Search Results (1,393)

Microglia-mediated chronic neuroinflammation is a common pathological feature of Parkinson’s disease (PD). Strong evidence suggests that activated microglia can lesion neurons by releasing exosomes. However, the mechanisms of exosome release from activated microglia remain unclear. We recently revealed a key role of complement receptor 3 (CR3) in regulating microglial activation in the process of progressive neurodegeneration. This study aimed to investigate whether CR3 can regulate exosome release from activated microglia, as well as the underlying mechanisms. We found that LPS, an inducer of microglial M1 activation, induced exosome release from activated microglia. Inhibition of exosome synthesis suppressed LPS-induced microglial activation, gene expression of proinflammatory factors, and related neurotoxicity. Silencing or knocking out CR3 attenuated LPS-induced exosome release in microglia. NADPH oxidase (NOX2) was further identified as a downstream signal of CR3, mediating microglial exosome release and related neurotoxicity. CR3 silencing blocked LPS-induced NOX2 activation and superoxide production through inhibition of p47^phox phosphorylation and membrane translocation. Moreover, NOX2 activation elicited by PMA or supplementation of H₂O₂ recovered exosome release from CR3-silenced microglia. Subsequently, we demonstrated that the CR3-NOX2 axis regulates syntenin-1 to control microglial exosome release. Finally, we observed that the expression of CR3 was increased in the brain of LPS-treated mice, and genetic ablation of CR3 significantly reduced LPS-induced NOX2 activation, microglial M1 polarization, and exosome production in mice. Overall, our findings revealed a critical role of the CR3-NOX2 axis in controlling microglial exosome release and related neurotoxicity through syntenin-1, providing a novel target for the development of a therapeutic strategy for neuroinflammation-mediated neurodegeneration. Full article

One major challenge in cellular neuroscience is to elucidate how the accurate alignment of presynaptic release sites with postsynaptic densely clustered ligand-gated ion channels at chemical synapses is achieved upon synapse assembly. The clustering of neurotransmitter receptors at postsynaptic sites is a key moment of synaptogenesis and determinant for effective synaptic transmission. The number of the ionotropic neurotransmitter receptors at these postsynaptic sites of both excitatory and inhibitory synapses is variable and is regulated by different mechanisms, thus allowing the modulation of synaptic strength, which is essential to tune neuronal network activity. Several well-regulated processes seem to be involved, including lateral diffusion within the plasma membrane and local anchoring as well as receptor endocytosis and recycling. The molecular mechanisms implicated are numerous and were reviewed recently in great detail. The role of pre-synaptically released neurotransmitters within the complex regulatory apparatus organizing the postsynaptic site underneath presynaptic terminals is not completely understood, even less for inhibitory synapses. In this mini review article, we focus on this aspect of synapse formation, summarizing and contrasting findings on the functional role of the neurotransmitters glycine and γ-aminobutyric acid (GABA) for initiation of postsynaptic receptor clustering and regulation of Cl⁻ channel receptor numbers at inhibitory synapses gathered over the last two decades. Full article

Status epilepticus occurs when a seizure lasts more than five minutes or when multiple seizures occur with incomplete return to baseline. SE induces a myriad of pathological changes involving synaptic and extra-synaptic factors. The transition from a self-limiting seizure to a self-sustaining one is established by maladaptive receptor trafficking, whereby GABA_A receptors are progressively endocytosed while glutamatergic receptors (NMDA and AMPA) are transported to the synaptic membrane, causing excitotoxicity and alteration in glutamate-dependent downstream signaling. The subsequent influx of Ca²⁺ exposes neurons to increased levels of [Ca²⁺]i, which overwhelms mitochondrial buffering, resulting in irreversible mitochondrial membrane depolarization and mitochondrial injury. Oxidative stress resulting from mitochondrial leakage and increased production of reactive oxygen species activates the inflammasome and induces a damage-associated molecular pattern. Neuroinflammation perpetuates oxidative stress and exacerbates mitochondrial injury, thereby jeopardizing mitochondrial energy supply in a state of accelerated ATP consumption. Additionally, Ca²⁺ overload can directly damage neurons by activating enzymes involved in the breakdown of proteins, phospholipids, and nucleic acids. The cumulative effect of these effector pathways is neuronal injury and neuronal death. Surviving neurons undergo long-term alterations that serve as a substrate for epileptogenesis. This review highlights the multifaceted mechanisms underlying SE self-sustainability, pharmacoresistance, and subsequent epileptogenesis. Full article

Two-pore-domain K⁺ channels (K2p), known previously as leak channels, are responsible for maintaining the resting membrane potential of cells. Fifteen subtypes are known to exist in humans and eleven are known in Drosophila melanogaster, as well as six subfamilies; however, little is known about the expression of these subtypes in various animal tissues or the impact of altered expression on cellular physiology. The Drosophila melanogaster model allows for selective misexpression of certain neuron subsets, providing insight into individual cell types and the animal’s physiology more generally. Prior research on the overexpression of K2p channels and the resulting behavioral and neuronal effects is limited. This project expanded upon this prior research by using Drosophila motor neurons to examine the effects of K2p overexpression on behavior and physiology. After conducting various assays, it was concluded that K2p overexpression in motor neurons had the most prominent effects on Drosophila functioning, with sensory, cardiac, and chordotonal neurons also generating differences in behavior. Altered expression levels of K2p channels could result in tissue-specific and/or whole-animal dysfunction. Full article

Synthetic nanopores were recently demonstrated with memristive and nonlinear voltage-current behaviors, akin to ion channels in a cell membrane. Such ionic devices are considered a promising candidate for the development of brain-inspired neuromorphic computing techniques. In this work, we show the composite behavior of nanopore-array large memristors, formed with different membrane materials, pore sizes, electrolytes, and device arrangements. Anodic aluminum oxide (AAO) membranes with 5 nm and 20 nm diameter pores and track-etched polycarbonate (PCTE) membranes with 10 nm diameter pores are tested and shown to demonstrate memristive and nonlinear behaviors with approximately 10⁷–10¹⁰ pores in parallel when electrolyte concentration across the membranes is asymmetric. Ion diffusion through the large number of channels induces time-dependent electrolyte asymmetry that drives the system through different memristive states. The behaviors of series composite memristors with different configurations are also presented. In addition to helping understand fluidic devices and circuits for neuromorphic computing, the results also shed light on the development of field-assisted ion-selection-membrane filtration techniques as well as the investigations of large neurons and giant synapses. Further work is needed to de-embed parasitic components of the measurement setup to obtain intrinsic large memristor properties. 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

Sleep paralysis (SP), an REM parasomnia, can be characterized as one of the symptoms of narcolepsy. The SP phenomenon involves regaining meta-consciousness by the dreamer during REM, when the physiological atonia of skeletal muscles is accompanied by visual and auditory hallucinations that are perceived as vivid and distressing nightmares. Sensory impressions include personification of an unknown presence, strong chest pressure sensation, and intense fear resulting from subjective interaction with the unfolding nightmare. While the mechanism underlying skeletal muscle atonia is known, the physiology of hallucinations remains unclear. Their complex etiology involves interactions among various membrane receptor systems and neurotransmitters, which leads to altered neuronal functionality and disruptions in sensory perception. According to current knowledge, serotonergic activation of 5-hydroxytryptamine-receptor-2A (5-HT2A)-associated pathways plays a critical role in promoting hallucinogenesis during SP. Furthermore, they share similarities with psychedelic-substance-induced ones (i.e., LSD, psilocybin, and 2,5-dimethoxy-4-iodoamphetamine). These compounds also target the 5-HT2A receptor; however, their molecular mechanism varies from serotonin-induced ones. The current review discusses the intracellular signaling pathways responsible for promoting hallucinations in SP, highlighting the critical role of β-arrestin-2. We propose that the β-arrestin-2 signaling pathway does not directly induce hallucinations but creates a state of network susceptibility that facilitates their abrupt emergence in sensory areas. Understanding the molecular basis of serotonergic hallucinations and gaining better insight into 5-HT2A-receptor-dependent pathways may prove crucial in the treatment of multifactorial neuropsychiatric disorders associated with the dysfunctional activity of serotonin receptors. Full article

In familial Alzheimer’s disease (FAD), presenilin 1 (PSEN1) E280A cholinergic-like neurons (ChLNs) induce aberrant secretion of extracellular amyloid beta (eAβ). How PSEN1 E280A ChLNs-eAβ affects microglial activity is still unknown. We obtained induced microglia-like cells (iMG) from human peripheral blood cells (hPBCs) in a 15-day differentiation process to investigate the effect of bolus addition of Aβ42, PSEN1 E280A cholinergic-like neuron (ChLN)-derived culture supernatants, and PSEN1 E280A ChLNs on wild type (WT) iMG, PSEN1 E280A iMG, and sporadic Alzheimer’s disease (SAD) iMG. We found that WT iMG cells, when challenged with non-cellular (e.g., lipopolysaccharide, LPS) or cellular (e.g., Aβ42, PSEN1 E280A ChLN-derived culture supernatants) microenvironments, closely resemble primary human microglia in terms of morphology (resembling an “amoeboid-like phenotype”), expression of surface markers (Ionized calcium-binding adapter molecule 1, IBA-1; transmembrane protein 119, TMEM119), phagocytic ability (high pHrodo™ Red E. coli BioParticles™ phagocytic activity), immune metabolism (i.e., high generation of reactive oxygen species, ROS), increase in mitochondrial membrane potential (ΔΨm), response to ATP-induced transient intracellular Ca²⁺ influx, cell polarization (cluster of differentiation 68 (CD68)/CD206 ratio: M1 phenotype), cell migration activity according to the scratch wound assay, and especially in their inflammatory response (secretion of cytokine interleukin-6, IL-6; Tumor necrosis factor alpha, TNF-α). We also found that PSEN1 E280A and SAD iMG are physiologically unresponsive to ATP-induced Ca²⁺ influx, have reduced phagocytic activity, and diminished expression of Triggering Receptor Expressed on Myeloid Cells 2 (TREM2) protein, but when co-cultured with PSEN1 E280A ChLNs, iMG shows an increase in pro-inflammatory phenotype (M1) and secretes high levels of cytokines IL-6 and TNF-α. As a result, PSEN1 E280A and SAD iMG induce apoptosis in PSEN1 E280A ChLNs as evidenced by abnormal phosphorylation of protein TAU at residue T205 and cleaved caspase 3 (CC3). Taken together, these results suggest that PSEN1 E280A ChLNs initiate a vicious cycle between damaged neurons and M1 phenotype microglia, resulting in excessive ChLN death. Our findings provide a suitable platform for the exploration of novel therapeutic approaches for the fight against FAD. Full article

Background/Objectives: Niemann-Pick disease Type C (NPC) represents an autosomal recessive disorder with an incidence rate of 1 in 100,000 live births that belongs to the lysosomal storage diseases (LSDs). NPC is characterized by the abnormal accumulation of unesterified cholesterol, in addition to being an autosomal recessive inherited pathology, which belongs to LSDs. It occurs in 95% of cases due to mutations in the NPC1 gene, while 5% of cases are due to mutations in the NPC2 gene. In the cerebral cortex (CC), the disease shows lipid inclusions, increased cholesterol and multiple sphingolipids in neuronal membranes, and protein aggregates such as hyperphosphorylated tau, α-Synuclein, TDP-43, and β-amyloid peptide. Mitochondrial damage and oxidative stress are some alterations at the cellular level in NPC. Therefore, the aim of this work was to determine the gene expression profile in the CC of NPC1 mice in order to identify altered molecular pathways that may be related to the pathophysiology of the disease. Methods: In this study, we performed a microarray analysis of a 22,000-gene chip from the cerebral cortex of an NPC mutant mouse compared to a WT mouse. Subsequently, we performed a bioinformatic analysis in which we found groups of dysregulated genes, and their expression was corroborated by qPCR. Finally, we performed Western blotting to determine the expression of proteins probably dysregulated. Results: We found groups of dysregulated genes in the cerebral cortex of the NPC mouse involved in the ubiquitination, fatty acid metabolism, differentiation and development, and underexpression in genes with mitochondrial functions, which could be involved in intrinsic apoptosis reported in NPC, in addition, we found a generalized deregulation in the cortical circadian rhythm pathway, which could be related to the depressive behavior that has even been reported in NPC patients. Conclusions: Recognizing that there are changes in the expression of genes related to ubiquitination, mitochondrial functions, and cortical circadian rhythm in the NPC mutant mouse lays the basis for targeting treatments to new potential therapeutic targets. Full article

Modified oligonucleotides (oligos) are widely used as convenient tools in many scientific fields, including biomedical applications and therapies. In particular, oligos with lipophilic groups attached to the backbone ensure penetration of the cell membrane without the need for transfection. This study examines the interaction between amphiphilic DNA duplexes, in which one of the chains contains a lipophilic substituent, and several DNA repair proteins, particularly DNA-damage-dependent PARPs, using various biochemical approaches. DNA with a lipophilic substituent (LS-DNA) demonstrates more efficient binding with DNA damage activated poly(AD-ribose) polymerases 1-3 (PARP1, PARP2, PARP3) and DNA polymerase β. Chemically reactive LS-DNA derivatives containing a photoactivatable nucleotide (photo-LS-DNAs) or a 5′ deoxyribose phosphate (dRP) group in the vicinity of double-strand breaks (DSBs) are used for the affinity labelling of PARPs and other proteins in several whole-cell extracts of human cells. In particular, photo-LS-DNAs are used to track the level of Ku antigen in the extracts of neuron-like differentiated SH-SY5Y, undifferentiated SH-SY5Y, and olfactory epithelial cells. In vitro, PARP1–PARP3 are shown to be able to slowly excise the 5′ dRP group at DSBs. LS-DNAs can activate PARP1 and PARP2 for autoPARylation, albeit less effectively than regular DNA duplexes. Full article

Background/Objectives: Oxidative stress constitutes a principal pathophysiological mechanism driving neurodegeneration and brain aging. α-Ketoglutarate (AKG), a key intermediate of the tricarboxylic acid (TCA) cycle, has shown potential in longevity and oxidative stress resistance. However, the role of AKG in oxidative stress-induced neuronal senescence and its interaction with the mTOR signaling pathway during neuronal aging remain poorly understood, posing a key challenge for developing senescence-targeted therapies. Methods: We investigated the neuroprotective effects of AKG using H₂O₂-induced senescence in HT22 cells and a D-galactose-induced brain aging mouse model. Assessments encompassed SA-β-gal staining, EdU incorporation, mitochondrial membrane potential (JC-1), and ROS measurement. Antioxidant markers, ATP levels, and the NAD⁺/NADH ratio were also analyzed. Proteomic profiling (DIA-MS) and KEGG/GSEA enrichment analyses were employed to identify AKG-responsive signaling pathways, and Western blotting validated changes in mTOR signaling and downstream effectors. Results: AKG significantly alleviated H₂O₂-induced senescence in HT22 cells, evidenced by enhanced cell viability, reduced ROS level, restored mitochondrial function, and downregulated p53/p21 expression. In vivo, AKG administration improved cognitive deficits and vestibulomotor dysfunction while ameliorating brain oxidative damage in aging mice. Proteomics revealed mTOR signaling pathways as key targets for AKG’s anti-aging activity. Mechanistically, AKG suppressed mTOR phosphorylation and activated ULK1, suggesting modulation of autophagy and metabolic homeostasis. These effects were accompanied by enhanced antioxidant enzyme activities and improved redox homeostasis. Conclusions: Our study demonstrates that AKG mitigates oxidative stress-induced neuronal senescence through suppression of the mTOR pathway and enhancement of mitochondrial and antioxidant function. These findings highlight AKG as a metabolic intervention candidate for age-related neurodegenerative diseases. Full article

α-Latrotoxin stimulates neurotransmitter release by binding to a presynaptic receptor and then forming ion-permeable membrane pores and/or stimulating the receptor, latrophilin-1, or Adhesion G-protein-coupled receptor type L1 (ADGRL1). To avoid pore formation, we use the mutant α-latrotoxin (LTX^N4C), which does not form pores and only acts through ADGRL1. ADGRL1 is cleaved into an N-terminal fragment (NTF) and a C-terminal fragment (CTF), which behave as independent cell-surface proteins, reassociating upon binding LTX^N4C. We investigated the role of the NTF-CTF association in LTX^N4C action, using perfluorooctanoic acid (PFOA). We demonstrate that at low concentrations (≤100 μM) PFOA does not adversely affect ADGRL1-expressing neuroblastoma cells or inhibit LTX^N4C binding. However, it causes the dissociation of the NTF-CTF complexes, independent redistribution of the fragments on the cell surface, and their separate internalization. PFOA also promotes the dissociation of NTF-CTF complexes induced by LTX^N4C binding. When applied to mouse neuromuscular junctions, PFOA inhibits LTX^N4C-induced neurotransmitter release in a concentration-dependent manner. Our results indicate that ADGRL1 can mediate LTX^N4C signaling only while its fragments remain associated. These findings explain some aspects of receptor-dependent toxin action and contribute to a mechanistic understanding of ADGRL1 functions in neurons. Full article

Amyotrophic lateral sclerosis (ALS) is characterized by upper and lower motor neuron failure and poor prognosis. This study performed a meta-analysis of gene expression datasets that compared bulk-processed post-mortem spinal cord from ALS and control (CTL) patients. The analysis included 569 samples (454 ALS, 115 CTL) from 348 individuals (262 ALS, 86 CTL). Patterns of differential expression bias, related to mRNA abundance, gene length and GC content, were discernable from individual studies but attenuated by meta-analysis. A total of 213 differentially expressed genes (DEGs) were identified (144 ALS-increased, 69 ALS-decreased). ALS-increased DEGs were most highly expressed by microglia and associated with MHC class II, immune response and leukocyte activation. ALS-decreased DEGs were abundantly expressed by mature oligodendrocytes (e.g., the MOL5 phenotype) and associated with myelin production, plasma membrane and sterol metabolism. Comparison to spatial transcriptomics data showed that DEGs were prominently expressed in white matter, with increased DEG expression strongest in the ventral/lateral white matter. These results highlight white matter as the spinal cord region most strongly associated with the shifts in mRNA abundance observed in bulk-processed tissues. These shifts can be explained by attrition of mature oligodendrocytes and an ALS-emergent microglia phenotype that is partly shared among neurodegenerative conditions. Full article

Wilson’s disease (WD) is an autosomal recessive disorder of copper metabolism caused by mutations in the ATP7B gene. While hepatic manifestations are frequent, psychiatric symptoms occur in up to 30% of patients and may precede neurological signs. This study was the first to assess the relationship between oxidative stress, selected genetic polymorphisms, and psychiatric symptoms in WD. A total of 464 patients under the care of the Institute of Psychiatry and Neurology in Warsaw were studied. Genotyping for GPX1 (rs1050450), SOD2 (rs4880), and CAT (rs1001179) was performed, along with biochemical analyses of copper metabolism, oxidative DNA, lipid and protein damage, and systemic antioxidant capacity. Among the most important observations are the following: the homozygous GPX1 rs1050450 TT and SOD2 rs4880 CC genotypes were associated with the lowest prevalence of psychiatric symptoms. The CAT rs1001179 TT genotype was linked to a delayed onset of psychiatric symptoms by 6.0–8.5 years. Patients with or without psychiatric symptoms did not differ significantly in saliva 8-OHdG, total antioxidant capacity, serum glutathione (GSH), catalase, and MnSOD; however, patients reporting psychiatric symptoms had significantly higher prostaglandin F2α 8-epimer (8-iso-PGF2α) concentrations and tended to have lower serum glutathione peroxidase (Gpx) concentrations compared to those without such symptoms. Our data firstly provide consistent evidence that oxidative stress balance associated with copper overload in the CNS may be associated with CNS damage and the development of psychiatric symptoms of WD. In particular, our findings of increased oxidative lipid damage together with decreased Gpx activity indirectly suggest that damage to neuronal membrane lipids, which may be potentially related to abnormalities in GSH metabolism, may have an etiological role in CNS damage and related symptoms. Full article

This scoping review explores the expression patterns and molecular features of sarcoglycans (SGs) in non-muscle organs, challenging the long-standing assumption that their function is confined to skeletal and cardiac muscle. By analyzing evidence from both animal models and human studies, the review highlights the widespread presence of SG subunits in organs, including the nervous system, glands, adipose tissue, oral mucosa, retina, and other structures, with distinct regional and cell-type-specific patterns. Studies on the central nervous system demonstrate a widespread “spot-like” distribution of SG subunits in neurons and glial cells, implicating their involvement in synaptic organization and neurotransmission. Similarly, SGs maintain cellular integrity and homeostasis in glands and adipose tissue. At the same time, the altered expression of SGs is associated with pathological conditions in the gingival epithelium of the oral mucosa. These findings underscore the multifaceted roles of SGs beyond muscle, suggesting that they may contribute to cellular signaling, membrane stability, and neurovascular coupling. However, significant gaps remain regarding SG post-translational modifications and functional implications in non-muscle organs. Future research integrating molecular, cellular, and functional approaches in animal models and human tissues is essential to fully elucidate these roles and explore their potential as therapeutic targets in various diseases. Full article