The International Journal of Developmental Biology

ABSTRACT

The digestive tract is a series of organs with specific functions and specialized anatomy. Each organ is organized similarly with concentric layers of epithelial, connective, smooth muscle, and neural tissues. Interstitial cells of Cajal (ICC) are distributed in smooth muscle layers and contribute to the organization of repetitive and rhythmic smooth muscle contractions. Understanding ICC development is critical to understanding gastrointestinal motility patterns. Experiments determining ICC origin and development in mice, chicken, and humans are described, as well as what is known in the zebrafish. At least six types of ICC in the digestive tract have been described and ICC heterogeneity in adult tissues is reviewed. Factors required for ICC development and for maintenance of ICC subclasses are described. This review is suitable for those new to ICC development and physiology, especially those focused on using zebrafish and other model systems.

ABSTRACT

The axolotl, a legendary creature with the potential to regenerate complex body parts, is positioned as a powerful model organism due to its extraordinary regenerative capabilities. Axolotl can undergo successful regeneration of multiple structures, providing us with the opportunity to understand the factors that exhibit altered activity between regenerative and non-regenerative animals. This comprehensive review will explore the mysteries of axolotl regeneration, from the initial cellular triggers to the intricate signaling cascades that guide this complex process. We will delve deeply into the multifaceted interplay of genes and factors, highlighting the key role of signaling pathways and the influence of epigenetic modifications (such as DNA methylation, histone modification, and miRNA regulation) during regeneration. Furthermore, we will discuss how axolotls defy the odds by showing remarkable resistance to cancer, offering insights into potential therapeutic strategies. However, that is not the end; we will also highlight how age might affect the regenerative power of this creature. We hope this review will help navigate the awe-inspiring realm of axolotl regeneration,...

ABSTRACT

The presence of horns in domestic ruminants, such as cattle, sheep and goats, has financial and welfare implications. The genetic interactions that lead to horn development are not known. Hornless, or polled, cattle occur naturally. The known causative DNA variants (Celtic, Friesian, Mongolian and Guarani) are in intergenic regions on bovine chromosome 1, but their functions are not known. It is thought that horns may be derived from cranial neural crest stem cells and the POLLED variants disrupt the migration or proliferation of these cells. Relaxin family peptide receptor 2 (RXFP2) is more highly expressed in developing horns in cattle compared to nearby skin and has been shown to play a role in horn development in sheep. However, the role of RXFP2 in horn formation is not understood. Histological analyses of cranial tissues from homozygous horned and polled cattle fetuses at day 58 of development was carried out to determine the differences in the structure of the horn bud region. Condensed cells were only observed in the horn bud mesenchyme of horned fetuses and could be the progenitor horn cells. The distribution of neural crest markers (SOX10 and NGFR) and RXFP2...

ABSTRACT

Aggregates of two mouse embryos produce viable offspring of normal size, indicating that there are mechanisms in the embryo that can downregulate their size to the size of the corresponding normal (single) embryos. Very little is known about the mechanisms controlling compensation for increased preimplantation size. Also, it is still elusive when exactly during development chimeric embryos regulate their size. Here, we determined the exact period of size regulation in chimeras. Using a chimeric embryo produced by aggregating two 8-cell stage embryos, we revealed that size regulation initiates shortly after implantation (E5.5) and ends with the start of gastrulation (E7.5). Importantly, processes that regulate cell number in chimeric embryos do not disturb morphogenesis, so that the formation of the proamniotic cavity occurs in parallel with size regulation.

ABSTRACT

The neural crest (NC) is an embryonic cell population with high migratory capacity. It contributes to forming several organs and tissues, such as the craniofacial skeleton and the peripheral nervous system of vertebrates. Both pre-migratory and post-migratory NC cells are plastic, adopting multiple differentiation paths by responding to different inductive environmental signals. Cephalic neural crest cells (CNCCs) give rise to most of the cartilage and bone tissues in the head. On the other hand, the mesenchymal potential of trunk neural crest cells (TNCCs) is sparsely detected in some animal groups. The mesenchymal potential of TNCCs can be unveiled through specific environmental conditions of NC cultures. In this study, we present evidence that FGF8 treatment can foster increased chondrogenic differentiation of TNCCs, particularly during treatment at the migratory stage. Additionally, we conducted a transcriptomic analysis of TNCCs in the post-migratory stage, noting that exogenous FGF8 signaling can sustain multipotent status and, possibly, at the same time, a pro-cartilage regulatory gene network. Our results provide a more comprehensive understanding of the mechanisms...