Effect of Menin Deletion in Early Osteoblast Lineage on the Mineralization of an In Vitro 3D Osteoid-like Dense Collagen Gel Matrix

Ildi Troka; Gabriele Griffanti; Lucie Canaff; Geoffrey N Hendy; David Goltzman; Showan N Nazhat

doi:10.3390/biomimetics7030101

Effect of Menin Deletion in Early Osteoblast Lineage on the Mineralization of an In Vitro 3D Osteoid-like Dense Collagen Gel Matrix

Biomimetics (Basel). 2022 Jul 22;7(3):101. doi: 10.3390/biomimetics7030101.

Authors

Ildi Troka¹, Gabriele Griffanti², Lucie Canaff³, Geoffrey N Hendy³, David Goltzman³, Showan N Nazhat²

Affiliations

¹ Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC H3A 1G1, Canada.
² Department of Mining and Materials Engineering, McGill University, Montreal, QC H3A 0C5, Canada.
³ Department of Medicine, McGill University and McGill University Health Centre, Montreal, QC H4A 3J1, Canada.

Abstract

Bone has a complex microenvironment formed by an extracellular matrix (ECM) composed mainly of mineralized type I collagen fibres. Bone ECM regulates signaling pathways important in the differentiation of osteoblast-lineage cells, necessary for bone mineralization and in preserving tissue architecture. Compared to conventional 2D cell cultures, 3D in vitro models may better mimic bone ECM and provide an environment to support osteoblastic differentiation. In this study, a biomimetic 3D osteoid-like dense collagen gel model was used to investigate the role of the nuclear protein menin plays in osteoblastic differentiation and matrix mineralization. Previous in vitro and in vivo studies have shown that when expressed at later stages of osteoblastic differentiation, menin modulates osteoblastogenesis and regulates bone mass in adult mice. To investigate the role of menin when expressed at earlier stages of the osteoblastic lineage, conditional knockout mice in which the Men1 gene is specifically deleted early (i.e., at the level of the pluripotent mesenchymal stem cell lineage), where generated and primary calvarial osteoblasts were cultured in plastically compressed dense collagen gels for 21 days. The proliferation, morphology and differentiation of isolated seeded primary calvarial osteoblasts from knockout (Prx1-Cre; Men1f/f) mice were compared to those isolated from wild-type (Men1f/f) mice. Primary calvarial osteoblasts from knockout and wild-type mice did not show differences in terms of proliferation. However, in comparison to wild-type cells, primary osteoblast cells derived from knockout mice demonstrated deficient mineralization capabilities and an altered gene expression profile when cultured in 3D dense collagen gels. In summary, these findings indicate that when expressed at earlier stages of osteoblast differentiation, menin is important in maintaining matrix mineralization in 3D dense collagen gel matrices, in vitro.

Keywords: dense collagen; menin; mineralization; osteoblastic differentiation; plastic compression.

Grants and funding

This work was made possible through funding from FRQNT, NSERC and CFI, McGill Faculty of Engineering. I.T. is a recipient of a Research Fellowship from the Réseau de Recherche en Santé Buccodentaire et Osseuse du Québec.