Ho Thanh, M. T. | Search bioRxiv

bioRxiv2025

Harnessing cell-encapsulated hydrogels to study astrocyte mechanoresponse in 4D

In glaucoma, the optic nerve head (ONH) is exposed to increased biomechanical strain, impacting the resident astrocytes that maintain neural homeostasis. During disease progression astrocytes exhibit morphologic and metabolic shifts; however, the specific impact of glaucoma-related biomechanical strains on astrocyte behavior remains poorly understood. To address this, we used our previously established 3D cell-encapsulated extracellular matrix (ECM) hydrogel to investigate ONH astrocyte cellular and transcriptomic responses to varying biomechanical strain levels over time. Murine ONH astrocyte were encapsulated within an ECM hydrogel made from photocrosslinkable collagen type I and hyaluronic acid, and subjected to 0, 3, or 10% cyclic compression for 4h and 24h. We found significant restructuring of cytoskeletal morphology, metabolic dysregulation, and astrocyte-mediated ECM modulation that were strain-, duration- and hydrogel subregion-dependent. These phenotypic alterations were associated with diverse transcriptional changes in genes related to cell cycle and morphology, inflammation, metabolism and matrix remodeling that were driven by compressive strain intensity and duration. Our work reveals the direct role of compressive strain in eliciting a complex astrocyte response, supports targeting mechanosensation to prevent these pathologic astrocyte responses, and establishes ECM-based hydrogels as a platform to test mechanisms driving astrocyte mechanodysfunction. Altogether, our study offers new insights into astrocyte responses to biomechanical insult and demonstrates the use of a tunable 3D ECM hydrogel for future mechanistic studies of neurodegeneration. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/660800v2_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@f355fborg.highwire.dtl.DTLVardef@191e096org.highwire.dtl.DTLVardef@2fae32org.highwire.dtl.DTLVardef@55913c_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

Vimentin promotes collective cell migration through collagen networks via increased matrix remodeling and spheroid fluidity

The intermediate filament (IF) protein vimentin is associated with many diseases with phenotypes of enhanced cellular migration and aggressive invasion through the extracellular matrix (ECM) of tissues, but vimentins role in in-vivo cell migration is still largely unclear. Vimentin is important for proper cellular adhesion and force generation, which are critical to cell migration; yet the vimentin cytoskeleton also hinders the ability of cells to squeeze through small pores in ECM, resisting migration. To identify the role of vimentin in collective cell migration, we generate spheroids of wide-type and vimentin-null mouse embryonic fibroblasts (mEFs) and embed them in a 3D collagen matrix. We find that loss of vimentin significantly impairs the ability of the spheroid to collectively expand through collagen networks and remodel the collagen network. Traction force analysis reveals that vimentin null spheroids exert less contractile force than their wild-type counterparts. In addition, spheroids made of mEFs with only vimentin unit length filaments (ULFs) exhibit similar behavior as vimentin-null spheroids, suggesting filamentous vimentin is required to promote 3D collective cell migration. We find the vimentin-mediated collective cell expansion is dependent on matrix metalloproteinase (MMP) degradation of the collagen matrix. Further, 3D vertex model simulation of spheroid and embedded ECM indicates that wild-type spheroids behave more fluid-like, enabling more active pulling and reconstructing the surrounding collagen network. Altogether, these results signify that VIF plays a critical role in enhancing migratory persistence in 3D matrix environments through MMP transportation and tissue fluidity.

biophysics↗