IN-VITRO CHARACTERIZATION OF CHONDROGENIC CELLS ISOLATED FROM CHICK EMBRYONIC MUSCLE USING PEANUT AGGLUTININ AFFINITY-CHROMATOGRAPHY

Specific binding to the lectin, peanut agglutinin (PNA), has been repo rted in embryonic precartilage tissues, including the condensing limb bud blastema and the caudal half of the developing somite. The present study aimed to test the hypothesis that PNA-binding may be a surface characteristic of chondroprogenitor cells residing within noncartilage tissues, such as muscle, which have the potential of being induced to form cartilage, e.g., in the presence of bane matrix-derived factors. Day-14 chick embryonic pectoral muscle, which contained histochemical ly detectable PNA-binding cells, was dissociated into single cells (TM cells) and fractionated by PNA affinity chromatography into PNA-bindi ng (PNA+) and nonbinding (PNA-) cells by PNA-Sepharose 6 MB affinity c hromatography. The differentiation potential of the PNA-affinity fract ionated cells in vitro was analyzed as a function of culture plating c ell density. Immunohistochemistry of a number of cell type-specific di fferentiation markers, including sarcomeric actin, collagen type II, a nd aggrecan core protein, demonstrated that PNA+ cells, when cultured as a micromass at high density (20 x 10(6) cells/ml), exhibited a chon drocyte-like phenotype, whereas the PNA- cells remained myogenic; howe ver, both PNA+ and PNA- monolayer cultures (4 x 10(4) cells/ml) behave d as myoblastic cells. The expression of collagen type II mRNA was als o confirmed by coupled reverse transcription/polymerase chain reaction analysis. These observations suggest that PNA binding, i.e., the pres ence of specific galactose-containing cell surface moieties, is likely to be one of the characteristics of chondrogenic cells residing in me senchymally derived embryonic tissues. (C) 1997 Academic Press.