Biology subjects

Garske, D. S.

Publications and source records attributed to Garske, D. S..

6 recordsLinked to original sources

bioRxiv2026

Patterned alginate hydrogel spatially guides collagen fibrillogenesis, viscoelasticity and endothelial cell invasion

Angiogenesis following injury has been shown to be driven by fibrillar proteins of the extracellular matrix (ECM), such as collagen. However, the use of protein-based biomaterials presents some challenges, such as uncontrolled degradation and limited tuneability. We demonstrate how to create patterned interpenetrating networks (IPNs) based on covalently crosslinked alginate and physically crosslinked collagen that provide suitable mechanical properties to support migration of endothelial cells (ECs) in a spatially controlled manner. Low molecular weight alginate is functionalized with norbornene (N) or tetrazine (T), which enables two independent covalent crosslinking methods: UV-mediated and degradable crosslinks with matrix metalloproteinase (MMP) sensitive peptides (Deg) and slower spontaneous N:T non-degradable crosslinks (noDeg). Using photolithography, patterns in degradation, collagen fibrillogenesis, microarchitecture and matrix viscoelasticity are created. The potential of such 3D patterned alginate-collagen (Alg-Col) IPNs to spatially guide EC invasion and proliferation was tested in a microfluidics platform resembling an early healing setting. Only regions combining collagen fibrillogenesis, alginate degradability and viscoelasticity demonstrated EC cell invasion similar to the ones found in vivo following injury. The 3D patterned Alg-Col IPNs are compatible with microfluidics, offer an strategy to widen the applications of protein-based hydrogels and present a versatile platform for tissue engineering and disease modeling.

bioengineering↗

bioRxiv2026

Extracellular Matrix Mechanobiology in Pancreatic Ductal Adenocarcinoma: Correlating In Vivo Patient Magnetic Resonance Elastography with Ex Vivo Tissue Mechanics and Histopathology

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dense desmoplastic extracellular matrix (ECM) that contributes to tumor progression, therapeutic resistance, and poor patient survival. However, the relationship between in vivo imaging-derived mechanical properties, ex vivo tissue biomechanics, ECM architecture, and cellularity remains incompletely understood. Here, we combined pre-operative in vivo clinical magnetic resonance elastography (MRE) with ex vivo biomechanical testing of fresh human PDAC tissue and histopathological analyses. Nine patients undergoing pancreatic resection were prospectively enrolled. Quantitative MRE was performed pre-operatively to assess tissue stiffness through shear wave speed (c) and relative viscosity or fluidity through the loss angle ({varphi}). Fresh tumor and adjacent non-malignant tissue biopsies were subsequently analyzed ex vivo by unconfined uniaxial compression testing to determine elastic moduli and stress relaxation halftime. Histological analyses quantified collagen-rich fibrous tissue area, cell nuclei density, and nuclear morphology. Tumor tissue exhibited significantly increased stiffness and collagen fraction compared with adjacent non-malignant tissue, together with reduced cellularity, smaller nuclear area and more elongated nuclei. Ex vivo stiffness positively correlated with collagen content and negatively correlated with patient survival. Reduced stress relaxation halftime, indicative of increased tissue viscosity, was associated with lower cellularity and elongated nuclei. Importantly, pre-operative MRE parameters of the intact surrounding environment correlated significantly with ex vivo tumor mechanics, cellular organization, and survival. Specifically, a softer and less viscous surrounding environment was associated with stiffer and more viscous tumors, with lower cellularity and elongated nuclei, and poorer prognosis. These findings demonstrate that MRE-derived mechanical biomarkers reflect underlying ECM remodeling and tumor mechanobiology in PDAC. Integrating in vivo imaging with ex vivo tissue mechanics and histopathology may improve non-invasive disease characterization and support biomechanically-informed therapeutic strategies.

bioengineering↗

bioRxiv2024

3D patterns in alginate hydrogel degradation spatially guide YAP nuclear translocation and hMSC osteogenic differentiation

Tissue engineering involves assembling cells and mimicking the complex anisotropic architecture of biological tissues to perform specific functions. This study explores the impact of patterned hydrogels with anisotropic degradation compared to single-phase materials on the potential of enhancing cell spreading, collective alignment, mechanotransduction and osteogenic differentiation of encapsulated human mesenchymal stromal cells (hMSCs). Spatial patterns of degradable (Deg) and non-degradable (noDeg) subregions are formed by photolithography: UV-triggered thiol-ene crosslinking with matrix metalloprotease (MMP) sensitive peptides form Deg phases, while non-UV exposed regions result in Diels-Alder spontaneous click crosslinking and noDeg phases. 3D patterns in hydrogel degradation enhance hMSC spreading and allow collective cell alignment in Deg areas, while cells remain rounded with no alignment in noDeg regions. In addition, we observe a boosted osteogenic differentiation when compared to single-phase materials, as mid osteogenic markers (osteocalcin) are expressed at day 14 in anisotropic gels, whereas in single-phase only early osteogenic markers are found (osterix). Mechanosensing pathways were evaluated using the expression and localization of YAP. Deg sections in patterned materials have an enhanced nuclear translocation and higher YAP expression compared to single-phase Deg materials and noDeg sections. This effect is lost and no patterns in YAP expression and localization emerge when using an MMP-scramble peptide or no-RGD materials. These findings demonstrate that 3D patterns in alginate hydrogel degradation guide hMSC spreading, collective alignment, enhance YAP nuclear translocation and osteogenic differentiation. Mimicking tissue anisotropy in 3D patterned hydrogels could have broad applications in biofabrication and tissue engineering. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=79 SRC="FIGDIR/small/588803v3_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@f7aa3aorg.highwire.dtl.DTLVardef@1c8d2a4org.highwire.dtl.DTLVardef@17d2371org.highwire.dtl.DTLVardef@a1d6a2_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG

bioengineering↗

bioRxiv2023

Hydrogels with stiffness-degradation spatial patterns control anisotropic 3D cell response

In nature, tissues are patterned, but most biomaterials used in human applications are not. Patterned biomaterials offer the opportunity to mimic spatially segregating biophysical and biochemical properties found in nature. Engineering such properties allows to study cell-matrix interactions in anisotropic matrices in great detail. Here, we developed alginate-based hydrogels with patterns in stiffness and degradation, composed of distinct areas of soft non-degradable (Soft-NoDeg) and stiff degradable (Stiff-Deg) material properties. The hydrogels exhibit emerging patterns in stiffness and degradability over time, taking advantage of dual Diels-Alder covalent crosslinking and UV-mediated peptide crosslinking. The materials were mechanically characterized using rheology for single-phase and surface micro-indentation for patterned materials. 3D encapsulated mouse embryonic fibroblasts (MEFs) allowed to characterize the anisotropic cell-matrix interaction in terms of cell morphology by employing a novel image-based quantification tool. Live/dead staining showed no differences in cell viability but distinct patterns in proliferation, with higher cell number in Stiff-Deg materials at day 14. Patterns of projected cell area became visible already at day 1, with larger values in Soft-NoDeg materials. This was inverted at day 14, when larger projected cell areas were identified in Stiff-Deg. This shift was accompanied by a significant decrease in cell circularity in Stiff-Deg. The control of anisotropic cell morphology by the material patterns was also confirmed by a significant increase in filopodia number and length in Stiff-Deg materials. The novel image-based quantification tool was useful to spatially visualize and quantify the anisotropic cell response in 3D hydrogels with stiffness-degradation spatial patterns. Our results show that patterning of stiffness and degradability allows to control cell anisotropic response in 3D and can be quantified by image-based strategies. This allows a deeper understanding of cell-matrix interactions in a multicomponent material.

bioengineering↗

bioRxiv2023

From breast cancer cell homing to the onset of early bone metastasis: dynamic bone (re)modeling as a driver of osteolytic disease

Breast cancer often metastasizes to bone causing osteolytic lesions. Structural and biophysical changes are rarely studied, yet are hypothesized to influence metastatic progression. Here, we developed a mouse model of early bone metastasis and multimodal 3D imaging to quantify cancer cell homing, dynamic bone (re)modeling and onset of bone metastasis. Using 3D light sheet fluorescence microscopy, we show eGFP+ cancer cells and small clusters in 3D (intact) bones. We detect early bone lesions using time-lapse in vivo microCT and reveal altered bone (re)modeling in absence of detectable lesions. With a new microCT image analysis tool, we detect and track the growth of early bone lesions over time. We show that cancer cells home in all bone compartments, while osteolytic lesions are only detected in the metaphysis, a region of high (re)modeling. Our study provides novel insights of dynamic bone (re)modeling as a driver during the early phase of metastasis.

bioengineering↗

bioRxiv2023

Quiescence-inducing 3D-engineered matrix uncovers mechanosensitive and drug protective FHL2-p21 signaling axis

Resected tumors frequently relapse with distant metastasis, despite systemic treatment. Cellular dormancy has been identified as an important mechanism underlying such drug resistance enabling late relapse. Nonetheless, hurdles associated with detection and isolation of disseminated cancer cells (DCCs) in disease-free patients urge the need for in vitro models of dormant cells suited for drug discovery. Here, we explore dormancy-inducing 3D-engineered matrices, which generate mechanical confinement and induce growth arrest and survival against chemotherapy in cancer cells. We characterized the dormant phenotype of solitary cells by P-ERKlow:P-p38high dormancy signaling ratio, along with Ki67-expression. As underlying mechanism, we identified stiffness-dependent nuclear localization of the four-and-a-half LIM domains 2 (FHL2) protein, leading to p53-independent high p21Cip1/Waf1 nuclear expression, validated in murine and human tissue. Suggestive of a resistance-causing role, cells in the dormancy-inducing matrix became sensitive against chemotherapy upon FHL2 downregulation. Thus, our biomaterial-based approach will enable systematic screens for novel compounds suited to eradicate potentially relapsing, dormant cancer cells. TeaserUsing semi-synthetic bioengineered hydrogels, we reveal a mechanosensitive and drug protective mechanism of dormant cancer cells in tissues

bioengineering↗