# Biomechanical mechanisms underlying the formation of the vertebrate body axis

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA SANTA BARBARA · 2021 · $373,759

## Abstract

PROJECT SUMMARY
Sculpting tissues and organs into their 3D functional morphologies requires a tight spatiotemporal control of
tissue mechanics. While cell-generated mechanical forces power morphogenesis, the resulting tissue flows
that shape embryonic tissues in 3D depend strongly on the local tissue material properties, which govern the
system's response to the internally generated forces. As a consequence, spatiotemporal variations in both
mechanical forces and material properties can, independently or in combination, guide morphogenesis. The
complexity of probing tissue mechanics within developing embryos has so far hindered our ability to dissect
their specific roles and, more generally, to understand the biomechanical mechanisms that govern 3D tissue
and organ morphogenesis.
Using novel microdroplet-based techniques that the PI recently developed to measure both the tissue material
properties and endogenous mechanical stresses within developing embryos, we propose to reveal the
biomechanical mechanisms that underlie the formation of the zebrafish body axis. During posterior body axis
elongation, cells display an anteroposterior gradient in their motility. Our preliminary data suggest that the
anteroposterior variations in cellular movements may be caused by a transition between a fluid-like state of the
tissue at the posterior end to a solid-like state in the presomitic mesoderm. Our hypothesis is that regional
differences in fluid-like and solid-like tissue states control 3D tissue morphogenesis by enabling or restricting
morphogenetic flows. Specifically, we hypothesize that during zebrafish body elongation the paraxial
mesoderm transits from a fluid-like behavior in the tailbud to a solid-like behavior in the presomitic mesoderm,
allowing tissue flows at the elongating body end while providing mechanical integrity to developmentally older
structures, thereby guiding the nearly unidirectional tissue elongation of the body axis. In order to test this
hypothesis, we plan to (1) measure and compare anteroposterior variations in tissue yield stress and
endogenous mechanical stresses to establish the existence of fluid-like or solid-like tissue regions during body
axis elongation, (2) establish how key functional molecules (actin, non-muscle myosin II and N-cadherin)
control gradients in tissue mechanics and solid-like and fluid-like tissue states, and (3) integrate molecular, cell
and tissue mechanics into a multiscale biomechanical model of body elongation.
We believe this research will reveal a novel biomechanical mechanism of 3D tissue and organ morphogenesis,
in which the spatial control of fluid-like and solid-like tissue regions guides the shaping of embryonic tissues.
Moreover, it will dissect the specific roles of mechanical stresses and material properties in 3D tissue
morphogenesis and establish how key functional molecules control tissue mechanics in vivo. !

## Key facts

- **NIH application ID:** 10152375
- **Project number:** 5R01HD095797-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA SANTA BARBARA
- **Principal Investigator:** Otger Campas
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $373,759
- **Award type:** 5
- **Project period:** 2018-08-01 → 2023-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10152375

## Citation

> US National Institutes of Health, RePORTER application 10152375, Biomechanical mechanisms underlying the formation of the vertebrate body axis (5R01HD095797-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10152375. Licensed CC0.

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