Biology subjects

Moore, J. L.

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

7 recordsLinked to original sources

bioRxiv2025

Skin capillary endothelial cells form a network of spatiotemporally conserved Ca2+ activity

Ca2+ signaling and its regulation are important for endothelial cell (EC) function and signaling. Yet, the spatiotemporal organization of Ca2+ activity and its regulation across a vascular plexus is poorly understood in an in vivo mammalian context. To overcome this gap in knowledge, we developed an intravital imaging approach to resolve Ca2+ activity with single cell resolution in skin vasculature of adult mice via multiphoton microscopy. Here, we tracked thousands of Ca2+ events in the skin capillary plexus during homeostasis and observed signaling heterogeneity between ECs, with just over half displaying Ca2+ activity at any given time. Longitudinal tracking of the same mice revealed that the same capillary ECs maintain Ca2+ activity over days to weeks. Interestingly, activity dynamics, such as frequency and event duration, are not conserved at a single cell level but are maintained at an EC population level. Molecularly, conditional deletion of the gap junction protein Connexin 43 (Cx43cKO) in ECs lead to a subset of ECs displaying sustained Ca2+ activity, biasing signaling dynamics of the whole network towards chronically persistent activity over time. Sustained capillary Ca2+ activity resulted in vascular permeability and flow dysregulation. Lastly, through pharmacological targeting of known agonists/antagonists, we showed that inhibition of L-type Voltage Gated Ca2+ channels (VGCCs) non cell-autonomously restores Ca2+ activity, blood flow, and barrier function in Cx43cKO mice. Collectively, our work provides insight into the characteristics, extent, and regulation of Ca2+ activity in skin capillaries of live mice with unprecedented spatial and temporal resolution. Significance StatementCa2+ signaling in mammalian endothelial cells (ECs) locally regulates blood flow, force sensing, and vessel permeability. Past studies have investigated Ca2+ signaling during vascular remodeling and repair. However, there is a gap in our understanding of how tissue-level Ca2+ is spatiotemporally organized and regulated during homeostasis. Intravital imaging in skin vasculature of live mice reveals that a conserved network of ECs participates in tissue-wide Ca2+ signaling over weeks. How this network maintains itself over time requires cellular communication through gap junction protein Connexin 43 (Cx43). Loss of EC Cx43 leads to heightened plexus-wide Ca2+ activity, and vessel barrier and flow dysregulation. Inhibition of L-type Ca2+ channels non-cell autonomously restores the capillary Ca2+ landscape, and rescues both barrier and flow dysfunction.

developmental biology↗

bioRxiv2025

Fibroblast depletion reveals mammalian epithelial resilience across neonatal and adult stages

Regenerative organs, like the skin, depend on niche-stem cell interactions that sustain continuous cellular turnover. In cell culture, skin fibroblasts promote epidermal stem cell proliferation and differentiation. Yet, it remains elusive how fibroblasts regulate epidermal stem cell behaviors and differentiation in skin in vivo. Here, we asked how fibroblast depletion may impact epidermal stem cell proliferation in the context of adult homeostasis. Surprisingly, we find that significant depletion of fibroblast density does not affect epidermal stem cell proliferative capacity during adult stages in vivo. We next probed earlier neonatal stages when skin is actively remodeling but found no change in epidermal stem cell proliferative capacity following fibroblast depletion. These results demonstrate that across different ages, epidermal stem cell proliferative capacity can persist in the face of a largely reduced fibroblast population. Interestingly, neonatal fibroblast depletion does not significantly reduce their secreted collagen I density but affects basement membrane mechanics and epidermal stem cell delamination. Despite these changes, the skin continues to maintain its protective barrier function. Thus, our work demonstrates the skin regenerative program employs robust compensatory mechanisms in the face of fibroblast depletion to maintain functional capacity.

cell biology↗

bioRxiv2025

Dose response comparison of Nipah virus strains Malaysia and Bangladesh in hamsters exposed by the intranasal or intraperitoneal route

Nipah virus, a zoonotic pathogen, can cause debilitating disease and death in humans. Currently, countermeasures are limited, with several in various stages of testing but none yet FDA-approved for human use. Evaluation of countermeasure candidates requires safety testing in humans, as well as efficacy testing against lethal challenge in animal models. Herein, we describe the characterization and comparison of the intraperitoneal and intranasal Syrian golden hamster models for Nipah virus strains Malaysia and Bangladesh. Overall, the intraperitoneal route of exposure resulted in a more consistent lethal outcome, regardless of virus strain. Therefore, the IP model was subsequently used to evaluate the use of Favipiravir as a potential positive control for future studies investigating NiV countermeasures. In contrast to prior reported results regarding Favipiravir in Nipah virus-infected hamsters, Favipiravir was only fifty percent effective at preventing death following lethal challenge, regardless of Nipah virus strain. The data suggest that Favipiravir is only partially protective against Nipah virus in hamsters, and, thus, would likely not be an ideal candidate as a positive control in future efficacy studies.

microbiology↗

bioRxiv2023

Capturing Spatiotemporal Signaling Patterns in Cellular Data with Geometric Scattering Trajectory Homology

Neural signals are high-dimensional, noisy, and dynamic, making it challenging to extract interpretable features linked to behavior or disease. We introduce Neurospectrum, a framework that encodes neural activity as latent trajectories shaped by spatial and temporal structure. At each timepoint, signals are represented on a graph capturing spatial relationships, with a learnable attention mechanism highlighting important regions. These are embedded using graph wavelets and passed through a manifold-regularized autoencoder that preserves temporal geometry. The resulting latent trajectory is summarized using a principled set of descriptors - including curvature, path signatures, persistent homology, and recurrent networks -that capture multiscale geometric, topological, and dynamical features. These features drive downstream prediction in a modular, interpretable, and end-to-end trainable framework. We evaluate Neurospectrum on simulated and experimental datasets. It tracks phase synchronization in Kuramoto simulations, reconstructs visual stimuli from calcium imaging, and identifies biomarkers of obsessive-compulsive disorder in fMRI. Across tasks, Neurospectrum uncovers meaningful neural dynamics and outperforms traditional analysis methods.

bioinformatics↗

bioRxiv2021

Tissue-wide coordination of calcium signaling regulates the epithelial stem cell pool during homeostasis

Skin epidermal homeostasis is maintained via constant regeneration by stem cells, which must communicate to balance their self-renewal and differentiation. A key molecular pathway, Ca2+ signaling has been implicated as a signal integrator in developing and wounded epithelial tissues[1, 2, 3, 4]. Yet how stem cells carry out this signaling across a regenerative tissue remains unknown due to significant challenges in studying signaling dynamics in live mice, limiting our understanding of the mechanisms of stem cell communication during homeostasis. To interpret high dimensional signals that have complex spatial and temporal patterns, we combined optimized imaging of Ca2+ signaling in thousands of epidermal stem cells in living mice with a new machine learning tool, Geometric Scattering Trajectory Homology (GSTH). Using a combination of signal processing, data geometry, and topology, GSTH captures patterns of signaling at multiple scales, either between direct or distant stem cell neighbors. Here we show that epidermal stem cells display dynamic intercellular Ca2+ signaling among neighborhoods of up to 10 cells that is surprisingly coordinated and directed through time across a pool of thousands of stem cells. We find that this collective coordination is an emergent property of the stem cell compartment, distinct from excitatory quiescent neuronal tissues. We demonstrate that cycling stem cells, specifically G2 cells, govern homeostatic patterns of Ca2+ signaling. Stem cells in different cell cycle stages dynamically regulate localization of the gap junction component Connexin43 (Cx43). Lastly, we uncouple global from local communication and identify Cx43 as the molecular mediator necessary for connectivity between local signaling neighborhoods. This work provides resolution in how stem cells at different stages of the cell cycle communicate and how that diversity of phases is essential for tissue wide communication and signaling flow during epidermal regeneration. Our approach provides a framework to investigate stem cell populations and their signaling dynamics, previously not possible.

cell biology↗

bioRxiv2021

Skin-resident immune cells actively coordinate their distribution with epidermal cells during homeostasis

Our organs consist of multiple cell types that ensure proper architecture and function. How different cell types coexist and interact to maintain their homeostasis in vivo remain elusive. The skin epidermis comprises mostly epithelial cells, but also harbors Langerhans cells (LCs) and Dendritic Epidermal T cells (DETCs). In response to injury or infection, LCs and DETCs become activated and play critical immunological roles. During homeostasis, they coexist with epithelial cells in the basal layer of the epidermis. Whether, and how, distributions of LCs and DETCs are regulated during homeostasis is unclear. Here, we addressed this question by tracking LCs, DETCs and epithelial basal cells over time within the skin of live adult mice. We show that LCs and DETCs maintain their overall position despite continuous turnover of neighboring basal epithelial stem cells. Moreover, LCs and DETCs rapidly and maximally explore basal epithelial cell junctions through their dendritic extensions. Altering the epithelial cell density triggers corresponding changes in the immune cell density, but not vice versa, suggesting that epithelial cells determine immune tissue composition in the epidermis. Moreover, LCs and DETCs are organized in a tiling pattern that is actively maintained. When LCs or DETCs are ectopically removed, neighboring epidermal LCs or DETCs, respectively, move into the emptied spaces and re-establish the tiling pattern. Finally, LCs require the GTPase Rac1 to maintain their positional stability, density and tiling pattern. Overall, we discovered that epidermal cells regulate the density of immune cells during homeostasis, and that immune cells actively maintain a non-random spatial distribution, reminiscent of neuronal self-avoidance. We propose that these cellular mechanisms provide the epidermis with an optimal response to environmental insults.

cell biology↗

bioRxiv2019

Inhibition of miR-22-3p reduces kidney disease associated with systemic lupus erythematosus

Cellular microRNAs (miRNA) have proven to be critical regulators of inflammatory gene expression across many pathways within autoimmunity. Circulating miRNAs serve as a new class of disease biomarkers. Nevertheless, the functional roles of miRNAs, particularly extracellular miRNAs, in systemic lupus erythematosus (SLE) remain poorly understood. Therefore, we aimed to link changes in extracellular miRNAs to lymphocyte gene regulation and the pathophysiology of SLE. Here, we demonstrate that circulating miR-22-3p levels are associated with SLE, and miR-22-3p regulates T and B cell function and SLE-associated kidney disease. Based on high-throughput small RNA sequencing and real-time PCR, extracellular miR-22-3p levels were found to be significantly increased in whole plasma in human SLE subjects. To determine the functional impact of miR-22-3p in SLE, miR-22-3p loss-of-function studies were performed in a mouse model of SLE (B6.SLE1.2.3). We found that in vivo administration of locked-nucleic acid inhibitors of miR-22-3p (LNA-22) reduced lymphocyte accumulation in both the spleen and lymph nodes compared to LNA scramble (LNA-Scr) control-treated mice. Strikingly, LNA-22-3p treatments reduced kidney disease pathology and glomerular IgG deposition compared to LNA-Scr treatments in SLE mice. Moreover, miR-22-3p inhibition reduced the proportion of T effector memory IFN-{gamma} producing CD4+ T cells, suggesting that miR-22-3p regulates Th1 T cell differentiation. We also found that miR-22 inhibition in mice reduced STAT1 phosphorylation in the kidney which was correlated with loss of IFN-{gamma} production by splenic CD4+ T cells. In conclusion, our findings suggest that miR-22-3p is a critical regulator of SLE-associated CD4+ T cell immunity and kidney disease. These results provide therapeutic potential for limiting splenic Th1 signaling and preventing the progression of lupus nephritis.\n\nKey FindingsO_LIExtracellular miR-22-3p levels are significantly increased in plasma from human SLE subjects.\nC_LIO_LIInhibition of miR-22-3p in vivo significantly reduced lymphocyte accumulation in both the spleen and lymph nodes in a mouse model of SLE, thus reducing splenomegaly and lymphadenopathy.\nC_LIO_LImiR-22-3p inhibition significantly reduced IFN-{gamma} expression and secretion from splenic T cell subsets.\nC_LIO_LIInhibition of miR-22-3p in vivo resulted in decreased IgG deposition in the kidney, decreased STAT1 phosphorylation, and decreased kidney disease in a mouse model of SLE.\nC_LI

immunology↗