Biology subjects

Fuqua, H.

Publications and source records attributed to Fuqua, H..

5 recordsLinked to original sources

bioRxiv2026

Injury-induced Cxcl11 and neutrophil signaling drive zebrafish kidney regeneration by generating a nephrogenic niche of Fgf and Wnt expression

Adult zebrafish regenerate their kidneys after injury by activating quiescent renal stem cells, however the injury signals that activate kidney stem cells are not known. We show here that an innate immune, cytokine response after tubule injury is required and sufficient to induce adult zebrafish kidney regeneration. An injury reporter zebrafish transgenic, Tg(kim1:mScarlet3), revealed that tubule injury occurred specifically in kidney proximal tubules and was associated with a rapid accumulation of neutrophils and macrophages. Injury also activated a Tg(NFkB:GFP) reporter transgene specifically in kidney tubules where RNA seq revealed NFkB target gene and cytokine expression. Inhibition of NFkB signaling with JSH-23 blocked Tg(NFkB:GFP) reporter activation and also inhibited induction of new nephrons. Systemic injection of the immune activators lipopolysaccharide or zymosan into uninjured fish rapidly induced cytokine expression followed by nephrogenic gene expression and the appearance of new, functional nephrons. Analysis of injury-induced cytokines revealed that several paralogs of cxcl11 were strongly expressed throughout the regeneration response and injection of recombinant Cxcl11 was sufficient to induce FGF-dependent kidney stem cell aggregation, but not Wnt-dependent epithelial differentiation. Kidney injury in zebrafish expressing a neutrophil dominant negative rac2D57N transgene activated Fgf signaling but failed to induce wnt9b or downstream Wnt target genes. Nephrogenic gene expression and epithelial tubule formation was rescued by treatment with the canonical Wnt agonist CHIR. Our findings demonstrate that an injury-induced, sterile immune response regulates kidney regeneration by establishing a nephrogenic niche of Fgf and Wnt signaling that supports tissue-resident kidney stem cell differentiation into functional nephrons.

developmental biology↗

bioRxiv2025

Glucocorticoid and Mineralocorticoid Receptors Jointly Promote Vascular Development in Kidney Organoids

To examine the co-development of vasculature and renal epithelial tissue, we employed a human pluripotent stem cell-derived kidney organoid system. We found that cooperative signaling through the glucocorticoid receptor and mineralocorticoid receptor via hydrocortisone enabled rich endothelial cell differentiation and vessel formation. Bulk RNA sequencing analysis revealed that hydrocortisone perturbs an angiogenic transcriptional program early in development and promotes instead a pro-endothelial survival transcriptional program, with upregulation of angiopoietin 1 at both the mRNA and protein level. Additionally, we saw that hydrocortisone does not seem to significantly affect gene expression of canonical nephrogenic genes compared to our controls, suggesting its effect is largely restricted to endothelial cell differentiation. Our results show that kidney organoids offer a unique platform to study developmental signals that drive endothelial cell differentiation and vessel formation.

developmental biology↗

bioRxiv2025

SGLT2 Inhibition Ameliorates Age-Dependent Renovascular Rarefaction

IntroductionAging is associated with progressive loss of renal function and vascular structure, with and without chronic kidney disease. However, the mechanisms driving renal vascular aging and potential therapeutic interventions remain poorly understood. MethodsTo model this state-of-affairs, we used African turquoise killifish (Nothobranchius furzeri), a naturally short-lived vertebrate. We then inhibited the sodium-glucose co-transporter 2 using dapagliflozin (SGLT2i) to test a potential therapeutic intervention. Histological, immunofluorescent, and 3D vascular imaging were used to evaluate glomerular, tubular, vascular and functional changes. Single-nuclei transcriptomic profiling was performed on whole kidneys to identify age- and treatment-associated molecular signatures. ResultsAged killifish kidneys exhibited hallmark features of renal aging, including glomerulosclerosis, tubular fibrosis, and vascular rarefaction. Functional changes included increased proteinuria and altered tubular transporter function. Transcriptomic profiling revealed a metabolic shift from oxidative phosphorylation to glycolysis and upregulation of pro-inflammatory pathways. Aged vasculature also displayed a marked reduction in tight junctions and cell-cell contacts. SGLT2i attenuated age-related vascular rarefaction, preserved functional capillary networks, reduced albuminuria, restored a youthful transcriptional profile and enhanced intercellular signaling. However, killifish lifespan was not extended. ConclusionThis study establishes the killifish as a translational model for investigating renal vascular aging. We show that SGLT2i preserves renal microvascular structure and function, reduces proteinuria, and reprograms the aged transcriptome. These results support a vascular-protective role of SGLT2i in mitigating age-related renal deterioration. Translational StatementThis study establishes the African turquoise killifish as a model for investigating renal and vascular aging. We found that SGLT2 inhibition preserves microvascular integrity and reduces proteinuria. These results mirror established benefits observed in mammalian models and patients with chronic kidney disease, reinforcing the kidney-protective role of SGLT2 inhibitors. However, the killifish offers a unique opportunity for rapid, translational aging research. By using a naturally short-lived vertebrate with mammalian-like renal aging, our model enables a rapid, preclinical, assessment of vascular outcomes and identifies microvascular preservation as a potential mechanistic target for renoprotection.

systems biology↗

bioRxiv2025

The essential role of connective-tissue cells during axolotl limb regeneration

Axolotls (Ambystoma mexicanum) are known for their remarkable limb-regeneration abilities, which involve the formation of the blastema, a specialized structure consisting of progenitor cells contributed by all major tissues of the limb. Lateral plate mesoderm (LPM)-derived connective tissue (CT) cells dedifferentiate and play a critical role in blastema formation and subsequent limb regeneration. However, the complexity of the blastemas cellular composition and the extent of CT participation and necessity have not been rigorously explored. To address this gap, we conducted spatial transcriptomics using a select array of probes, revealing that CT cells constitute up to 75% of the blastema cells at their peak. Genetic ablation of CT cells significantly delays or truncates limb regeneration, underscoring their necessity during this process. Finally, we analyzed the molecular profile of CT cells throughout the stages of blastema formation and made it accessible through an interactive web platform. Our work reaffirms the central role of CT cells in axolotl limb regeneration and lays the foundation for identifying molecular mechanisms that govern blastema formation during the initial phases of limb regeneration.

developmental biology↗

bioRxiv2025

Zebrafish genetic model of neuromuscular degeneration associated with Atrogin-1 expression

The degenerative loss of muscle associated with aging leading to muscular atrophy is called sarcopenia. Currently, practicing regular physical exercise is the only efficient way to delay sarcopenia onset. Identification of therapeutic targets to alleviate the symptoms of aging requires in vivo model organisms of accelerated muscle degeneration and atrophy. The zebrafish undergoes aging, with hallmarks including mitochondrial dysfunction, telomere shortening, and accumulation of senescent cells. However, zebrafish age slowly, and no specific zebrafish models of accelerated muscle atrophy associated with molecular events of aging are currently available. We have developed a new genetic tool to efficiently accelerate muscle-fiber degeneration and muscle-tissue atrophy in zebrafish larvae and adults. We used a gain-of-function strategy with a molecule that has been shown to be necessary and sufficient to induce muscle atrophy and a sarcopenia phenotype in mammals: Atrogin-1 (also named Fbxo32). We report the generation, validation, and characterization of a zebrafish genetic model of accelerated neuromuscular atrophy, the atrofish. We demonstrated that Atrogin-1 expression specifically in skeletal muscle tissue induces a muscle atrophic phenotype associated with locomotion dysfunction in both larvae and adult fish. We identified degradation of the myosin light chain as an event occurring prior to muscle-fiber degeneration. Biological processes associated with muscle aging such as proteolysis, inflammation, stress response, extracellular matrix (ECM) remodeling, and apoptosis are upregulated in the atrofish. Surprisingly, we observed a strong correlation between muscle-fiber degeneration and reduced numbers of neuromuscular junctions in the peripheral nervous system, as well as neuronal cell bodies in the spinal cord, suggesting that muscle atrophy could underly a neurodegenerative phenotype in the central nervous system. Finally, while atrofish larvae can recover locomotive functions, adult atrofish have impaired regenerative capacities, as is observed in mammals during muscle aging. In the future, the atrofish could serve as a platform for testing molecules aimed at treating or alleviating the symptoms of muscle aging, thereby opening new therapeutic avenues in the fight against sarcopenia.

developmental biology↗