broadest activity. So far all synthetic MP inhibitors failed in trials for
OA treatment, and TIMP-3 may prove to be a possible alternative. Notably
several synthetic mutants were generated to restrict its activity towards
metalloproteinases.
In order to test the potential therapeutic effects of these proteins, I decided to
employ transgenic overexpressing mice. However I appreciated that it is of
paramount importance to restrict the exogenous expression just to cartilage.
Moreover because it was previously observed that overexpression of TIMP-3 in
cartilage severely affects bone development and caused embryonic lethality, I
decided to generate tissue specific inducible transgenic mice. I focused on the
Aggrecan promoter in order to achieve specific cartilage expression and the
Cre/loxP system to obtain inducible expression.
Here I show the design and generation of a new aggrecan-driven Cre deleter
mouse line. These mice can effectively target floxed genes in cartilage. I also
show the generation of inducible TIMP-expressing mouse lines for both a
cartilage-specific and ubiquitous expression.
I aim to induce OA in those transgenic mice, after induction of TIMPs
expression, to evaluate the inhibitors role in OA treatment.
Version
Open Access
Date Issued
2015-09
Date Awarded
2016-02
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Bou-Gharios, George
Publisher Department
Department of Medicine
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)