Selected Grantee Publications
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- Aquatic Vertebrate Models
- New Approach Methodologies
De Novo and Inherited Variants in DDX39B Cause a Novel Neurodevelopmental Syndrome
Booth et al., Brain. 2025.
https://academic.oup.com/brain/advance-article/doi/10.1093/brain/awaf035/8004980?login=true
DDX39B is a core component of the TRanscription-EXport (TREX) super protein complex. Recent studies have highlighted the important role of TREX subunits in neurodevelopmental disorders. Researchers describe a cohort of six individuals (male and female) from five families with disease-causing de novo missense variants or inherited splice-altering variants in DDX39B. Three individuals in the cohort are affected by mild to severe developmental delay, hypotonia, history of epilepsy or seizure, short stature, skeletal abnormalities, variable dysmorphic features, and microcephaly. Using a combination of patient genomic and transcriptomic data, in silico modeling, in vitro assays, and in vivo Drosophila and zebrafish models, this study implicates disruption of DDX39B in a novel neurodevelopmental disorder called TREX-complex-related neurodevelopmental syndrome. Supported by ORIP (U54OD030165).
Differentiation Success of Reprogrammed Cells Is Heterogeneous In Vivo and Modulated by Somatic Cell Identity Memory
Zikmund et al., Stem Cell Reports. 2025.
https://pubmed.ncbi.nlm.nih.gov/40086446
Nuclear reprogramming can change cellular fates, yet reprogramming efficiency is low, and the resulting cell types are often not functional. Researchers used nuclear transfer to Xenopus eggs to follow single cells during reprogramming in vivo. Results showed that the differentiation success of reprogrammed cells varies across cell types and depends on the expression of genes specific to the previous cellular identity. Subsets of reprogramming-resistant cells fail to form functional cell types and undergo cell death or disrupt normal body patterning. Reducing expression levels of genes specific to the cell type of origin leads to better reprogramming and improved differentiation trajectories. This study demonstrates that failing to reprogram in vivo is cell type specific and emphasizes the necessity of minimizing aberrant transcripts of the previous somatic identity for improving reprogramming. Supported by ORIP (R24OD031956).
Enhanced RNA-Targeting CRISPR-Cas Technology in Zebrafish
Moreno-Sánchez et al., Nature Communications. 2025.
https://pubmed.ncbi.nlm.nih.gov/40091120
CRISPR-Cas13 RNA-targeting systems, widely used in basic and applied sciences, have generated controversy because of collateral activity in mammalian cells and mouse models. In this study, researchers optimized transient formulations as ribonucleoprotein complexes or mRNA-gRNA combinations to enhance the CRISPR-RfxCas13d system in zebrafish. Researchers used chemically modified gRNAs to allow more penetrant loss-of-function phenotypes, improve nuclear RNA targeting, and compare different computational models to determine the most accurate prediction of gRNA activity in vivo. Results demonstrate that transient CRISPR-RfxCas13d can effectively deplete endogenous mRNAs in zebrafish embryos without inducing collateral effects, except when targeting extremely abundant and ectopic RNAs. Their findings contribute to CRISPR-Cas technology optimization for RNA targeting in zebrafish through transient approaches and advance in vivo applications. Supported by ORIP (R21OD034161), NICHD, and NIGMS.
Matrikine Stimulation of Equine Synovial Fibroblasts and Chondrocytes Results in an In Vitro Osteoarthritis Phenotype
Gagliardi et al., Journal of Orthopaedic Research. 2025.
https://pubmed.ncbi.nlm.nih.gov/39486895
Advancements in therapy development for osteoarthritis (OA) currently are limited due to a lack of physiologically relevant in vitro models. This study aimed to understand the effect of matrikine stimulation, using human recombinant fibronectin fragment containing domains 7–10 (FN7–10), on equine synovial fibroblasts and chondrocytes. Inflammatory cytokines, chemokines, and matrix degradation genes in equine synovial fibroblasts and chondrocytes were significantly altered in response to FN7–10 stimulation; marked upregulation was observed in interleukin-6 (IL-6), IL-4, IL-10, matrix metalloproteinase 1 (MMP1), MMP3, MMP13, CCL2/MCP1, and CXCL6/GCP-2 gene expression. Only IL-6 protein production was significantly increased in media isolated from cells stimulated with FN7–10. These results support the potential use of equine synovial fibroblasts and chondrocytes—employing FN7–10—as representative in vitro models to study OA. Supported by ORIP (T32OD011130) and NIAMS.
Stat3 Mediates Fyn Kinase-Driven Dopaminergic Neurodegeneration and Microglia Activation
Siddiqui et al., Disease Models & Mechanisms. 2024.
https://pubmed.ncbi.nlm.nih.gov/39641161
The FYN gene is a risk locus for Alzheimer’s disease and several other neurodegenerative disorders. FYN encodes Fyn kinase, and previous studies have shown that Fyn signaling in dopaminergic neurons and microglia plays a role during neurodegeneration. This study investigated Fyn signaling using zebrafish that express a constitutively active Fyn Y531F mutant in neural cells. Activated neural Fyn signaling in the mutant animals resulted in dopaminergic neuron loss and induced inflammatory cytokine expression when compared with controls. Transcriptomic and chemical inhibition analyses revealed that Fyn-driven changes were dependent on the Stat3 and NF-κB signaling pathways, which work synergistically to activate neuronal inflammation and degeneration. This study provides insight into the mechanisms underlying neurodegeneration, identifying Stat3 as a novel effector of Fyn signaling and a potential translational target. Supported by ORIP (R24OD020166).
Temperature-Dependent Alterations in the Proteome of the Emergent Fish Pathogen Edwardsiella piscicida
Jacobsen et al., Journal of Fish Diseases. 2024.
https://pubmed.ncbi.nlm.nih.gov/39304982
Reported outbreaks of Edwardsiella piscicida, a bacterial pathogen among cultured and wild fish, have been steadily increasing over the past decade in tandem with climate change–mediated increases in water temperatures. The capacity for this increasingly prevalent fish pathogen to infect and cause disease in mammals is important to understand. Researchers examined the role of temperature on the virulence of E. piscicida to understand its pathogenesis in the context of climate warming trends and better understand its zoonotic potential. Findings revealed downregulation of virulence-related proteins, such as flagellar and Type VI secretion system proteins, at colder temperatures. These findings highlight the potential environmental factors influencing the pathogen’s threat to aquaculture and public health. Supported by ORIP (S10OD026918, T32OD011147).
Enterohemorrhagic Escherichia coli (EHEC) Disrupts Intestinal Barrier Integrity in Translational Canine Stem Cell-Derived Monolayers
Nagao et al., Microbiology Spectrum. 2024.
https://pubmed.ncbi.nlm.nih.gov/39162490/
EHEC produces Shiga toxin, which causes acute colitis with symptoms such as hemolytic uremic syndrome and bloody diarrhea. The researchers developed a colonoid-derived monolayer model to understand EHEC’s impact on canine gut health. Colonoid-derived monolayers co-cultured with EHEC demonstrated key differences compared with the control and nonpathogenic E. coli co-cultures. Scanning electron microscopy displayed EHEC aggregated and attached to the microvilli. EHEC-infected monolayers demonstrated significantly weakened membrane integrity and increased inflammatory cytokine production, specifically TNFα. The researchers developed a novel in vitro model that offers an additional platform for understanding the mechanisms of EHEC pathogenicity, developing therapeutics for EHEC, and studying additional enteric pathogens. Supported by ORIP (K01OD030515, R21OD031903).
A New Atlas to Study Embryonic Cell Types in Xenopus
Petrova et al., Developmental Biology. 2024.
https://pubmed.ncbi.nlm.nih.gov/38614285
Petrova et al. have designed a new single-cell atlas for developmental stages in Xenopus tropicalis that encompasses gastrulation, neurulation, and early tail bud. Compared to its predecessors, the new atlas enhances gene mapping, read counts, and gene/cell-type nomenclature. The atlas also leverages the latest X. tropicalis genome version to maintain consistency with previous cell-type annotations while rectifying prior nomenclature issues. The new resource emphasizes previously unexplored germ-cell populations in which novel transcription onset features have been uncovered. Finally, the new atlas offers interactive exploration through a user-friendly web portal and allows users to download complete data sets. Supported by ORIP (R24OD031956).
Gap-Junction-Mediated Bioelectric Signaling Required for Slow Muscle Development and Function in Zebrafish
Lukowicz-Bedford et al., Current Biology. 2024.
https://pubmed.ncbi.nlm.nih.gov/38936363
Using the neuromuscular system of embryonic zebrafish as a model, Lukowicz-Bedford et al. have identified a protein that is responsible for controlling bioelectric signaling in slow muscle development and function. Bioelectric signaling is a form of intercellular communication that has emerged as a key regulator of animal development. These signals can be mediated by gap junction channels—fast, direct pathways between cells for the movement of ions and other small molecules—that are formed in vertebrates by a highly conserved transmembrane protein family called connexins. However, the connexin gene family is large and complex, making it challenging to identify specific connexins that create channels within developing and mature tissues. This work reveals a molecular basis for gap-junction communication among developing muscle cells and shows how disruptions to bioelectric signaling in the neuromuscular system may contribute to developmental myopathies. Supported by ORIP (R24OD026591), NINDS, and NIGMS.
Controlled Stiffness of Direct-Write, Near-Field Electrospun Gelatin Fibers Generates Differences in Tenocyte Morphology and Gene Expression
Davis, Journal of Biomechanical Engineering. 2024.
https://pubmed.ncbi.nlm.nih.gov/38529730/
Tendinopathy is associated with mobility issues, and the cell–matrix interactions involved in the development of tendinopathy are not fully understood. In this study, researchers fabricated micron-scale fibrous scaffolds that mimic native collagen fiber size and orientation. They reported that matrix metalloproteinase and proteoglycans (possible indicators of tendinopathy) were more upregulated in the presence of high-stiffness fibers than low-stiffness fibers. The authors’ findings suggest that scaffolds can serve as in vitro models for tendinopathy. Additionally, their work suggests that matrix mechanical properties contribute to cell–matrix interactions during tendinopathy formation. Supported by ORIP (T32OD011130) and NIA.