Spinal cord injury (SCI) poses significant challenges for regeneration due to a series of seconda... more Spinal cord injury (SCI) poses significant challenges for regeneration due to a series of secondary injury mechanisms, including ischemia, oxidative stress, and neuroinflammation. These pathological processes lead to neuronal apoptosis and create a microenvironment that hinders neural regeneration. Recent advancements in tissue engineering have introduced biomaterials that feature precisely engineered micro-and nanoscale topographical cues, representing a novel class of therapeutic interventions. These biomimetic scaffolds are designed to modulate the mechanotransduction pathways of neural stem cells (NSCs), thereby enhancing neurogenesis and guiding neuronal differentiation. They also influence essential cellular processes such as adhesion, cytoskeletal alignment, morphological polarization, and gene regulation. This review systematically evaluates current strategies for optimizing topographical designs, emphasizing their role in promoting neurite outgrowth, axonal guidance, and synaptic reformation. The mechanisms are elucidated by which scaffold topographies regulate NSC fate decisions through mechanobiological signaling and interactions with the extracellular matrix. Additionally, critical barriers are analyzed for clinical translation, including the precision fabrication of tunable architectures, the scalability of novel materials, and strategies to mitigate glial scar formation. By synthesizing interdisciplinary insights from biomaterial science, neurobiology, and translational medicine, this work aims to provide a roadmap for developing next-generation topographical scaffolds that address the pressing clinical need for effective SCI repair.
Macrophages are highly plastic cells that act as key regulators in the inflammatory process by re... more Macrophages are highly plastic cells that act as key regulators in the inflammatory process by releasing cytokines to facilitate immune cell infiltration, orchestrate various cellular responses, and help clear bacteria and cellular debris. In chronic inflammatory conditions, macrophages fail to polarize from a pro-inflammatory to an antiinflammatory phenotype, and the constant inflammatory environment leads to an increase in both apoptosis and unprogrammed cellular death cascades that exacerbate the pathology To address this problem, we developed a biodegradable nanoparticle platform (PCaP NP) that encapsulates a nonimmunogenic nucleic acid in the form of a DNAzyme to suppress IRF5 expression, which promotes macrophage depolarization from a pro-inflammatory state. Our system is comprised of three unique components: 1) a calcium phosphate nanoparticle core designed for predictable biodegradability and optimal retention of nucleic acid payloads, 2) an IRF5-specific DNAzyme designed to silence the expression of IRF5 while mitigating adverse immunogenic responses, and 3) a poly (β-amino ester) (PBAE) polymeric coating to aid with endosomal escape, higher cellular interaction and uptake, and reduced NP-degradability at physiological pH. In this work, we have demonstrated the ability to transfect classically activated macrophages, directly suppress IRF5 expression and downstream cytokines, and cause metabolic changes that are indicative of an alternatively activated phenotype. These results suggest that PCaP NP offers a therapeutic approach to modulate inflammatory pathways in pro-inflammatory macrophages using a biodegradable and non-immunogenic platform.
Traumatic Brain Injury (TBI) is a common and debilitating injury, causing long-lasting neurologic... more Traumatic Brain Injury (TBI) is a common and debilitating injury, causing long-lasting neurological deficits. Current therapeies for recovery remain inadequate, undersing the urgent need for innovative interventions. In this study, a novel therapeutic approach is introduced that delivers extracellular vesicles (EVs) derived from human-induced pluripotent stem cell-derived neural progenitor cells (hiPSC-NPCs) with a gelatin-based injectable bioorthogonal hydrogel (BIOGEL). The hiPSC-NPCs are conditioned with deferoxamine (DFO) to simulate hypoxia, resulting in EVs enriched with neurotrophic and angiogenic factors critical for neural repair. The biomimetic mechanical properties of BIOGEL, similar to those of native brain tissue, contribute to sustained EV delivery and promote neural regeneration. BIOGEL with hypoxia-conditioned EVs showed significant tissue regeneration in vivo using a rat model of TBI. Our nanomaterial platform reduced cortical lesions, improved neurological and motor recovery, enhanced hippocampal neurogenesis and myelination, and reduced neuroinflammation, demonstrating strong therapeutic potential for neural repair. In summary, this study demonstrated proof-of-concept for a multifaceted therapeutic platform that simultaneously targets key pathological features of TBI, providing a scalable and clinically translatable approach to effective neural tissue regeneration. The synergistic combination of hypoxia-conditioned EVs and biomaterial delivery offers a promising strategy for advancing regenerative medicine techniques for neural repair.
The limited regenerative capacity of the central nervous system (CNS) following injury or disease... more The limited regenerative capacity of the central nervous system (CNS) following injury or disease requires the development of novel therapeutic strategies to promote endogenous repair. Extracellular vesicles (EVs) have emerged as a promising cell-free therapeutic that naturally encapsulates bioactive paracrine factors responsible for tissue repair. Achieving optimal therapeutic outcomes with EVs requires rational engineering to improve their delivery, targeting, and efficacy. Here, we present a comprehensive overview of the recent advacements in EV engineering. To improve their capacity to bypass biological barriers and enhance therapeutic effectiveness, key strategies such as surface ligand functionalization, therapeutic drug loading, and cellular preconditioning are used. We then explore the application of these engineered EVs in treating major CNS pathologies, including traumatic brain and spinal cord injuries (TBIs and SCIs), glioma, stroke, and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Finally, we discuss current challenges in accelerating the clinical translation of engineered EVs as next-generation therapeutics for CNS disorders.
Motivation: Single-cell and spatial transcriptomics provide unprecedented insight into diseases. ... more Motivation: Single-cell and spatial transcriptomics provide unprecedented insight into diseases. Pharmacotranscriptomic approaches are powerful tools that leverage gene expression data for drug repurposing and discovery. Multiple databases attempt to connect human cellular transcriptional responses to small molecules for use in transcriptome-based drug discovery efforts. However, preclinical research often requires in vivo experiments in non-human species, which makes utilizing such valuable resources difficult. To facilitate both human orthologous conversion of non-human transcriptomes and the application of pharmacotranscriptomic databases to pre-clinical research models, we introduce OrthologAL. OrthologAL interfaces with BioMart to access different gene sets from the Ensembl database, allowing for ortholog conversion without the need for user-generated code. Results: Researchers can input their single-cell or other high-dimensional gene expression data from any species as a Seurat object, and OrthologAL will output a human ortholog-converted Seurat object for download and use. To demonstrate the utility of this application, we tested OrthologAL using single-cell, single-nuclei, and spatial transcriptomic data derived from common preclinical models, including patient-derived orthotopic xenografts of medulloblastoma, and mouse and rat models of spinal cord injury. OrthologAL can convert these data types efficiently to that of corresponding orthologs while preserving the dimensional architecture of the original non-human expression data. OrthologAL will be broadly useful for the simple conversion of Seurat objects and for applying preclinical, high-dimensional transcriptomics data to functional human-derived small molecule predictions.
Fullerene derivatives are known radical scavengers and quenchers of reactive oxygen species and h... more Fullerene derivatives are known radical scavengers and quenchers of reactive oxygen species and have been studied as promising antioxidative agents in biological systems, yet the correlation between the structural features and their efficiency has not been well understood. In this report, we synthesized eight representative water-soluble fullerene derivatives and compared their radical scavenging properties via electron paramagnetic resonance in solution and antioxidative capacity in the H 2 O 2 -treated RAW 264.7 macrophage cell model. Through this systematic study, we identified multiple key parameters contributing to their radical scavenging and antioxidative effects, including the number and identity of functional groups on the C 60 cage, the size of aggregates, and their cellular uptake in RAW 264.7 cells.
Immunotherapy has reached clinical success in the last decade, with the emergence of new and effe... more Immunotherapy has reached clinical success in the last decade, with the emergence of new and effective treatments such as checkpoint blockade therapy and CAR T-cell therapy that have drastically improved patient outcomes. Still, these therapies can be improved to limit off-target effects, mitigate systemic toxicities, and increase overall efficacies. Nanoscale engineering offers strategies that enable researchers to attain these goals through the manipulation of immune cell functions, such as enhancing immunity against cancers and pathogens, controlling the site of immune response, and promoting tolerance via the delivery of small molecule drugs or biologics. By tuning the properties of the nanomaterials, such as size, shape, charge, and surface chemistry, different types of immune cells can be targeted and engineered, such as dendritic cells for immunization, or T cells for promoting adaptive immunity. Researchers have come to better understand the critical role the immune system plays in the progression of pathologies besides cancer, and developing nanoengineering approaches that seek to harness the potential of immune cell activities can lead to favorable outcomes for the treatment of injuries and diseases.
in HER-2+ cells in contrast to HER-2-cells, supporting the cellspecific targeting ability of the ... more in HER-2+ cells in contrast to HER-2-cells, supporting the cellspecific targeting ability of the nanotherapeutic. [102] 4.2. Nanomaterial-Enhanced Chemotherapy Delivery for the Reduction of Chemo-Induced Neuropathy
Although there have been decades of research on spinal cord injury (SCI), it is still one of the ... more Although there have been decades of research on spinal cord injury (SCI), it is still one of the most challenging medical conditions to treat in developed countries worldwide. 1-6 Clinical manifestations of SCI (e.g., paralysis, autonomic nervous system dysregulation) can severely impact the quality of life and burden social security systems. 1-6 The primary mechanism of disease and cause of clinical symptoms is the death of neurons and supporting glial cells in the spinal cord. 1-6 Thus, to achieve a lasting and successful SCI treatment, it is imperative to prevent the death of cells post-injury (Fig. 1). Previous attempts to broadly suppress well-known SCI pathophysiological processes have been controversial. In a high-profile example, methylprednisolone (a glucocorticoid with broad anti-inflammatory action) was investigated to limit the neurological and functional damage in SCI patients. 5 Unfortunately, the broad immunosuppressive and side effects of methylprednisolone have been found to be potentially deleterious in large human clinical trials. 5,6 A more nuanced approach to regulating specific cellular pathways may be warranted to prevent side effects during clinical use (Fig. 1). In the June 2023 issue of Neurospine, Guha et al. 7 have compiled the most pertinent literature on cell death mechanisms in SCI. In this manuscript, the authors investigated the key cellular pathways related to SCI pathogenesis, the key signaling proteins involved, and the current treatment options (Fig. 1). Here, readers are encouraged to use this manuscript as a stepping stone toward the next step in targeted SCI treatment research and development. For example, the systematic review of key cellular death pathways laid in the manuscript of Guha et al. 7 can be readily integrated into a variety of studies. Mechanistic investigations into novel SCI treatment options, such as systemic hypothermia, can be accelerated with the manuscript of Guha et al. 6,7 For example, future studies into the antiapoptotic effects of hypothermia can be distinguished from confounding (non-)programmed and nonapoptotic pathways of cell death. 6 Stem cell therapies can benefit by anticipating and counteracting key death mechanisms that would cause transplanted cells to die within the patient. 2 Alternatively, stem cell-secreted antiapoptosis/necrosis growth factors can be identified as a low immunogenicity substitute for allogeneic stem cell transplantation. 2 More efficient treatment options can be determined by further examination into which pathway contains the most "druggable" target. Protein-ligand simulations with critical apoptosis and necrosis checkpoints can give rise to more specific therapeutics with fewer off-target effects. 4 Novel drug combinations that have either synergistic effects, such as targeting multiple checkpoints within the same pathway, or complementary effects, like targeting different pathways leading to
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Papers by Joshua Stein