A study, led by CSIC researchers at the Institute of Molecular Biology of Barcelona (IBMB-CSIC) in the Barcelona Science Park, analyses the mechanisms regulating the condensation of embryonic nervous system of Drosophila fly, a process that remains largely unknown, and reveals a mathematical model that describes this process in the early stages of development and the cellular mechanisms involved. The work, published in the journal Developmental Cell, establishes principles that could help to understand equivalent events in the human nervous system.

During the development of an organism, organs grow to a very precise shape and size by adding new cells. However, organs do not always form through cell growth and multiplication.

This is the case of the embryonic ventral nerve cord of the Drosophila fly (equivalent to the spinal cord in vertebrates), which does not grow but shortens during the formation of the organism, in a process known as a ‘condensation’.

This process has been analysed in a study led by Enrique Martín Blanco, a researcher at the Institute of Molecular Biology of Barcelona of the Spanish National Research Council (IBMB-CSIC). The team has analysed the mechanics of condensation and has implemented a predictive mathematical model of the cellular mechanisms involved during brain development of fly Drosophila.

The work, published in the journal Developmental Cell, involved researchers from the IBMB-CSIC Institute at the Barcelona Science Park (PCB), the UPC, the UB, IBEC and the Mechanobiology Institute of Singapore. The results may help to understand similar processes, such as those, that can occur in the formation of the human brain.

A model that can predict possible alterations

“When fly embryo grows, its ventral nerve cord is packed in phases, becoming condensed”, explains Enrique Martin Blanco, from IBMB-CSIC. But this shortening does not occur continuously but in phases which happen more or less quickly, resulting in “an oscillatory movement that we compare to an accordion”.

The condensation of the ventral nerve cord, as Martín Blanco explains, responds to the coordination of the contractile activity of different cells that form it, neurons and glia. And these oscillations depend on the mechanical properties of the cells that form the tissue, such as viscosity and elasticity. IBMB-CSIC researcher Katerina Karkali, first author of the paper, explains: “Our model explains this oscillatory movement as a function of the mechanical properties of the tissue, and allows us to predict possible alterations.

The work describes the whole process and presents a computational model that provides important predictions about cell behaviour in oscillatory morphogenetic processes.

The researchers hope this study will pave the way for understanding similar processes in the development of the human central nervous system, “a highly complex and orchestrated process that establishes a structural framework for cognition, behaviour and emotion”.

» Reference article: “Condensation of the Drosophila Nerve Cord is Oscillatory and depends on Coordinated Mechanical Interactions”. Katerina Karkali, Prabhat Tiwari, Anand Singh, Sham Tlili, Ignasi Jorba, Daniel Navajas, José J. Muñoz, Timothy E. Saunders and Enrique Martin-Blanco Developmental Cell – Volume 57, Issue 7, 11 April 2022, Pages 867-882.e5. DOI: https://doi.org/10.1016/j.devcel.2022.03.007