Sonic Hedgehog promotes the development of multipotent neural crest progenitors endowed with both mesenchymal and neural potentials

Abstract

In the vertebrate embryo, the cephalic neural crest cells (CNCCs) produce cells belonging to two main lineages: the neural [including neurons, glial cells of the peripheral nervous system (PNS), and melanocytes] and the mesenchymal (chondrocytes, osteoblasts, smooth muscle cells, and connective tissue cells), whereas the trunk NCCs (TNCCs) in amniotes yield only neural derivatives. Although multipotent cells have previously been evidenced by in vitro clonal analysis, the issue as to whether all of the mesenchymal and neural phenotypes can be derived from a unique NC stem cell has remained elusive. In the present work, we devised culture conditions that led us to identify a highly multipotent NCC endowed with both neural and mesenchymal potentials, which lies upstream of all the other NC progenitors known so far. We found that addition of recombinant Sonic Hedgehog (Shh) increased the number of CNCC progenitors yielding both mesenchymal and neural lineages and promoted the development of such precursors from the TNCC. Shh decreased the neural-restricted precursors without affecting the overall CNCC survival and proliferation. By showing a differential positive effect of Shh on the expression of mesenchymal phenotypes (i.e., chondrocytes and smooth muscle cells) by multipotent CNCCs, these results shed insights on the in vivo requirement of Shh for craniofacial morphogenesis. Together with evolutionary considerations, these data also suggest that the mesenchymal-neural precursor represents the ancestral form of the NC stem cell, which in extinct forms of vertebrates (the ostracoderms) was able to yield both the PNS and superficial skeleton.chondrogenesis ͉ clonal culture ͉ embryo ͉ quail ͉ stem cell

Transforming Growth Factor β-Mediated Sox10 Suppression Controls Mesenchymal Progenitor Generation in Neural Crest Stem Cells

“…The potential to generate chondrocytes and osteocytes has mainly been attributed to cranial neural crest (NC) cells [1]. In support of this, multipotent progenitors with neural as well as mesenchymal potentials were rarely observed in clonal cell culture assays of trunk NC cells [2,3] and trunk NC was ineffective in forming cartilage after transplantation in vivo [4]. However, incubating trunk NC cells in tailor-made chondrogenesis-permissive media for a prolonged time period led to the emergence of mature chondrocytic markers [5,6].…”

The stem cells of the neural crest

“…In contrast, when the duration of the co-culture did not exceed 15 hours, mass cultures of mesencephalic NCC exhibited cartilage nodules in a significant proportion (15%) of the cultures and GNMFC clonogenic cells were recorded in 6.5% of the clones examined (n = 126). 19 It seems therefore that the presence of the neural tube in the culture medium does not favor the development of these multipotent "mesenchymal-neural" precursors that are present (at least for a while) in the early migrating NCC population. Similar observations had been reported concerning other cell phenotypes such as the influence of the neural tube on the differentiation of pigment cells and adrenergic cells in trunk NCC cultures.…”

“…In a recent work, 19 we have raised the question of the nature of the putative factors involved in the growth and differentiation of the mesenchymal precursors of the cephalic NC, which are responsible for the development of the facial skeleton. 50,51 Several lines of evidence based on in vivo experiments in the mouse 52,53 and chick [54][55][56][57] embryos pointed to the requirement of Sonic Hedgehog (Shh) for facial morphogenesis by cephalic NCC.…”

“…[15][16][17][18][19] Here we discuss insights provided by in vitro experiments aimed at deciphering the developmental capacities of individual NCC and namely, their potential to giving rise to both "neural derivatives" (including neurons, glia, endocrine cells and melanocytes) and "mesenchymal derivatives" (such as myofibroblasts, bone and cartilage, and adipose tissue cells (see Table 1). This issue is interesting in the present context where mesenchymal progenitors and stem cells have been found in various adult tissues (reviewed in refs.…”

Lessons from Genetically Altered Mesenchymal Stem Cells (MSCs): Candidates for Improved MSC-Directed Myocardial Repair

“…Signaling cascades involved in the particular disease, and the method of administration of MSCs. in vivo generation of these neural crest mesenchymal progenitor cells have been identified (9,33).…”