Biology subjects

Young, J. L.

Publications and source records attributed to Young, J. L..

7 recordsLinked to original sources

bioRxiv2026

Enzymatic extracellular matrix remodeling in ex vivo slices of aged myocardium

Cardiac aging is accompanied by extracellular matrix (ECM) remodeling and increased myocardial stiffness, which may contribute to age-associated functional decline. However, whether direct remodeling of the aged cardiac ECM can modify myocardial mechanics and function remains poorly understood. Here, we established an ex vivo living myocardial slice platform to investigate whether enzymatic remodeling of the aged ECM can alter myocardial structure, mechanics, and function. Left ventricular myocardial slices (LMS) from young and aged mice were maintained under static stretch for 48 hours using a custom 3D-printed culture setup. Aged slices were treated with collagenase and subsequently characterized using quantitative imaging, tensile testing, contractility measurements, and transcriptomic analysis. Aged myocardium exhibited increased collagen and fibronectin abundance, altered collagen network architecture, and increased stiffness compared with young tissue. Collagenase treatment reduced collagen and network complexity and reduced myocardial stiffness toward young tissue values without compromising ultimate tensile stress. Despite these structural and biomechanical changes, age-associated differences in myocardial contractility remained comparable across groups. Transcriptomic analysis indicated that treated aged tissue largely retained its age-associated molecular phenotype, despite pathway-level shifts involving metabolism, cardiac function, and inflammatory responses. These findings demonstrate that enzymatic ECM remodeling can modify the aged myocardial mechanical environment while selected functional and transcriptional features of aging persist over 48 hours. The LMS platform provides a controllable ex vivo tissue-level approach for investigating ECM contributions during cardiac aging and evaluating strategies for ECM engineering.

bioengineering↗

bioRxiv2026

Ovarian extracellular matrix mechanics regulate oocyte-follicle interactions during female reproductive aging

Female reproductive aging is associated with ovarian functional decline, leading to infertility. During aging, biochemical and biophysical changes in the ovarian extracellular matrix (ECM) occur, yet how these properties affect follicle growth and oocyte quality remains poorly understood. Here we describe spatiotemporal changes in the ovarian ECM with age using mass spectrometry, immunohistochemistry, and nanoindentation. While follicle stiffness remains unchanged, stromal matrix remodeling is associated with a [~]2.5-fold increase in stiffness. To understand how this increase in stromal stiffness affects age-related follicular dysfunction, isolated young follicles were cultured in soft and stiff hydrogels mimicking young and aged ovarian stromal stiffness, respectively. Higher stiffness leads to a decrease in granulosa cell (GC) proliferation, oocyte quality, and GC-oocyte interactions mediated via transzonal projections (TZPs). RNA-seq revealed TGF-{beta} signaling as a major pathway affected by stiffness, and activation of TGF-{beta} signaling through Mongersen treatment rescued TZP formation and oocyte quality in stiff matrix. These findings provide mechanistic insight into how changes in ECM mechanics contribute to ovarian aging functional decline and reveal potential therapeutic targets to counter fertility loss associated with tissue aging and fibrosis.

cell biology↗

bioRxiv2026

Theca cell mechanosensing and regulation of follicular extracellular matrix during ovarian follicle development

Mammalian folliculogenesis is essential for female hormonal regulation and successful reproduction. While the steroidogenic functions of theca cells (TCs) have been implicated in ovarian diseases and infertility, the physico-structural properties of TCs and their associated extracellular matrix (ECM), or theca matrix, remain poorly understood. Using murine ovaries, we show that a stiff basement membrane (BM) and theca matrix constitute a mechanically instructive niche that modulates TC proliferation and Yes-associated protein (YAP) signalling in secondary follicles. We identify hyaluronic acid (HA) as a key matrix component that is actively secreted by contractile TCs. The HA scaffold, in turn, regulates TC proliferation, YAP signalling and motility, and is required for overall follicle growth. We showed that stiffer substrates enhance YAP nuclear transport in TCs, while mechanical stretch, cell packing, and curvature affect TC proliferation. In addition, TCs exhibit directed migration towards regions of positive curvature. Together, this study reveals a mechanochemical feedback mechanism that establishes TC mechanics and HA as key regulators of theca matrix formation that is essential for mammalian folliculogenesis. SIGNIFICANCEThe structural properties and mechanical functions of the basement membrane and theca cell-matrix encapsulating mammalian ovarian follicles are poorly understood. Our findings reveal that during early stage of follicle development, the basement membrane remains thin and stiff, while the theca cells actively secrete hyaluronic acid in a contractility-dependent manner. The hyaluronic acid scaffold, in turn, regulates theca cell YAP signalling, proliferation and motility that are required for functional growth of follicles. We further showed that the theca cells are mechanosensitive and fine-tune their proliferative capacity and Hippo pathways in response to substrate stiffness, stretch and curvature. Together, our study uncovers mechanoregulatory feedback between theca cells and associated extracellular matrix, offering new insights into environmental control of folliculogenesis in female reproduction.

developmental biology↗

bioRxiv2026

Volumetric mechanosensing of CAF in 3D hydrogels drive altered drug response in breast cancer

Altered mechanical properties of the tumor microenvironment (TME) influence cancer progression, yet the mechanistic basis by which 3D mechanics shape CAF heterogeneity and downstream tumor drug response remains poorly understood. Here, we engineered a modulus-tunable gelatin methacryloyl (GelMA) hydrogel platform spanning a normal-like (soft [~]2 kPa) to desmoplastic-like (stiff[~]40 kPa) range to culture primary breast CAFs under 3D confinement. CAFs exhibited pronounced volumetric morphoadaptation across matrices, with soft 3D matrices supporting larger, more protrusive morphologies and stiff gels constraining cell geometry. In contrast to canonical 2D paradigms, nuclear YAP localization was reduced in stiff 3D matrices and varied substantially across cells, consistent with a dominant role for 3D geometric/volumetric state in regulating mechanotransduction. Functionally, in transwell co-culture with MCF-7 spheroids under paclitaxel treatment, CAFs cultured in stiff 3D matrices induced a broader chemoresistance-associated transcriptional program, whereas soft 3D matrices CAFs favored stress/checkpoint-like responses. A 2D monolayer comparator indicated that coordinated resistance-associated programs emerge most clearly in 3D tumor architecture. Together, these results establish a GelMA-based biomaterials framework in which CAF volumetric state provides a quantifiable intermediate linking 3D matrix mechanics to mechanotransduction and tumor drug-response programs, motivating future strategies to modulate stromal function through mechanically controlled cell-state regulation.

bioengineering↗

bioRxiv2025

Mechanical Memory Primes Cells for Confined Migration

When migratory cells move from one stiffness niche to another in vivo, they are exposed to highly confined spaces imposed by dense extracellular matrix (ECM) networks and inter-tissue boundaries. Cells that originate from one niche possess distinct mechanosensitive adaptations that influence their response to their new niche, a concept known as mechanical memory. However, the mechanisms by which this memory is acquired, and the degree to which it influences migratory potential and decision-making processes in confinement remain poorly understood. Here, we combine stiffness priming using polyacrylamide hydrogels with a confinement platform to screen mechanical memory across healthy and transformed cells. Using a dose-and- passage approach, we find that in stiffness-sensitive cells primed on soft substrates navigate confinement more efficiently. Bulk RNA sequencing identifies NFATC2 as a transcription factor that mediates mechanical memory by reprogramming gene expression in stiffness-sensitive cells. siRNA-induced knockdown of NFATC2 in memory-sensitive cells confirmed its necessity for mechanical memory acquisition and subsequent confined migration enhancement. Interestingly, highly invasive cancer cells exhibit minimal sensitivity to prior mechanical priming, suggesting differential adaptation strategies. These findings reveal mechanical memory as a cell-intrinsic property shaped by past mechanical environments and highlight potential implications for controlling migration in wound repair, fibrosis, and disease progression.

cell biology↗

bioRxiv2023

Hybrid hydrogel-extracellular matrix scaffolds identify distinct ligand and mechanical signatures in cardiac aging

Extracellular matrix (ECM) remodeling of cardiac tissue is a key contributor to age-related cardiovascular disease and dysfunction. Aberrant secretion, structural perturbations, and degradation of specific ECM components lead to significant alterations in ECM properties that disrupt healthy cell and tissue homeostasis. These changes in ECM are multifaceted, as alterations in ligand presentation, including both biochemical and architectural aspects, are often accompanied by stiffness changes, clouding our understanding of how and which ECM properties contribute to a dysfunctional state. To identify the specific roles of these interconnected ECM cues and elucidate their mechanistic regulation in cellular function, we developed a material system that can independently present these two distinct matrix properties, i.e., ligand presentation and stiffness, to cultured cells in vitro. We describe a decellularized ECM-synthetic hydrogel hybrid scaffold that maintains native matrix composition and organization of young or aged murine cardiac tissue with independently tunable scaffold mechanics that mimic young or aged tissue stiffness. Seeding these scaffolds with primary cardiac fibroblasts (CFs) from young or aged mice, we identify distinct age- and ECM-dependent mechanisms of CF activation. Importantly, we show that ligand presentation of young ECM can outweigh profibrotic stiffness cues typically present in aged ECM in maintaining or driving CF quiescence, thereby highlighting the unique roles of ECM in aging. Ultimately, these tunable scaffolds can enable the discovery of specific ECM targets to prevent aging dysfunction and promote rejuvenation. DECIPHER: DECellularized In Situ Polyacrylamide Hydrogel-ECM hybRid

bioengineering↗

bioRxiv2021

Integrin α5β1 nano-presentation regulates collective keratinocyte migration independent of substrate rigidity

Nanometer-scale properties of the extracellular matrix influence many biological processes, including cell motility. While much information is available for single cell migration, to date, no knowledge exists on how the nanoscale presentation of extracellular matrix receptors influences collective cell migration. In wound healing, basal keratinocytes collectively migrate on a fibronectin-rich provisional basement membrane to re-epithelialize the injured skin. Among other receptors, the fibronectin receptor integrin 5{beta}1 plays a pivotal role in this process. Using a highly specific integrin 5{beta}1 peptidomimetic combined with nanopatterned hydrogels, we show that keratinocyte sheets regulate their migration ability at an optimal integrin 5{beta}1 nanospacing. This efficiency relies on the effective propagation of stresses within the cell monolayer independent of substrate stiffness. For the first time, this work highlights the importance of extracellular matrix receptor nanoscale organization required for efficient tissue regeneration.

biophysics↗