Biology subjects

Steele, S.

Publications and source records attributed to Steele, S..

4 recordsLinked to original sources

bioRxiv2026

Loss of Hippo signaling causes transdifferentiation of neural retina between the optic fissure edges causing coloboma

Optic fissure (OF) is a transient structure in the ventral optic cup, which acts as a conduit for periocular mesenchyme cells to enter the eye, forming hyaloid vasculature and retinal ganglion axons to exit. Optic fissure closes to form a continuous layer of retinal pigment epithelium and neural retina. Failure of OF closure results in coloboma, which is mostly genetic in nature. The severity of blindness depends on the tissue it effects and accounts for 10% of childhood blindness. In the current study, we describe coloboma pathogenesis caused by hippo effectors yap1 and wwtr1. Both the paralogs are expressed in the OF edges, possibly in the pioneer cells. wwtr1 homozygotes do not have coloboma, while yap1 homozygotes have coloboma and pigment defects which are exacerbated by absence of one copy of wwtr1 (yap1-/-; wwtr1+/-). The coloboma observed in these mutants is not due to defective optic cup morphogenesis nor an overgrown optic nerve. The pigment defects are more pronounced at the OF with complete absence of RPE specific transcription factors mitfA, tfec, and pigmentation gene dct. On the other hand, NR specific genes are upregulated and the unpigmented region at the OF have transdifferentiated retinal ganglion cells, amacrine, and photoreceptor cells. Our observations indicate that in the absence of yap1 and wwtr1, the cells at the OF cannot attain a conducive state to fuse nor they maintain the RPE specific fate and instead they transdifferentiate into unpigmented retina, causing a steric block for fusion, resulting in coloboma.

genetics↗

bioRxiv2026

cloneXplorer: A high-throughput clone discovery platform based on conical microwell arrays

Antigen-specific T cell populations are of great value for studying immune recognition but tedious to generate by limiting dilution or cloning. Here, we develop a streamlined approach to generate antigen-specific T cell clones directly from peripheral blood using the cloneXplorer, a live-cell analysis and clone isolation platform based on conical microwell arrays. This platform continuously monitors cell proliferation, cytokine secretion, and surface markers in up to 100,000 single cell co-cultures, enabling the identification of rare, functionally defined T cells, which can be recovered for clonal expansion or sequence analysis. We benchmark the platform by performing several key demonstrations. First, we show that this platform can efficiently generate monoclonal cell populations from cell lines and human T cells. Next, we demonstrate that antigen-specificity can be identified at single cell resolution using a co-culture of Jurkat cells expressing NFAT-GFP, CD8, and a T cell receptor and K562 antigen presenting cells (APC) expressing a peptide library. Thereafter, we show that immune activation in mouse and human primary samples can be monitored by time lapse analysis of Interferon gamma (IFN-{gamma}) secretion in individual microwell co-cultures using a fluorescent sandwich assay. Finally, we combine these capabilities in a proof-of-concept demonstration, which uses IFN-{gamma} secretion and the presence of CD8 surface markers as hierarchical gates to isolate and expand antigen-specific T cells from human peripheral blood, and we verify their specificity by tetramer staining. Together, these results showcase potential applications of the cloneXplorer platform in cell line development, and in screening and validating immune receptor interactions with specific antigens. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=156 SRC="FIGDIR/small/699323v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@1aafc29org.highwire.dtl.DTLVardef@91272dorg.highwire.dtl.DTLVardef@1a306eeorg.highwire.dtl.DTLVardef@1bfd54_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2025

Drought-associated genes exhibit high constitutive expression in Quercus douglasii, a drought tolerant California oak

Drought stress is a strong selective pressure for all plant species. Plants can respond to water shortage through various strategies that confer drought tolerance, but with a potential cost for growth. These strategies may be plastic responses that occur with the onset of stress or may comprise continuously-expressed (constitutive) traits regardless of water availability. Here, we used RNA-Seq to characterize transcriptional responses to dehydration in seedlings of a drought tolerant oak, Quercus douglasii, from a population in the Sierra Nevada Foothills in California. In the greenhouse, we subjected 24 seedlings from six maternal families to dry-down or well-watered treatments and prepared RNA libraries from tissue collected before and after each treatment (48 libraries). Our goals were to characterize the pattern of up- and down-regulated genes in response to dehydration and to assess the extent to which this drought tolerant species shows differential versus constitutive expression as a drought response strategy. We identified few differentially expressed genes in response to dehydration. Up-regulated genes were related to known drought response functions, while down-regulated genes were enriched for gene ontology terms related to growth and carbohydrate metabolism. We discovered high constitutive expression of many putatively drought-responsive genes that had been found to exhibit gene expression plasticity in a drought sensitive oak, which a novel finding for drought tolerance strategies in tree species. We conclude that the drought tolerant strategy of Q. douglasii incorporates high constitutive expression levels of drought-responsive genes, as well as some plasticity in its response once environmental stress is experienced.

plant biology↗

bioRxiv2022

Wireless closed-loop smart bandage for chronic wound management and accelerated tissue regeneration

Chronic non-healing wounds represent a major source of morbidity for patients and a significant economic burden. Current wound care treatments are generally passive and are unable to adapt to changes in the wound environment in real time. By integrating multimodal sensors and adding stimulators in a bandage, real-time physiological monitoring is possible and provides an opportunity for active intervention into the complex wound environment. Here, we develop a battery-free flexible bioelectronic system consisting of wirelessly powered, closed-loop sensing and stimulation circuits with tissue-interfacing tough conducting hydrogel electrodes for robust signal transduction, on-demand adhesion, and detachment. Using multiple pre-clinical models, we demonstrate the capability of our wound care system to continuously monitor skin impedance and temperature, to trigger directional electrical stimulation. The accelerated wound closure was confirmed to be due to the activation of pro-regenerative genes linked to accelerated wound closure, increased neovascularization, and enhanced dermal recovery.

bioengineering↗