β-Catenin has sequential roles in the survival and specification of ventral dermis

Abstract

The dermis promotes the development and maintains the functional components of skin, such as hair follicles, sweat glands, nerves and blood vessels. The dermis is also crucial for wound healing and homeostasis of the skin. The dermis originates from the somites, the lateral plate mesoderm and the cranial neural crest. Despite the importance of the dermis in the structural and functional integrity of the skin, genetic analysis of dermal development in different parts of the embryo is incomplete. The signaling requirements for ventral dermal cell development have not been established in either the chick or the mammalian embryo. We have shown previously that Wnt signaling specifies the dorsal dermis from the somites. In this study, we demonstrate that Wnt/β-catenin signaling is necessary for the survival of early ventral dermal progenitors. In addition, we show that, at later stages, Wnt/β-catenin signaling is sufficient for ventral dermal cell specification. Consistent with the different origins of dorsal and ventral dermal cells, our results demonstrate both conserved and divergent roles of β-catenin/Wnt signaling in dermal development.

Twist1 mediates repression of chondrogenesis by β-catenin to promote cranial bone progenitor specification

“…In situ hybridization, -galactosidase with Eosin counterstaining, and immunohistochemistry were performed essentially as described (Atit et al, 2006;Ohtola et al, 2008). For skeletal preparations, embryos were stained in 0.03% Alcian Blue and 0.005% Alizarin Red.…”

“…One of its targets, the Twist family, has roles in head morphogenesis, skull osteoblast differentiation and repression of cartilage growth, suggesting a role in intramembranous progenitor specification (Bialek et al, 2004;Logan and Nusse, 2004;Soo et al, 2002). -catenin activates Twist1 in vitro and Twist2 in vivo, making these transcription factors nuclear targets of -catenin (Howe et al, 2003;Ohtola et al, 2008;Reinhold et al, 2006;Tran et al, 2010). Twist1 is required for the early migration and survival of cranial mesenchyme, which gives rise to the skull bones (Bildsoe et al, 2009;Soo et al, 2002).…”

Role of canonical Wnt signaling/β-catenin viaDermo1in cranial dermal cell development

“…Tissue preparation, histology, immunohistochemistry, X-gal staining, TUNEL, BrdU incorporation and in situ hybridization were performed as previously described (Gavrieli et al, 1992;Kanzler et al, 2000;Atit et al, 2006;Ohtola et al, 2008;Li et al, 1995). Dermo1 probe was a gift from Eric Olson (Li et al, 1995); Axin2 probe (Open Biosystems, clone 6827741) was obtained from C. Brian Bai (Case Western Reserve University, OH, USA).…”

“…In the mouse embryo, the dermis arises from spatially distinct locations. The dorsal and ventral trunk dermis originate from the somites (Atit et al, 2006) and the lateral plate mesoderm, respectively (Ohtola et al, 2008). By contrast, mouse craniofacial dermis originates from ectoderm-derived cranial neural crest and paraxial mesoderm (Fernandes et al, 2004;Jiang et al, 2002;Yoshida et al, 2008).…”

“…However, the location and timing of craniofacial dermal cell fate selection in the embryo is not known. Whereas Wnt signaling is crucial for dermal cell determination in the mammalian trunk dermis (Atit et al, 2006;Ohtola et al, 2008), the inductive and differentiation cues that direct the craniofacial dermal lineage remain to be identified. Genetic tools to functionally manipulate only the craniofacial dermal progenitors without compromising head development are lacking.…”