α11β1 Integrin-Dependent Regulation of Periodontal Ligament Function in the Erupting Mouse Incisor

SN Popova, M Barczyk, CF Tiger… - … and cellular biology, 2007 - Taylor & Francis
SN Popova, M Barczyk, CF Tiger, W Beertsen, P Zigrino, A Aszodi, N Miosge, E Forsberg…
Molecular and cellular biology, 2007Taylor & Francis
The fibroblast integrin α 11β1 is a key receptor for fibrillar collagens. To study the potential
function of α 11 in vivo, we generated a null allele of the α 11 gene. Integrin α 11−/− mice are
viable and fertile but display dwarfism with increased mortality, most probably due to
severely defective incisors. Mutant incisors are characterized by disorganized periodontal
ligaments, whereas molar ligaments appear normal. The primary defect in the incisor
ligament leads to halted tooth eruption. α 11β1-defective embryonic fibroblasts displayed …
The fibroblast integrin α11β1 is a key receptor for fibrillar collagens. To study the potential function of α11 in vivo, we generated a null allele of the α11 gene. Integrin α11−/− mice are viable and fertile but display dwarfism with increased mortality, most probably due to severely defective incisors. Mutant incisors are characterized by disorganized periodontal ligaments, whereas molar ligaments appear normal. The primary defect in the incisor ligament leads to halted tooth eruption. α11β1-defective embryonic fibroblasts displayed severe defects in vitro, characterized by (i) greatly reduced cell adhesion and spreading on collagen I, (ii) reduced ability to retract collagen lattices, and (iii) reduced cell proliferation. Analysis of matrix metalloproteinase in vitro and in vivo revealed disturbed MMP13 and MMP14 synthesis in α11−/− cells. We show that α11β1 is the major receptor for collagen I on mouse embryonic fibroblasts and suggest that α11β1 integrin is specifically required on periodontal ligament fibroblasts for cell migration and collagen reorganization to help generate the forces needed for axial tooth movement. Our data show a unique role for α11β1 integrin during tooth eruption.
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