Altered proteoglycan metabolism in mouse limb mesenchyme cell cultures treated with vitamin A

The inhibition of chondrogenesis by vitamin A was examined in mouse limb mesenchyme cultures. Chondrogenesis in control cultures was characterized by increased synthesis of proteoglycans composed predominantly of chondroitin sulfate. The proteoglycans synthesized in vitamin A cultures were smaller than those from cartilage and were found to contain mainly heparan sulfate and dermatan sulfate. No indication of increased proteoglycan degradation resulting from vitamin A treatment was observed. The similarity in size and glycosaminoglycan composition of proteoglycans from control cultures prior to chondrogenesis and vitamin A cultures suggests that vitamin A maintains the cells in a mesenchyme-like state. Vitamin A also stimulated the mannosylation of a specific fraction of glycopeptides.