Collective durotaxis along a self-generated stiffness gradient in vivo

Area of Science:

• Developmental Biology
• Cell Biology
• Biophysics

Background:

• Collective cell migration is crucial for development, healing, and disease.
• Chemotaxis (following chemical gradients) is the established mechanism for directed cell movement in vivo.
• Durotaxis (following stiffness gradients) has been observed in vitro, but its in vivo relevance was unknown.

Purpose of the Study:

• To investigate the existence and mechanism of durotaxis in vivo.
• To determine if embryonic cells can generate and respond to substrate stiffness gradients.
• To understand how mechanical and chemical cues cooperate in directing cell migration.

Main Methods:

• Utilized Xenopus laevis embryos to study neural crest cell migration.
• Investigated self-generation of stiffness gradients by neural crest cells in placodal tissue.
• Analyzed cell-matrix adhesions, N-cadherin interactions, and downstream signaling pathways (Rac activity, actomyosin contractility).

Main Results:

• Demonstrated that Xenopus neural crest cells self-generate a dynamic stiffness gradient in adjacent tissues.
• Showed that neural crest cells migrate directionally by following this self-generated stiffness gradient (durotaxis).
• Revealed that durotaxis synergizes with chemotaxis, enhancing collective cell migration through coordinated actomyosin activity.

Conclusions:

• Provided the first in vivo evidence for durotaxis and dynamic substrate stiffness gradients.
• Established that N-cadherin interactions and cell-matrix adhesions mediate gradient sensing and response.
• Concluded that combined chemical and mechanical cues cooperatively drive efficient directional collective cell migration in vivo.