Avinava Roy

The vascular system exhibits complex, nonplanar geometries that become further distorted during pathological remodeling, including arterial tortuosity and aneurysms. Although hemodynamic shear stress is a well‐established regulator of vascular function, the direct effects of curvature as an intrinsic geometric cue remain poorly defined. This is largely because existing in vitro models are static and fail to capture the dynamic changes that accompany disease progression. To address this gap, we used a magnetoactive hydrogel platform that enables real‐time, on‐demand curvature of endothelial monolayers to reproduce clinically established tortuosity metrics. Using this system, we found that elevated curvature increased nuclear localization of Yes‐associated protein (YAP), with the strongest response in convex relative to concave regions of highly tortuous endothelial monolayers. This mechanosensitive response was accompanied by reduced VE‐Cadherin junctional thickness and increased membrane localization of endothelial nitric oxide synthase. These findings identify local curvature, independent of shear stress, as a regulator of endothelial cell mechanosensing and function, and establish a dynamic hydrogel platform for isolating geometric regulation from shear stress inputs in vascular mechanobiology.

Hydrogels serve as powerful models for investigating cell‐extracellular matrix (ECM) interactions. While chemical modifications are routinely used to tune hydrogel properties, it remains unclear whether these modifications mediate cell fate. Previous work has shown that cells deposit newly synthesized (nascent) ECM at the cell‐hydrogel interface. Here, we demonstrate that this nascent ECM interface regulates how cells interpret chemical modifications. Using hydrogels with varied chemical modifications, we isolated the effects of chemical modification on nascent ECM and cell fate. Nascent ECM deposition increased as a function of hydrogel modification and with distinct matrisome compositions. While low‐modification hydrogels promoted cell differentiation, high modifications increased cell proliferation. Perturbing cell‐ nascent ECM interactions reversed this cell fate. Our findings reveal that nascent ECM regulates cell fate by converting hydrogel cues into signals that control cell fate. This tri‐directional interplay among hydrogel chemical modifications, nascent ECM, and cell fate reframes how we interpret cell‐hydrogel interactions.

The vascular system exhibits complex, non-planar geometries that become further distorted during pathological remodeling, including arterial tortuosity and aneurysms. Although hemodynamic shear stress is a well-established regulator of vascular function, the direct effects of curvature as an intrinsic geometric cue remain poorly defined. This is largely because existing in vitro models are static and fail to capture the dynamic changes that accompany disease progression. To address this gap, we used a magnetoactive hydrogel platform that enables real-time, on-demand curvature of endothelial monolayers to reproduce clinically established tortuosity metrics. Using this system, we found that elevated curvature increased nuclear localization of yes-associated protein (YAP), with the strongest response in convex relative to concave regions of highly tortuous endothelial monolayers. This mechanosensitive response was accompanied by reduced VE-Cadherin junctional thickness and increased membrane localization of endothelial nitric oxide synthase. Together, these findings identify local curvature, independent of shear stress, as a regulator of endothelial cell mechanosensing and function, and establish a dynamic hydrogel platform for isolating geometric regulation from shear stress inputs in vascular mechanobiology.

The endometrium, the mucosal lining of the uterus, is a highly regenerative tissue that undergoes cyclic remodeling guided by tightly regulated levels of estrogen and progesterone. Stromal cells, including fibroblasts, are embedded within the connective tissue of the endometrium and contribute to the rapidly changing extracellular matrix (ECM). During the secretory phase, high levels of progesterone induce decidualization of endometrial fibroblasts, which changes their morphology and protein secretion. While it has been shown that the mechanical properties of endometrial tissue, such as the elastic modulus, also contribute to tissue homeostasis and pathology, the interplay between hormones and tissue modulus in contributing to ECM remodeling remains unknown. To address this, we used hydrogels of varying elastic moduli (5 and 15 kPa) to induce decidualization of endometrial fibroblasts. Using metabolic labeling of glycosylated nascent ECM proteins, we then visualized and measured the deposition of newly secreted (nascent) ECM proteins during decidualization. In addition, we designed an automated ImageJ‐based workflow for unbiased quantification of nascent ECM deposition. Our results demonstrate that both 5 and 15 kPa hydrogels support decidualization of endometrial stromal fibroblasts as shown by an increase in cell flattening and prolactin secretion. While increased hydrogel modulus alone enhances nascent ECM deposition, decidualization produces an additional increase that converges to similar levels regardless of the initial hydrogel modulus. Collectively, these findings demonstrate that endometrial stromal fibroblasts deposit nascent ECM that is enhanced during decidualization. These observations may provide new insights toward future studies addressing the mechanisms of ECM remodeling in endometrial tissue.

The endometrium, the mucosal lining of the uterus, is a highly regenerative tissue that undergoes cyclic remodeling guided by tightly regulated levels of estrogen and progesterone. Stromal cells are embedded within the connective tissue of the endometrium and contribute to the rapidly changing extracellular matrix (ECM). With hormone exposure, endometrial stromal cells undergo decidualization, which alters their morphology and protein secretion. While an increase in tissue modulus is associated with gynecological diseases, the relationship between mechanical properties, hormone exposure, and ECM deposition remains poorly understood. Here, we investigated how both stiffness and hormones regulate ECM deposition by human endometrial stromal cells during decidualization. Using metabolic labeling with sugar analogs and click chemistry, we measure newly secreted ECM proteins deposited by endometrial stromal cells during decidualization. Additionally, we study the nascent ECM in response to different mechanical properties using hyaluronic acid hydrogels. To increase throughput and reproducibility, we designed an automated ImageJ-based workflow for unbiased quantification of nascent ECM deposition. Our results demonstrate that hormones induce decidualization, characterized by F-actin stress fiber formation and prolactin secretion. In addition, we show that decidualization on hydrogels is characterized by an increase in nascent ECM deposition which depends on the initial hydrogel modulus. In contrast, endometrial stromal cells on glass show little change in nascent ECM deposition during hormone exposure. Collectively, these findings demonstrate that both mechanical and biochemical cues regulate ECM deposition during endometrial remodeling. These observations may provide new insights towards future studies addressing the mechanisms of ECM remodeling in gynecological diseases.

Folding of mucosal tissues, such as the tissue within the epithelium of the upper respiratory airways, is critical for organ function. Studying the influence of folded tissue patterns on cellular function is challenging mainly due to the lack of suitable cell culture platforms that can recreate dynamic tissue folding in vitro. Here, a bilayer hydrogel folding system, composed of alginate/polyacrylamide double‐network (DN) and hyaluronic acid (HA) hydrogels, to generate static folding patterns based on mechanical instabilities, is described. By encapsulating human fibroblasts into patterned HA hydrogels, human bronchial epithelial cells form a folded pseudostratified monolayer. Using magnetic microparticles, DN hydrogels reversibly fold into pre‐defined patterns and enable programmable on‐demand folding of cell‐laden hydrogel systems upon applying a magnetic field. This hydrogel construction provides a dynamic culture system for mimicking tissue folding in vitro, which is extendable to other cell types and organ systems.