Biology subjects

Halwachs, K. N.

Publications and source records attributed to Halwachs, K. N..

2 recordsLinked to original sources

bioRxiv2025

Tuning Scaffold Degradation with Non-Natural Peptidomimetics to Control Human Umbilical Vein Endothelial Cell Morphology and Vessel Formation

The in vitro vascularization of 3D tissue constructs, such as hydrogels, remains a paramount challenge in tissue engineering. Extracellular matrix degradation and remodeling are key parts of the vascularization process; however, it is difficult to isolate the effects of degradability in both natural and synthetic matrix models. Naturally-derived matrices typically couple degradability to other material properties, whereas synthetic matrices rely on short peptide sequences to impart degradability, which typically exhibit substrate overlap to many proteases. Here, we present a method to independently and broadly tune 3D hydrogel degradation using crosslinkers with non-natural peptoid (N-substituted glycine) substitutions. Increased peptoid substitutions reduced hydrogel degradability to collagenases without altering hydrogel modulus, swelling ratio, or crosslinker length. Using this approach, human umbilical vein endothelial cells (HUVECs) encapsulated in more degradable hydrogels proliferated more, formed more vessels, exhibited higher metabolic activity, and secreted more extracellular matrix than HUVECs encapsulated in less degradable or non-degradable hydrogels. Interestingly, HUVECs encapsulated in the least degradable hydrogels secreted significantly higher matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) than HUVECs encapsulated in the most degradable hydrogels, suggesting higher MMP secretion to compensate for the reduced matrix degradability. Overall, this work highlights the importance of protease-mediated remodeling on vascularization and suggests that peptoid substitutions are effective for tuning hydrogel degradability for a variety of 3D cell applications. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/684851v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@c22b3corg.highwire.dtl.DTLVardef@1a4ae14org.highwire.dtl.DTLVardef@a0ad1forg.highwire.dtl.DTLVardef@c5def5_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

Matrix Stiffness Regulates Mechanotransduction and Vascular Network Formation of hiPSC-Derived Endothelial Progenitors Encapsulated in 3D Hydrogels

The mechanical properties of the extracellular matrix (ECM), particularly stiffness, regulate endothelial progenitor responses during vascular development, yet their behavior in physiologically compliant matrices (<1 kPa) remains underexplored. Using norbornene-modified hyaluronic acid (NorHA) hydrogels with tunable stiffness (190-884 Pa), we investigated how hydrogel stiffness influences cell morphology, endothelial maturation, mechanotransduction, and microvascular network formation in human induced pluripotent stem cell-derived endothelial progenitors (hiPSC-EPs). Our findings reveal a stiffness-dependent tradeoff between mechanotransduction and vascular network formation. At intermediate stiffness (551 Pa), cells exhibited the greatest increase in endothelial marker CD31 expression and Yes-associated protein (YAP)/ transcriptional coactivator with PDZ-binding motif (TAZ) nuclear translocation, indicating enhanced mechanotransduction and endothelial maturation. However, this did not translate to superior plexus formation. Instead, the most compliant matrix (190 Pa) supported greater vascular connectivity, characterized by longer branches ([~]0.03/volume vs. 0.015 at 551 Pa) and enhanced actin remodeling. 3D cell contraction measurements revealed a 15.6-fold higher basal displacement in compliant hydrogels, suggesting that cell-generated forces and matrix deformability collectively drive vascular morphogenesis. Unlike prior studies focusing on pathological stiffness ranges (>10 kPa), our results emphasize that vascularization is not solely driven by the most mechanotransductive environment but rather by a balance of compliance, contractility, and cell-induced remodeling. These findings underscore the need to design hydrogels that provide sufficient mechanotransduction for endothelial maturation while maintaining compliance to support dynamic vascular morphogenesis. This work provides a mechanically tuned framework for optimizing microenvironments to balance endothelial differentiation and vascular network formation in tissue engineering and regenerative medicine.

bioengineering↗