Search Results (489)

Given the central role of neurogenesis in building a functional nervous system, we recently developed a zebrafish-based drug-screening protocol to uncover molecules and signalling pathways regulating spinal cord neurogenesis. In this study, we have expanded this drug screen and discovered a previously unknown role of deacetylase sirtuin 2 (SIRT2) in promoting the generation of serotonergic interneurons in the spinal cord. Treatments with specific SIRT2 inhibitors reduced the generation of serotonergic neurons in the spinal cord, which led to locomotor deficits. Our data suggest that SIRT2 regulates mitotic activity in progenitor cells to promote the generation of serotonergic neurons in developing animals. Together, our results uncover SIRT2 as a key regulator of spinal cord neurogenesis and position it as a promising target for strategies aimed at neural repair in spinal cord disorders. Full article

Zika virus (ZIKV) can infect and replicate in the endoplasmic reticulum (ER) of different human cell types, including neural progenitor cells, radial glial cells, astrocytes, and microglia in the brain. ZIKV infection of microglia is expected to trigger both ER stress and the induction of an antiviral response through production of type-I interferons and pro-inflammatory cytokines, contributing to neuroinflammation during infection. Despite their critical role in ZIKV pathogenesis, the interplay between ER stress and the antiviral response during infection has not been fully characterized in human microglia. In this work, we show that infection of a human microglia cell line with ZIKV triggers the induction of an antiviral response and the activation of the endonuclease activity of the unfolded protein response sensor IRE1. Interestingly, we observed that both IRE1 and XBP1 were sequestered to the viral replication sites during infection. Moreover, pharmacological inhibition or hyperactivation of the endonuclease activity of IRE1 resulted in reduced viral titers. As such, while inhibition of IRE1 resulted in an increased type-I interferon response, hyperactivation led to a decrease in ZIKV RNA levels and the appearance of ER-derived cytoplasmic structures containing NS3, IRE1, and XBP1. Together, our data indicate that regulation of the endonuclease activity of IRE1 is critical for both ZIKV replication and immune activation, highlighting the potential of the ER stress sensor as a target for the development of antivirals to treat ZIKV infections. Full article

The ultrastructural organization of different cell types involved in homeostatic growth in the cerebellum of juvenile chum salmon (Oncorhynchus keta) was investigated using transmission and scanning electron microscopy. The organization of astrocytes, oligodendrocytes, dark cells, adult-type glial and non-glial progenitors, stellate neurons, and eurydendroid cells (EDCs) in the molecular and granular layers and granular eminences was characterized. The organization of dendritic bouquets of Purkinje cells and climbing fibers was studied for the first time at the ultrastructural level, and the ultrastructural features of mossy fibers and the rosettes they form were characterized. Scanning electron microscopy (SEM) revealed the presence of single and paired adult-type neural stem/progenitor cells (aNSPCs) on the cerebellar surface and stromal clusters of aNSPCs outside the dorsal matrix zone (DMZ). Immunohistochemical (IHC) verification of proliferating cell nuclear antigen (PCNA) revealed five types of proliferating cells in the cerebellum of juvenile chum salmon: neuroepithelial cells (NECs), glial aNSPCs, and non-glial aNSPCs. A glial fibrillary acidic protein-positive (GFAP) complex consisting of radial glial fibers and aNSPCs was detected in the DMZ. At the same time, a complex of GFAP+ cerebellar afferents, consisting of differentiating mossy and climbing fibers, was found to develop in the cerebellum of juvenile chum salmon. Nestin+ non-glial aNSPCs and small nestin+ resident cells were detected in the dorsal, lateral, and basal areas, as well as in the granular layer (GrL) and granular eminences (GrEm). These cell types may contribute to the homeostatic growth of the cerebellum by acting as both active participants (PCNA+) and resident (silent) aNSPCs. Studying vimentin-positive systems in the cerebellum revealed a widespread presence of proliferating glial aNSPCs that actively contribute to homeostatic growth, as well as small resident immunopositive cells throughout the cerebellum of juvenile chum salmon. Immunolocalization of the neuronal RNA-binding protein marker (HuCD) was detected in numerous molecular layer (ML) cells at the early stages of neuronal differentiation in the dorsal and lateral regions of the cerebellum of juvenile chum salmon. HuCD + EDCs were detected for the first time in the dorsal (DZ) and basal (BZ) zones, forming broad axonal arborization. Immunolabeling of HuCD in combination with transmission electron microscopy (TEM) allowed EDCs to be characterized in the cerebellum of juvenile chum salmon for the first time. Full article

Human stem cell research is entering a stage where disease modeling, translational applications, and clinical therapies are increasingly connected. This editorial provides an overview of the contributions included in this Special Issue, titled “Human Stem Cells in Disease Modelling and Treatment”, placing them within the wider landscape of stem cell science. We summarize advances in ovarian stem cells for infertility, mesenchymal stem cells for neurodegeneration, pluripotent stem cell-derived cardiovascular and kidney organoids, adipose-derived stem cells, and emerging immunomodulatory and neural progenitor approaches. These studies illustrate the breadth of stem cell research and its potential to inform clinical practice. At the same time, challenges remain in reproducibility, safety, scalability, and ethical oversight. Looking forward, collaborative work and harmonized global standards will be important to bring laboratory findings into therapies that are safe, effective, and accessible. This editorial closes the first edition of the Special Issue with a reflection on current progress and directions for the future. Full article

Human induced pluripotent stem cells (hiPSCs) hold great potential for patient-specific therapies. Transplantation of hiPSC-derived neural progenitor cells (NPCs) is a promising reparative strategy for spinal cord injury (SCI), but clinical translation requires efficient differentiation into desired neural lineages and purification before transplantation. Here, differentiated hiPSCs—reprogrammed from human skin fibroblasts using Sendai virus-mediated expression of OCT4, SOX2, KLF4, and C-MYC—into neural rosettes expressing SOX1 and PAX6, followed by neuronal precursors (β-tubulin III⁺/NESTIN⁺) and glial precursors (GFAP+/NESTIN+). Both neuronal and glial precursors expressed the A2B5 surface antigen. A2B5+ NPCs, purified by fluorescence-activated cell sorting (FACS), proliferated in vitro with mitogens, and differentiated into mature neurons and astrocytes under lineage-specific conditions. Then, NOD-SCID mice received a T9 contusion injury followed by transplantation of A2B5+ NPCs, human fibroblasts, or control medium at 8 days post-injury. At two months, grafted NPCs showed robust survival, progressive neuronal maturation (β-tubulin III⁺→doublecortin⁺→NeuN⁺), and astrocytic differentiation (GFAP+), particularly in spared white matter. Transplantation significantly increased spared white matter volume and improved hindlimb locomotor recovery, with no teratoma formation observed. These results demonstrate that hiPSC-derived, FACS-purified A2B5+ NPCs can survive, differentiate into neurons and astrocytes, and enhance functional recovery after SCI. This approach offers a safe and effective candidate cell source for treating SCI and potentially other neurological disorders. Full article

Thyroid hormones (THs) are essential for brain development, and their dysregulation is associated with cognitive deficits and neurodevelopmental disorders. Down syndrome (DS), caused by trisomy 21, is frequently associated with thyroid dysfunction and impaired neurogenesis. Here, we investigated THs signaling dynamics during neural differentiation using human induced pluripotent stem cells (hiPSCs) derived from individuals with DS and controls. We analyzed the gene expression of key THs regulators—deiodinases, transporters, and receptors—and downstream target genes in hiPSCs, hiPSC-derived neural progenitor cells (NPCs), hiPSC-derived astrocytes, and hiPSC-derived neurons. DS-derived hiPSCs, hiPSC-derived NPCs, and hiPSC-derived neurons exhibited 2- to 7-fold increases in the gene expression of DIO2 and 3- to 8-fold reductions in DIO3, alongside 1- to 3-fold downregulation of THRA and THRB isoforms. hiPSC-derived astrocytes showed a 4-fold decrease in the gene expression of DIO2, a 4-fold increase in DIO3, upregulation of SLC16A10 (2-fold), and downregulation of SLC7A5 (0.5-fold) and THs receptors (0.5- to 12-fold). hiPSC-derived neurons exhibited marked downregulation of the gene expression of HOMER1 (0.5-fold), GRIN3A (14-fold), and GRIN3B (4-fold), accompanied by impaired spontaneous activity in multi-electrode array recordings. These findings reveal a robust, cell-type-specific imbalance between THs availability and signaling competence in DS hiPSC-derived neural cells, providing mechanistic insight into THs-related contributions to the function of DS hiPSC-derived neural cells and identifying potential therapeutic targets. Full article

Histone deacetylases (HDACs) are key epigenetic regulators that influence chromatin remodeling, gene expression, and cellular plasticity in the central nervous system (CNS). This review provides a comprehensive overview of the classification and functional diversity of HDACs, with particular emphasis on their roles in neural progenitor cells, mature neurons, and glial populations. In neural stem and progenitor cells, HDACs modulate neurogenesis, fate specification, and lineage commitment. In differentiated neurons, HDACs govern synaptic plasticity, memory formation, and survival. In glial cells, including astrocytes and microglia, HDACs orchestrate inflammatory responses, redox balance, and metabolic adaptations. We further examine the dysregulation of HDAC expression and activity in major neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. Evidence from human post-mortem brain studies reveals region- and isoform-specific alterations in HDAC expression, which are closely associated with cognitive decline, mitochondrial dysfunction, and neuroinflammation. Preclinical studies support the use of HDAC inhibitors (HDACi) as neuroprotective agents, capable of restoring acetylation homeostasis, reducing neuroinflammation, and improving neuronal function. Given the relevance of HDACi, we summarize current clinical studies assessing the safety of these compounds in the context of tumor biology, as well as their potential future applications in neurodegenerative diseases. Together, this review underscores the dual significance of HDACs as biomarkers and therapeutic targets in the context of CNS disorders. Full article

Background: The vast majority of GBMs recur within 2 years following standard treatment, including radiotherapy. Seizures and epilepsy are common in GBM patients, suggesting tumor-cell-induced neuron toxicity. Additionally, the tumor cells and neurons interact during tumor development; however, the effects of tumor cells on the neurons remain unclear. Methods: Orthotopic xenografts initiated from GSCs expressing GFP implanted into the right striatum of nude mice were irradiated (10 Gy) 35 days after implantation, followed by immunohistochemistry (IHC) to investigate the tumor cell–neuron interactions. Moreover, we established a direct coculture of human GSCs and neurons differentiated from human iPSC-derived neural progenitor cells (NPCs) to investigate the impact of the tumor cells on the neurons. Neuronal cell counts were monitored to assess neurotoxicity. Culture CM were analyzed through cytokine profiling. Results: In untreated mice, tumors invaded across the right hemisphere (RH), with increased cell contact with the mouse neurons. In irradiated mice, the tumor regrowth was less invasive and had fewer neurons. In vitro, the GSCs induced neuronal death in the direct coculture. Similarly, the CM from the direct cocultures caused significant neuronal death. The cytokine analysis revealed that the cocultures uniquely secreted IL-8 into the CM. Furthermore, treatment with recombinant (r) human IL-8 caused significant neuron death, while IL-8 blocking antibodies prevented this neurotoxicity in the coculture. Conclusions: This study demonstrates that GBM tumors regrown after radiation lack neurons, and direct interaction between GSCs and the neurons is necessary for GSC-mediated neurotoxicity, likely involving IL-8 in neuronal death. Full article

CD44, a structurally diverse cell-surface glycoprotein, plays a multifaceted and indispensable role in neural tissue across both physiological and pathological conditions. It orchestrates complex cell–extracellular matrix interactions and intracellular signaling through its variant isoforms and post-translational modifications and is broadly expressed in neural stem/progenitor cells, microglia, astrocytes, and selected neuronal populations. The interactions of CD44 with ligands such as hyaluronan and osteopontin regulate critical cellular functions, including migration, differentiation, inflammation, and synaptic plasticity. In microglia and macrophages, CD44 mediates immune signaling and phagocytic activity, and it is dynamically upregulated in neuroinflammatory diseases, particularly through pathways involving Toll-like receptor 4. CD44 expression in astrocytes is abundant during central nervous system development and in diseases, contributing to glial differentiation, reactive astrogliosis, and scar formation. Though its expression is less prominent in mature neurons, CD44 supports neural plasticity, circuit organization, and injury-induced repair mechanisms. Additionally, its expression at nervous system barriers, such as the blood–brain barrier, underscores its role in regulating vascular permeability during inflammation and ischemia. Collectively, CD44 emerges as a critical integrator of neural cell function and intercellular communication. Although the roles of CD44 in glial cells appear to be similar to those explored in other tissues, the expression of this molecule and its variants on neurons reveals peculiar functions. Elucidating the cell-type-specific roles and regulation of CD44 variants may offer novel therapeutic strategies for diverse neurological disorders. Full article

Rafiq syndrome (RAFQS) is a rare autosomal recessive disorder that is classified as a type II congenital disorder of glycosylation (CDG-II), and caused by MAN1B1 gene mutation. To date, 24 pathogenic MAN1B1 mutations have been reported in association with MAN1B1-CDG. However, the underlying pathogenic mechanisms remain poorly understood. In this study, we recruited a consanguineous family from Pakistan with multiple affected individuals exhibiting mild facial dysmorphism, developmental delay, and intellectual disability. Utilizing exome sequencing and homozygosity mapping, we identified a novel MAN1B1 mutation (c.772_775del) that co-segregated with RAFQS in this family. Analysis of public single-cell transcriptomic data revealed that MAN1B1 is predominantly expressed in dorsal progenitors and intermediate excitatory neurons during human brain development. Knockdown of Man1b1 in primarily cultured mouse excitatory neurons disrupted axon growth, dendrite formation, and spine maturation, and could not be rescued by truncated variants identified in the family. Furthermore, in utero, electroporation experiments revealed that Man1b1 knockdown in the murine cortex impaired neural stem cells’ proliferation and differentiation, as well as cortical neuron migration. Collectively, these findings elucidate a critical role for MAN1B1 in the etiology of RAFQS and demonstrate that loss-of-function mutation in MAN1B1 disrupt neuro-developmental processes, providing mechanistic insights into the pathogenesis of this disorder. Full article

Neural stem/progenitor cells (NSPCs) in the subventricular zone (SVZ) of the central nervous system (CNS) are critical for tissue repair following injury or disease. These cells retain the capacity to proliferate, migrate, and differentiate into neurons, astrocytes, and oligodendrocytes, making them a promising therapeutic target for neurodegenerative disorders and traumatic injuries. However, the molecular mechanisms regulating their proliferation remain incompletely understood. This study investigates the role of cAMP responsive element-binding protein 5 (CREB5) in the proliferation of rat SVZ-derived NSPCs and elucidates its regulatory mechanism. Using RNA interference, we demonstrated that CREB5 knockdown significantly reduced cell viability, neurosphere formation capacity, and the number of proliferating cells (BrdU- and Ki-67-positive cells) both in vitro and in vivo. In contrast, CREB5 overexpression played opposing roles in cell proliferation. Additionally, alteration of CREB5 expression did not affect apoptosis, as assessed by TUNEL staining, indicating a specific role in proliferation rather than in cell death. Mechanistically, we identified Nuclear Factor One X (NFIX) as a transcriptional target of CREB5. CREB5 binds to the AP-1 site in the NFIX promoter, enhancing its expression. CREB5 knockdown inhibited NFIX expression, while CREB5 overexpression exerted the opposite function. ChIP and luciferase reporter assays further confirmed that CREB5 directly regulates NFIX promoter activity. More importantly, alteration of NFIX expression could reverse the effect of CREB5 on NSPC proliferation. These findings highlight CREB5 as a key regulator of NSPC proliferation through its interaction with NFIX, providing a potential therapeutic target for stem cell-based treatments of CNS disorders. Full article

Glioblastoma (GBM) remains one of the most aggressive and treatment-resistant brain tumors, largely due to its profound intratumoral heterogeneity and immunosuppressive microenvironment. Various classifications of GBM subtypes were created based on transcriptional and methylation profiles. This effort, followed by the development of new technology such as single-nuclei sequencing (snRNAseq) and spatial transcriptomics, led to a better understanding of the glioma cells’ plasticity and their ability to transition between diverse cellular states. GBM cells can mimic neurodevelopmental programs to resemble oligodendrocyte or neural progenitor behavior and hitchhike the local neuronal network to support their growth. The tumor microenvironment, especially under hypoxic conditions, drives the tumor cell clonal selection, which then reshapes the immune cells’ functions. These adaptations contribute to immune evasion by progressively disabling T cell and myeloid cell functions, ultimately establishing a highly immunosuppressive tumor milieu. This complex and metabolically constrained environment poses a major barrier to effective antitumor immunity and limits the success of conventional therapies. Understanding the dynamic interactions between glioma cells and their microenvironment is essential for the development of more effective immunotherapies and rational combination strategies aimed at overcoming resistance and improving patient outcomes. Full article

Developmental exposure to polybrominated diphenyl ethers (PBDEs), which are commonly used as flame retardants, results in irreversible cognitive impairments. Postnatal hippocampal neurogenesis, which occurs in the subgranular zone (SGZ) of the dentate gyrus, is critical for neuronal circuits and plasticity. Wnt7a-Frizzled5 (FZD5) is essential for both neurogenesis and synapse formation; moreover, Wnt signaling participates in PBDE neurotoxicity and also contributes to the neuroprotective effects of melatonin. Therefore, we investigated the impacts of perinatal decabromodiphenyl ether (BDE-209) exposure on hippocampal neurogenesis and synaptogenesis in juvenile rats through BrdU injection and Golgi staining, as well as the alleviation of melatonin pretreatment. Additionally, we identified the structural basis of Wnt7a and two compounds via molecular docking. The hippocampal neural progenitor pool (Sox2+BrdU+ and Sox2+GFAP+cells), immature neurons (DCX+) differentiated from neuroblasts, and the survival of mature neurons (NeuN+) in the dentate gyrus were inhibited. Moreover, in BDE-209-exposed offspring rats, it was observed that dendritic branching and spine density were reduced, alongside the long-lasting suppression of the Wnt7a-FZD5/β-catenin pathway and targeted genes (Prox1, Neurod1, Neurogin2, Dlg4, and Netrin1) expression. Melatonin alleviated BDE-209-disrupted memory, along with hippocampal neurogenesis and dendritogenesis, for which the restoration of Wnt7a-FZD5 signaling may be beneficial. This study suggested that melatonin could represent a potential intervention for the cognitive deficits induced by PBDEs. Full article

As the global population continues to age, the incidence of neurodegenerative diseases and neural injuries is increasing, presenting major challenges for healthcare systems. Due to the brain’s limited regenerative capacity, there is an urgent need for strategies that promote neuronal repair and functional integration. Brain-derived neurotrophic factor (BDNF) is a key regulator of synaptic plasticity and neuronal development. In this study, we investigated whether constitutive BDNF expression in human induced pluripotent stem cell (iPSC)-derived neural progenitor cells (NPCs) enhances their neurogenic and integrative potential in vitro. We found that NPCs engineered to overexpress BDNF produced neuronal cultures with increased numbers of mature and spontaneously active neurons, without altering the overall structure or organization of functional networks. Furthermore, BDNF-expressing neurons exhibited significantly greater axonal outgrowth, including directed axon extension in a compartmentalized microfluidic system, suggesting a chemoattractive effect of localized BDNF secretion. These effects were comparable to those observed with the early supplementation of recombinant BDNF. Our results demonstrate that sustained BDNF expression enhances neuronal maturation and axonal projection without disrupting network integrity. These findings support the use of BDNF not only as a therapeutic agent to improve cell therapy outcomes but also as a tool to accelerate the development of functional neural networks in vitro. Full article

Spinal cord injury (SCI) is a debilitating condition that results from a culmination of acute and chronic damage to neural tissue, specifically the myelin sheath, thus impacting neurons’ abilities to synergistically perform their physiological roles. This review explores the molecular underpinnings of myelination, demyelination, and remyelination, emphasizing the role of oligodendrocyte progenitor cells (OPCs), astrocytes, and microglia in physiological, and pathophysiological, healing. Furthermore, we link these processes with emerging therapeutic strategies currently under investigation in animal and human models, underscoring areas of translational medicine that remain underutilized. The goal of this review is to provide a framework for developing more advanced interventions to restore function and improve outcomes for individuals with SCI. Full article