West Toni M, Han Jiwan, Peery Gabriel, Zoldan Janet, Sacks Michael S
Willerson Center, Oden Institute for Computational Engineering and Sciences, University of Texas at Austin.
Department of Biomedical Engineering, University of Texas at Austin.
bioRxiv. 2025 Jun 24:2025.06.18.660409. doi: 10.1101/2025.06.18.660409.
Human induced pluripotent stem cells (hiPSCs) offer patient-specific and immune-evasive sources for generating diverse cell types; yet lack of vascularization in hiPSC-derived tissues remains a major limitation for both therapeutic applications and disease modeling. Elucidating the mechanisms underlying vascular network formation in hiPSC-derived cells is therefore imperative. We and others have previously demonstrated that hiPSC-derived endothelial progenitor cells (hiPSC-EPs) self-assemble into lumenized microvascular networks when cultured in 3D norbornene-functionalized hyaluronic acid-based hydrogels. Herein we investigated the early period of culturing to characterize contractility of hiPSC-EPs. We hypothesized that multi-cell cooperativity would increase over time and would be dependent on the original hydrogel storage modulus. To quantify cellular contractility either 4 or 7 days after encapsulation, 3D kinematic analysis was performed on single and small multi-cell clusters of hiPSC-EPs embedded in NorHA-based hydrogels. Contractile responses were significantly and non-linearly influenced by multicellularity, culture duration, and hydrogel stiffness. Novel to this study was the observation that NorHA hydrogels exhibited compressible behaviors, with greater compressibility occurring in NorHA hydrogels with lower stiffness. Hence, the kinematic analysis was modified to incorporate separate deviatoric and volumetric strain indices. At day 7, multicellularity synergistically increased both strain components. These findings indicated that hiPSC-EP contractility and mechanical interactions with the hydrogel are governed by culture duration, multicellularity, and hydrogel stiffness; providing mechanical insight on hiPSC-EP self-assembly into microvasculature networks, a critical step towards development of functional vascular tissues for regenerative medicine and disease models.
人诱导多能干细胞（hiPSC）为生成多种细胞类型提供了患者特异性且具有免疫逃避特性的来源；然而，hiPSC衍生组织中缺乏血管化仍然是治疗应用和疾病建模的主要限制因素。因此，阐明hiPSC衍生细胞中血管网络形成的潜在机制至关重要。我们和其他人之前已经证明，hiPSC衍生的内皮祖细胞（hiPSC-EP）在3D降冰片烯功能化的基于透明质酸的水凝胶中培养时会自组装成有腔的微血管网络。在此，我们研究了培养早期以表征hiPSC-EP的收缩性。我们假设多细胞协同作用会随着时间增加，并且会依赖于原始水凝胶的储能模量。为了量化包封后4天或7天的细胞收缩性，对嵌入基于NorHA水凝胶中的hiPSC-EP的单个和小多细胞簇进行了3D运动学分析。收缩反应受到多细胞性、培养持续时间和水凝胶硬度的显著且非线性影响。本研究的新颖之处在于观察到NorHA水凝胶表现出可压缩行为，在较低硬度的NorHA水凝胶中可压缩性更大。因此，对运动学分析进行了修改，以纳入单独的偏应变和体积应变指数。在第7天，多细胞性协同增加了两种应变成分。这些发现表明，hiPSC-EP的收缩性以及与水凝胶的机械相互作用受培养持续时间、多细胞性和水凝胶硬度的控制；为hiPSC-EP自组装成微血管网络提供了力学见解，这是朝着为再生医学和疾病模型开发功能性血管组织迈出的关键一步。
