Biology subjects

Zurcher, K. J.

Publications and source records attributed to Zurcher, K. J..

4 recordsLinked to original sources

bioRxiv2026

Neural graft elimination via dual safety switch compromises therapeutic recovery after stroke

Safety switch systems are increasingly incorporated into stem cell therapies to enable selective graft elimination in the event of adverse outcomes. Yet how removing transplanted cells affects the underlying pathology remains largely unexplored. Here, we show that iPSC-derived neural stem cells (NSCs) co-transduced with herpes simplex virus thymidine kinase (HSV-TK) and inducible caspase-9 (iC9) are more efficiently ablated by combined ganciclovir (GCV) and chemical inducer of dimerization (CID) treatment than either single switch alone, under both proliferating and differentiating conditions. Using bioluminescence imaging to track graft survival longitudinally, we demonstrate that dual safety switch NSC (DS-NSC) grafts are selectively eliminated by GCV and CID administration in immunodeficient mice following photothrombotic stroke. The combination treatment initiated on day 8 post-transplantation resulted in reduced graft volume, lower NSC proliferation, and persistently reduced bioluminescence signal compared to mice receiving only solvent. Histological analysis revealed that combination treatment was associated with larger stroke lesions, higher IBA1 fluorescence intensity, and reduced vascular density in the ischemic border zone. Mice receiving GCV and CID showed persistently elevated contralateral hindlimb error rates on a ladder walk task from day 28 post-stroke onward compared to solvent-treated mice. These findings demonstrate that while DS-NSC elimination is feasible, the pharmacological activation of the safety switch system is associated with impaired functional stroke recovery.

neuroscience↗

bioRxiv2026

Targeting integrin αvβ3 by chimeric antigen receptor neural stem cell (CAR-NSC) therapy for stroke

Stroke remains a leading cause of adult disability due to the brains limited regenerative capacity. Although stem cell therapies show favorable safety and feasibility profiles in early clinical trials, poor spatial retention and limited engagement with peri-infarct salvageable tissue constrain efficacy. Here, we engineered human induced pluripotent stem cell-derived neural stem cells (NSC) with a chimeric antigen receptor (CAR)-like architecture to enable targeted recognition of injury-associated cues. Specifically, cells were modified to express a membrane-anchored single chain variable fragment (scFv) targeting integrin v{beta}3, a receptor selectively upregulated in peri-infarct vasculature after stroke. Engineered CAR-NSC retained progenitor identity and selectively bound recombinant integrin v{beta}3 in vitro. Following focal transplantation into a photothrombotic stroke mouse model, CAR-NSC displayed broader dispersion within peri-infarct tissue and covered a greater proportion of the ischemic lesion compared to non-binding control-CAR-NSC. CAR-NSC grafts extended longer neurites that aligned more closely with the lesion border. In addition, CAR-NSC transplantation reduced microglial activation and was associated with increased vascular density and blood-brain barrier integrity in the peri-infarct zone. Together, these findings establish a CAR-like NSC strategy for stroke to direct the spatial distribution and tissue engagement of transplanted cells. Molecular targeting of injury-associated cues may improve the precision and regenerative efficacy of cell-based therapies for stroke and related neurological disorders.

neuroscience↗

bioRxiv2025

Hypoxia preconditioned neural xenografts promote repair of brain tissue after stroke

Stroke is a leading cause of long-term disability, yet no effective regenerative therapies exist. While cell-based therapies have shown promise in preclinical animal models, their clinical application remains limited due to poor survival of transplanted cells in the ischemic stroke environment. Hypoxic preconditioning has emerged as a strategy to potentially enhance graft survival, but the cellular mechanisms and translational relevance in human iPSC-derived neural progenitor cells (NPCs) are not fully understood. Here, we tested whether hypoxic preconditioning of NPCs affects their molecular and functional properties including proliferation and survival in vitro and after transplantation into a stroke mouse model. Hypoxic preconditioning enhanced proliferation and glial differentiation in vitro, improved cell survival post-transplantation, and enhanced regeneration-associated tissue responses such as vascular remodeling in the peri-infarct brain. These findings suggest that hypoxic preconditioning is a clinically translatable approach to increase the NPC graft survival in the post-stroke brain.

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↗