SFRP2 expression in rabbit myogenic progenitor cells and in adult skeletalmuscles

Satellite cells derived from fast- and slow-twitch muscles have different p roperties in culture. We have used the differential display technique to re trieve genes differentially expressed in fast- and slow-twitch muscle satel lite cell cultures. Amongst these genes we have identified, cloned, sequenc ed and studied the expression in muscle of rabbit secreted frizzled related protein 2 (SFRP2) mRNA, whose importance in cell fate determination has be en well documented. It has been shown that SFRP2 is widely expressed in the developing embryo but its expression in the adult is much more restricted. We show that primary cultures of satellite cells from adult rabbit fast- a nd slow-twitch muscles strongly and differentially express SFRP2 mRNA. Embr yonic rabbit muscle cell primary cultures also strongly express SFRP2 mRNA whereas the myoblast C2.7 cell line shows little expression. We also studie d SFRP2 mRNA expression in growing, regenerating and denervated muscles. Em bryonic rabbit muscles express SFRP2 mRNA but this rapidly falls off after birth. In adult rabbit muscles SFRP2 mRNA is detected within 1 day of eithe r muscle damage or denervation. Thereafter the SFRP2 mRNA expression profil es are different for fast- and slow-twitch muscle. The function of SFRP2 in muscle is unknown but its putative activity as a Wnt antagonist and its pr ecocious expression after muscle damage suggest a role in satellite cell ac tivation.