Biology subjects

Hutchins, E. J.

Publications and source records attributed to Hutchins, E. J..

8 recordsLinked to original sources

bioRxiv2026

FAM83H couples keratin organization to Notch signaling during epidermal morphogenesis

Keratin intermediate filaments are essential for epidermal integrity, yet how keratin organization is coupled to the cell fate signaling that coordinates keratinocyte differentiation during epidermal morphogenesis remains poorly understood. Here, we identify FAM83H as a previously unrecognized regulator that links keratin cytoskeletal organization to epidermal cell fate decisions. Using mouse models and a human 3D microphysiological epidermis model, we show that loss of FAM83H disrupts epidermal architecture by impairing basal keratinocyte differentiation, organization, and cell-cell adhesion. Single-cell transcriptomic analysis of 3D epidermal tissues identified Notch signaling as prominently associated with cell populations lost upon FAM83H depletion. Mechanistically, FAM83H localizes to cell-cell junctions, where it organizes keratin filaments and desmosome integrity. Loss of FAM83H disrupts a desmoplakin-keratin-Notch1 complex at junctions, impairing Notch1 proteolytic activation and proper keratinocyte differentiation. Together, our work identifies FAM83H as a key regulator of epidermal morphogenesis that couples keratin cytoskeletal architecture to Notch1 signaling, and positions keratin-associated proteins as active participants in the epithelial fate decisions that govern epidermal homeostasis.

cell biology↗

bioRxiv2026

StrataChip: a microphysiological system capturing dynamic keratinocyte fate and mechanical transitions during human epidermal morphogenesis

Epidermal development and homeostasis require precise coordination between keratinocyte differentiation and mechanics. Still, the mechanisms integrating these processes remain poorly understood in part due to limitations of existing experimental systems. Here, we introduce StrataChip, a tractable microphysiological system that enables dynamic, multimodal interrogation of human epidermal morphogenesis. The platform integrates a media perfused dermal tissue with human epidermal keratinocytes within a microfluidic device and supports rapid epidermal stratification following establishment of an air-liquid interface. High-resolution confocal imaging and single-cell RNA-sequencing demonstrate that the StrataChip recapitulates key architectural and molecular features of human epidermis, including distinct basal, spinous, and granular layers defined by canonical differentiation markers and adhesion molecule organization. Single-cell profiling reveals transcriptionally distinct basal and spinous subpopulations, including transitional states associated with suprabasal commitment. Live 3D imaging in situ captures keratinocyte morphodynamics including basal cell delamination and asymmetric division, linking dynamic cellular behaviors to defined differentiation fates and stratification. Altogether, StrataChip provides a robust platform for a dynamic and mechanistic interrogation of how gene regulation and cell mechanics are coupled during epidermal morphogenesis.

bioengineering↗

bioRxiv2026

Cellular diversity of the developing chick trigeminal ganglion at single-cell resolution

BackgroundThe trigeminal ganglion (TG) is a structure of the peripheral nervous system, composed of neuronal and non-neuronal cell types, that integrates sensory input from the face and jaw. The developing TG is derived from two embryonic cell populations: neural crest and cranial placode. Both populations play critical roles in TG development and must interact to coordinate changes in gene expression that regulate specification, differentiation, and organization. However, the molecular characteristics of the heterogeneous cell populations within the developing TG remain poorly defined. ResultsWe performed single-cell RNA-sequencing (scRNA-seq) on TG from developing chick embryos at HH17. Our high-resolution dataset (14 clusters, [~]87000 cells) provides insight into cellular diversity within the developing TG. As expected, we identified placode-derived neurons as well as neural crest cells prior to neuronal differentiation. In addition to classic markers, we identified novel transcripts with unknown roles in TG development, including several long non-coding RNAs (lncRNAs). ConclusionsWe generated a single-cell atlas of the developing chick trigeminal ganglion during early axonogenesis and defined the transcriptomic states of its diverse cell populations. Our results provide a useful resource for better understanding the cell populations contributing to TG development and gene expression that drives cell identity and differentiation.

developmental biology↗

bioRxiv2024

CRISPR-Cas13d as a molecular tool to achieve targeted gene expression knockdown in chick embryos

The chick embryo is a classical model system commonly used in developmental biology due to its amenability to gene perturbation experiments. Pairing this powerful model organism with cutting-edge technology can significantly expand the range of experiments that can be performed. Recently, the CRISPR-Cas13d system has been successfully adapted for use in zebrafish, medaka, killifish, and mouse embryos to achieve targeted gene expression knockdown. Despite its success in other animal models, no prior study has explored the potential of CRISPR-Cas13d in the chick. Here, we present an adaptation of the CRISPR-Cas13d system to achieve targeted gene expression knockdown in the chick embryo. As proof-of-principle, we demonstrate the knockdown of PAX7, an early neural crest marker. Application of this adapted CRISPR-Cas13d technique resulted in effective knockdown of PAX7 expression and function, comparable to knockdown achieved by translation-blocking morpholino. CRISPR-Cas13d complements preexisting knockdown tools such as CRISPR-Cas9 and morpholinos, thereby expanding the experimental potential and versatility of the chick model system.

developmental biology↗

bioRxiv2020

Temporal changes in plasma membrane lipid content induce endocytosis to regulate developmental epithelial-to-mesenchymal transition

Epithelial-to-mesenchymal transition (EMT) is a dramatic change in cellular physiology during development and metastasis which involves coordination between cell signaling, adhesion, and membrane protrusions. These processes all involve dynamic changes in the plasma membrane, yet how membrane lipid content regulates membrane function during developmental EMT remains incompletely understood. By screening for differential expression of lipid-modifying genes over the course of EMT in avian neural crest, we have identified the ceramide-producing enzyme neutral sphingomyelinase 2 (nSMase2) as a critical regulator of a developmental EMT. nSMase2 expression begins at the onset of EMT, and in vivo knockdown experiments demonstrate that nSMase2 is necessary for neural crest migration. Further, we find that nSMase2 promotes Wnt and BMP signaling, and is required to activate the mesenchymal gene expression program. Mechanistically, we show that nSMase2 is sufficient to induce endocytosis, and that inhibition of endocytosis mimics nSMase2 knockdown. Our results support a model in which nSMase2 is expressed at the onset of neural crest EMT to produce ceramide and induce membrane curvature, thus increasing endocytosis of Wnt and BMP signaling complexes and activating pro-migratory gene expression. These results highlight the critical role of plasma membrane lipid metabolism in regulating transcriptional changes during developmental EMT programs.

developmental biology↗

bioRxiv2020

RNA-binding protein Elavl1/HuR is required for maintenance of cranial neural crest specification

While neural crest development is known to be transcriptionally controlled via sequential activation of gene regulatory networks (GRNs), recent evidence increasingly implicates a role for post-transcriptional regulation in modulating the output of these regulatory circuits. Using available single cell RNA-sequencing datasets from avian embryos to identify potential post-transcriptional regulators, we found that Elavl1, which encodes for an RNA-binding protein with roles in transcript stability, was enriched in the premigratory cranial neural crest. Perturbation of Elavl1 resulted in premature neural crest delamination from the neural tube as well as significant reduction in transcripts associated with the neural crest specification GRN, phenotypes that are also observed with downregulation of the canonical Wnt inhibitor Draxin. That Draxin is the primary target for stabilization by Elavl1 during cranial neural crest specification was shown by RNA-sequencing, RNA-immunoprecipitation, RNA decay measurement and proximity ligation assays, further supporting the idea that the downregulation of neural crest specifier expression upon Elavl1 knockdown was largely due to loss of Draxin. Importantly, exogenous Draxin rescued cranial neural crest specification defects observed with Elavl1 knockdown. Thus, Elavl1 plays a critical a role in the maintenance of cranial neural crest specification via Draxin mRNA stabilization. Together, these data highlight an important intersection of post-transcriptional regulation with modulation of the neural crest specification GRN.

developmental biology↗

bioRxiv2020

P-bodies are sites of rapid RNA decay during the neural crest epithelial-mesenchymal transition

The epithelial--mesenchymal transition (EMT) drives cellular movements during development to create specialized tissues and structures in metazoans, using mechanisms often coopted during metastasis. Neural crest cells are a multipotent stem cell population that undergo a developmentally regulated EMT and are prone to metastasis in the adult, providing an excellent model to study cell state changes and mechanisms underlying EMT. A hallmark of neural crest EMT during avian development is temporally restricted expression followed by rapid down-regulation of the Wnt antagonist Draxin. Using live RNA imaging, here we demonstrate that rapid clearance of Draxin transcripts is mediated post-transcriptionally via localization to processing bodies (P-bodies), small cytoplasmic granules which are established sites of RNA processing. Contrasting with recent work in immortalized cell lines suggesting that P-bodies are sites of storage rather than degradation, we show that targeted decay of Draxin occurs within P-bodies during neural crest migration. Furthermore, P-body disruption via DDX6 knockdown inhibits not only endogenous Draxin down-regulation but also neural crest EMT in vivo. Together, our data highlight a novel and important role for P-bodies in an intact organismal context--controlling a developmental EMT program via post-transcriptional target degradation.

cell biology↗

bioRxiv2018

Draxin alters laminin expression during basement membrane reorganization to control cranial neural crest EMT

Premigratory neural crest cells arise within the dorsal neural tube and subsequently undergo an epithelial-to-mesenchymal transition (EMT) to leave the neuroepithelium and initiate migration. Draxin is a Wnt modulator that has been shown to control the timing of cranial neural crest EMT. Here we show that this process is accompanied by three stages of remodeling of the basement membrane protein laminin, from regression to expansion and channel formation. Loss of Draxin results in blocking laminin remodeling at the regression stage, whereas ectopic maintenance of Draxin blocks remodeling at the expansion stage. The latter effect is rescued by addition of Snail2, previously shown to be downstream of Draxin. Our results demonstrate an essential function for the Wnt modulator Draxin in regulating basement membrane remodeling during cranial neural crest EMT.\n\nHIGHLIGHTSO_LICranial neural crest migrate through a laminin-rich basement membrane channel\nC_LIO_LIPerturbation of Draxin, a Wnt antagonist, alters laminin channel formation\nC_LIO_LIDraxins effect on laminin channel formation is largely mediated by Snail2\nC_LI

developmental biology↗