Control of Chondrogenic Expression in Mesodermal Cells of Embryonic Chick Limb

Abstract

Chick-limb mesodermal cells have been maintained in tissue culture under conditions that permit development of muscle and cartilage. 3-Acetylpyridine, a nicotinamide-antagonized muscle teratogen, potentiates chondrogenic expression in cell cultures, as evidenced by histological and biochemical criteria, including the production of chondromucoprotein. Xylosyltransferase and N-acetylgalactosaminyltransferase are two enzymes required for chondromucoprotein synthesis; the specific activities of these enzymes were measured in differentiating mesodermal cells cultured for various periods of time in the presence and absence of 3-acetylpyridine and in intact limb tissue. The ratios of specific enzyme activities were nearly the same in both cultured cells and limb tissue, although the levels of both transferases increased severalfold during chondrogenic expression by mesodermal cells in culture. 3-Acetylpyridine causes the specific activities of xylosyl-and N-acetylgalactosaminyltransferases to increase 10-and 2-fold, respectively, above those of untreated cultures. Compared to the ratio of transferase activities in limb tissue and differentiating cell cultures, 3-acetylpyridine appears to increase the activity of xylosyltransferase, the initiator of chondroitin sulfate chain synthesis, more than does N-acetylgalactosaminyltransferase; this finding implies that the synthesis of these two enzymes may be separately regulated.

Mesenchymal Stem Cells: Time to Change the Name!

“…In the early 1970s into the 1980s, my colleagues and I published a number of papers based on the culturing of stage 24, embryonic chick limb bud mesodermal cells (ECLBMCs) that were observed to differentiate into cartilage, muscle, and bone under certain culture conditions [18][19][20][21][22]. These in vitro studies were correlated with a variety of in vivo studies that focused on the cellular and molecular events associated with the formation of embryonic limb bone [23,24], cartilage [25], and muscle [26] in which several very prominent dogmas-of-the-day were challenged. For example, the concept that "cartilage is replaced by bone" led to the implication that if one could form cartilage in culture from embryonic mesodermal progenitor cells, one could observe the transition of that new cartilage into bone.…”

Apoptosis in chondrogenesis of human mesenchymal stem cells: effect of serum and medium supplements

“…The defined media used to induce chondrogenesis by MSCs are originally derived from the media for a prechondrocyte condensation in avian and mammalian embryonic cells, that is, a DMEM or a-MEM based medium supplemented with ITS-premix in the presence of certain growth factors [6,7]. Despite the importance and the frequency in using it for chondrogenic induction of MSCs, there are few, if any, studies aimed at selecting and comparing the components used in the medium [8].…”

Differentiation of muscle, fat, cartilage, and bone from progenitor cells present in a bone-derived clonal cell population: effect of dexamethasone.

“…Osteoblasts, chondrocytes, myotubes, and adipocytes may be related at the level of a less restricted precursor cell population. This is suggested by the observation that demineralized bone induces formation of cartilage in rat skeletal muscle (49,65); by the finding that embryonic chick limb bud mesenchymal cells differentiate into muscle, cartilage, and bone (9,10,45,46); and by the observed differentiation of clonal mouse embryo fibroblasts into muscle, fat, and cartilage (63). Recently, we (7) and others (41) have shown that mixed populations of cells enzymatically isolated from 21-d fetal rat calvaria and cultured for periods ranging from 14 to 21 d form bone nodules which mineralize in the presence of organic phosphate.…”