Influence of mechanical regulation during zebrafish somitogenesis in a quasi-2D in vitro system

• Grant number: 25/22776-8
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: January 24, 2026
• End date: January 23, 2027
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Fabiana Fernandes Bressan
• Grantee: Jenyffer Mairely Rosero Alpala
• Supervisor: Alessandro Mongera
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil
• Institution abroad: University College London (UCL), England
• Associated to the scholarship: 23/08890-7 - Derivation of embryonic somatic cells and transgene-free iPSCs from two important Neotropical fish species, BP.DR

Abstract

In vitro systems are powerful platforms for dissecting the molecular mechanisms that govern embryonic development, as they can reproduce essential aspects of the cellular microenvironment. Recent advances have successfully recapitulated processes such as body axis elongation and segmentation. However, it remains unclear how individual cells respond to mechanical constraints during the sequential formation of body segments-a process regulated by a network of genetic oscillators known as the segmentation clock. This study aims to investigate how mechanical cues influence the segmentation clock using a novel quasi-2D (q2D) in vitro system designed to drive the differentiation of (i) zebrafish primary embryonic stem cells (zESCs) and (ii) zebrafish induced pluripotent stem cells (ziPSCs) into presomitic mesoderm (PSM) cells, the tissue that undergoes segmentation and gives rise to skeletal muscles. This system, developed so far only for human iPSCs, allows the precise imposition of physical constraints on differentiating cells and the application of well-defined mechanical cues. Extending this approach to zebrafish offers two main advantages: (1) it will substantially accelerate the protocol, as zebrafish embryos develop much faster than human ones, and (2) it will enable comparative studies to test whether mechanical factors contribute to the much shorter segmentation clock period observed in zebrafish relative to humans. Initially, differentiation using the q2D protocol will be performed with zESCs, while in parallel, I will attempt to reprogram zebrafish fibroblasts into ziPSCs. We will alter the viscoelastic properties of the substrate to assess how these changes affect both PSM differentiation and somitogenesis through modulation of the segmentation clock. This work represents an important step toward elucidating the cellular pathways dependente on mechanical cues that govern mesodermal differentiation and establishing a new platform for muscle tissue Generation using fish.