Search Results (138)

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

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

Heparan sulfate proteoglycans (HSPGs) within the neuronal niche are expressed during brain development, contributing to multiple aspects of neurogenesis, yet their roles in glial lineage commitment remain elusive. This study utilised three human cell models expanded under basal culture conditions followed by media-induced lineage induction to identify a reproducible and robust model of gliogenesis. SH-SY5Y human neuroblastoma cells (neuronal control), ReNcell CX human neural progenitor cells (astrocyte inductive) and ReNcell VM human neural progenitor (mixed neural induction) models were examined. The cultures were characterised during basal and inductive states via Q-PCR, Western Blotting, immunocytochemistry (ICC) and calcium signalling activity analyses. While the ReNcell lines did not produce fully mature or homogeneous astrocyte cultures, the ReNcell CX cultures most closely resembled an astrocytic phenotype with ReNcell VM cells treated with platelet-derived growth factor (PDGF) biased toward an oligodendrocyte lineage. The glycated variant of surface-bound glypican-2 (GPC2) was found to be associated with lineage commitment, with GPC6 and 6-O HS sulfation upregulated in astrocyte lineage cultures. Syndecan-3 (SDC3) emerged as a lineage-sensitive proteoglycan, with its cytoplasmic domain enriched in progenitor-like states and lost upon differentiation, supporting a role in maintaining neural plasticity. Conversely, the persistence of transmembrane-bound SDC3 in astrocyte cultures suggest continued involvement in extracellular signalling and proteoglycan secretion, demonstrated by increased membrane-bound HS aggregates. This data supports HSPGs and HS GAGs as human neural lineage differentiation and specification markers that may enable better isolation of human neural lineage-specific cell populations and improve our understanding of human neurogenesis. Full article

Glial cells, once considered mere support for neurons, have emerged as key players in brain function across vertebrates. The historical study of glia dates to the 19th century with the identification of ependymal cells and astrocytes, followed by the discovery of oligodendrocytes and microglia. While neurocentric perspectives overlooked glial functions, recent research highlights their essential roles in neurodevelopment, synapse regulation, brain homeostasis, and neuroimmune responses. In teleost fish, a group comprising over 32,000 species, glial cells exhibit unique properties compared to their mammalian counterparts. Thus, the aim of this review is synthesizing the current literature on fish glial cells, emphasizing their evolutionary significance, diversity, and potential as models for understanding vertebrate neurobiology. Microglia originate from both yolk sac cells and hematopoietic stem cells, forming distinct populations with specialized functions in the adult brain. Neural stem cells, including radial glial cells (RGCs) and neuroepithelial cells, remain active throughout life, supporting continuous neuro- and gliogenesis, a phenomenon far more extensive than in mammals. Ependymocytes line brain ventricles and show structural variability, with some resembling quiescent progenitor cells. Astrocytes are largely absent in most fish species. However, zebrafish exhibit astrocyte-like glial cells which show some structural and functional features in common with mammalian astrocytes. Oligodendrocytes share conserved mechanisms with mammals in myelination and axon insulation. Full article

Multiple sclerosis (MS) is a multifaceted inflammatory, demyelinating, and neurodegenerative disease typified by lesions with distinct hallmarks in the central nervous system. Dysregulation of micro-environmental factors, including extracellular matrix (ECM) remodelling and glial cell activation, has a decisive effect on lesion development and disease progression. Understanding the biological and pathological features of lesions would aid in prognosis and personalised treatment decision making. Positron emission tomography (PET) is an imaging technique that uses radio-labelled tracers to detect specific biological phenomena. Recent PET hardware developments enable high-resolution, quantitative imaging, which may allow biological characterisation of relatively small MS lesions. PET may complement MRI by offering objective, quantitative insights into lesion characteristics, including myelin density, inflammation and axonal integrity. Moreover, PET may provide information on lesion traits supporting decision making on upcoming therapeutic strategies for progressive MS, such as the availability of oligodendrocyte progenitor cells and ECM composition that affect remyelination and/or axon regeneration. This review explores the cellular and molecular ECM signatures and neuropathological processes of white matter MS lesions, discusses current and potential novel PET targets that may help characterise MS lesions in vivo, and addresses the potential of PET as a decision tool for selection and evaluation of therapeutic strategies, with a focus on remyelination. Full article

In the adult central nervous system (CNS), myelin regeneration primarily occurs through the differentiation of oligodendrocyte progenitor cells into mature oligodendrocytes. In men, declining testosterone levels accelerate the progression of multiple sclerosis (MS), while in women, menopause worsens MS-related disability. We previously demonstrated that functional testes and testosterone are required for the spontaneous remyelination of a focal lysolecithin (LPC)-induced demyelinating lesion in the spinal cords of male mice. Testosterone-dependent myelin repair was dependent on the induction of the chemokine receptor CXCR4 in astrocytes that repopulated the lesion and on cooperation between androgen-receptor signaling and CXCR4 signaling. In the present study, we investigated whether ovaries and estradiol have a comparable key role in female mice. Ovariectomy prevents, the appearance of astrocytes, while treatment with estradiol enhances astrocyte numbers and promotes remyelination by oligodendrocytes within the LPC-demyelinated lesion. Unlike testosterone, estradiol did not induce CXCR4 expression, and its effects remained unaffected by the CXCR4 inhibitor AMD3100. As was seen with testosterone treatment, the presence of astrocytes and myelinating oligodendrocytes within the LPC lesion of estradiol-treated females prevented the incursion of Schwann cells. These findings highlight estradiol’s crucial role in CNS remyelination in females, providing a strong rationale for estrogen-replacement therapy in estrogen-deficient and menopausal women with MS. Full article

Neurodegenerative diseases (NDs), including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis/motor neuron disease, and multiple sclerosis, are characterized by progressive loss of neuronal structure and function, leading to severe cognitive, motor, and behavioral impairments. They pose a significant and growing challenge due to their rising prevalence and impact on global health systems. The societal and emotional toll on patients, caregivers, and healthcare infrastructures is considerable. While significant progress has been made in elucidating the pathological hallmarks of these disorders, the underlying cellular and molecular mechanisms remain incompletely understood. Increasing evidence implicates oligodendrocytes and their progenitors—oligodendrocyte progenitor cells (OPCs)—in the pathogenesis of several NDs, beyond their traditionally recognized role in demyelinating conditions such as MS. Oligodendrocytes are essential for axonal myelination, metabolic support, and neural circuit modulation in the central nervous system. Disruptions in oligodendrocyte function and myelin integrity—manifesting as demyelination, hypomyelination, or dysmyelination—have been associated with disease progression in various neurodegenerative contexts. This review consolidates recent findings on the role of OPCs in NDs, explores the concept of myelin plasticity, and discusses therapeutic strategies targeting oligodendrocyte dysfunction. By highlighting emerging research in oligodendrocyte biology, this review aims to provide a short overview of its relevance to neurodegenerative disease progression and potential therapeutic advances. Full article

Mesenchymal progenitor cells (MPC) are effective in reducing tissue loss, preserving white matter, and improving forelimb function after a spinal cord injury (SCI). We proposed that by preconditioning the mouse by the intravenous delivery (IV) of MPCs for 24 h following SCI, this would provide a more favorable tissue milieu for an NSC intraspinal bridging transplantation at day three and day seven. In combination, these transplants will provide better anatomical and functional outcomes. The intravenous MSCs would provide cell protection and reduce inflammation. NSCs would provide a tissue bridge for axonal regeneration and myelination and reconnect long tract spinal pathways. Results showed that initial protection of the injury site by IV MPCs transplantation resulted in no increased survival of the NSCs transplanted at day seven. However, integration of transplanted NSCs was increased at the day three timepoint, indicating MPCs influence very early immune signaling. We show, in this study, that MPC transplantation resulted in a co-operative NSC cell survival improvement on day three post-SCI. In addition to increased NSC survival on day three, there was an increase in NSC-derived mature oligodendrocytes at this early timepoint. An in vitro analysis confirmed MPC-driven oligodendrocyte differentiation, which was statistically increased when compared to control NSC-only cultures. These observations provide important information about the combination, delivery, and timing of two cellular therapies in treating SCI. This study provides important new data on understanding the MPC inflammatory signaling within the host tissue and timepoints for cellular transplantation survival and oligodendroglia differentiation. These results demonstrate that MPC transplantation can alter the therapeutic window for intraspinal transplantation by controlling both the circulating inflammatory response and local tissue milieu. Full article

Spinal cord injury (SCI) is a life-altering condition that leads to severe neurological deficits and significantly impacts patients’ quality of life. Despite advancements in medical care, current treatment options remain largely palliative, with limited ability to promote meaningful functional recovery. Induced pluripotent stem cells (iPSCs) have emerged as a promising avenue for regenerative medicine, offering patient-specific, cell-based therapeutic potential for SCI repair. This review provides a comprehensive overview of recent advancements in iPSC-based approaches for SCI, detailing the strategies used to generate neural cell types, including neural progenitor cells, oligodendrocytes, astrocytes, and microglia, and their roles in promoting neuroprotection and regeneration. Additionally, we examine key preclinical and clinical studies, highlighting functional recovery assessments and discussing both standardized and debated evaluation metrics. Furthermore, we address critical challenges related to safety, tumorigenicity, immune response, survival, integration, and overcoming the inhibitory microenvironment of the injured spinal cord. We also explore emerging approaches in biomaterial scaffolds, gene editing, and rehabilitation strategies that may enhance the clinical applicability of iPSC-based therapies. By addressing these challenges and refining translational strategies, iPSC-based interventions hold significant potential to revolutionize SCI treatment and improve outcomes for affected individuals. Full article

Background/Objectives: Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition marked by challenges in social communication, restricted interests, and repetitive behaviors. Recent studies highlight the crucial roles of neuroglial cells—astrocytes, microglia, and oligodendrocytes—in synaptic function, neural connectivity, and neuroinflammation. These findings offer a fresh perspective on ASD pathophysiology. This review synthesizes current knowledge on neuroglial dysfunction in ASD, emphasizing its role in pathophysiological mechanisms, genetic influences, and potential therapeutic strategies. Methods: We conducted a comprehensive literature review, integrating insights from neuroscience, molecular biology, and clinical studies. Special focus was given to glial-mediated neuroinflammatory mechanisms, synaptic plasticity regulation, and the impact of genetic mutations on neuroglial signaling and homeostasis. Results: Neuroglial dysfunction in ASD is evident in abnormal synaptic pruning by microglia, impaired astrocytic glutamate regulation, and defective oligodendrocyte-driven myelination, which collectively disrupt neuronal architecture. Emerging therapies targeting these pathways, including anti-inflammatory drugs, microglial modulators, and cell-based approaches, show promise in alleviating key ASD symptoms. Additionally, advanced interventions such as gene editing and glial progenitor therapy present opportunities to correct underlying neuroglial dysfunction. Conclusions: This review establishes a comprehensive framework for understanding neuroglial contributions to ASD. By integrating insights from diverse disciplines, it enhances our understanding of ASD pathophysiology and paves the way for novel therapeutic strategies targeting neuroglial pathways. Full article

Our recent study revealed that continuous prenatal low-dose-rate irradiation did not induce cellular changes in the dentate gyrus of the hippocampus in male B6C3F1 mice exposed to gamma rays during prenatal development. However, changes in body weight, body mass index (BMI), locomotor ability, and mRNA and miRNA expressions in the hippocampus and blood were observed. To investigate potential sex differences in the effects of prenatal gamma irradiation, we conducted a parallel study on female B6C3F1 mice. The results showed significant reductions in the weight of the lungs and left kidney in prenatally irradiated female offspring, accompanied by significantly increased fat deposits in the mesentery, retroperitoneal, and left perigonadal areas. Despite these systemic changes, no cellular alterations were observed in the subgranular zone (immature neurons) or the hilus of the dentate gyrus (mature neurons and glial cells, including astrocytes, microglia, and oligodendrocyte progenitor cells). However, significant increases in hippocampal mRNA expression were detected for genes such as H2bc24, Fos, Cd74, Tent5a, Traip, and Sap25. Conversely, downregulation of mRNAs Inpp5j and Gdf3 was observed in whole blood. A Venn diagram highlighted the differential expression of two mRNAs, Ttn and Slc43a3, between the hippocampus and whole blood. Comparisons between prenatally irradiated male and female B6C3F1 mice revealed sex-specific differences. In whole blood, 4 mRNAs (Scd1, Cd59b, Vmn1r58, and Gm42427) and 1 miRNA (mmu-miR-8112) exhibited differential expression. In the hippocampus, 12 mRNAs and 2 novel miRNAs were differentially expressed between the sexes. qRT-PCR analysis validated the upregulation of H2bc24, Fos, Cd74, and Tent5a in the female hippocampus. These gene expression changes may be associated with the increased fat deposition observed following chronic low-dose-rate gamma irradiation exposure. This study underscores the importance of investigating sex-specific biological responses to prenatal gamma irradiation and highlights potential molecular pathways linked to observed physiological changes. Full article

DNA methylation and demethylation are key epigenetic events that regulate gene expression and cell fate. DNA demethylation via oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) is typically mediated by TET (ten-eleven translocation) enzymes. The 5hmC modification is considered an intermediate state of DNA demethylation; it is particularly prevalent in the brain and is believed to play a role in the development of many cell types in the brain. Our previous studies have identified that vitamin C (Vc) and MEK inhibitor PD0325901 could significantly promote OPC (oligodendrocyte progenitor cell)-to-OL (oligodendrocyte) differentiation. Here we discovered that Vc and PD0325901 may promote OPC-to-OL differentiation by inducing DNA demethylation via hydroxymethylation. Blocking 5hmC formation almost totally blocked Vc- and PD0325901-stimulated OPC-to-OL differentiation. In addition, TET1 is not involved in Vc,- and PD0325901-promoted OL generation. We also found a synergistic effect between the two compounds in inducing OL generation, suggesting the possibility of a combination therapy for demyelination diseases in the future. Full article

In Alzheimer’s disease (AD), tau dissociates from microtubules (MTs) due to hyperphosphorylation and misfolding. It is degraded by various mechanisms, including the 20S proteasome, chaperone-mediated autophagy (CMA), 26S proteasome, macroautophagy, and aggrephagy. Neurofibrillary tangles (NFTs) form upon the impairment of aggrephagy, and eventually, the ubiquitin chaperone valosin-containing protein (VCP) and heat shock 70 kDa protein (HSP70) are recruited to the sites of NFTs for the extraction of tau for the ubiquitin–proteasome system (UPS)-mediated degradation. However, the impairment of tau degradation in neurons allows tau to be secreted into the extracellular space. Secreted tau can be monomers, oligomers, and paired helical filaments (PHFs), which are seeding competent pathological tau that can be endocytosed/phagocytosed by healthy neurons, microglia, astrocytes, oligodendrocyte progenitor cells (OPCs), and oligodendrocytes, often causing proteotoxic stress and eventually triggers senescence. Senescent cells secrete various senescence-associated secretory phenotype (SASP) factors, which trigger cellular atrophy, causing decreased brain volume in human AD. However, the molecular mechanisms of proteotoxic stress and cellular senescence are not entirely understood and are an emerging area of research. Therefore, this comprehensive review summarizes pertinent studies that provided evidence for the sequential tau degradation, failure, and the mechanistic link between tau-driven proteotoxic stress and cellular senescence in AD. Full article

Failure of myelin regeneration by oligodendrocytes contributes to progressive decline in many neurological diseases. Here, using in vitro and in vivo rodent models, functional blockade, and mouse brain demyelination, we demonstrate that Sonic hedgehog (Shh) expression in a subset of oligodendrocyte progenitor cells precedes the expression of myelin basic protein (MBP), a major myelin sheath protein. Primary cultures of rodent cortical oligodendrocytes show that Shh mRNA and protein are upregulated during oligodendrocyte maturation before the upregulation of MBP expression. Importantly, almost all MBP-positive cells are Shh positive during differentiation. During remyelination, we identify a rapid induction of Shh mRNA and peptide in oligodendroglial cells present in the demyelinated corpus callosum of mice, including a population of PDGFRα-expressing cells. Shh invalidation by an adeno-associated virus strategy demonstrates that the downregulation of Shh impairs the differentiation of oligodendrocytes in vitro and decreases MBP and myelin proteolipid protein expression in the demyelinated mouse brain at late stages of remyelination. We also report a parallel expression of Shh and MBP in oligodendroglial cells during early post-natal myelination of the mouse brain. Thus, we identify a crucial Shh signal involved in oligodendroglial cell differentiation and remyelination, with potential interest in the design of better-targeted remyelinating therapeutic strategies. Full article

Glial cell dysfunction results in myelin loss and leads to subsequent motor and cognitive deficits throughout the demyelinating disease course.Therefore, in various therapeutic approaches, significant attention has been directed toward glial-restricted progenitor (GRP) transplantation for myelin repair and remyelination, and numerous studies using exogenous GRP injection in rodent models of hypomyelinating diseases have been performed. Previously, we proposed the transplantation of canine glial-restricted progenitors (cGRPs) into the double-mutant immunodeficient, demyelinated neonatal shiverer mice (shiverer/Rag2^−/−). The results of our previous study revealed the myelination of axons within the corpus callosum of transplanted animals; however, the extent of myelination and lifespan prolongation depended on the transplantation site (anterior vs. posterior). The goal of our present study was to optimize the therapeutic effect of cGRP transplantation by using a multisite injection protocol to achieve a broader dispersal of donor cells in the host and obtain better therapeutic results. Experimental analysis of cGRP graft recipients revealed a marked elevation in myelin basic protein (MBP) expression and prominent axonal myelination across the brains of shiverer mice. Interestingly, the proportion of galactosyl ceramidase (GalC) positive cells was similar between the brains of cGRP recipients and control mice, implying a natural propensity of exogenous cGRPs to generate mature, myelinating oligodendrocytes. Moreover, multisite injection of cGRPs improved mice survival as compared to non-transplanted animals. Full article