Neuronal Differentiation Research Articles

Ultrastructural Study and Immunohistochemical Characteristics of Mesencephalic Tegmentum in Juvenile Chum Salmon (Oncorhynchus keta) Brain After Acute Traumatic Injury

The ultrastructural organization of the nuclei of the tegmental region in juvenile chum salmon (Oncorhynchus keta) was examined using transmission electron microscopy (TEM). The dorsal tegmental nuclei (DTN), the nucleus of fasciculus longitudinalis medialis (NFLM), and the nucleus of the oculomotor nerve (NIII) were studied. The ultrastructural examination provided detailed ultrastructural characteristics of neurons forming the tegmental nuclei and showed neuro–glial relationships in them. Neurons of three size types with a high metabolic rate, characterized by the presence of numerous mitochondria, polyribosomes, Golgi apparatus, and cytoplasmic inclusions (vacuoles, lipid droplets, and dense bodies), were distinguished. It was found that large interneurons of the NFLM formed contacts with protoplasmic astrocytes. Excitatory synaptic structures were identified in the tegmentum and their detailed characteristic are provided for the first time. Microglia-like cells were found in the NIII. The ultrastructural characteristics of neurogenic zones of the tegmentum of juvenile chum salmon were also determined for the first time. In the neurogenic zones of the tegmentum, adult-type neural stem progenitor cells (aNSPCs) corresponding to cells of types III and IVa Danio rerio. In the neurogenic zones of the tegmentum, neuroepithelial-like cells (NECs) corresponding to cells previously described from the zebrafish cerebellum were found and characterized. In the tegmentum of juvenile chum salmon, patterns of paracrine neurosecretion were observed and their ultrastructural characteristics were recorded. Patterns of apoptosis in large neurons of the tegmentum were examined by TEM. Using immunohistochemical (IHC) labeling of the brain lipid-binding protein (BLBP) and aromatase B (AroB), patterns of their expression in the tegmentum of intact animals and in the post-traumatic period after acute injury to the medulla oblongata were characterized. The response to brainstem injury in chum salmon was found to activate multiple signaling pathways, which significantly increases the BLBP and AroB expression in various regions of the tegmentum and valvula cerebelli. However, post-traumatic patterns of BLBP and AroB localizations are not the same. In addition to a general increase in BLBP expression in the tegmental parenchyma, BLBP overexpression was observed in the rostro-lateral tegmental neurogenic zone (RLTNZ), while AroB expression in the RLTNZ was completely absent. Another difference was the peripheral overexpression of AroB and the formation of dense reactive clusters in the ventro-medial zone of the tegmentum. Thus, in the post-traumatic period, various pathways were activated whose components were putative candidates for inducers of the “astrocyte-like” response in the juvenile chum salmon brain that are similar to those present in the mammalian brain. In this case, BLBP acted as a factor enhancing the differentiation of both radial glia and neurons. Estradiol from AroB+ astrocytes exerted paracrine neuroprotective effects through the potential inhibition of inflammatory processes. These results indicate a new role for neuronal aromatization as a mechanism preventing the development of neuroinflammation. Moreover, our findings support the hypothesis that BLBP is a factor enhancing neuronal and glial differentiation in the post-traumatic period in the chum salmon brain.

Genetically Programmed Single-Component Protein Hydrogel for Spinal Cord Injury Repair.

Protein self-assembly allows for the formation of diverse supramolecular materials from relatively simple building blocks. In this study, a single-component self-assembling hydrogel is developed using the recombinant protein CsgA, and its successful application for spinal cord injury repair is demonstrated. Gelation is achieved by the physical entanglement of CsgA nanofibrils, resulting in a self-supporting hydrogel at low concentrations (≥5mg mL-1). By leveraging the programmability of the CsgA gene sequence, the bioactive hydrogel is enhanced by fusing functional peptide GHK. GHK is recognized for its anti-inflammatory, antioxidant, and neurotrophic factor-stimulating properties, making it a valuable addition to the hydrogel for spinal cord injury repair applications. In vitro experiments demonstrate that the CsgA-GHK hydrogel can modulate microglial M2 polarization, promote neuronal differentiation of neural stem cells, and inhibit astrocyte differentiation. Additionally, the hydrogel shows efficacy in alleviating inflammation and promotes neuronal regeneration at the injury site, leading to significant functional recovery in a rat model with compression injury spinal cord cavity. These findings lay the groundwork for developing a modular design platform for recombinant CsgA protein hydrogels in tissue repair applications.

Multinodular and Vacuolating Neuronal Tumors of the Cerebrum: A Systematic Review of the Literature.

Multinodular and vacuolating neuronal tumors (MVNTs) of the cerebrum are rare, seizure-related, low-grade tumors of the central nervous system that usually affect young adults. First described by Huse etal. in 2013, these neoplasms are usually located within the deep cortical ribbon and the superficial white matter and have a characteristic cytoarchitecture of cells with neuronal and glial differentiation that form multiple nodules with conspicuous vacuolation. Because of their benign nature and indolent clinical course, radiologically based differentiation from other entities is of paramount importance to avoid unnecessary surgical intervention. To the best of our knowledge, our study represents the first systematic review in the literature aiming to delineate the characteristics of MVNTs regarding epidemiology, clinical manifestation, histopathology, imaging, and management. PubMed/MEDLINE and SCOPUS databases were systematically investigated for MVNT cases until November 2023. The search yielded 29 case reports comprising 41 patients with a mean age of 32.6 years and 7 case series with 164 patients. MVNTs were most commonly located in the supratentorial compartment, affecting the temporal, frontal, or parietal lobes. Their most frequent initial clinical manifestation was either seizures or headaches. On conventional magnetic resonance imaging techniques, they usually appear hypointense in T1-weighted images and hyperintense in T2-weighted and fluid-attenuated inversion recovery images and lack perilesional edema or postcontrast enhancement. MVNTs do not seem to change size or recur, even after partial resection of the tumor, indicating their indolent course, and, thus, surveillance with serial magnetic resonance imaging is the most appropriate management technique for these lesions.

Posttranscriptional Control of Neural Progenitors Temporal Dynamics During Neocortical Development by Syncrip.

The development of the mammalian neocortex is precisely regulated by temporal gene expression, yet the temporal regulatory mechanisms of cortical neurogenesis, particularly how radial glial cells (RGCs) sequentially generate deep to superficial neurons, remain unclear. Here, the hnRNP family member Syncrip (hnRNP Q) is identified as a key modulator of superficial neuronal differentiation in neocortical neurogenesis. Syncrip knockout in RGCs disrupts differentiation and abnormal neuronal localization, ultimately resulting in superficial cortical layer defects as well as learning and memory impairments in mice. Single-cell RNA sequencing analysis demonstrated that the knockout of Syncrip disrupts the late-stage neurogenesis, stalling transcriptional progression in RGCs. Mechanistically, Syncrip maintains the transcription of temporal process-related transcription factors by recruiting stabilization complexes through phase separation, crucially regulating the Notch signaling pathway that determines the fate of RGCs. Furthermore, pathogenic human mutations in Syncrip weaken its phase-separation capability, failing to form stable complexes normally. Thus, Syncrip acts as a mediator of posttranscriptional regulatory mechanisms, governing the fate progression of RGCs and the advancement of intrinsic temporal programs. This study establishes an intracellular mechanism for posttranscriptional regulation of progressive fate determination in cortical neurogenesis.

Functional analysis of conserved C. elegans bHLH family members uncovers lifespan control by a peptidergic hub neuron.

Throughout the animal kingdom, several members of the basic helix-loop-helix (bHLH) family act as proneural genes during early steps of nervous system development. Roles of bHLH genes in specifying terminal differentiation of postmitotic neurons have been less extensively studied. We analyze here the function of 5 Caenorhabditis elegans bHLH genes, falling into 3 phylogenetically conserved subfamilies, which are continuously expressed in a very small number of postmitotic neurons in the central nervous system. We show (a) that 2 orthologs of the vertebrate bHLHe22/e23 genes, called hlh-17 and hlh-32, function redundantly to specify the identity of a single head interneuron class (AUA), as well as an individual motor neuron (VB2); (b) that the PTF1a ortholog hlh-13 acts as a terminal selector to control terminal differentiation and function of the sole octopaminergic neuron class in C. elegans, RIC; and (c) that the NHLH1/2 ortholog hlh-15 controls terminal differentiation and function of the peptidergic AVK head interneuron class, a known neuropeptidergic signaling hub in the animal. Strikingly, through null mutant analysis and cell-specific rescue experiments, we find that loss of hlh-15/NHLH in the peptidergic AVK neurons and the resulting abrogation of neuropeptide secretion from these neurons causes a substantially extended lifespan of the animal, which we propose to be akin to hypothalamic control of lifespan in vertebrates. Our functional analysis reveals themes of bHLH gene function during terminal differentiation that are complementary to the earlier lineage specification roles of other bHLH family members. However, such late functions are much more sparsely employed by members of the bHLH transcription factor family, compared to the function of the much more broadly employed homeodomain transcription factor family.

A multi-functional platform for stimulating and recording electrical responses of SH-SY5Y cells.

In recent years, multifunctional cell regulation on a single chip has become an imperative need for cell research. In this study, a novel multi-functional micro-platform integrating wireless electrical stimulation, mechanical stimulation and electrical response recording of cells was proposed. Controlling cell fate by photoexcited radio stimulation of cells on photosensitive films can precisely orchestrate biological activities. This is the first report of combining hydrogenated amorphous silicon (a-Si:H) photosensitive films and a 532 nm green laser for cell stimulation and electrical response recording. Remote wireless electrical stimulation of nerve cells through photoelectric effects based on photosensitive films evoked a change in membrane potential and promoted the neurite growth and neuronal differentiation. These effects were confirmed in a cell model of the human neuroblastoma cell line. The electrical response of cells demonstrated that the photocurrent generated by laser irradiation of the photosensitive film induced a redistribution of ions inside and outside the cell. Furthermore, a mechanical stimulus was applied to cells using a probe placed above them. The chip was used as a signal output to simultaneously obtain the electrical response of cells. The ability of photosensitive films to precisely excite cellular activity offers a novel prospect for wireless electrical stimulation. This work provides a promising strategy for the design of multi-functional biological devices based on a single chip.

Indirect influence on the BDNF/TrkB receptor signaling pathway via GPCRs, an emerging strategy in the treatment of neurodegenerative disorders.

Neuronal survival depends on neurotrophins and their receptors. There are two types of neurotrophin receptors: a nonenzymatic, trans-membrane protein of the tumor necrosis factor receptor (TNFR) family-p75 receptor and the tyrosine kinase receptors (TrkR) A, B, and C. Activation of the TrkBR by brain-derived neurotrophic factor (BDNF) or neurotrophin 4/5 (NT-4/5) promotes neuronal survival, differentiation, and synaptic function. It is shown that in the pathogenesis of several neurodegenerative conditions (Alzheimer's disease, Parkinson's disease, Huntington's disease) the BDNF/TrkBR signaling pathway is impaired. Since it is known that GPCRs and TrkR are regulating several cell functions by interacting with each other and generating a cross-communication in this review we have focused on the interaction between different GPCRs and their ligands on BDNF/TrkBR signaling pathway.

Establishment of a novel method for differentiating into dopaminergic neurons using charged hydrogels.

Parkinson's disease (PD) is a neurodegenerative disease primarily affecting the central nervous system and impacting both the motor system and non-motor systems. Although administration of L-DOPA is effective, it is not a fundamental treatment and has side effects such as diurnal fluctuation and dyskinesia, highlighting the need for new treatment methods. There is a growing interest in dopaminergic neuron transplantation as a potential treatment. Dopaminergic neurons derived from pluripotent stem (iPS) cells provide a valuable source for transplantation therapies. Developing an efficient method to differentiate iPS cells into dopaminergic cells is essential for cell transplantation therapy. While Cell differentiation is typically controlled by the addition of specific reagents, the physical characteristics of culture substrate, especially in the charge and stiffness, are also crucial factors in regulating differentiation. In this research, we show that two newly developed electrically charged polymeric hydrogels composed of cationic (C) and anionic (A) monomers inratio of 1-9 and 2 to 8 can significantly promote Dopaminergic neuron differentiation. Our findings emphasize the importance of culture substrates in effective dopaminergic cell differentiation.

The Effect of Nerve Growth Factor on Cartilage Fibrosis and Hypertrophy during In Vitro Chondrogenesis Using Induced Pluripotent Stem Cells.

Nerve growth factor (NGF) is a neurotrophic factor usually involved in the survival, differentiation, and growth of sensory neurons and nociceptive function. Yet, it has been suggested to play a role in the pathogenesis of osteoarthritis (OA). Previous studies suggested a possible relationship between NGF and OA; however, the underlying mechanisms remain unknown. Therefore, we investigated the impact of NGF in chondrogenesis using human induced pluripotent stem cells (hiPSCs)-derived chondrogenic pellets. To investigate how NGF affects the cartilage tissue, hiPSC-derived chondrogenic pellets were treated with NGF on day 3 of differentiation, expression of chondrogenic, hypertrophic, and fibrotic markers was confirmed. Also, inflammatory cytokine arrays were performed using the culture medium of the NGF treated chondrogenic pellets. As a result, NGF treatment decreased the expression of pro-chondrogenic markers by approximately 2∼4 times, and hypertrophic (pro-osteogenic) markers and fibrotic markers were increased by approximately 3-fold or more in the NGF-treated cartilaginous pellets. In addition, angiogenesis was upregulated by approximately 4-fold or more, bone formation by more than 2-fold, and matrix metalloproteinase induction by more than 2-fold. These inflammatory cytokine array were using the NGF-treated chondrogenic pellet cultured medium. Furthermore, it was confirmed by Western blot to be related to the induction of the glycogen synthase kinase-3 beta (GSK3β) pathway by NGF. In Conclusions, these findings provide valuable insights into the multifaceted role of NGF in cartilage hypertrophy and fibrosis, which might play a critical role in OA progression.

Alternative splicing controls pan-neuronal homeobox gene expression.

The pan-neuronally expressed and phylogenetically conserved CUT homeobox gene ceh-44/CUX orchestrates pan-neuronal gene expression throughout the nervous system of Caenorhabditis elegans. As in many other species, including humans, ceh-44/CUX is encoded by a complex locus that also codes for a Golgi-localized protein, called CASP (Cux1 alternatively spliced product) in humans and CONE-1 ("CASP of nematodes") in C. elegans How gene expression from this complex locus is controlled-and, in C. elegans, directed to all cells of the nervous system-has not been investigated. We show here that pan-neuronal expression of CEH-44/CUX is controlled by a pan-neuronal RNA splicing factor, UNC-75, the C. elegans homolog of vertebrate CELF proteins. During embryogenesis, the cone-1&ceh-44 locus exclusively produces the Golgi-localized CONE-1/CASP protein in all tissues, but upon the onset of postmitotic terminal differentiation of neurons, UNC-75/CELF induces the production of the alternative CEH-44/CUX CUT homeobox gene-encoding transcript exclusively in the nervous system. Hence, UNC-75/CELF-mediated alternative splicing not only directs pan-neuronal gene expression but also excludes a phylogenetically deeply conserved golgin from the nervous system, paralleling surprising spatial specificities of another golgin that we describe here as well. Our findings provide novel insights into how all cells in a nervous system acquire pan-neuronal identity features and reveal unanticipated cellular specificities in Golgi apparatus composition.

Hyperbaric Oxygen Therapy Increases Brain-Derived Neurotrophic Factor as well as Decreases Systemic Immune-Inflammatory Index and Systemic Inflammatory Response Index in Autism Spectrum Disorder

BACKGROUND: Neuroinflammation and immune dysregulation are frequently viewed as contributing factors of autism spectrum disorder (ASD). Brain-derived neurotrophic factor (BDNF) is involved in the maintenance of neuron viability, as well as in neuron differentiation. Meanwhile, Systemic Immune-Inflammatory Index (SII) and Systemic Inflammatory Response Index (SIRI) are basic hematological indices used to assess inflammation and immune status. Hyperbaric oxygen (HBO) is known to enhance cerebral blood flow and reduce inflammation, however, not many studies have observed the its effect on BDNF level, SII, and SIRI in ASD subjects; therefore, this study was performed.METHODS: Fifteen ASD subjects were involved in this study and received HBO therapy 10 times within a 2-week period. The HBO therapy was performed by letting the subjects got into an isolated chamber filled with 100% oxygen and 1.3 ATA pressure for 60 minutes. Pre- and post-therapy blood samples were taken from subjects. BDNF level was measured with Enzyme Linked Immunosorbent Assay (ELISA), while neutrophils, monocytes, lymphocytes and platelets were measured by hematology analyzer for the calculation of SII and SIRI.RESULTS: Post-therapy BDNF level was higher than pre-therapy (1.84 ng/mL vs. 1.46 ng/mL; p=0.039). The increased in BDNF suggested reduced neuroinflammation and enhanced connections between neurons. Both post-therapy SII (672.4 vs. 359.4; p=0.005) and SIRI (1.3 vs. 0.7; p=0.009) were significantly lower than pre-therapy indexes. Decreased in SII and SIRI signified a reduction in neuroinflammation.CONCLUSION: HBO therapy increases BDNF level, also decreases SII and SIRI in ASD subjects. These results suggest that HBO has an effect on neuroinflammation, specifically in ameliorating inflammation.KEYWORDS: autism spectrum disorder, BDNF, SII, SIRI, hyperbaric oxygen therapy

Nanoelectrode-Mediated Extracellular Electrical Stimulation Directing Dopaminergic Neuronal Differentiation of Stem Cells for Improved Parkinson's Disease Therapy.

Parkinson's disease (PD) is a neurodegenerative disease caused by the dysfunction and death of dopaminergic neurons. Neural-stem-cell (NSC)-based therapy is a promising approach for the treatment of PD but its therapeutic performance is limited by low efficiency of differentiation of NSCs to dopaminergic neurons. Although electrical stimulation can promote neuronal differentiation, it is not verified whether it can induce the NSCs to specifically differentiate into dopaminergic neurons. Meanwhile, it is a great challenge to precisely apply electrical stimulation to dynamically migrating NSCs after transplantation. Here, electrochemically exfoliated graphene nanosheets are designed to anchor to the membrane of NSCs to serve as wireless nanoelectrodes. After anchoring to the cell membrane, these nanoelectrodes are able to migrate together with the cells and precisely apply extracellular electrical stimulation to the receptors or ion transport channels on the membrane of transplanted cells under alternating magnetic field. The nanoelectrode-mediated electrical stimulation induces 38.46% of the NSCs to specifically differentiate into dopaminergic neurons, while the percentage is only 5.82% for NSCs without the nanoelectrode stimulation. Transplantation of NSCs anchored with the nanoelectrodes effectively improves the recovery of the motor and memory ability of PD mice under alternating magnetic field within 2 weeks.

Nucleosomal asymmetry shapes histone mark binding and promotes poising at bivalent domains.

Promoters of developmental genes in embryonic stem cells (ESCs) are marked by histone H3 lysine 4 trimethylation (H3K4me3) and H3K27me3 in an asymmetric nucleosomal conformation, with each sister histone H3 carrying only one of the two marks. These bivalent domains are thought to poise genes for timely activation upon differentiation. Here, we show that asymmetric bivalent nucleosomes recruit repressive H3K27me3 binders but fail to enrich activating H3K4me3 binders, thereby promoting a poised state. Strikingly, the bivalent mark combination further promotes recruitment of specific chromatin proteins that are not recruited by each mark individually, including the lysine acetyltransferase (KAT) complex KAT6B. Knockout of KAT6B blocks neuronal differentiation, demonstrating that KAT6B is critical for proper bivalent gene expression during ESC differentiation. These findings reveal how readout of the bivalent histone marks directly promotes a poised state at developmental genes while highlighting how nucleosomal asymmetry is critical for histone mark readout and function.

The Emerging Role of PCSK9 in the Pathogenesis of Alzheimer's Disease: A Possible Target for the Disease Treatment.

Alzheimer's disease (AD) is a multifactorial neurodegenerative disease mainly caused by β-amyloid (Aβ) accumulation in the brain. Among the several factors that may concur to AD development, elevated cholesterol levels and brain cholesterol dyshomeostasis have been recognized to play a relevant role. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a protein primarily known to regulate plasma low-density lipoproteins (LDLs) rich in cholesterol and to be one of the main causes of familial hypercholesterolemia. In addition to that, PCSK9 is also recognized to carry out diverse important activities in the brain, including control of neuronal differentiation, apoptosis, and, importantly, LDL receptors functionality. Moreover, PCSK9 appeared to be directly involved in some of the principal processes responsible for AD development, such as inflammation, oxidative stress, and Aβ deposition. On these bases, PCSK9 management might represent a promising approach for AD treatment. The purpose of this review is to elucidate the role of PCSK9, whether or not cholesterol-related, in AD pathogenesis and to give an updated overview of the most innovative therapeutic strategies developed so far to counteract the pleiotropic activities of both humoral and brain PCSK9, focusing in particular on their potentiality for AD management.

Impact of photobiomodulation on neural embryoid body formation from immortalized adipose-derived stem cells

BackgroundEmbryoid bodies (EBs) are three-dimensional (3D) multicellular cell aggregates that are derived from stem cell and play a pivotal role in regenerative medicine. They recapitulate many crucial aspects of the early stages of embryonic development and is the first step in the generation of various types of stem cells, including neuronal stem cells. Current methodologies for differentiating stem cells into neural embryoid bodies (NEBs) in vitro have advanced significantly, but they still have limitations which necessitate improvement. Photobiomodulation (PBM) a low powered light therapy is a non-invasive technique shown to promote stem cell proliferation and differentiation.MethodsThis in vitro study elucidated the effects of photobiomodulation (PBM) on the differentiation of immortalized adipose-derived stem cells (iADSCs) into NEBs within a 3D cell culture environment. The study utilized PBM at wavelengths of 825 nm, 525 nm, and a combination of both, with fluences of 5 and 10 J/cm2. Morphology, viability, metabolic activity, and differentiation following PBM treatment was analysed.ResultsThe results revealed that the effects of photobiomodulation (PBM) are dose dependent. PBM, at 825 nm with a fluence of 10 J/cm2, significantly enhanced the size of neural embryoid bodies (NEBs), improved cell viability and proliferation, and reduced lactate dehydrogenase (LDH) levels, indicating minimal cell damage. Interestingly, the stem cell marker CD 44 was upregulated at 5 J/cm2 in all treatment groups at 24 and 96 hpi, CD105 increased with 825 nm at 10 J/cm2 at 24 hpi, which may be attributed to a heterogeneous cell population within the NEBs. Pax6 expression showed transient activation. Nestin was upregulated at 825 nm with 10 J/cm2 at 96 hpi, suggesting a promotion of neural precursor populations. GFAP an intermediate filament protein was upregulated at 825 nm at 10 J/cm2 at both 24 and 96 hpi. SOX2, a pluripotency marker, was expressed at 5 J/cm2 across all wavelengths. Neu N a neuronal nuclei marker was expressed at 5 J/cm2 in all treatments at 24 hpi and over time the expression was observed in all treatment groups at 10 J/cm2.ConclusionIn conclusion, the application of PBM at 825 nm with a fluence of 10 J/cm2 during the differentiation of iADSCs into NEBs resulted in optimal differentiation. Notably, the neuronal marker Nestin was significantly upregulated, highlighting the potential of the PBM approach for enhancing neuronal differentiation its promising applications in regenerative medicine.Graphical

Structural and functional alterations of neurons derived from sporadic Alzheimer’s disease hiPSCs are associated with downregulation of the LIMK1-cofilin axis

BackgroundAlzheimer's Disease (AD) is a neurodegenerative disorder characterized by the accumulation of pathological proteins and synaptic dysfunction. This study aims to investigate the molecular and functional differences between human induced pluripotent stem cells (hiPSCs) derived from patients with sporadic AD (sAD) and age-matched controls (healthy subjects, HS), focusing on their neuronal differentiation and synaptic properties in order to better understand the cellular and molecular mechanisms underlying AD pathology.MethodsSkin fibroblasts from sAD patients (n = 5) and HS subjects (n = 5) were reprogrammed into hiPSCs using non-integrating Sendai virus vectors. Through karyotyping, we assessed pluripotency markers (OCT4, SOX2, TRA-1–60) and genomic integrity. Neuronal differentiation was evaluated by immunostaining for MAP2 and NEUN. Electrophysiological properties were measured using whole-cell patch-clamp, while protein expression of Aβ, phosphorylated tau, Synapsin-1, Synaptophysin, PSD95, and GluA1 was quantified by western blot. We then focused on PAK1-LIMK1-Cofilin signaling, which plays a key role in regulating synaptic structure and function, both of which are disrupted in neurodegenerative diseases such as AD.ResultssAD and HS hiPSCs displayed similar stemness features and genomic stability. However, they differed in neuronal differentiation and function. sAD-derived neurons (sAD-hNs) displayed increased levels of AD-related proteins, including Aβ and phosphorylated tau. Electrophysiological analyses revealed that while both sAD- and HS-hNs generated action potentials, sAD-hNs exhibited decreased spontaneous synaptic activity. Significant reductions in the expression of synaptic proteins such as Synapsin-1, Synaptophysin, PSD95, and GluA1 were found in sAD-hNs, which are also characterized by reduced neurite length, indicating impaired differentiation. Notably, sAD-hNs demonstrated a marked reduction in LIMK1 phosphorylation, which could be the underlying cause for the changes in cytoskeletal dynamics that we found, leading to the morphological and functional modifications observed in sAD-hNs. To further investigate the involvement of the LIMK1 pathway in the morphological and functional changes observed in sAD neurons, we conducted perturbation experiments using the specific LIMK1 inhibitor, BMS-5. Neurons obtained from healthy subjects treated with the inhibitor showed similar morphological changes to those observed in sAD neurons, confirming that LIMK1 activity is crucial for maintaining normal neuronal structure. Furthermore, administration of the inhibitor to sAD neurons did not exacerbate the morphological alterations, suggesting that LIMK1 activity is already compromised in these cells.ConclusionOur findings demonstrate that although sAD- and HS-hiPSCs are similar in their stemness and genomic stability, sAD-hNs exhibit distinct functional and structural anomalies mirroring AD pathology. These anomalies include synaptic dysfunction, altered cytoskeletal organization, and accumulation of AD-related proteins. Our study underscores the usefulness of hiPSCs in modeling AD and provides insights into the disease's molecular underpinnings, thus highlighting potential therapeutic targets.

The neurodevelopmental regulatory role and clinical value of hsa-circ-CORO1C–hsa-miR-708-3p–JARID2 + LNPEP axis in early-onset schizophrenia

Genes discovered by previous epigenetic studies of schizophrenia have focused solely on diagnostics or pathology, potentially leading to a disconnection between them. Using these molecules to identify the disease is considered insufficient. MicroRNAs (miRNAs) binding to messenger RNAs (mRNAs) can lead to mRNA degradation, while circular RNAs (circRNAs), by binding to miRNAs as sponge, can reduce the inhibitory effect of miRNAs on mRNAs. CircRNAs, miRNAs, and mRNAs form the multi-molecular axis that can bind and regulate expression between each other, thereby affecting biological function. This study focused on early-onset schizophrenia (EOS), aiming to identify the multi-molecular axis consisting of circRNAs, miRNAs, and mRNAs with both neurobiological function and diagnostic value to assist in disease identification. In the discovery cohort of 10 drug-naïve, first-episode patients with EOS and 10 matched healthy controls (HCs), differentially expressed (DE) circRNAs and miRNAs were identified via Illumina high-throughput sequencing. In the validation cohort-1 (40 EOS v.s. 50 HCs), the candidate circRNAs and miRNAs were further screened using Real-time polymerase chain reaction, Sanger sequencing, and RNase R assay. Combining dual-luciferase reporter assay with overexpression/knockdown experiments, the axis consisting of circRNAs–miRNAs-mRNAs with binding and regulatory relationships has been established. Subsequently, the functions of genes on the axis were explored through zebrafish embryo manipulation and neural differentiation. The clinical value of the entire axis was assessed in the validation cohort-2 (84 EOS v.s. 67 HCs). Patients with EOS exhibited expression profiles of 487 DE circRNAs and 101 DE miRNAs compared to HCs. The binding relationships and regulatory effects of hsa-circ-CORO1C on hsa-miR-708-3p, hsa-miR-708-3p on target JARID2 and LNPEP were elucidated. Among them, hsa-miR-708-3p caused aberrant phenotypes including significant craniocerebral malformation and impaired neuron axon growth. JARID2 and LNPEP could facilitate neuronal differentiation and augment synaptic formation. In addition to their neurobiological functions, the combined diagnostic efficacy of the whole axis, where hsa-circ-CORO1C could serve as a sponge for hsa-miR-708-3p to alleviate its suppressive effects on JARID2 and LNPEP, surpassed any individual gene we found in EOS. Our study demonstrated a multi-molecular axis, hsa-circ-CORO1C–hsa-miR-708-3p–JARID2 + LNPEP, in EOS for the first time. By integrating evidence from genetic, neurophenotypic, and clinical perspectives, we have expanded the comprehension of the pathological mechanism and provided the reference for identifying reliable objective diagnostic biomarkers for EOS.

Co-culturing neural and bone mesenchymal stem cells in photosensitive hydrogel enhances spinal cord injury repair.

In mammalian species, neural tissues cannot regenerate following severe spinal cord injury (SCI), for which stem cell transplantation is a promising treatment. Neural stem cells (NSCs) have the potential to repair SCI; however, in unfavourable microenvironments, transplanted NSCs mainly differentiate into astrocytes rather than neurons. In contrast, bone mesenchymal stem cells (BMSCs) promote the differentiation of NSCs into neurons and regulate inflammatory responses. Owing to their easily controllable mechanical properties and similarities to neural tissue, gelatin methacrylate (GelMA) hydrogels offer remarkable cell biocompatibility and regulate the differentiation of NSCs. Therefore, in this study, we propose co-culturing NSCs and BMSCs within low-modulus GelMA hydrogel scaffolds to promote regeneration following SCI. In vitro comparisons revealed that the viability, proliferation, migration, and neuron differentiation capacity of cells in these low-modulus scaffolds exhibit substantially superior performance compared to those in high-modulus hydrogel scaffolds. To the best of our knowledge, this study is the first to report that NSCs/BMSCs co-culture implants can remarkably enhance motor function recovery in SCI rats, reduce the area of spinal cord cavities, stimulate neuron regeneration, and suppress scar tissue formation. Thus, this hydrogel system loaded with co-cultured cells represents a promising therapeutic approach for SCI repair.

(Re)building the nervous system: A review of neuron-glia interactions from development to disease.

Neuron-glia interactions are fundamental to the development and function of the nervous system. During development, glia, including astrocytes, microglia, and oligodendrocytes, influence neuronal differentiation and migration, synapse formation and refinement, and myelination. In the mature brain, glia are crucial for maintaining neural homeostasis, modulating synaptic activity, and supporting metabolic functions. Neurons, inherently vulnerable to various stressors, rely on glia for protection and repair. However, glia, in their reactive state, can also promote neuronal damage, which contributes to neurodegenerative and neuropsychiatric diseases. Understanding the dual role of glia-as both protectors and potential aggressors-sheds light on their complex contributions to disease etiology and pathology. By appropriately modulating glial activity, it may be possible to mitigate neurodegeneration and restore neuronal function. In this review, which originated from the International Society for Neurochemistry (ISN) Advanced School in 2019 held in Montreal, Canada, we first describe the critical importance of glia in the development and maintenance of a healthy nervous system as well as their contributions to neuronal damage and neurological disorders. We then discuss potential strategies to modulate glial activity during disease to protect and promote a properly functioning nervous system. We propose that targeting glial cells presents a promising therapeutic avenue for rebuilding the nervous system.

Function of Brain-Derived Neurotrophic Factor in the Vestibular-Cochlear System.

Brain-derived neurotrophic factor (BDNF) is essential for the development and functioning of the vestibular system. BDNF promotes the growth, differentiation, and synaptic plasticity of vestibular neurons, ensuring their normal operation and maintenance. According to research, BDNF is pivotal during vestibular compensation, aiding in the recovery of neuron function by remodeling the spontaneous resting potentials of damaged vestibular neurons. Additionally, BDNF exhibits dose-dependent and age-dependent characteristics during vestibular system development, with its deficiencies leading to the degeneration of vestibular neurons. BDNF dynamically interacts with other neurotrophic factors, such as fibroblast growth factor-2 (FGF-2) and glial cell line-derived neurotrophic factor (GDNF), synergistically enhancing neuron survival and functionality. This review outline the function of BDNF in the vestibulocochlear system and explores its potential therapeutic applications, offering fresh perspectives and guidance for future research and treatment of vestibulocochlear system disorders.