ECM-Stiffness Mediated Persistent Fibroblast Activation Requires Integrin and Formin Dependent Chromatin Remodeling.

Area of Science:

• Cell Biology
• Biochemistry
• Cancer Research

Background:

• Fibroblast activation is crucial for wound healing but can lead to fibrosis in diseases.
• The mechanisms underlying the switch from transient to persistent fibroblast activation in cancer remain unclear.

Purpose of the Study:

• To investigate how cancer-associated fibroblasts (CAFs) transition to a persistently activated state.
• To identify the molecular pathways involved in this persistent activation driven by the extracellular matrix (ECM).

Main Methods:

• Utilized human cancer-associated fibroblasts (CAFs) exposed to varying ECM stiffness.
• Investigated mechanotransduction pathways, nuclear architecture, and chromatin interactions.
• Examined the roles of β1 integrins, mammalian Diaphanous-related formin 2 (mDia2), and histone deacetylases.

Main Results:

• Prolonged exposure to stiff ECMs induces persistent CAF activation.
• Two key pathways identified: ECM ligand binding via β1 integrins and mDia2 activation.
• These pathways alter nuclear lamina and lamin-chromatin coupling, influencing chromatin accessibility.

Conclusions:

• Integrin and mDia2 pathways mediate ECM-stiffness-induced persistent fibroblast activation.
• Dynamic chromatin modifications downstream of these pathways establish fibroblast memory.
• Findings highlight potential therapeutic targets for stromal plasticity in the tumor microenvironment.