Use of VSV-G pseudotyped retroviral vectors to target murine osteoprogenitor cells

Marrow stromal cells (MSC) and neonatal calvarial cells have the potential to differentiate and express markers of mature osteoblasts. Furthermore, MS Cs can generate multiple differentiated connective tissue phenotypes. These properties and their ability to be expanded ex vivo make them good models for ex vivo gene therapy. In this study we examined the ability of vesicula r stomatitis virus (VSV-G) pseudotyped retroviral vectors to transduce oste oprogenitor cells derived from bone marrow and from neonatal calvaria. Retr ovectors encoding either beta -galactosidase or green fluorescent protein ( eGFP) were used for transduction of primary murine marrow stromal and prima ry neonatal calvarial cell cultures. High infection efficiency was demonstr ated by fluorescence-activated cell analysis when GFP was used as a marker or by estimating the number of P-galactosidase-positive cells. Expression o f markers of differentiated bone cells, including Col1a1, bone sialoprotein , and osteocalcin mRNA and alkaline phosphatase activity was not impaired b y retroviral transduction. Our data suggest that VSV-G pseudotypes retrovir al Vectors are suitable for introducing genes into osteoprogenitor cells wi thout affecting osteoprogenitor lineage progression, (C) 2001 Academic Pres s.