Cranial neural crest cells regulate head muscle patterning and differentiation during vertebrate embryogenesis

Abstract

In the vertebrate head, mesoderm cells fuse together to form a myofiber,which is attached to specific cranial neural crest (CNC)-derived skeletal elements in a highly coordinated manner. Although it has long been recognized that CNC plays a role in the formation of the head musculature, the precise molecular underpinnings of this process remain elusive. In the present study we explored the nature of the crosstalk between CNC and mesoderm cells during head muscle development, employing three models for genetic perturbations of CNC development in mice, as well as experimental ablation of CNC in chick embryos. We demonstrate that although early myogenesis is CNC-independent, the migration, patterning and differentiation of muscle precursors are regulated by CNC. In the absence of CNC cells, accumulated myoblasts are kept in a proliferative state, presumably because of an increase of Fgf8 in adjacent tissues, which leads to abnormalities in both differentiation and subsequent myofiber organization in the head. These results have uncovered a surprising degree of complexity and multiple distinct roles for CNC in the patterning and differentiation of muscles during craniofacial development. We suggest that CNC cells control craniofacial development by regulating positional interactions with mesoderm-derived muscle progenitors that together shape the cranial musculoskeletal architecture in vertebrate embryos.

Functionally Convergent White Adipogenic Progenitors of Different Lineages Participate in a Diffused System Supporting Tissue Regeneration

“…Likewise, CNC cells interact closely with cranial mesoderm-derived mesenchyme during the formation of different craniofacial tissues. In line with this notion, we show here that NC-FAPs, a CNC-derived population, reside within craniofacial muscles, which are of mesodermal origin [26]. Our results show that similarly to what we previously reported for limb M-FAPs, NC-FAP expands following acute muscle injury, supporting the case for homoplasy.…”

Downregulation of Dlx5 and Dlx6 expression by Hand2 is essential for initiation of tongue morphogenesis

“…Dimer partner choice is known to influence strongly the cellular response to Twist family proteins , with changes in Twist1-Hand2 dimerization resulting in SaethreChotzen syndrome (Firulli et al, 2005). In addition, conditional disruption of either Hand2 (this study) or Twist1 (Rinon et al, 2007) in NCCs results in defects in craniofacial bone and cartilage structures. To understand fully the role of Hand2 in facial morphogenesis, it will therefore be important to understand how loss of Hand2 affects the function of other Twist family members, including Twist1.…”

The developmental basis of bat wing muscle

“…In vertebrates, skeletal muscles which form in the head, trunk and limbs are patterned by extrinsic cues from surrounding tissues to adopt specific arrangements of muscle fibres in the adult form [23][24][25][26][27][28][29][30][31] . For example, somite-derived limb muscle precursor cells migrate into the limb bud which is filled with lateral platederived connective tissue.…”