Biology subjects

Bosworth, A.

Publications and source records attributed to Bosworth, A..

6 recordsLinked to original sources

bioRxiv2026

Vascular and synaptic proteomes reveal blood-brain barrier disruption and postsynaptic remodeling in human temporal lobe epilepsy

Blood-brain barrier (BBB) dysfunction and mesial temporal lobe epilepsy (MTLE) are considered to be engaged in a pathological feedback loop, with the consequent worsening of both conditions. However, the molecular landscape of the disruptions at the synapse and the blood-brain barrier during MTLE remains poorly characterized. Here, we perform quantitative proteomics on paired brain microvessel and vessel-depleted postsynaptic density (PSD) enriched fractions isolated from the epileptic hippocampus and ipsilateral temporal pole of patients with drug-resistant MTLE. The microvessel fraction (1,541 proteins; 439 differentially expressed proteins (DEPs)) reveals loss of tight-junction and endothelial adhesion proteins together with pericyte markers, concurrent with a significant increase of fibrinogen, plasminogen, complement C3, GFAP, and enrichment for complement and coagulation cascades. The PSD enriched fraction (7,450 proteins; 1,881 DEPs) shows the consequences of BBB leakage with an increase of protein infiltration, alongside inflammatory and extracellular-matrix proteins, together with disruption of the pre- and postsynaptic signaling machinery and loss of GABAergic interneurons. Cross-referencing healthy-brain expression confirms that the dysregulation of the processes reflects disease-associated changes rather than regional differences. Immunohistochemistry confirms microvascular remodeling, pericyte loss, parenchymal fibrinogen extravasation, microglial activation and presynaptic marker depletion in the epileptic hippocampus. Ligand-receptor mapping reveals dysregulation of the neurovascular ECM-adhesion interface, with upregulated parenchymal ECM ligands and downregulated vascular integrin receptors. Network-proximity analyses nominate candidate disease-modifying compounds for reversing the combined vascular and synaptic MTLE signature. Together, these findings establish a molecular map of vascular and synaptic dysfunction in human MTLE.

neuroscience↗

bioRxiv2025

Brain pericytes derived from human pluripotent stem cells retain vascular and phagocytic functions under hypoxia

The integrity and function of the blood-brain barrier (BBB) are largely regulated by pericytes. Pericyte deficiency leads to BBB breakdown and neurological dysfunction in major neurological disorders including stroke and Alzheimers disease (AD). Transplantation of pericytes derived from induced pluripotent stem cells (iPSC-PC) has been shown to restore the BBB and improve functional recovery in mouse models of stroke and pericyte deficiency. However, the molecular profile and functional properties of iPSC-PC under hypoxic conditions, similar to those found in ischemic and neurodegenerative diseases remain largely unexplored. Here, we demonstrate that iPSC-PC under severe hypoxia retain essential functional properties, including key molecular markers, proliferation rates, and the ability to migrate to host brain vessels via function-associated PDGFRB-PDGF-BB signaling. Additionally, we show that iPSC-PC exhibit similar clearance of amyloid beta (A{beta}) neurotoxins from AD mouse brain sections under both normoxic and hypoxic conditions. These findings suggest that iPSC-PC functions are largely resilient to hypoxia, highlighting their potential as a promising cell source for treating ischemic and neurodegenerative disorders.

neuroscience↗

bioRxiv2024

A molecular brain atlas reveals cellular shifts during the repair phase of stroke

Ischemic stroke triggers a cascade of pathological events that affect multiple cell types and often lead to incomplete functional recovery. Despite advances in single-cell technologies, the molecular and cellular responses that contribute to long-term post-stroke impairment remain poorly understood. To gain better insight into the underlying mechanisms, we generated a single-cell transcriptomic atlas from distinct brain regions using a mouse model of permanent focal ischemia at one month post-injury. Our findings reveal cell- and region-specific changes within the stroke-injured and peri-infarct brain tissue. For instance, GABAergic and glutamatergic neurons exhibited upregulated genes in signaling pathways involved in axon guidance and synaptic plasticity, and downregulated pathways associated with aerobic metabolism. Using cell-cell communication analysis, we identified increased strength in predicted interactions within stroke tissue among both neural and non-neural cells via signaling pathways such as those involving collagen, protein tyrosine phosphatase receptor, neuronal growth regulator, laminin, and several cell adhesion molecules. Furthermore, we found a strong correlation between mouse transcriptome responses after stroke and those observed in human nonfatal brain stroke lesions. Common molecular features were linked to inflammatory responses, extracellular matrix organization, and angiogenesis. Our findings provide a detailed resource for advancing our molecular understanding of stroke pathology and for discovering therapeutic targets in the repair phase of stroke recovery.

neuroscience↗

bioRxiv2024

Human iPSC-derived cell grafts promote functional recovery by molecular interaction with stroke-injured brain

Stroke is a leading cause of disability and death due to the brains limited ability to regenerate damaged neural circuits. To date, stroke patients have only few therapeutic options and are often left with considerable disabilities. Induced pluripotent stem cell (iPSC)-based therapies are emerging as a promising therapeutic approach for stroke recovery. In this study, we demonstrate that local transplantation of iPSC-derived neural progenitor cells (NPCs) improves long-term brain tissue repair responses and reduces neurological deficits after cerebral ischemia in mice. Using in vivo bioluminescence imaging and post-mortem histology, we show long-term graft survival over the course of five weeks and preferential graft differentiation into mature neurons without signs of pluripotent residuals. Transplantation of NPCs led to a set of brain tissue repair responses including increased vascular sprouting and repair, improved blood-brain barrier integrity, reduced microglial activation, and increased neurogenesis compared to littermate control animals receiving sham transplantation. Employing deep learning-assisted behavior analysis, we found that NPC-treated mice displayed improved gait performance and complete fine-motor recovery in the horizontal ladder rung walk, five weeks post-injury. To dissect the molecular graft composition and identify graft-host interactions, single nucleus profiling of the cell transplants and host stroke tissue was performed. We identified graft differentiation preferentially towards neurons with GABAergic and glutamatergic phenotypes in similar proportions, with the remaining cells acquiring astrocyte and NPC-like phenotypes. Interaction between graft and host transcriptome indicated that GABAergic cell grafts were primarily involved in graft-host communication through the regeneration-associated neurexin (NRXN), neuregulin (NRG), neural cell adhesion molecule (NCAM) and SLIT signalling pathways. In conclusion, our study reveals that transplanted iPSC-derived NPCs primarily differentiate into GABAergic neurons contributing to long-term recovery and further delineates the regenerative interactions between the graft and the stroke-injured host tissue.

neuroscience↗

bioRxiv2023

Molecular signature and functional properties of human pluripotent stem cell-derived brain pericytes

Brain pericytes maintain the blood-brain barrier (BBB), secrete neurotrophic factors and clear toxic proteins. Their loss in neurological disorders leads to BBB breakdown, neuronal dysfunction, and cognitive decline. Therefore, cell therapy to replace lost pericytes holds potential to restore impaired cerebrovascular and brain functions. However, the molecular composition and function of human iPSC-derived brain pericytes (iPSC-PC) remains poorly characterized. Here, we show by a quantitative analysis of 8,344 proteins and 20,572 phosphopeptides that iPSC-PC share 96% of total proteins and 98% of protein phosphorylation sites with primary human brain pericytes. This includes cell adhesion and tight junction proteins, transcription factors, and different protein kinase families of the human kinome. In pericyte-deficient mice, iPSC-PC home to host brain capillaries to form hybrid human-mouse microvessels with ligand-receptor associations. They repair BBB leaks and protect against neuron loss, which we show requires PDGRFB and pleiotrophin. They also clear Alzheimers amyloid-{beta} and tau neurotoxins in an ex vivo brain slice assay via lipoprotein receptor. Thus, iPSC-PC may have potential as a replacement therapy for pericyte-deficient neurological disorders.

neuroscience↗

bioRxiv2021

Influence of substrate stiffness on barrier function in an iPSC-derived in vitro blood-brain barrier model

IntroductionVascular endothelial cells respond to a variety of biophysical cues such as shear stress and substrate stiffness. In peripheral vasculature, extracellular matrix (ECM) stiffening alters barrier function, leading to increased vascular permeability in atherosclerosis and pulmonary edema. The effect of ECM stiffness on blood-brain barrier (BBB) endothelial cells, however, has not been explored. To investigate this topic, we incorporated hydrogel substrates into an in vitro model of the human BBB. MethodsInduced pluripotent stem cells were differentiated to brain microvascular endothelial-like (BMEC-like) cells and cultured on hydrogel substrates of varying stiffness. Cellular changes were measured by imaging, functional assays such as transendothelial electrical resistance (TEER) and p-glycoprotein efflux activity, and bulk transcriptome readouts. ResultsThe magnitude and longevity of TEER in iPSC-derived BMEC-like cells is enhanced on compliant substrates. Quantitative imaging shows that BMEC-like cells form fewer intracellular actin stress fibers on substrates of intermediate stiffness (20 kPa relative to 1 kPa and 150 kPa). Chemical induction of actin polymerization leads to a rapid decline in TEER, agreeing with imaging readouts. P-glycoprotein activity is unaffected by substrate stiffness. Modest differences in RNA expression corresponding to specific signaling pathways were observed as a function of substrate stiffness. ConclusionsiPSC-derived BMEC-like cells exhibit differences in passive but not active barrier function in response to substrate stiffness. These findings may provide insight into BBB dysfunction during neurodegeneration, as well as aid in the optimization of more complex threedimensional neurovascular models utilizing compliant hydrogels.

bioengineering↗