Dissection of the osteogenic effects of laminin-332 utilizing specific LG domains: LG3 induces osteogenic differentiation, but not mineralization

Abstract

The overall mechanisms governing the role of laminins during osteogenic differentiation of human mesenchymal stem cells (hMSC) are poorly understood. We previously reported that laminin-332 induces an osteogenic phenotype in hMSC and does so through a focal adhesion kinase (FAK) and extracellular signal-related kinase (ERK) dependent pathway. We hypothesized that this is a result of integrin-ECM binding, and that it occurs via the known alpha3 LG3 integrin binding domain of laminin-332. To test this hypothesis we cultured hMSC on several different globular domains of laminin-332. hMSC adhered best to the LG3 domain, and this adhesion maximally activated FAK and ERK within 120 min. Prolonged culturing (8 or 16 days) of hMSC on LG3 led to activation of the osteogenic transcription factor Runx2 and expression of key osteogenic markers (osterix, bone sialoprotein 2, osteocalcin, alkaline phosphatase, extracellular calcium) in hMSC. LG3 domain binding did not increase matrix mineralization, demonstrating that the LG3 domain alone is not sufficient to induce complete osteogenic differentiation in vitro. We conclude that the LG3 domain mediates attachment of hMSC to laminin-332 and that this adhesion recapitulates most, but not all, of the osteogenic differentiation associated with laminin-5 binding to hMSC.

Effects of a surface topography composite with puerariae radix on human STRO-1-positive stem cells

“…neurogenic has been suggested by others (67) and osteogenic differentiation (20). Furthermore, previous studies have also indicated that activation of a focal adhesion kinase (FAK) and extracellular signal-related kinase (ERK) dependent pathway by laminin binding to LG3 integrin binding domain mediated osteogenic differentiation but did not increase matrix mineralization, demonstrating that the activation of FAK and ERK signaling is not sufficient to induce complete osteogenic differentiation in vitro (68). A previous study indicated that phytoestrogen, puerarin, act via phosphatidylinositol-3-kinase/Akt (PI3K/Akt) (54) thus complete osteogenic differentiation might need more than one signaling pathway working in concert with each other.…”

A Pilot Study of Antibody Drug Therapy to Regulate Cell Adhesion in Dental Implants

“…Laminin-332 is also detected in periosteum, not only in the basement membrane [21]. Moreover, laminin-332 affects osteoblast differentiation and calcification [22] [23] [24]. Therefore, laminin-332 plays important roles not only in epithelial cell function but also in the function of mesenchymal cells.…”

Laminin-5 and type I collagen promote adhesion and osteogenic differentiation of animal serum-free expanded human mesenchymal stromal cells

“…Several ECM-proteins, such as type I collagen, laminin-5, and vitronectin, have been identified as regulators of MSC-adhesion and inducers of osteogenic differentiation in vitro . 4–10 Fetal calf serum (FCS) is widely used for cell culture, 4–7 but in the context of possible further clinical applications animal serum does not meet the European Good Manufacturing Practice (GMP) regulations for medical products. The risk of immunological reactions, prion transmission and potential metabolic changes in cultured cells must be considered.…”