Biology subjects

Fox, K.

Publications and source records attributed to Fox, K..

8 recordsLinked to original sources

bioRxiv2026

Safety and Feasibility of Infusing Ex Vivo Expanded Allogeneic Canine Natural Killer Cells for the Treatment of Metastatic Solid Tumors

BackgroundCompanion canines need advances in therapeutic options for solid tumor malignancies. Prior studies established feasibility of autologous natural killer (NK) cell infusions in canines with solid tumors; however, autologous products are limited by dysfunctional immunity and a manufacturing process that delays care. Allogeneic NK cells offer the possibility of "off-the-shelf" therapy to be administered from healthy donors. MethodsPeripheral blood mononuclear cells (PBMCs) were isolated from healthy canine donors via density gradient separation. NK cells were expanded with recombinant human IL-2 and canine IL-21 with the addition of K562 feeder cells transfected with CD137 ligand and membrane bound human IL-15. Additional experiments included IL-12 in the expansions. In vitro potency was assessed via co-culture with the D17-mKate2 canine osteosarcoma cell line. Three canines were enrolled in a phase 1 trial infusing ex vivo expanded allogeneic NK cells after lymphodepletion. ResultsFlow cytometric analysis confirmed successful expansion of canine NK cells with up to 50% of cells demonstrating NKp46+ after 14 days of expansion. Residual T cell numbers varied based on donor. The addition of IL-12 led to increased NK cell expansion. Incucyte demonstrated potency with increasing osteosarcoma cell death at higher effector to target ratios. Three canines with metastatic/refractory solid tumors were successfully lymphodepleted and infused with allogeneic NK cell products. The canines tolerated the infusions well. ConclusionsCanine allogeneic NK cells were successfully expanded and activated ex vivo, demonstrated potency in vitro, and safety in vivo. Further studies will optimize the NK cell product and escalate dosing to reach the maximal tolerable dose.

cancer biology↗

bioRxiv2025

Untangling dopamine and glutamate in the ventral tegmental area

Ventral tegmental area (VTA) dopamine neurons are of great interest for their central roles in motivation, learning, and psychiatric disorders. While hypotheses of VTA dopamine neuron function posit a homogenous role in behavior (e.g., prediction error), they do not account for molecular heterogeneity. We find that glutamate-dopamine, nonglutamate-dopamine, and glutamate-only neurons are dissociable in their signaling of reward and aversion-related stimuli, prediction error, and electrical properties. In addition, glutamate-dopamine and nonglutamate-dopamine neurons differ in dopamine release dynamics. Aversion-related recordings of all dopamine neurons (not considering glutamate co-transmission) showed a mixed response that obscured dopamine subpopulation function. Within glutamate-dopamine neurons, glutamate and dopamine release had dissociable contributions toward reward and aversion-based learning and performance. Based on our results, we propose a new hypothesis on VTA dopamine neuron function: that dopamine neuron signaling patterns and their roles in motivated behavior depend on whether or not they co-transmit dopamine with glutamate.

neuroscience↗

bioRxiv2024

A Hopfield network model of neuromodulatory arousal state

Neural circuits display both input-driven activity that is necessary for the real-time control of behavior and internally generated activity that is necessary for memory, planning, and other cognitive processes. A key mediator between these intrinsic and evoked dynamics is arousal, an internal state variable that determines an animals level of engagement with its environment. It has been hypothesized that arousal state acts through neuromodulatory gain control mechanisms that suppress recurrent connectivity and amplify bottom-up input. In this paper, we instantiate this longstanding idea in a continuous Hopfield network embellished with a gain parameter that mimics arousal state by suppressing recurrent interactions between the networks units. We show that dynamics capturing some essential effects of arousal state at the neural and cognitive levels emerge in this simple model as a single parameter--recurrent gain--is varied. Using the models formal connections to the Boltzmann machine and the Ising model, we offer functional interpretations of arousal state rooted in Bayesian inference and statistical physics. Finally, we liken the dynamics of neuromodulator release to an annealing schedule that facilitates adaptive behavior in ever-changing environments. In summary, we present a minimal neural network model of arousal state that exhibits rich but analytically tractable emergent behavior and reveals conceptually clarifying parallels between arousal state and seemingly unrelated phenomena.

neuroscience↗

bioRxiv2024

Real-time Biomechanical Characterisation of Cytoskeletal Remodelling

As progenitors for tissue, human mesenchymal stem cells (hMSCs) with ability of self-proliferation and differentiation into various cell types such as osteocytes and adipocytes show great potential applications for tissue engineering. Stem cell fate regulation is highly affected by the cytoskeleton structure and mechanical properties. In this paper, quantitative Atomic Force Microscopy (Q-AFM) was used to continuously characterise topography and biomechanical properties while applying cytoskeleton disruptors to hMSCs. The cell stiffness (quantified by Youngs modulus), primarily governed by the cytoskeleton network, had quantifiable changes associated with cytoskeleton polymerisation and depolymerisation when treatments were applied. Furthermore, with Q-AFM measurements, these changes were tracked in real time over a period of minutes to hours, and the biomechanical properties of the cells were tracked through the applied treatment and subsequent recovery post treatment. Here we present the capability of Q-AFM to perform real time biomechanical characterisation of living cells, directly correlated to intracellular structure and cytoskeletal remodelling.

biophysics↗

bioRxiv2023

The mechanics of bronchoconstriction cause airway epithelial damage and inflammation by excess crowding-induced extrusion

Asthma is deemed an inflammatory disease, yet the defining diagnostic symptom is mechanical bronchoconstriction. We previously discovered a conserved process that drives homeostatic epithelial cell death in response to mechanical cell crowding called cell extrusion(1, 2). Here, we show that the pathological crowding of a bronchoconstrictive attack causes so much epithelial cell extrusion that it damages the airways, resulting in inflammation and mucus secretion. While relaxing airways with the rescue treatment albuterol did not impact these responses, inhibiting live cell extrusion signaling during bronchoconstriction prevented all these symptoms. Our findings propose a new etiology for asthma, dependent on the mechanical crowding of a bronchoconstrictive attack. Our studies suggest that blocking epithelial extrusion, instead of ensuing downstream inflammation, could prevent the feed-forward asthma inflammatory cycle.

cell biology↗

bioRxiv2022

Behavioral benefits of spatial attention explained by multiplicative gain, not receptive field shifts, in a neural network model

Attention allows us to focus sensory processing on behaviorally relevant aspects of the visual world. One potential mechanism of attention is a change in the gain of sensory responses. However, changing gain at early stages could have multiple downstream consequences for visual processing. Which, if any, of these effects can account for the benefits of attention for detection and discrimination? Using a model of primate visual cortex we document how a Gaussian-shaped gain modulation results in changes to spatial tuning properties. Forcing the model to use only these changes failed to produce any benefit in task performance. Instead, we found that gain alone was both necessary and sufficient to explain category detection and discrimination during attention. Our results show how gain can give rise to changes in receptive fields which are not necessary for enhancing task performance.

neuroscience↗

bioRxiv2020

ABO genetic variation in Neanderthals and Denisovans

1Variation at the ABO locus was one of the earliest sources of data in the study of human population identity and history, and to this day remains widely genotyped due to its importance in blood and tissue transfusions. Here, we look at ABO blood type variants in our archaic relatives: Neanderthals and Denisovans. Our goal is to understand the genetic landscape of the ABO gene in archaic humans, and how it relates to modern human ABO variation. We found two derived Neanderthal variants of the O allele in the Siberian Neanderthals (O1 and O2), one of these variants is shared with an European Neanderthal, who is a heterozygote for this O1 variant and a rare cis-AB variant. The Denisovan individual is heterozygous for two ancestral variant of the O1 allele, similar to variants found widely in modern humans. Perhaps more surprisingly, the O2 allele variant found in Siberian Neanderthals can be found at low frequencies in modern Europeans and Southeast Asians, and the O1 allele variant found in Siberian and European Neanderthal is also found at very low frequency in modern East Asians. Our genetic distance analyses suggest both alleles survive in modern humans due to inbreeding with Neanderthals. We find that the sequence backgrounds of the surviving Neanderthal-like O alleles in modern humans retain a higher sequence divergence than other surviving Neanderthal genome fragments, supporting a view of balancing selection operating in the Neanderthal ABO alleles by retaining highly diverse haplotypes compared to portions of the genome evolving neutrally.

genomics↗

bioRxiv2017

Capture-based DNA methylation sequencing facilitates diagnosis and reveals potential pathogenic mechanisms in teratogenic diabetes exposure

Diabetic embryopathy (DE) describes a spectrum of birth defects associated with a teratogenic exposure to maternal diabetes in utero. These defects strongly overlap the phenotypes of known genetic syndromes; however, the pathogenic mechanisms underlying DE remain uncertain and there are no definitive tests that distinguish the diagnosis. Here, we explore the potential of DNA methylation as both a diagnostic biomarker and a means of informing disease pathogenesis in DE. Capture-based bisulfite sequencing was used to compare patterns of DNA methylation at 2,800,516 sites genome-wide in seven DE neonates and 11 healthy neonates, including five with in utero diabetes exposure. DE infants had significantly lower global DNA methylation (ANOVA, Tukey HSD p=0.045) than diabetes-unexposed, healthy controls (UH), with multiple sites showing large (mean methylation difference = 16.6%) and significant (p<0.001) differential methylation between the two groups. We found that a subset of 237 highly differentially methylated loci could accurately distinguish DE infants from both UH and diabetes-exposed healthy infants (sensitivity 80% -100%). Differentially methylated sites were enriched in intergenic (p<3.52x10-15) and intronic (p<0.001) regions found proximal to genes either associated with Mendelian syndromes that overlap the DE phenotype (e.g. TRIO, ANKRD11), or known to influence early organ development (e.g. BRAX1, RASA3). Further, by integrating information on cis-sequence variation, we found that 39.3% of loci with evidence for allele-specific methylation also showed differential methylation between DE and controls. Our study suggests a role for aberrant DNA methylation and cis-sequence variation in the pathogenesis of DE, and highlights the diagnostic potential of DNA methylation for teratogenic birth defects.

genetics↗