A Focal Traumatic Injury to the Neonatal Rodent Spinal Cord Causes an Immediate and Massive Spreading Depolarization Sustained by Chloride Ions, with Transient Network Dysfunction
In clinics, physical injuries to the spinal cord cause a temporary motor areflexia below lesion, known as spinal shock. This topic is still underexplored due to the lack of preclinical spinal cord injury (SCI) models that do not use anesthesia, which would affect spinal excitability. Our innovative design considered a custom-made micro impactor that provides localized and calibrated strikes to the ventral surface of the thoracic spinal cord of the entire CNS isolated from neonatal rats. Before and after injury, multiple ventral root (VR) recordings continuously traced respiratory rhythm, baseline spontaneous activities, and electrically induced reflex responses. As early as 200 ms after the lowering of the impactor, an immediate transient depolarization spread from the injury site to the whole spinal cord with distinct segmental velocities. Stronger strikes induced higher potentials causing, close by the site of injury, a transient drop in spinal cord oxygenation (SCO) and a massive cell death with a complete functional disconnection of input along the cord. Below the impact site, expiratory rhythm and spontaneous lumbar activity were suppressed. On lumbar VRs, reflex responses transiently halted but later recovered to control values, while electrically induced fictive locomotion remained perturbed. Moreover, low-ion modified Krebs solutions differently influenced impact-induced depolarizations, the magnitude of which amplified in low Cl. Overall, our novel ex vivo platform traces the immediate functional consequences of impacts to the spinal cord during development. This basic study provides insights on the SCI pathophysiology, unveiling an immediate chloride dysregulation.
Correction: Docosahexaenoic Acid Alleviates Oxidative Stress-Based Apoptosis Via Improving Mitochondrial Dynamics in Early Brain Injury After Subarachnoid Hemorrhage
Correction: Sevoflurane Induces Learning and Memory Impairment in Young Mice Through a Reduction in Neuronal Glucose Transporter 3
Correction: Expression of CGRP in the Trigeminal Ganglion and Its Effect on the Polarization of Macrophages in Rats with Temporomandibular Arthritis
Aging and MPTP Sensitivity Depend on Molecular and Ultrastructural Signatures of Astroglia and Microglia in Mice Substantia Nigra
Both astroglia and microglia show region-specific distribution in CNS and often maladapt to age-associated alterations within their niche. Studies on autopsied substantia nigra (SN) of Parkinson's disease (PD) patients and experimental models propose gliosis as a trigger for neuronal loss. Epidemiological studies propose an ethnic bias in PD prevalence, since Caucasians are more susceptible than non-whites. Similarly, different mice strains are variably sensitive to MPTP. We had earlier likened divergent MPTP sensitivity of C57BL/6 J and CD-1 mice with differential susceptibility to PD, based on the numbers of SN neurons. We examined whether the variability was incumbent to inter-strain differences in glial features of male C57BL/6 J and CD-1 mice. Stereological counts showed relatively more microglia and fewer astrocytes in the SN of normal C57BL/6 J mice, suggesting persistence of an immune-vigilant state. MPTP-induced microgliosis and astrogliosis in both strains suggest their involvement in pathogenesis. ELISA of pro-inflammatory cytokines in the ventral-midbrain revealed augmentation of TNF-α and IL-6 at middle age in both strains that reduced at old age, suggesting middle age as a critical, inflamm-aging-associated time point. TNF-α levels were high in C57BL/6 J, through aging and post-MPTP, while IL-6 and IL-1β were upregulated at old age. CD-1 had higher levels of anti-inflammatory cytokine TGF-β. MPTP challenge caused upregulation of enzymes MAO-A, MAO-B, and iNOS in both strains. Post-MPTP enhancement in fractalkine and hemeoxygenase-1 may be neuron-associated compensatory signals. Ultrastructural observations of elongated astroglial/microglial mitochondria vis-à-vis the shrunken ones in neurons suggest a scale-up of their functions with neurotoxic consequences. Thus, astroglia and microglia may modulate aging and PD susceptibility.
AMPA Receptors in Synaptic Plasticity, Memory Function, and Brain Diseases
Tetrameric AMPA-type ionotropic glutamate receptors are primary transducers of fast excitatory synaptic transmission in the central nervous system, and their properties and abundance at the synaptic surface are crucial determinants of synaptic efficacy in neuronal communication across the brain. The induction of long-term potentiation (LTP) leads to the insertion of GluA1-containing AMPA receptors at the synaptic surface, whereas during long-term depression (LTD), these receptors are internalized into the cytoplasm of the spine. Disruptions in the trafficking of AMPA receptors to and from the synaptic surface attenuate both forms of synaptic plasticity. Homeostatic scaling up and scaling down, which are additional types of plasticity similar to LTP and LTD, are also regulated by the insertion and removal of GluA1-containing AMPA receptors from the synaptic surface. The trafficking of AMPA receptors is an intricate process assisted by various proteins. Furthermore, AMPA receptors are critical for the formation and consolidation of various types of memory, and alterations in their function are intimately associated with cognitive dysfunction in aging and several neurological and psychiatric diseases. In this review, we will provide an overview of the current understanding of how AMPA receptors regulate various forms of synaptic plasticity, their contribution to memory functions, and their role in aging and brain diseases.
Genetically Predicted Leucine Level Mediates Association Between CD4/CD8br T Lymphocytes and Insomnia
Immune and metabolic factors play an important role in the onset and development of insomnia. This study aimed to investigate the causal relationship between insomnia and immune cells and metabolites. Data for 731 immune cell phenotypes, 1400 metabolites, and insomnia in this study were obtained from the GWAS open-access database. Two-way Mendelian randomization was used to (1) detect the causal relationship between immune cells and insomnia and (2) identify potential mediating metabolites. Mendelian randomization analysis identified eight immune cell phenotypes with a causal relationship to insomnia, and two immune cell phenotypes were protective factors for insomnia, namely CD8br %T cells and CD80 on CD62L + myeloid dendritic cells. The other six immune cell phenotypes were risk factors for insomnia, i.e., CD4/CD8br, CD16-CD56 on NKT, CCR2 on myeloid dendritic cells, CD40 on monocytes, CD38 on CD3-CD19-, and CD25 on CD45RA + CD4 not Treg. Further Mendelian randomization revealed 11 metabolites that were causally related to insomnia. Five metabolites were protective factors for insomnia, i.e., 3-hydroxy-3-methylglutarate, cholate, dodecanedioate, N-formylmethionine, and x-26054. Six metabolites were risk factors for insomnia, 3-amino-2-piperidone, 6-oxopiperdine-2-carboxylate, caffeine to theophylline ratio, leucine, maltose, and x-24736. In addition, our analysis showed that leucine mediated the association between CD4/CD8br and insomnia. From genetic information, we confirmed the causal relationship between insomnia, eight immune cell phenotypes, and eleven metabolite levels. Notably, we found a relationship between leucine-mediated CD4/CD8br and insomnia, providing evidence supporting the causal relationship between immune cell and insomnia, with plasma metabolites serving as mediators.
Correction: Myosin IIA Regulated Tight Junction in Oxygen Glucose-Deprived Brain Endothelial Cells Via Activation of TLR4/PI3K/Akt/JNK1/2/14-3-3ε/NF-κB/MMP9 Signal Transduction Pathway
Exosomal MiRNA Therapy for Central Nervous System Injury Diseases
Central nervous system diseases include central nervous system injury diseases, neurodegenerative diseases, and other conditions. MicroRNAs (miRNAs) are important regulators of gene expression, with therapeutic potential in modulating genes, pathways, and cells associated with central nervous system injury diseases. This article comprehensively reviews the therapeutic role of exosomal miRNAs in various central nervous system injury diseases, including traumatic brain injury, ischemic stroke, intracerebral hemorrhage, optic nerve injury, and spinal cord injury. This review covers the pathophysiology, animal models, miRNA transfection, administration methods, behavioral tests for evaluating treatment efficacy, and the mechanisms of action of miRNA-based therapies. Finally, this article discusses the future directions of miRNA therapy for central nervous system injury diseases.
Single-Cell RNA-Seq Reveals the Pseudo-temporal Dynamic Evolution Characteristics of ADSCs to Neuronal Differentiation
Adipose-derived stromal cells (ADSCs) are commonly used in regenerative medicine, but the genetic features of their development into neuronal cells are unknown. This study used single-cell RNA sequencing (scRNA-seq) to reveal gene expression changes during ADSCs to neuronal differentiation. Sequencing of the ADSCs group, the prei-1d group, and the induction 1 h, 3 h, 5 h, 6 h, and 8 h groups was performed using the BD Rhapsody platform. Sequence data were analyzed using t-SNE, Monocle2, GO, and KEGG algorithms. Results showed that a total of 38,453 cells were collected, which were divided into 0-13 clusters. Monocle2 structured analysis revealed that ADSCs were located at the beginning of the trajectory, and the cells after 5 h of induction were mainly distributed at the end of the trajectory in branches 1 and 2. Up-regulated differentially expressed genes (DEGs) at 5 h after induction enriched GO items including cellular protein metabolism, cell adhesion, endocytosis, and cell migration. KEGG analysis showed that induced 6 h and 8 h groups mainly enriched pathways were oxidative phosphorylation, glutathione metabolism, and expression of Parkinson's disease-related genes. In conclusion, two distinct cell state mechanisms stimulate ADSCs to develop into mature neurons. ADSCs induced for 5 h had developed into mature neurons. Later, the differentiated cells undergo degenerative changes associated with senescence.
Exploring the Neuroprotective Effects of Rufinamide in a Streptozotocin-Induced Dementia Model
Due to the complex pathophysiology of AD (Alzheimer's Disease), there are currently no effective clinical treatments available, except for acetylcholinesterase inhibitors. However, CREB (cyclic AMP-responsive element binding protein) has been identified as the critical factor for the transcription in memory formation. Understanding the effect of potential drugs on the CREB pathway could lead to the development of new therapeutic molecules. Rufinamide has shown promise in improving memory in animal models, and these effects may be associated with modulation of the CREB pathway, however, this has not been previously reported. Thus, the present study aimed to determine the involvement of the CREB pathway in the cognitive improvement effects of rufinamide in STZ (streptozotocin) induced mouse model of dementia. Administration of STZ [3 mg/kg, i.c.v. (intracerebroventricular) bilaterally] significantly impaired cognitive performance in step-down passive avoidance and Morris water maze tests in animals, reduced brain endogenous antioxidant levels (GSH, superoxide dismutase, and catalase), and increased marker of brain oxidative stress [TBARS (thiobarbituric acid reactive substances)] and inflammation [IL-1β (Interleukin-1 beta), IL-6 (Interleukin-6), TNF-α (Tumor necrosis factor alpha) and NF-κB (Nuclear factor kappa B)], along with neurodegeneration. These effects were markedly reversed by rufinamide (50 and 100 mg/kg) when administered to STZ animals. However, the pre-treatment with the CREB inhibitor (666-15) in STZ and rufinamide-administered animals neutralized the beneficial influence of rufinamide. Our data suggest that rufinamide, acting via CREB signaling, reduced oxidative stress and inflammatory markers while elevating anti-oxidant levels. Our study has established that rufinamide may act through CREB signaling in an investigational AD model, which could be crucial for developing new treatments beneficial in progressive neurological disorders.
Application of Circulating Tumor DNA in the Auxiliary Diagnosis and Prognosis Prediction of Glioma
Glioma is the most common primary malignant brain tumor. Despite significant advances in the past decade in understanding the molecular pathogenesis of this tumor and exploring therapeutic strategies, the prognosis of patients with glioma remains poor. Accurate diagnosis of glioma is very important for the treatment and prognosis. Although the gold-standard method for the diagnosis and prognosis prediction of patients with glioma is tissue biopsy, it still has many limitations. Liquid biopsy can provide information on the auxiliary diagnosis and prognosis of gliomas. In this review, we summarized the application of cell-free DNA (cfDNA) and circulating tumor DNA (ctDNA) in the auxiliary diagnosis and prognosis of glioma. The common methods used to detect ctDNA in gliomas using samples including blood and cerebrospinal fluid (CSF) and the detection techniques for ctDNA, including droplet digital PCR (ddPCR) and next-generation sequencing (NGS), were discussed. Detection of ctDNA from plasma of patients with brain tumors remains challenging because of the blood-brain barrier (BBB). CSF has been proposed as a medium for ctDNA analysis in brain tumors, and mutation detection using plasma ctDNA was less sensitive than CSF ctDNA sequencing. Moreover, ongoing relevant clinical studies were summarized. Finally, we discussed the challenges, and future directions for the studies on ctDNA in glioma.
Molecular Signaling Pathways of Quercetin in Alzheimer's Disease: A Promising Arena
Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognitive impairment and memory deficit. Even with extensive research and studies, presently, there is no effective treatment for the management of AD. Besides, most of drugs used in the treatment of AD did not avert the AD neuropathology, and the disease still in a progressive status. For example, acetyl cholinesterase inhibitors are associated with many adverse effects, such as insomnia and nightmares. As well, acetylcholinesterase inhibitors augment cholinergic neurotransmission leading to the development of adverse effects related to high acetylcholine level, such as salivation, rhinorrhea, vomiting, loss of appetite, and seizure. Furthermore, tacrine has poor bioavailability and causes hepatotoxicity. These commonly used drugs do not manage the original causes of AD. For those reasons, natural products were repurposed for the treatment of AD and neurodegenerative diseases. It has been shown that phytochemicals produce neuroprotective effects against the development and progression of neurodegenerative diseases by different mechanisms, including antioxidant and anti-inflammatory effects. Quercetin (QCN) has been reported to exert an effective neuroprotective effect against AD and other neurodegenerative diseases by lessening oxidative stress. In this review, electronic databases such as PubMed, Scopus, and Web of Science were searched for possible relevant studies and article linking the effect of QCN on AD. Findings from this review highlighted that many studies highlighted different mechanistic signaling pathways regarding the neuroprotective effect of QCN in AD. Nevertheless, the precise molecular mechanism of QCN in AD was not completely clarified. Consequently, this review aims to discuss the molecular mechanism of QCN in AD.
The Role of Extracellular Vesicles and Microparticles in Central Nervous System Disorders: Mechanisms, Biomarkers, and Therapeutic Potential
Microscopic, membranous vesicles known as extracellular vesicles (EVs) have been proposed to play a role in the mechanisms underlying central nervous system (CNS) diseases. EVs are secreted by a variety of cells, including myeloid, endothelial, microglial, oligodendroglial, and mesenchymal stem cells (MSCs). Body fluids such as plasma, urine, and cerebrospinal fluid (CSF) contain microparticles (MPs). The detection of MPs in CSF may indicate genetic or environmental susceptibility to conditions such as schizophrenia, schizoaffective disorder, and bipolar disorder. MPs of different origins can exhibit changes in specific biomarkers at various stages of the disease, aiding in the diagnosis and monitoring of neurological conditions. However, understanding the role and clinical applications of MPs is complicated by challenges such as their isolation and dual roles within the CNS. In this review, we discuss the history, characteristics, and roles of MPs in CNS diseases. We also provide practical insights for future research and highlight the challenges that obscure the therapeutic potential of MPs.
TMEM16A Activation Inhibits Autophagy in Dorsal Root Ganglion Cells, Which is Associated with the p38 MAPK/mTOR Pathway
Transmembrane member 16A (TMEM16A) exhibits a negative correlation with autophagy, though the underlying mechanism remains elusive. This study investigates the mechanism between TMEM16A and autophagy by inducing autophagy in DRG neuronal cells using Rapamycin. Results indicated that TMEM16A interference augmented cell viability and reduced Rapamycin-induced apoptosis. Autophagosome formation increased with TMEM16A interference but decreased upon overexpression. A similar increase in autophagosomes was observed with SB203580 treatment. Furthermore, TMEM16A interference suppressed Rapamycin-induced gene and protein expression of p38 MAPK and mTOR, whereas overexpression had the opposite effect. These findings suggest that TMEM16A activation inhibits autophagy in DRG cells, which is associated with the p38 MAPK/mTOR pathway, offering a potential target for mitigating neuropathic pain (NP).
Identification of miRNA-TF Regulatory Pathways Related to Diseases from a Neuroendocrine-Immune Perspective
The neuroendocrine-immune (NEI) network is fundamental for maintaining body's homeostasis and health. While the roles of microRNAs (miRNAs) and transcription factors (TFs) in disease processes are well-established, their synergistic regulation within the NEI network has yet to be elucidated. In this study, we constructed a background NEI-related miRNA-TF regulatory network (NEI-miRTF-N) by integrating NEI signaling molecules (including miRNAs, genes, and TFs) and identifying miRNA-TF feed-forward loops. Our analysis reveals that the number of immune signaling molecules is the highest and suggests potential directions for signal transduction, primarily from the nervous system to both the endocrine and immune systems, as well as from the endocrine system to the immune system. Furthermore, disease-specific NEI-miRTF-Ns for depression, Alzheimer's disease (AD) and dilated cardiomyopathy (DCM) were constructed based on the known disease molecules and significantly differentially expressed (SDE) molecules. Additionally, we proposed a novel method using depth-first-search algorithm for identifying significantly dysregulated NEI-related miRNA-TF regulatory pathways (NEI-miRTF-Ps) and verified their reliability from multiple perspectives. Our study provides an effective approach for identifying disease-specific NEI-miRTF-Ps and offers new insights into the synergistic regulation of miRNAs and TFs within the NEI network. Our findings provide information for new therapeutic strategies targeting these regulatory pathways.
Differences in Blood and Cerebrospinal Fluid Between Parkinson's Disease and Related Diseases
It is difficult to distinguish Parkinson's disease (PD) in the early stage from those of various disorders including atypical Parkinson's syndrome (APS), vascular parkinsonism (VP), and even essential tremor (ET), because of the overlap of symptoms. Other, more challenging problems will arise when Parkinson's disease develops into Parkinson's disease dementia (PDD) in the middle and late stages. At this time, the differential diagnosis of PDD and DLB becomes thorny. These complicate the diagnostic process for PD, which traditionally heavily relies on symptomatic assessment and treatment response. Recent advances have identified several biomarkers in the blood and cerebrospinal fluid (CSF), including α-synuclein, lysosomal enzymes, fatty acid-binding proteins, and neurofilament light chain, whose concentration differs in PD and the related diseases. However, not all these molecules can effectively discriminate PD from related disorders. This review advocates for a paradigm shift toward biomarker-based diagnosis to effectively distinguish between PD and similar conditions. These biomarkers may reflect the diversity that exist among different diseases and provide an effective way to accurately understand their mechanisms. This review focused on blood and CSF biomarkers of PD that may have differential diagnostic value and the related molecular measurement methods with high diagnostic performance due to emerging technologies.
Glucocorticoid-Dependent Retinal Degeneration and Vision Impairment in Mice Susceptible to Prenatal Stress-Induced Behavioral Abnormalities
Chronic exposure to prenatal stress can impair neurogenesis and lead to irreversible cognitive and neuropsychiatric abnormalities in offspring. The retina is part of the nervous system; however, the impacts of prenatal stress on retinal neurogenesis and visual function remain unclear. This study examined how elevated prenatal glucocorticoid levels differentially affect retinal development in the offspring of pregnant mice exposed to chronic unpredictable mild stress (CUMS). Offspring were classified into control, stress-resilient, and stress-susceptible groups based on behavioral tests assessing spatial memory and depression-like behaviors. The stress-susceptible group exhibited significantly altered synaptogenesis, reduced ganglion cell development, decreased retinal thickness, and visiual impairment. These mice also showed a pervasive transformation of retinal astrocytes into a proinflammatory A1-like reactive state, evidenced by increased GFAP and decreased STAT3 expression levels. This astrocyte phenotype shift coincided with disruptions in neurogenesis and synaptic formation. Furthermore, prenatal exposure to exogenous corticosterone confirmed that the effects of prenatal stress are mediated by glucocorticoid-induced retinal neurodegeneration. Our findings suggest that elevated prenatal glucocorticoid levels trigger a series of neurodevelopmental disturbances leading to retinal neurodegeneration and vision impairment. This research highlights the impact of prenatal stress on retinal development and visual health, suggesting new avenues for understanding and potentially mitigating the negative effects of early-life stress on neurodevelopment.
Neuropathic Pain Induced by Spinal Cord Injury from the Glia Perspective and Its Treatment
Regional neuropathic pain syndromes above, at, or below the site of spinal damage arise after spinal cord injury (SCI) and are believed to entail distinct pathways; nevertheless, they may share shared defective glial systems. Neuropathic pain after SCI is caused by glial cells, ectopic firing of neurons endings and their intra- and extracellular signaling mechanisms. One such mechanism occurs when stimuli that were previously non-noxious become so after the injury. This will exhibit a symptom of allodynia. Another mechanism is the release of substances by glia, which keeps the sensitivity of dorsal horn neurons even in regions distant from the site of injury. Here, we review, the models and identifications of SCI-induced neuropathic pain (SCI-NP), the mechanisms of SCI-NP related to glia, and the treatments of SCI-NP.
The Role of Inflammatory Cascade and Reactive Astrogliosis in Glial Scar Formation Post-spinal Cord Injury
Reactive astrogliosis and inflammation are pathologic hallmarks of spinal cord injury. After injury, dysfunction of glial cells (astrocytes) results in glial scar formation, which limits neuronal regeneration. The blood-spinal cord barrier maintains the structural and functional integrity of the spinal cord and does not allow blood vessel components to leak into the spinal cord microenvironment. After the injury, disruption in the spinal cord barrier causes an imbalance of the immunological microenvironment. This triggers the process of neuroinflammation, facilitated by the actions of microglia, neutrophils, glial cells, and cytokines production. Recent work has revealed two phenotypes of astrocytes, A1 and A2, where A2 has a protective type, and A1 releases neurotoxins, further promoting glial scar formation. Here, we first describe the current understanding of the spinal cord microenvironment, both pre-, and post-injury, and the role of different glial cells in the context of spinal cord injury, which forms the essential update on the cellular and molecular events following injury. We aim to explore in-depth signaling pathways and molecular mediators that trigger astrocyte activation and glial scar formation. This review will discuss the activated signaling pathways in astrocytes and other glial cells and their collaborative role in the development of gliosis through inflammatory responses.
Molecular and Cellular Foundations of Aging of the Brain: Anti-aging Strategies in Alzheimer's Disease
Alzheimer's disease (AD) is a condition characterized by the gradual degeneration of the nervous system that poses significant challenges to cognitive function and overall mental health. Given the increasing global life expectancy, there is an urgent need for effective strategies to prevent and manage Alzheimer's disease, with a particular focus on anti-aging interventions. Recent scientific advancements have unveiled several promising strategies for combating Alzheimer's disease (AD), ranging from lifestyle interventions to cutting-edge pharmacological treatments and therapies targeting the underlying biological processes of aging and AD. Regular physical exercise, cognitive engagement, a balanced diet, and social interaction serve as key pillars in maintaining brain health. At the same time, therapies target key pathological mechanisms of AD, such as amyloid-beta accumulation, tau abnormalities, neuroinflammation, mitochondrial dysfunction, and synaptic loss, offering potential breakthroughs in treatment. Moreover, cutting-edge innovations such as gene therapy, stem cell transplantation, and novel drug delivery systems are emerging as potential game-changers in the fight against AD. This review critically evaluates the latest research on anti-aging interventions and their potential in preventing and treating Alzheimer's disease (AD) by exploring the connections between aging mechanisms and AD pathogenesis. It provides a comprehensive analysis of both well-established and emerging strategies, while also identifying key gaps in current knowledge to guide future research efforts.