Spatially controlling morphogenesis is a challenge for many organoid systems that manifests as a limited understanding of self-organization of differentiating cells and leads to a high degree of heterogeneity in organoid morphometrics. Current methods to grow organoids rely on temporal presentation of soluble cues that are not controllably delivered, and little is known about the role of the extracellular microenvironment in this process. Here, we present a material-based strategy to spatiotemporally control morphogenesis of human intestinal organoids (HIOs) with predictable crypt morphometrics and cell composition that match their in vivo tissue counterparts. We first optimize culture conditions to generate more reproducible HIOs with predictable growth in phototunable poly (ethylene glycol)-based hydrogels, and then systematically investigate the role of light-mediated matrix softening in guiding crypt formation. The light dose delivered to crypt-sized regions adjacent to growing organoids is a key factor in maintaining organoid cell viability, as well as crypt budding and elongation. With optimized light doses, predictable epithelial shape changes result in programmable crypt formation, confirmed by the presence of proliferative (Ki67+) and niche-defining Paneth (Lyz+) cells. This methodology could be readily adopted for other budding and branching organoids to facilitate controllable changes in morphogenesis or cell migration. Sequential patterning approaches and more complex pattern designs could further open the parameter space to facilitate modeling of a wide array of engineered tissues for applications ranging from fundamental biology to disease modeling and translational medicine.

Fission increases the number of crypts in the intestine during neonatal growth and also restores crypt density after injury by bifurcation of a pre-existing parent crypt into daughter crypts. While fission is typically symmetric in healthy crypts, it is more asymmetric in diseases, and the relationship between parent crypt shape and daughter crypt (a)symmetry is difficult to study as crypt budding and fission are stochastic in organoid models and difficult to control in vivo. Here, a photoresponsive hydrogel is introduced to spatiotemporally control daughter crypt emergence from mature parent crypts in intestinal organoids, enabling longitudinal tracking of crypt bifurcation in vitro. Variation of the photopatterned dimensions tunes parent crypt shape and reveals that both fission efficiency and crypt symmetry depend on parent crypt geometry. Epithelial boundary analysis identified parent crypt curvature as a key factor influencing daughter crypt symmetry. High-curvature or narrow crypts yielded symmetric daughter crypts, whereas wider parent crypts with lower epithelial curvature generated progressively more asymmetric crypts. Mechanistically, non-muscle myosin IIA acts as one key regulator of crypt symmetry. Overall, this work introduces a reproducible and spatiotemporally controllable in vitro model of crypt fission, allowing identification of mechanical determinants of fission that influence intestinal regeneration and development.

Taste dysfunction, or dysgeusia, is a common side effect of many cancer drugs. Dysgeusia is often reported by people treated with antiangiogenic tyrosine kinase inhibitors (TKIs), which inhibit receptor tyrosine kinases (RTKs). However, the mechanisms by which TKIs cause dysgeusia are not understood, as the role of RTKs in adult taste homeostasis is unknown. Here, we find that treating adult mice with the TKI cabozantinib shifts the fate of differentiating functional taste cell subtypes within taste buds. Through behavioral assays, we find this cell fate shift leads to blunted responses to sweet tastants in cabozantinib-treated mice. Finally, we show that inducible knockout of the RTK KIT, which is inhibited by cabozantinib, phenocopies taste cell fate shifts induced by TKI treatment. Our results establish KIT as a regulator of taste cell homeostasis and suggest that KIT inhibition may underlie TKI-induced dysgeusia in humans.

Initial landmark studies in the design of synthetic hydrogels for intestinal organoid culture identify precise matrix requirements for differentiation, namely decompression of matrix-imposed forces and supplementation of laminin. But beyond stating the necessity of laminin, organoid-laminin interactions have gone largely unstudied, as this ubiquitous requirement of exogenous laminin hinders investigation. In this work, a fast stress relaxing, boronate ester-based synthetic hydrogel is used for the culture of intestinal organoids, and it is fortuitously discovered that unlike all other synthetic hydrogels to date, laminin does not need to be supplemented for crypt formation. This highly defined material provides a unique opportunity to investigate laminin-organoid interactions and how it influences crypt evolution and organoid function. Via fluorescent labeling of non-canonical amino acids, it is further shown that adaptable boronate ester bonds increase deposition of nascent proteins, including laminin. Collectively, these results advance the understanding of how mechanical and matricellular signaling influence intestinal organoid development.

INTRODUCTION: Notch signaling is a principal niche pathway crucial for intestinal stem cells (ISCs), directing ISC self-renewal and lineage commitment to absorptive enterocytes. Because Notch signaling requires cell-cell contact, Paneth cells are considered to be the Notch niche cells as they neighbor each ISC and express the key Notch ligands Dll1 and Dll4. However, no functional studies have investigated the Paneth cell-specific role in the Notch niche. Additionally, ISCs function normally after Paneth cell ablation, yet how they maintain Notch signaling without Paneth cells remains unknown. We aimed to define the ISC response to Paneth cell-specific Notch ligand depletion. We hypothesized that loss of DLL1 and DLL4 in Paneth cells inhibits Notch signaling in ISCs, leading to loss of ISCs as well as impaired proliferation and differentiation. METHODS: To deplete Dll1 and Dll4 in Paneth cells, we crossed Dll1 f/f ; Dll4 f/f mice with a constitutive Paneth cell-specific Cre reporter mouse ( Defensin4-Cre; Rosa-LSL-tdTomato ). To deplete these Notch ligands after intestinal maturation, we crossed Dll1 f/f ; Dll4 f/f mice to a tamoxifen-inducible Paneth cell Cre strain ( Lysozyme-CreER T2 ; Rosa-LSL-tdTomato ), and induced ligand gene deletion in adult mice by treatment with 100mg/kg tamoxifen for 5 days, harvesting intestines 2 days later. Crypt cells were characterized by histological analysis of proliferation (EdU), and ISC (OLFM4), Paneth cell (tdTomato, LYZ, MMP7, UEA1), goblet cell (MUC2, UEA1), and endocrine cell (CHGA) marker expression. RESULTS: Surprisingly, constitutive Paneth cell-specific deletion of Dll1 and Dll4 did not affect overall morphology or proliferation of the intestinal epithelium, suggesting that normal ISC function was maintained throughout development. However, analysis of the ISC marker and Notch target OLFM4, showed a loss of ISC Notch signaling at the crypt base. Instead, cells expressing OLFM4 were shifted higher into the transit-amplifying region of the crypt, indicating that ISCs migrated away from defective Paneth cells and next to Notch ligand-expressing progenitors in the upper crypt. Paneth cells remained clustered at the crypt base, exhibiting hyperplasia with increased numbers of marker-expressing cells. Furthermore, the villus epithelium harbored mislocated tdTomato-positive cells that co-expressed Paneth and goblet cell markers, a feature of Paneth cell progenitors. These changes imply a drive to generate new Paneth cells to replace the ones lacking Notch ligands. In addition, increased numbers of endocrine cells were observed at the crypt base; although their numbers were not sufficient to replace the Paneth cell Notch niche. Like the constitutive model, tamoxifen-inducible deletion of Dll1 and Dll4 in Paneth cells promoted OLFM4 mislocation to the upper crypt, indicating ISC movement out of the crypt base. Interestingly, cleaved caspase 3 staining revealed increased apoptotic cells at the crypt base after inducible Dll1 and Dll4 deletion, suggesting that acute cell death plays a role in the crypt cell remodeling. CONCLUSION: Paneth cell-specific Dll1 and Dll4 deletion induces crypt remodeling to rebuild the ISC Notch niche. This project was funded by NIH R01 DK118023 awarded to L.C. Samuelson. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Plasticity is needed during development and homeostasis to generate diverse cell types from stem and progenitor cells. Following differentiation, plasticity must be restricted in specialized cells to maintain tissue integrity and function. For this reason, specialized cell identity is stable under homeostatic conditions; however, cells in some tissues regain plasticity during injury-induced regeneration. While precise gene expression controls these processes, the regulatory mechanisms that restrict or promote cell plasticity are poorly understood. Here we use the mouse small intestine as a model system to study cell plasticity. We find that H3K36 methylation reinforces expression of cell-type-associated genes to maintain specialized cell identity in intestinal epithelial cells. Depleting H3K36 methylation disrupts lineage commitment and activates regenerative gene expression. Correspondingly, we observe rapid and reversible remodelling of H3K36 methylation following injury-induced regeneration. These data suggest a fundamental role for H3K36 methylation in reinforcing specialized lineages and regulating cell plasticity and regeneration. Pashos et al. show that H3K36 methylation maintains intestinal epithelial fate commitment, whereas its suppression, which is also observed upon injury, induces a plastic state and expression of genes involved in regeneration.

Tissue architecture and function are influenced by mechanical cues. Yet, how cell nuclei sense forces within 3D tissues and dictate differentiation remains unknown as prior studies focused on isolated mesenchymal cells, which fail to fully predict tissue-level mechanical properties. We fill this knowledge gap utilizing live reporters and material-based organoid models. We posit the nucleus as an active mechanosensor of tissue shape, with levels of the nuclear scaffolding protein lamin-A varying across intestinal stem cell differentiation trajectory. Elevated forces on differentiated Paneth cell nuclei, in both organoids and tissue explants, increase lamin-A and nuclear wrinkling. Enhancing nuclear mechanotransduction primes cell differentiation, in otherwise stem promoting conditions, revealing that nuclear mechanics can direct stem cell fate. By engineering spatiotemporally controlled de novo tissue curvature with photo-degradable hydrogels, we direct spatially patterned lamin-A levels across mouse and human organoids of healthy and diseased origin, uncovering conserved nuclear mechanosensing pathway in epithelial tissues.

The cellular organization within organoid models is important to regulate tissue specific function, yet few engineering approaches can control or direct cellular organization. Here, a photodegradable hydrogel is used to create softened regions that direct crypt formation within intestinal organoids, where the dimensions of the photosoftened regions generate predictable and defined crypt architectures. Guided by in vivo metrics of crypt morphology, this photopatterning method is used to control the width and length of in vitro organoid crypts, which ultimately defines the curvature of the epithelium. By tracking expression of differentiated Paneth cell markers in real-time, we show that epithelial curvature directs the localization of Paneth cells within engineered crypts, providing user-directed control over organoid functionality. We anticipate that our improved control over organoid architecture and thus Paneth cell localization will lead to more consistent in vitro organoid models for both mechanistic studies and translational applications.

Pancreatic ductal adenocarcinoma (PDAC) presents at advanced stages and is refractory to most treatment modalities. Wnt signaling activation plays a critical role in proliferation and chemotherapeutic resistance. Minimal media conditions, growth factor dependency, and Wnt dependency were determined via Wnt inhibition for seven patient derived organoids (PDOs) derived from pancreatic tumor organoid libraries (PTOL). Organoids demonstrating response in vitro were assessed in vivo using patient-derived xenografts. Wnt (in)dependent gene signatures were identified for each organoid. Panc269 demonstrated a trend of reduced organoid growth when treated with ETC-159 in combination with paclitaxel or gemcitabine as compared with chemotherapy or ETC-159 alone. Panc320 demonstrated a more pronounced anti-proliferative effect in the combination of ETC-159 and paclitaxel but not with gemcitabine. Panc269 and Panc320 were implanted into nude mice and treated with ETC-159, paclitaxel, and gemcitabine as single agents and in combination. The combination of ETC-159 and paclitaxel demonstrated an anti-tumor effect greater than ETC-159 alone. Extent of combinatory treatment effect were observed to a lesser extent in the Panc320 xenograft. Wnt (in)dependent gene signatures of Panc269 and 320 were consistent with the phenotypes displayed. Gene expression of several key Wnt genes assessed via RT-PCR demonstrated notable fold change following treatment in vivo. Each pancreatic organoid demonstrated varied niche factor dependencies, providing an avenue for targeted therapy, supported through growth analysis following combinatory treatment of Wnt inhibitor and standard chemotherapy in vitro. The clinical utilization of this combinatory treatment modality in pancreatic cancer PDOs has thus far been supported in our patient-derived xenograft models treated with Wnt inhibitor plus paclitaxel or gemcitabine. Gene expression analysis suggests there are key Wnt genes that contribute to the Wnt (in)dependent phenotypes of pancreatic tumors, providing plausible mechanistic explanation for Wnt (in)dependency and susceptibility or resistance to treatment on the genotypic level.

As a model of the intestinal epithelium, intestinal stem cells (ISCs) have been grown and differentiated as monolayers on materials where stochastic organization of the crypt and villi cells occurs. We developed an allyl sulfide crosslinked photoresponsive hydrogel with a shear modulus of 1.6 kPa and functionalized with GFOGER, Bm-binder peptide ligands for monolayer growth of ISCs. The allyl sulfide chemistry allowed in situ control of mechanics in the presence of growing ISC monolayers, and structured irradiation afforded spatial regulation of the hydrogel properties. Specifically, ISC monolayers grown on 1.6 kPa substrates were in situ softened to 0.29 kPa, using circular patterns 50, 75, and 100 μm in diameter, during differentiation, resulting in control over the size and arrangement of de novo crypts and monolayer cellularity. These photoresponsive materials should prove useful in applications ranging from studying crypt evolution to drug screening and transport across tissues of changing cellular composition.

AbstractStromal fibrosis activates prosurvival and proepithelial-to-mesenchymal transition (EMT) pathways in pancreatic ductal adenocarcinoma (PDAC). In patient tumors treated with neoadjuvant stereotactic body radiation therapy (SBRT), we found upregulation of fibrosis, extracellular matrix (ECM), and EMT gene signatures, which can drive therapeutic resistance and tumor invasion. Molecular, functional, and translational analysis identified two cell-surface proteins, a disintegrin and metalloprotease 10 (ADAM10) and ephrinB2, as drivers of fibrosis and tumor progression after radiation therapy (RT). RT resulted in increased ADAM10 expression in tumor cells, leading to cleavage of ephrinB2, which was also detected in plasma. Pharmacologic or genetic targeting of ADAM10 decreased RT-induced fibrosis and tissue tension, tumor cell migration, and invasion, sensitizing orthotopic tumors to radiation killing and prolonging mouse survival. Inhibition of ADAM10 and genetic ablation of ephrinB2 in fibroblasts reduced the metastatic potential of tumor cells after RT. Stimulation of tumor cells with ephrinB2 FC protein reversed the reduction in tumor cell invasion with ADAM10 ablation. These findings represent a model of PDAC adaptation that explains resistance and metastasis after RT and identifies a targetable pathway to enhance RT efficacy.Significance:Targeting a previously unidentified adaptive resistance mechanism to radiation therapy in PDAC tumors in combination with radiation therapy could increase survival of the 40% of PDAC patients with locally advanced disease.See related commentary by Garcia Garcia et al., p. 3158

SummaryTaste buds on the tongue are collections of taste receptor cells (TRCs) that detect sweet, sour, salty, umami and bitter stimuli. Like non-taste lingual epithelium, TRCs are renewed from basal keratinocytes, many of which express the transcription factor SOX2. Genetic lineage tracing has shown SOX2+ lingual progenitors give rise to both taste and non-taste lingual epithelium in the posterior circumvallate taste papilla (CVP) of mice. However, SOX2 is variably expressed among CVP cells suggesting that their progenitor potential may vary. Using transcriptome analysis and organoid technology, we show highly expressing SOX2+ cells are taste-competent progenitors that give rise to organoids comprising both TRCs and lingual epithelium, while organoids derived from low-expressing SOX2+ progenitors are composed entirely of non-taste cells. Hedgehog and WNT/ß-catenin are required for taste homeostasis in adult mice, but only WNT/ß-catenin promotes TRC differentiation in vitro and does so only in organoids derived from higher SOX2+ taste lineage-competent progenitors.

Spatiotemporally coordinated transformations in epithelial curvature are necessary to generate crypt-villus structures during intestinal development. However, the temporal regulation of mechanotransduction pathways that drive crypt morphogenesis remains understudied. Intestinal organoids have proven useful to study crypt morphogenesis in vitro, yet the reliance on static culture scaffolds limits the ability to assess the temporal effects of changing curvature. Here, a photoinduced hydrogel cross-link exchange reaction is used to spatiotemporally alter epithelial curvature and study how dynamic changes in curvature influence mechanotransduction pathways to instruct crypt morphogenesis. Photopatterned curvature increased membrane tension and depolarization, which was required for subsequent nuclear localization of yes-associated protein 1 (YAP) observed 24 hours following curvature change. Curvature-directed crypt morphogenesis only occurred following a delay in the induction of differentiation that coincided with the delay in spatially restricted YAP localization, indicating that dynamic changes in curvature initiate epithelial curvature–dependent mechanotransduction pathways that temporally regulate crypt morphogenesis.

3D organoid models have recently seen a boom in popularity, as they can better recapitulate the complexity of multicellular organs compared to other in vitro culture systems. However, organoids are difficult to image because of the limited penetration depth of high-resolution microscopes and depth-dependent light attenuation, which can limit the understanding of signal transduction pathways and characterization of intimate cell-extracellular matrix (ECM) interactions. To overcome these challenges, phototransfer by allyl sulfide exchange-expansion microscopy (PhASE-ExM) is developed, enabling optical clearance and super-resolution imaging of organoids and their ECM in 3D. PhASE-ExM uses hydrogels prepared via photoinitiated polymerization, which is advantageous as it decouples monomer diffusion into thick organoid cultures from the hydrogel fabrication. Apart from compatibility with organoids cultured in Matrigel, PhASE-ExM enables 3.25× expansion and super-resolution imaging of organoids cultured in synthetic poly(ethylene glycol) (PEG) hydrogels crosslinked via allyl-sulfide groups (PEG-AlS) through simultaneous photopolymerization and radical-mediated chain-transfer reactions that complete in <70 s. Further, PEG-AlS hydrogels can be in situ softened to promote organoid crypt formation, providing a super-resolution imaging platform both for pre- and post-differentiated organoids. Overall, PhASE-ExM is a useful tool to decipher organoid behavior by enabling sub-micrometer scale, 3D visualization of proteins and signal transduction pathways.

Roundabout 4 (Robo4) is a transmembrane receptor that expresses specifically in endothelial cells. Soluble Robo4 was reported in the human plasma and mouse serum and is inhibitory towards FGF- and VEGF-induced angiogenesis. It remains unknown how soluble Robo4 is generated and if soluble Robo4 regulates additional angiogenic signaling. Here, we report soluble Robo4 is the product of constitutive ectodomain shedding of endothelial cell surface Robo4 by disintegrin metalloproteinases ADAM10 and ADAM17 and acts to inhibit angiogenic Slit3 signaling. Meanwhile, the ligand Slit3 induces cell surface receptor Robo4 endocytosis to shield Robo4 from shedding, showing Slit3 inhibits Robo4 shedding to enhance Robo4 signaling. Our study delineated ADAM10 and ADAM17 are Robo4 sheddases, and ectodomain shedding, including negative regulation by its ligand Slit3, represents a novel control mechanism of Robo4 signaling in angiogenesis.