Compression injury regulates astrocyte morphology, metabolic function, and extracellular matrix modification in a 3D...

Area of Science:

• Ophthalmology
• Neuroscience
• Biomaterials Science

Background:

• Glaucoma increases biomechanical strain on the optic nerve head (ONH), altering astrocyte function.
• The precise effects of glaucoma-induced biomechanical strain on astrocyte behavior are not fully understood.

Purpose of the Study:

• To investigate the transcriptomic and cellular responses of ONH astrocytes to varying levels of biomechanical strain over time.
• To establish a 3D cell-encapsulated extracellular matrix (ECM) hydrogel model for studying these responses.

Main Methods:

• Murine ONH astrocytes were encapsulated in a 3D hydrogel and subjected to 0%, 3%, or 10% cyclic strain for 4 and 24 hours.
• Confocal reflectance microscopy, RNA sequencing, and morphometric analyses were employed to assess cellular and molecular changes.

Main Results:

• Biomechanical strain significantly altered astrocyte gene expression within 4 hours, affecting morphology, metabolism, hypoxia, and ECM regulation.
• Strain-dependent changes included reduced F-actin, increased GFAP, HIF-1α, fibronectin, and collagen reorganization.
• Hydrogel porosity supported nutrient diffusion, while stiffness and cell viability remained unaffected by strain.

Conclusions:

• ONH astrocyte responses to biomechanical strain are dependent on strain duration, magnitude, and ECM density.
• These responses involve altered cell morphology, hypoxia, and ECM modification, crucial for understanding ONH pathophysiology.
• The developed hydrogel model offers a platform for future studies on biomechanical strain in ONH diseases.