Biology subjects

Loebel, C.

Publications and source records attributed to Loebel, C..

18 recordsLinked to original sources

bioRxiv2026

Hydrogel dimensionality directs mechanics-dependent nascent matrix deposition by tendon fibroblasts

Tendon fibroblasts continuously synthesize and remodel extracellular matrix (ECM) in response to their surrounding mechanical environment in vivo and in vitro, yet how dimensionality regulates the deposition of newly synthesized matrix remains poorly understood. Here, we investigated nascent matrix deposition by primary mouse tail tendon fibroblasts cultured on flat two-dimensional (2D) or encapsulated within three-dimensional (3D) norbornene-modified hyaluronic acid hydrogels with tunable mechanical properties. Newly synthesized matrix was visualized using metabolic labeling with azido-galactosamine (GalNAz), which labels nascent glycoproteins deposited during culture. In 2D, increasing hydrogel elastic modulus from 10 to 25 kPa enhanced nascent matrix deposition. This response was accompanied by increased cell spreading and YAP nuclear localization, indicating increased cellular mechanosensing. In contrast, tendon fibroblasts encapsulated within enzymatically degradable 3D hydrogels showed progressive matrix deposition over time but deposited less nascent matrix in stiffer (~50 kPa) hydrogels compared with softer 5 and 10 kPa hydrogels. YAP nuclear localization was increased in softer hydrogels compared with 50 kPa hydrogels. Bulk RNA sequencing showed increased expression of tendon matrisome-associated genes in softer 3D hydrogels, including increased tenascin C and collagen type I expression. These findings demonstrate that hydrogel dimensionality determines the relationship between matrix mechanics and nascent matrix deposition. This work establishes a framework for studying how engineered microenvironments regulate the matrix-producing behavior of tendon fibroblasts and provides insight into the design of biomaterials for investigating tendon biology and matrix remodeling.

bioengineering↗

bioRxiv2026

Decorin-mediated Extracellular Matrix Stabilization Maintains Cartilage Integrity During Aging

Aging is a primary risk factor for osteoarthritis (OA), yet the mechanisms that preserve extracellular matrix integrity in long-lived connective tissues remain poorly defined. The function of articular cartilage depends on maintaining extracellular matrix integrity over a lifetime of mechanical use. Here we identify failure of matrix stabilization as an initiating mechanism of age-associated OA. Cartilage-specific deletion of decorin in mature mice disrupted the superficial collagen II fibrillar network, reduced aggrecan retention, and impaired poroelastic fluid pressurization by 9 months of age, preceding substantial transcriptional changes in resident chondrocytes. With advancing age, these matrix defects culminated in cartilage erosion, fibrotic remodeling, and spontaneous OA by 18 months. Mechanistically, decorin attenuated force-induced collagen II fibril realignment and reinforced the superficial fibrillar network, preserving matrix architecture under sustained physiological loading. These findings establish decorin-mediated extracellular matrix stabilization as a critical determinant of cartilage longevity and support a matrix-first model of age-associated degeneration.

biophysics↗

bioRxiv2026

Suspension-Based Human Esophagoids Recapitulate WNT2B-Dependent Regulation of Esophageal Basal Progenitors

Background & AimsThe human esophagus undergoes a tightly regulated developmental program, transitioning from a simple columnar epithelium in early development to a mature stratified squamous tissue essential for adult barrier function. Here, we constructed a developmental cell atlas spanning early development to adulthood and leveraged it to generate physiologically relevant in vitro models. MethodsWe utilized single-cell RNA sequencing and spatial multiplex proteomics of human esophageal tissue from early development through adulthood. We established a feeder-supported 2D culture system and a Matrigel-free, suspension-based 3D esophagoid model in a 96-well format. To interrogate WNT2B function, we analyzed patient tissue harboring WNT2B loss-of-function mutations and performed WNT inhibition in esophagoids. ResultsSequencing profiling identified stage-specific epithelial populations: multiciliated and GPC3 basal cells were unique to early development; KRT14 basal and CRNN luminal cells were adult-specific; and COL17A1, LY6D, and KRT4 populations were shared across stages. Spatially organized WNT2B, KIT, and VWC2 mesenchymal subtypes were identified. The 2D system preserved both epithelial and mesenchymal compartments with transcriptional fidelity. Esophagoids exhibited basal-to-luminal stratification, mesenchymal compartmentalization, and required stromal interactions for formation. WNT2B repressed self-renewal of TP63 basal progenitors and inhibited proliferation, confirmed by pharmacologic inhibition of WNT in the in vitro esophagoids. ConclusionsWe present a stage-resolved atlas of human esophageal development and a scalable esophagoid platform recapitulating esophageal architecture. WNT2B regulates progenitor dynamics by restraining basal cell self-renewal. Esophagoids provide a physiologically relevant system for modeling esophageal development and disease. Visual Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/733451v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@1af5743org.highwire.dtl.DTLVardef@8a061dorg.highwire.dtl.DTLVardef@1975c3forg.highwire.dtl.DTLVardef@292ce9_HPS_FORMAT_FIGEXP M_FIG C_FIG Key Findings and ImplicationsO_LIDevelopmental Atlas: The study presents a comprehensive transcriptional and structural atlas of the human esophageal epithelium, identifying conserved and stage-specific epithelial populations from early development to adulthood. Notably, stage-specific gene expression of multiciliated and GPC3 basal cells were unique to early development, while KRT14 basal and CRNN luminal cells were adult specific, with COL17A1+ (basal), LY6D+ (epibasal), and KRT4+ (middle), shared at all stages. C_LIO_LIMesenchymal Diversity: Spatial and transcriptional profiling revealed distinct mesenchymal subtypes, including WNT2B, KIT, and VWC2 populations, which are spatially organized and contribute to epithelial-mesenchymal signaling. These findings reinforce the role of stromal-epithelial interactions in esophageal development. C_LIO_LI2D Esophagus Cell Culture System: A feeder-supported 2D cell culture system was developed that retains both epithelial and mesenchymal populations, preserving transcriptional fidelity and enabling long-term expansion for mechanistic studies. C_LIO_LI3D Esophagoid Model: A suspension-based 3D organoid system was optimized using a 96-well format, enabling high-throughput generation of esophagoids with robust epithelial stratification and mesenchymal compartmentalization. These organoids recapitulate key features of the human esophagus, including basal-to-luminal organization, and require stromal interactions for formation. C_LIO_LIFunctional Role of WNT2B in esophagus development: Both in vivo and in vitro analyses demonstrated that WNT2B regulates epithelial progenitor dynamics and tissue architecture by repressing self-renewal of basally localized TP63+ cells and inhibiting proliferation. Loss-of-function models and WNT pathway modulation confirmed its role in epithelial-mesenchymal crosstalk and organoid integrity. C_LI

developmental biology↗

bioRxiv2026

Reprogramming Dedifferentiation Regulatory Networks Preserves Human Chondrocyte Phenotypes

Chondrocyte-based cartilage repair strategies such as autologous chondrocyte implantation (ACI) require extensive in vitro expansion to obtain clinically relevant cell numbers. However, this expansion step progressively drives chondrocyte dedifferentiation, reducing matrix-forming capacity and contributing to variable repair outcomes. To better understand this process, we used single-nucleus multiome profiling (snRNA-Seq + snATAC-Seq) to define the transcriptional and chromatin accessibility programs underlying human chondrocyte dedifferentiation during expansion. Multiome integration across passages revealed a continuous dedifferentiation trajectory accompanied by coordinated remodeling of gene expression and chromatin accessibility, identifying chromatin destabilization as an early regulatory event during phenotype loss. Guided by these regulatory signatures, we screened available small-molecule inhibitors targeting candidate pathways and found that Fludarabine most consistently preserved chondrocyte identity during early expansion. Fludarabine was associated with suppression of STAT1-related programs and early stabilization of the chromatin landscape prior to broader transcriptional recovery. Functionally, treated cells demonstrated enhanced matrix-forming capacity in chondrogenic pellet culture and significantly increased nascent protein synthesis in 3D hydrogel culture, with biosynthetic output approaching unexpanded controls by day 21. Together, these findings identify chromatin stability as a key regulatory determinant of expansion-associated chondrocyte dedifferentiation and establish a pharmacologic strategy to preserve chondrocyte functional potency during cell manufacturing for cartilage repair.

bioengineering↗

bioRxiv2026

Magnetoactive hydrogels to probe curvature-directed endothelial cell mechanosensing

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.

bioengineering↗

bioRxiv2026

Nascent extracellular matrix converts biomaterial cues into cell fate decisions

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.

bioengineering↗

bioRxiv2025

The developing tendon and enthesis are hypoxic and rely on hypoxia-inducible factor 1a (Hif1a) during postnatal development

The tendon-bone enthesis is a specialized fibrocartilaginous tissue crucial for muscle-to-bone force transmission, yet its postnatal development is not fully understood. Emerging evidence suggests hypoxia plays a pivotal role in enthesis maturation akin to its function in skeletal growth plates, with Hypoxia Inducible Factor 1 alpha (HIF-1) acting as a key regulator of cellular adaptation (e.g., cell survival, extracellular matrix (ECM) deposition). Here, we investigated the spatial and temporal dynamics of hypoxia in the murine Achilles tendon enthesis and elucidated the role of Hif1a in enthesis cell survival and ECM formation using Scleraxis-lineage conditional knockout (ScxCre; Hif1a cKO) mice. We found that while neonatal tendons rapidly resolve hypoxia after birth, the enthesis maintains a hypoxic niche through postnatal day 5, mirroring a gradient observed in growth plates. Disruption of HIF-1 in enthesis-resident cells resulted in pronounced deficits in grip strength, abnormal tendon-bone attachment morphology, disrupted calcaneal architecture, impaired mineralization, and significant ECM disorganization. Histological analyses revealed persistent cell death and loss of the characteristic fibrocartilaginous gradient in cKO entheses, including dysregulated collagen alignment. In vitro, HIF-1-deficient tendon fibroblasts exhibited blunted transcriptional responses to hypoxia, altered metabolic gene expression, and changes in ECM deposition. Collectively, our findings illuminate hypoxia as a sustained niche in the postnatal enthesis, with HIF-1 critically required for cell survival, ECM organization, and enthesis structural integrity. This work advances our understanding of enthesis biology and provides insights relevant to tendon-bone attachment disorders and regenerative strategies.

developmental biology↗

bioRxiv2025

Mechanical Cues Regulate Estrogen and Progesterone-Induced Nascent ECM Deposition by Human Endometrial Stromal Cells

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.

bioengineering↗

bioRxiv2025

Hydrogel viscoelasticity modulates cell nascent extracellular matrix deposition

Polymeric hydrogels are valuable platforms for determining how specific mechanical properties of native tissue extracellular matrix (ECM) regulate cell function. Recent research has focused on incorporating viscous and elastic properties into hydrogels to investigate cellular responses to time-dependent mechanical properties of the ECM. However, a critical aspect often overlooked is that cells continuously remodel their microenvironment in hydrogels, such as by the deposition of newly secreted (nascent) ECM. While this nascent ECM has been demonstrated to play a vital role in transmitting mechanical signals across various biological contexts, the mechanisms by which it regulates cellular function in response to time-dependent mechanical properties remain poorly understood. In this study, we developed an interpenetrating polymer network that enables independent control of viscous and elastic hydrogel properties. We show that cells cultured on high-viscosity hydrogels deposit increased nascent ECM which also correlates with enhanced hydrogel remodeling. Interestingly, higher nascent ECM deposition on high-viscosity hydrogels was decoupled from intracellular contractility. These results establish a relationship between hydrogel viscosity and nascent ECM deposition that may extend to diverse cell types and offer new insights into cell-hydrogel interactions.

bioengineering↗

bioRxiv2024

Local photo-crosslinking of native tissue matrix regulates cell function

Within most tissues, the extracellular microenvironment provides mechanical cues that guide cell fate and function. Changes in the extracellular matrix such as aberrant deposition, densification and increased crosslinking are hallmarks of late-stage fibrotic diseases that often lead to organ dysfunction. Biomaterials have been widely used to mimic the mechanical properties of the fibrotic matrix and study cell function. However, the initiation of fibrosis has largely been overlooked, due to the challenges in recapitulating early fibrotic lesions within the native extracellular microenvironment. Using visible light mediated photochemistry, we induced local crosslinking and stiffening of extracellular matrix proteins within ex vivo murine and human tissue. In ex vivo lung tissue of epithelial cell lineage-traced mice, local matrix crosslinking mimicked early fibrotic lesions that increased alveolar epithelial cell spreading, differentiation and extracellular matrix remodeling. However, inhibition of cytoskeletal tension or integrin engagement reduced epithelial cell spreading and differentiation, resulting in alveolar epithelial cell dedifferentiation and reduced extracellular matrix deposition. Our findings emphasize the role of local extracellular matrix crosslinking and remodeling in early-stage tissue fibrosis and have implications for ex vivo disease modeling and applications to other tissues.

bioengineering↗

bioRxiv2024

Structure-Mechanics Principles and Mechanobiology of Fibrocartilage Pericellular Matrix: A Pivotal Role of Type V Collagen

The pericellular matrix (PCM) is the immediate microniche surrounding resident cells in various tissue types, regulating matrix turnover, cell-matrix cross-talk and disease initiation. This study elucidated the structure-mechanical properties and mechanobiological functions of the PCM in fibrocartilage, a family of connective tissues that sustain complex tensile and compressive loads in vivo. Studying the murine meniscus as the model tissue, we showed that fibrocartilage PCM contains thinner, random collagen fibrillar networks that entrap proteoglycans, a structure distinct from the densely packed, highly aligned collagen fibers in the bulk extracellular matrix (ECM). In comparison to the ECM, the PCM has a lower modulus and greater isotropy, but similar relative viscoelastic properties. In Col5a1+/D menisci, the reduction of collagen V, a minor collagen localized in the PCM, resulted in aberrant fibril thickening with increased heterogeneity. Consequently, the PCM exhibited a reduced modulus, loss of isotropy and faster viscoelastic relaxation. This disrupted PCM contributes to perturbed mechanotransduction of resident meniscal cells, as illustrated by reduced intracellular calcium signaling, as well as upregulated biosynthesis of lysyl oxidase and tenascin C. When cultured in vitro, Col5a1+/D meniscal cells synthesized a weakened nascent PCM, which had inferior properties towards protecting resident cells against applied tensile stretch. These findings underscore the PCM as a distinctive microstructure that governs fibrocartilage mechanobiology, and highlight the pivotal role of collagen V in PCM function. Targeting the PCM or its molecular constituents holds promise for enhancing not only meniscus regeneration and osteoarthritis intervention, but also addressing diseases across various fibrocartilaginous tissues.

bioengineering↗

bioRxiv2024

Nascent matrix deposition supports alveolar organoid formation from aggregates in synthetic hydrogels

HighlightsO_LIAlveolar organoids are formed with a two-step, Matrigel-free method in a semi-synthetic hyaluronic acid (HA) hydrogel C_LIO_LIThe two-step method offers control over alveolar size, density, and growth C_LIO_LIAlveolar organoids maintain their AT2 identity in HA hydrogels C_LIO_LIAlveolar organoids secrete nascent extracellular matrix supporting organoid growth without Matrigel C_LI SummaryHuman induced pluripotent stem cell (iPSC) derived alveolar organoids have emerged as a system to model the alveolar epithelium in homeostasis and disease. However, alveolar organoids are typically grown in Matrigel, a mouse-sarcoma derived basement membrane matrix that offers poor control over matrix properties, prompting the development of synthetic hydrogels as a Matrigel alternative. Here, we develop a two-step culture method that involves pre-aggregation of organoids in hydrogel-based microwells followed by embedding in a synthetic hydrogel that supports alveolar organoid growth, while also offering considerable control over organoid and hydrogel properties. We find that the aggregated organoids secrete their own nascent extracellular matrix (ECM) both in the microwells and upon embedding in the synthetic hydrogels. Thus, the synthetic gels described here allow us to de-couple exogenous and nascent ECM in order to interrogate the role of ECM in organoid formation.

cell biology↗

bioRxiv2024

Quantification of local matrix deposition during muscle stem cell activation using engineered hydrogels

Adult stem cells occupy a niche that contributes to their function, but how stem cells remodel their microenvironment remains an open-ended question. Herein, biomaterials-based systems and metabolic labeling were utilized to evaluate how skeletal muscle stem cells deposit extracellular matrix. Muscle stem cells and committed myoblasts were observed to generate less nascent matrix than muscle resident fibro-adipogenic progenitors. When cultured on substrates that matched the stiffness of physiological uninjured and injured muscles, the increased nascent matrix deposition was associated with stem cell activation. Reducing the ability to deposit nascent matrix in muscle stem cells attenuated function and mimicked impairments observed from muscle stem cells isolated from old aged muscles, which could be rescued with therapeutic supplementation of insulin-like growth factors. These results highlight how nascent matrix production is critical for maintaining healthy stem cell function.

bioengineering↗

bioRxiv2023

Coordinated differentiation of human intestinal organoids with functional enteric neurons and vasculature

Human intestinal organoids (HIOs) derived from human pluripotent stem cells co-differentiate both epithelial and mesenchymal lineages in vitro but lack important cell types such as neurons, endothelial cells, and smooth muscle. Here, we report an in vitro method to derive HIOs with epithelium, mesenchyme, enteric neuroglial populations, endothelial cells, and organized smooth muscle in a single differentiation, without the need for co-culture. When transplanted into a murine host, these populations expand and organize to support organoid maturation and function. Functional experiments demonstrate enteric nervous system function, with HIOs undergoing peristaltic-like contractions, suggesting the development of a functional neuromuscular unit. HIOs also form functional vasculature, demonstrated in vitro using microfluidic devices to introduce vascular-like flow, and in vivo following transplantation, where HIO endothelial cells anastomose with host vasculature. Collectively, we report an in vitro model of the human gut that simultaneously co-differentiates epithelial, stromal, endothelial, neural, and organized muscle populations.

bioengineering↗

bioRxiv2022

Engineered hydrogel reveals contribution of matrix mechanics to esophageal adenocarcinoma 3D organoids and identify matrix-activated therapeutic targets

Increased extracellular matrix (ECM) stiffness has been implicated in esophageal adenocarcinoma (EAC) progression, metastasis, and resistance to therapy. However, the underlying pro-tumorigenic pathways are yet to be defined. Additional work is needed to develop physiologically relevant in vitro 3D culture models that better recapitulate the human tumor microenvironment and can be used to dissect the contributions of matrix stiffness to EAC pathogenesis. Here, we describe a modular, tumor ECM-mimetic hydrogel platform with tunable mechanical properties, defined presentation of cell-adhesive ligands, and protease-dependent degradation that supports robust in vitro growth and expansion of patient-derived EAC 3D organoids (EAC PDOs). Hydrogel mechanical properties control EAC PDO formation, growth, proliferation and activation of tumor-associated pathways that elicit stem-like properties in the cancer cells, as highlighted through in vitro and in vivo environments. We also demonstrate that the engineered hydrogel serves as a platform to identify potential therapeutic targets to disrupt the contribution of pro-tumorigenic increased matrix mechanics in EAC. Together, these studies show that an engineered PDO culture platform can be used to inform the development of therapeutics that target ECM stiffness in EAC.

bioengineering↗

bioRxiv2022

A Development-Inspired Niche for Homeostatic Human Mini-Intestines

Epithelial organoids derived from intestinal tissue, also referred to as mini-intestines or mini-guts, recapitulate many aspects of the organ in vitro and can be used for biological discovery, personalized medicine, and drug development. Murine intestinal organoids represent a homeostatic system that balances stem cell maintenance within a crypt-like compartment and differentiation within a villus-like compartment1-3. However, this homeostatic balance and spatial organization has not been achieved with human intestinal organoids4. Here, we leverage single cell RNA-seq data (scRNA-seq) and high-resolution imaging to interrogate the developing human intestinal stem cell niche. We identified an EGF-family member, EPIREGULIN (EREG), as uniquely expressed in the developing crypt, and found that EREG can take the place of EGF as an in vitro niche factor. Unlike EGF, which leads to growth of thin-walled cystic organoids, EREG-organoids are spatially resolved into budded and proliferative crypt domains and a differentiated villus-like central lumen. Transcriptomics and epigenomics showed that EREG-organoids are globally similar to the native intestine while EGF-organoids have an altered chromatin landscape, downregulate the master intestinal transcription factor CDX25,6, and ectopically express stomach genes.

developmental biology↗

bioRxiv2021

Microstructured hydrogels to guide self-assembly and function of lung alveolospheres

Epithelial cell organoids have increased opportunities to probe questions on tissue development and disease in vitro and for therapeutic cell transplantation. Despite their potential, current protocols to grow these organoids almost exclusively depend on culture within three-dimensional (3D) Matrigel, which limits defined culture conditions, introduces animal components, and results in heterogenous organoids (i.e., shape, size, composition). Here, we describe a method that relies on polymeric hydrogel substrates for the generation and expansion of lung alveolar organoids (alveolospheres). Using synthetic hydrogels with defined chemical and physical properties, human induced pluripotent stem cell (iPSC)-derived alveolar type 2 cells (iAT2s) self-assemble into alveolospheres and propagate in Matrigel-free conditions. By engineering pre-defined microcavities within these hydrogels, the heterogeneity of alveolosphere size and structure was reduced when compared to 3D culture while maintaining alveolar type 2 cell fate of human iAT2 and primary mouse tissue-derived progenitor cells. This hydrogel system is a facile and accessible culture system for the culture of primary and iPSC-derived lung progenitors and the method could be expanded to the culture of other epithelial progenitor and stem cell aggregates.

bioengineering↗

bioRxiv2021

Chemo-Mechanical Cues Modulate Nano-Scale Chromatin Organization in Healthy and Diseased Connective Tissue Cells

Microscale changes in tissue environment are translated to changes in cell behavior and phenotype, yet the mechanisms behind how these phenotypic changes occur are poorly understood. Here, we describe and model chromatin, which stores genetic information within the cell nucleus, as a dynamic nanomaterial whose configuration is modulated by chemo-mechanical cues in the microenvironment. Our findings indicate that physiologic chemo-mechanical cues can directly regulate chromatin architecture in progenitor cell populations. Via direct experimental observation and modeling that incorporates phase transitions and histone methylation kinetics, we demonstrate that soft environmental cues drive chromatin relocalization to the nuclear boundary and compaction. Conversely, dynamic stiffening attenuates these changes. Interestingly, in diseased human fibrous tissue cells, this link between mechanical inputs and chromatin nano-scale remodeling is abrogated. These data indicate that chromatin dynamics and plasticity may be hallmarks of disease progression and targets for therapeutic intervention.

bioengineering↗