PEDF: An essential stem cell regulator in models of Osteogenesis Imperfecta Type VI

Abstract

The rare bone disease Osteogenesis Imperfecta (OI) type VI is caused by mutations in the gene coding for PEDF, Serpinf1. Individuals with OI type VI have an accumulation of unmineralized bone matrix and multiple fractures. Our lab group has previously shown that PEDF restoration in the mouse model of OI type VI increases bone mass and mineralization. Further, we demonstrated that PEDF directs mesenchymal stem cells to the osteoblast lineage. One mechanism appears to involve modulation of canonical Wnt/βcatenin signaling in a temporally-defined manner. We have also induced pluripotent stem cells from a patient with OI type VI and differentiated the cells into osteoblasts to investigate how PEDF regulates the expression of various bone matrix proteins such as IBSP. In this brief review, we provide an overview of PEDF biology and highlight how PEDF's role as a stem cell regulator lends support to its causative role in OI type VI.