in: A Closer Look at Metalloproteinases, Lena Goodwin, Editor, NOVA Science Publishers Inc. , New-York, pp.153-249, 2019
Bone has a dynamic
structure, since it is remodelled during the lifespan to sustain its structure
and function. Extracellular
matrix (ECM) is playing a tremendously important role, such as cell
adhesion, immobilization of growth factors and nucleation of mineralization in
bone development phase. It consists of proteins and leads the bone remodelling
by the combined osteoblast (bone-forming cells) and osteoclast (bone-resorbing
cells) activities. Besides, ECM behaves as a scaffold for mineral deposition. Matrix metalloproteinases (MMPs),
a family of zinc-depended
proteolytic enzymes, are the most important enzymes used for the degradation of
unrelated proteins and structural components present in ECM. MMPs are highly
expressed in mammalian bone and cartilage cells and are able to cleave
collagens, thus function as collagenases. Furthermore, they lead remodelling of
ECM in connection with tissue specific and cell anchored inhibitors. Functions
of MMPs may vary bone quality via bone resorption and formation, i.e.,
osteoblast recruitment and survival, angiogenesis, osteocyte viability and
function, chondrocyte proliferation and differentiation. Abnormal expression of
MMPs can be related to pathological conditions such as unstable bone
remodelling, particularly osteoporosis,
rheumatoid arthritis and osteoarthritis. In this chapter, bone tissue components, MMP
properties and functions, bone modelling, remodelling and resorption, repair
and regeneration, and pathological bone resorption will be discussed.