Researchers have made a major advance in the study of early human development by successfully creating a laboratory-grown notochord, a key structural component in vertebrates. Based on a carefully orchestrated sequence of chemical signals, this model mimics the early stages of a human stem, complete with neural and bone stem cells. This discovery marks a new era in the study of human developmental disorders, offering a potential insight into congenital spine and intervertebral disc disorders.

A breakthrough in human development research

Scientists at the Francis Crick Institute have, for the first time, created human stem cell models that include chordae, the developing embryonic tissue that guides cells to form the spine and nervous system (trunk). The study published today (December 18) NatureIt marks a significant advance in understanding how the human body is formed in the early stages of development.

Chorda, a rod-shaped tissue, serves as an important structural milestone in the developing organism. This is a defining feature of all vertebrates and plays a key role in tissue organization during embryonic growth. Because of its complexity, chordae were conspicuously absent from previous laboratory models of human trunk development; This made this breakthrough particularly important for the development of developmental biology.

Deciphering the formation of the notochord

In this study, scientists analyzed chicken embryos for the first time to fully understand how the notochord forms naturally. By comparing this with existing published information on mouse and monkey embryos, they determined the timing and sequence of molecular signals required to form chordal tissue. With this plan, they created a precise sequence of chemical signals and used it to stimulate human stem cells to form chordae.

Improving lab-grown human body models

The stem cells spontaneously formed a miniature root-like structure that grew up to 1-2 millimeters long. It contained nerve tissue and bone stem cells arranged in a pattern that mirrored the development of a human embryo. This suggests that the chordae encourages cells to develop into the right type of tissue at the right time, in the right place.

Scientists believe this study could help study birth defects that affect the spine and spinal cord. It can also give insight into conditions affecting the intervertebral discs (shock-absorbing cushions between vertebrae that develop from the chordae). When these discs degenerate with age, they can cause back pain.

Implications for understanding human development

James Briscoe, Group Leader of the Developmental Dynamics Laboratory and senior author of the study, said: “The chorda acts as a GPS for the developing embryo, helping establish the main axis of the body and guiding the formation of the spine and nervous system. Until now, it has been difficult to create this vital tissue in the laboratory.” “This has limited our ability to study human development and disorders. Now that we have created a model that works, it opens the door to examining developmental conditions we didn’t know existed.”

Thiago Rito, a postdoctoral researcher in the Developmental Dynamics Laboratory and first author of the study, said: “Finding the precise chemical signals to form the notochord is like finding the right recipe. Previous attempts to grow notochords in the laboratory have failed because we did not understand the timing required to add the materials.” it could be.

“What’s particularly exciting is that the chordae in our laboratory-grown constructs function similarly to those in a developing embryo. They send chemical signals that help regulate surrounding tissue as they do during normal development.”