Biology subjects

Brandt, L.

Publications and source records attributed to Brandt, L..

4 recordsLinked to original sources

bioRxiv2025

Cellular Senescence Mediates Doxorubicin Chemotherapy-Induced Vascular Endothelial Dysfunction: Translational Evidence of Prevention with Senolytic Treatment

BackgroundMechanisms underlying Doxorubicin (Doxo) chemotherapy-induced vascular endothelial dysfunction are incompletely understood. ObjectivesDetermine the role of cellular senescence in mediating Doxo-induced vascular endothelial dysfunction and the influence of senolytic therapy as a therapeutic strategy to mitigate endothelial dysfunction with Doxo. MethodsEndothelial function (carotid artery endothelium-dependent dilation [EDD] to increasing concentrations of acetylcholine) and associated mechanisms were assessed in young adult p16-3MR mice (which allow for genetic-based clearance of senescent cells with ganciclovir [GCV]) injected with Doxo and subsequently treated with GCV or ABT263 (senolytic). We also assessed the influence of Doxo and ABT263 ex vivo on EDD to increased flow in human arterioles. ResultsLower peak EDD with Doxo (75{+/-}3% vs. control, 93{+/-}1%; P<0.05) was prevented with GCV (94{+/-}1%; P<0.05) and ABT263 (95{+/-}2%; P<0.05) treatment, which was mediated by preserved nitric oxide bioavailability and prevention of excess mitochondrial oxidative stress. In human arterioles, ex vivo Doxo exposure impaired peak EDD (Doxo, 32{+/-}10% vs. Control, 94{+/-}2%; P<0.05) which was prevented with concomitant incubation of Doxo with ABT263 (82{+/-}7%; P<0.05 vs. Doxo alone; P=0.63 vs. Control). ConclusionWe provide translational evidence that cellular senescence contributes to Doxo-induced vascular endothelial dysfunction and that senolytics hold promise for preserving vascular endothelial function following Doxo exposure.

physiology↗

bioRxiv2025

Sheathless elasto-inertial focusing of sub-25 nm particles in straight microchannels

Nanoscale biological particles, such as lipoproteins (10-80 nm) or extracellular vesicles (30-200 nm), play pivotal roles in health and disease, including conditions like cardiovascular disorders and cancer. Their effective analysis is crucial for applications in diagnostics, quality control, and nanomedicine development. While elasto-inertial focusing offers a powerful method to manipulate particles without external fields, achieving consistent focusing of nanoparticles (<500 nm) has remained a challenge. In this study, we experimentally demonstrate elasto-inertial focusing of nanoparticles as small as 25 nm using straight high-aspect-ratio microchannels in a sheathless flow. Systematic investigations reveal the influence of channel width, particle size, viscoelastic concentration, and flow rate on focusing behavior. Additionally, through numerical simulations and experimental validation, we provide insights into particle migration dynamics and viscoelastic forces governing nanoparticle focusing. Finally, we successfully focus biological particles, including liposomes (90-140 nm), extracellular vesicles (100 nm), and lipoproteins (10-25 nm), under optimized conditions, showcasing potential applications in medical diagnostics and targeted drug delivery. These findings mark a significant advancement toward size-based high-resolution particle separation, with implications for biomedicine and environmental sciences.

bioengineering↗

bioRxiv2020

Accumbens D2-MSN hyperactivity drives behavioral supersensitivity

Antipsychotic-induced behavioral supersensitivity is a problematic consequence of long-term treatment with antipsychotic drugs and is characterized by emergence of refractory symptoms and dyskinesias. The underlying mechanisms are unknown, and no rational approaches exist to prevent or reverse antipsychotic-induced supersensitivity. Here we describe major adaptations impacting populations of striatal medium spiny neurons (MSNs) during the development of behavioral supersensitivity and reveal a prominent role played by D2 receptor expressing MSNs. We show that enhanced D2-MSN activity underlies several symptoms spanning from psychostimulant sensitization, to antipsychotic treatment resistance and drug addiction. Our data warn against severe adverse events following antipsychotic treatment discontinuation and offer insight that may inform therapeutic approaches to overcome antipsychotic-induced supersensitivity.

neuroscience↗

bioRxiv2020

NK cells integrate signals over large areas when building immune synapses but require local stimuli for degranulation

Immune synapses are large-scale, transient molecular assemblies that serve as platforms for antigen presentation to B and T cells, and target recognition by cytotoxic T cells and natural killer (NK) cells. The formation of an immune synapse is a tightly regulated, stepwise process where the cytoskeleton, cell-surface receptors and signaling proteins rearrange into supramolecular activation clusters (SMACs). Here we use a reductionist system of microcontact-printed artificial immune synapses (AIS) shaped as hallmark SMAC structures to show that the spatial distribution of activating ligands influences the formation, stability and outcome of NK cell synapses. Organizing ligands into donut-shaped AIS resulted in fewer long-lasting, symmetrical synapses compared to dot-shaped AIS. NK cells spreading evenly over either AIS exhibited similar arrangement of the lytic machinery, however degranulation was only possible in regions allowing local signaling. Our results demonstrate that the macroscopic organization of ligands in the synapse can affect its outcome, which could be exploited by target cells as an escape mechanism.

immunology↗