Biology subjects

Rosner, A.

Publications and source records attributed to Rosner, A..

4 recordsLinked to original sources

bioRxiv2025

Evaluating Microglial Contributions to the Neurovascular Unit in Health and Neurodegeneration Using Human In Vitro Models

BackgroundMicroglia are emerging as critical regulators of neurovascular function in health and Alzheimers disease (AD), yet their interactions with the human neurovascular unit (NVU), particularly brain endothelial cells, remain incompletely understood. Current in vitro NVU platforms typically exclude microglia and lack perfusable vascular networks with physiologically relevant architecture. Here, we established complementary two-dimensional (2D) and three-dimensional (3D) NVU models to investigate microglia-endothelial and microglia-neurovascular interactions. MethodsHuman induced pluripotent stem cell derived-neurons (iNs), astrocytes (iAs), and microglia-like cells (iMGLs) were incorporated into a soft-lithography based engineered microvessel system to establish a multicellular neuroimmune-vascular model. To specifically evaluate iMGL-endothelial cell (EC) interactions, iMGL were co-cultured with primary human brain microvascular endothelial cells (HBMECs) and junctional protein localization was evaluated using immunofluorescence. The barrier integrity of engineered microvessels containing iMGL was evaluated using dextran permeability. Our 2D and 3D systems were stimulated with tumor necrosis factor- (TNF) to evaluate whether iMGL would promote or attenuate EC inflammation and barrier breakdown. ResultsIncorporation of iNs, iAs, and iMGLs into a perfusable vascular model enabled a more complete representation of NVU cellular diversity and promoted neuronal health. In monolayer co-culture with iMGL, HBMECs enhanced the junctional localization of tight and adherens junction proteins through both contact-dependent and paracrine mechanisms. Following an inflammatory challenge, iMGLs reduced endothelial inflammatory activation, suggesting a protective role in response to AD-relevant inflammatory conditions. Finally, when embedded in 3D collagen matrices surrounding perfusable endothelialized lumen networks, iMGLs reduced dextran permeability and preserved endothelial barrier integrity following TNF challenge. ConclusionsTogether, these findings establish a 3D perfusable neuroimmune-vascular model that enables the dissection of microglial contributions to neurovascular function in health and disease.

cell biology↗

bioRxiv2024

Wnt/β-Catenin coordinates muscle spindle development by regulating capsule differentiation, intrafusal fiber nuclei aggregation and proprioceptive nerve endings

Proprioception is essential for the regulation of posture, movement, and musculoskeletal integrity. The muscle spindle, a mechanosensory organ composed of multiple specialized tissues, detects stretch and provides proprioceptive feedback. Despite its importance, the molecular mechanisms that orchestrate the development of the spindle components remain poorly understood. Here, we reveal the involvement of the Wnt/{beta}-catenin pathway in muscle spindle development. We show that Wnt ligands and their Frizzled receptors are expressed in the developing spindle and that {beta}-catenin is active throughout development in capsule cells and in bag2 intrafusal fibers. Embryonic deletion of {beta}-catenin from capsule and intrafusal fibers induced widespread transcriptomic changes, which led to significant malformations, including impaired capsule cell differentiation, disrupted nuclear organization in intrafusal fibers, and disorganized proprioceptive nerve endings. Postnatal deletion of {beta}-catenin from intrafusal fibers resulted in abnormal nerve endings and impaired proprioceptive function, indicating that the development of proprioceptive afferents is regulated by {beta}-catenin through a non-cell-autonomous mechanism acting in bag2 fibers. Collectively, our findings position the Wnt/{beta}-catenin pathway as a central regulator that acts through both cell-autonomous and non-cell-autonomous mechanisms to coordinate the development of the various spindle tissues into a functional organ.

developmental biology↗

bioRxiv2021

Nonclinical Safety and Immunogenicity of an rVSV-ΔG-SARS-CoV-2-S vaccine in mice, hamsters, rabbits and pigs

rVSV-{Delta}G-SARS-CoV-2-S is a clinical stage (Phase 2) replication competent recombinant vaccine against SARS-CoV-2. Nonclinical safety, immunogenicity and efficacy studies were conducted in 4 animal species, using multiple dose levels (up to 108 PFU/animal) and various dosing regimens. There were no treatment related mortalities in any study, or any noticeable clinical signs. Compared to unvaccinated controls, hematology and biochemistry parameters were unremarkable and no adverse histopathological findings gave cause for safety concern in any of the studies. There was no viral shedding in urine, nor viral RNA detected in whole blood or serum samples 7 days post vaccination. The rVSV-{Delta}G-SARS-CoV-2-S vaccine immune response gave rise to neutralizing antibodies, cellular immune response, and increased lymphocytic cellularity in the spleen germinal centers and regional lymph node. No evidence for neurovirulence was found in C57BL/6 immune competent mice or in highly sensitive IFNAR KO mice. Vaccine virus replication and distribution in K18 hACE2 transgenic mice showed a gradual clearance from the vaccination site with no vaccine virus recovered from the lungs. The rVSV-{Delta}G-SARS-CoV-2-S vaccine was well tolerated locally and systemically and elicited an effective immunogenic response up to the highest dose tested, supporting further clinical development.

pharmacology and toxicology↗

bioRxiv2021

Monitoring group activity of hamsters and mice as a novel tool to evaluate COVID-19 progression, convalescence and rVSV-ΔG-spike vaccination efficacy

COVID-19 pandemic initiated a worldwide race toward the development of treatments and vaccines. Small animal models were the Syrian golden hamster and the K18-hACE2 mice infected with SARS-CoV-2 to display a disease state with some aspects of the human COVID-19. Group activity of animals in their home cage continuously monitored by the HCMS100 was used as a sensitive marker of disease, successfully detecting morbidity symptoms of SARS-CoV-2 infection in hamsters and in K18-hACE2 mice. COVID-19 convalescent hamsters re-challenged with SARS-CoV-2, exhibited minor reduction in group activity compared to naive hamsters. To evaluate rVSV-{Delta}G-spike vaccination efficacy against SARS-CoV-2, we used the HCMS100 to monitor group activity of hamsters in their home cage. Single-dose rVSV-{Delta}G-spike vaccination of immunized group showed a faster recovery compared to the non-immunized infected hamsters, substantiating the efficacy of rVSV-{Delta}G-spike vaccine. HCMS100 offers non-intrusive, hands-free monitoring of a number of home cages of hamsters or mice modeling COVID-19.

immunology↗