MT1-MMP and type II collagen specify skeletal stem cells and their bone and cartilage progeny.
Skeletal formation is dependent on timely recruitment of skeletal stem cells and their ensuing synthesis and remodeling of the major fibrillar collagens, type I collagen and type II collagen, in bone and cartilage tissues during development and postnatal growth. Loss of the major collagenolytic activity associated with the membrane-type 1 matrix metalloproteinase (MT1-MMP) results in disrupted skeletal development and growth in both cartilage and bone, where MT1-MMP is required for pericellular collagen dissolution. We show here that reconstitution of MT1-MMP activity in the type II collagen-expressing cells of the skeleton rescues not only diminished chondrocyte proliferation, but surprisingly, also results in amelioration of the severe skeletal dysplasia associated with MT1-MMP deficiency through enhanced bone formation. Consistent with this increased bone formation, type II collagen was identified in bone cells and skeletal stem/progenitor cells of wildtype mice. Moreover, bone marrow stromal cells isolated from mice expressing MT1-MMP under the control of the type II collagen promoter in an MT1-MMP-deficient background showed enhanced bone formation in vitro and in vivo compared with cells derived from nontransgenic MT1-MMP-deficient littermates. These observations show that type II collagen is not stringently confined to the chondrocyte but is expressed in skeletal stem/progenitor cells (able to regenerate bone, cartilage, myelosupportive stroma, marrow adipocytes) and in the chondrogenic and osteogenic lineage progeny where collagenolytic activity is a requisite for proper cell and tissue function.
Szabova
Ludmila
L
Matrix Metalloproteinase Unit, Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA.
Yamada
Susan S
SS
Wimer
Helen
H
Chrysovergis
Kaliopi
K
Ingvarsen
Signe
S
Behrendt
Niels
N
Engelholm
Lars H
LH
Holmbeck
Kenn
K
D017667:Adipocytes / Q000166:cytology; D000818:Animals; D001835:Body Weight; D001853:Bone Marrow / Q000201:enzymology; D001842:Bone and Bones / Q000033:anatomy & histology / Q000166:cytology* / Q000201:enzymology; D002356:Cartilage / Q000166:cytology* / Q000201:enzymology; D019070:Cell Lineage; D049109:Cell Proliferation; D019902:Chondrocytes / Q000166:cytology / Q000201:enzymology; D024043:Collagen Type II / Q000378:metabolism*; D053511:Matrix Metalloproteinase 14 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009928:Organ Specificity; D010012:Osteogenesis; D051381:Rats; D013234:Stem Cells / Q000166:cytology* / Q000201:enzymology*; D016019:Survival Analysis; D019076:Transgenes / Q000235:genetics; D015430:Weight Gain
D024043:Collagen Type II; D053511:Matrix Metalloproteinase 14