Alexander disease (AxD) is a rare and severe neurodegenerative disorder caused by mutations in glial fibrillary acidic protein (GFAP). While the exact disease mechanism remains unknown, previous studies suggest that mutant GFAP influences many cellular processes, including cytoskeleton stability, mechanosensing, metabolism, and proteasome function. While most studies have primarily focused on GFAP-expressing astrocytes, GFAP is also expressed by radial glia and neural progenitor cells, prompting questions about the impact of GFAP mutations on central nervous system (CNS) development. In this study, we observed impaired differentiation of astrocytes and neurons in co-cultures of astrocytes and neurons, as well as in neural organoids, both generated from AxD patient-derived induced pluripotent stem (iPS) cells with a GFAPR239C mutation. Leveraging single-cell RNA sequencing (scRNA-seq), we identified distinct cell populations and transcriptomic differences between the mutant GFAP cultures and a corrected isogenic control. These findings were supported by results obtained with immunocytochemistry and proteomics. In co-cultures, the GFAPR239C mutation resulted in an increased abundance of immature cells, while in unguided neural organoids and cortical organoids, we observed altered lineage commitment and reduced abundance of astrocytes. Gene expression analysis revealed increased stress susceptibility, cytoskeletal abnormalities, and altered extracellular matrix and cell-cell communication patterns in the AxD cultures, which also exhibited higher cell death after stress. Overall, our results point to altered cell differentiation in AxD patient-derived iPS-cell models, opening new avenues for AxD research.

• MeSH
• Alexander Disease * genetics   pathology   metabolism   MeSH
• Astrocytes * metabolism   pathology   MeSH
• Cell Differentiation * physiology   MeSH
• Glial Fibrillary Acidic Protein * metabolism   genetics   MeSH
• Induced Pluripotent Stem Cells * metabolism   MeSH
• Coculture Techniques MeSH
• Cells, Cultured MeSH
• Humans MeSH
• Mutation MeSH
• Neural Stem Cells metabolism   MeSH
• Neurons metabolism   pathology   MeSH
• Organoids metabolism   pathology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

The formation of memories is a complex, multi-scale phenomenon, especially when it involves integration of information from various brain systems. We have investigated the differences between a novel and consolidated association of spatial cues and amphetamine administration, using an in situ hybridisation method to track the short-term dynamics during the recall testing. We have found that remote recall group involves smaller, but more consolidated groups of neurons, which is consistent with their specialisation. By employing machine learning analysis, we have shown this pattern is especially pronounced in the VTA; furthermore, we also uncovered significant activity patterns in retrosplenial and prefrontal cortices, as well as in the DG and CA3 subfields of the hippocampus. The behavioural propensity towards the associated localisation appears to be driven by the nucleus accumbens, however, further modulated by a trio of the amygdala, VTA and hippocampus, as the trained association is confronted with test experience. Moreover, chemogenetic analysis revealed central amygdala as critical for linking appetitive emotional states with spatial contexts. These results show that memory mechanisms must be modelled considering individual differences in motivation, as well as covering dynamics of the process.

• MeSH
• Amphetamine pharmacology   MeSH
• Amygdala physiology   MeSH
• Hippocampus * physiology   MeSH
• Memory Consolidation * physiology   MeSH
• Rats MeSH
• Brain physiology   MeSH
• Neurons physiology   metabolism   MeSH
• Nucleus Accumbens * physiology   MeSH
• Reward * MeSH
• Memory physiology   MeSH
• Cues MeSH
• Prefrontal Cortex physiology   MeSH
• Mental Recall * physiology   MeSH
• Machine Learning MeSH
• Ventral Tegmental Area * physiology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

One of the main challenges in analyzing chemical messengers in the brain is the optimization of tissue sampling and preparation protocols. Limiting postmortem time and terminating enzyme activity is critical to identify low-abundance neurotransmitters and neuropeptides. Here, we used a rapid and uniform conductive heat transfer stabilization method that was compared with a conventional fresh freezing protocol. Together with a selective chemical derivatization method and an optimized quantitation approach using deuterated internal standards, we spatially mapped neurotransmitters and their related metabolites by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) in rat brain tissue sections. Although the heat stabilization did not show differences in the levels of dopamine, norepinephrine, and serotonin, their related metabolites 3,4-dihydroxyphenylacetaldehyde, 3,4-dihydroxyphenylacetic acid, homovanillic acid, 3-methoxy-4-hydroxyphenylacetaldehyde, dihydroxyphenylethyleneglycol, and 5-hydroxyindoleacetic acid were all significantly lower, indicating reduced neurotransmitter postmortem turnover ratios. Heat stabilization enabled detection of an increased number and higher levels of prodynorphin, proenkephalin, and tachykinin-derived bioactive neuropeptides. The low-abundant C-terminal flanking peptide, neuropeptide-γ, and nociceptin remained intact and were exclusively imaged in heat-stabilized brains. Without heat stabilization, degradation fragments of full-length peptides occurred in the fresh frozen tissues. The sample preparation protocols were furthermore tested on rat brains affected by acute anesthesia induced by isoflurane and medetomidine, showing comparable results to non-anesthetized animals on the neurotransmitters level without significant changes. Our data provide evidence for the potential use of heat stabilization prior to MALDI-MSI analyses to improve the examination of the in vivo state of neuronal chemical messengers in brain tissues not impacted by prior acute anesthesia.

• MeSH
• Rats MeSH
• Brain Chemistry * physiology   MeSH
• Brain * metabolism   MeSH
• Neurons * metabolism   chemistry   MeSH
• Neurotransmitter Agents * metabolism   analysis   MeSH
• Rats, Sprague-Dawley MeSH
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization * methods   MeSH
• Hot Temperature * MeSH
• Freezing MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Neural networks are responsible for processing sensory stimuli and driving the synaptic activity required for brain function and behavior. This computational capacity is expensive and requires a steady supply of energy and building blocks to operate. Importantly, the neural networks are composed of different cell populations, whose metabolic profiles differ between each other, thus endowing them with different metabolic capacities, such as, for example, the ability to synthesize specific metabolic precursors or variable proficiency to manage their metabolic waste. These marked differences likely prompted the emergence of diverse intercellular metabolic interactions, in which the shuttling and cycling of specific metabolites between brain cells allows the separation of workload and efficient control of energy demand and supply within the central nervous system. Nevertheless, our knowledge about brain bioenergetics and the specific metabolic adaptations of neural cells still warrants further studies. In this review, originated from the Fourth International Society for Neurochemistry (ISN) and Journal of Neurochemistry (JNC) Flagship School held in Schmerlenbach, Germany (2022), we describe and discuss the specific metabolic profiles of brain cells, the intercellular metabolic exchanges between these cells, and how these bioenergetic activities shape synaptic function and behavior. Furthermore, we discuss the potential role of faulty brain metabolic activity in the etiology and progression of Alzheimer's disease, Parkinson disease, and Amyotrophic lateral sclerosis. We foresee that a deeper understanding of neural networks metabolism will provide crucial insights into how higher-order brain functions emerge and reveal the roots of neuropathological conditions whose hallmarks include impaired brain metabolic function.

• MeSH
• Energy Metabolism * physiology   MeSH
• Humans MeSH
• Metabolic Networks and Pathways * physiology   MeSH
• Brain * metabolism   MeSH
• Nerve Net * metabolism   MeSH
• Neurons * metabolism   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

In the study, we employ an affordable, tissue-saving, and precise simultaneous multiplex immunofluorescence method with heat-induced antibody stripping to identify and structurally analyse nigral Lewy bodies in dopaminergic neurones. Analysis of different alpha-synuclein epitopes and proteoforms reveals an almost uniform, onion-like morphology of the Lewy bodies. The N-terminal and C-terminal domains are predominantly accessible to antibody binding in the peripheral shell of the bodies.

• MeSH
• alpha-Synuclein * metabolism   analysis   MeSH
• Lewy Body Disease pathology   MeSH
• Dopaminergic Neurons metabolism   pathology   MeSH
• Fluorescent Antibody Technique methods   MeSH
• Lewy Bodies * metabolism   pathology   MeSH
• Humans MeSH
• Substantia Nigra * metabolism   pathology   MeSH
• Hot Temperature MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Developmental remodeling shapes neural circuits via activity-dependent pruning of synapses and axons. Regulation of the cytoskeleton is critical for this process, as microtubule loss via enzymatic severing is an early step of pruning across many circuits and species. However, how microtubule-severing enzymes, such as spastin, are activated in specific neuronal compartments remains unknown. Here, we reveal that polyglutamylation, a post-translational tubulin modification enriched in neurons, plays an instructive role in developmental remodeling by tagging microtubules for severing. Motor neuron-specific gene deletion of enzymes that add or remove tubulin polyglutamylation-TTLL glutamylases vs. CCP deglutamylases-accelerates or delays neuromuscular synapse remodeling in a neurotransmission-dependent manner. This mechanism is not specific to peripheral synapses but also operates in central circuits, e.g., the hippocampus. Thus, tubulin polyglutamylation acts as a cytoskeletal rheostat of remodeling that shapes neuronal morphology and connectivity.

• MeSH
• Hippocampus metabolism   cytology   MeSH
• Polyglutamic Acid * metabolism   MeSH
• Microtubules * metabolism   MeSH
• Motor Neurons * metabolism   MeSH
• Mice MeSH
• Neuromuscular Junction metabolism   MeSH
• Synaptic Transmission MeSH
• Neurons * metabolism   MeSH
• Neuronal Plasticity * physiology   MeSH
• Peptide Synthases metabolism   genetics   MeSH
• Protein Processing, Post-Translational MeSH
• Spastin metabolism   MeSH
• Synapses metabolism   MeSH
• Tubulin metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

BACKGROUND: Tick-borne encephalitis virus (TBEV) is a significant threat to human health. The virus causes potentially fatal disease of the central nervous system (CNS), for which no treatments are available. TBEV infected individuals display a wide spectrum of neuronal disease, the determinants of which are undefined. Changes to host metabolism and virus-induced immunity have been postulated to contribute to the neuronal damage observed in infected individuals. In this study, we evaluated the cytokine, chemokine, and metabolic alterations in the cerebrospinal fluid (CSF) of symptomatic patients infected with TBEV presenting with meningitis or encephalitis. Our aim was to investigate the host immune and metabolic responses associated with specific TBEV infectious outcomes. METHODS: CSF samples of patients with meningitis (n = 27) or encephalitis (n = 25) were obtained upon consent from individuals hospitalised with confirmed TBEV infection in Brno. CSF from uninfected control patients was also collected for comparison (n = 12). A multiplex bead-based system was used to measure the levels of pro-inflammatory cytokines and chemokines. Untargeted metabolomics followed by bioinformatics and integrative omics were used to profile the levels of metabolites in the CSF. Human motor neurons (hMNs) were differentiated from induced pluripotent stem cells (iPSCs) and infected with the highly pathogenic TBEV-Hypr strain to profile the role(s) of identified metabolites during the virus lifecycle. Virus infection was quantified via plaque assay. RESULTS: Significant differences in proinflammatory cytokines (IFN-α2, TSLP, IL-1α, IL-1β, GM-CSF, IL-12p40, IL-15, and IL-18) and chemokines (IL-8, CCL20, and CXCL11) were detected between neurological-TBEV and control patients. A total of 32 CSF metabolites differed in TBE patients with meningitis and encephalitis. CSF S-Adenosylmethionine (SAM), Fructose 1,6-bisphosphate (FBP1) and Phosphoenolpyruvic acid (PEP) levels were 2.4-fold (range ≥ 2.3-≥3.2) higher in encephalitis patients compared to the meningitis group. CSF urocanic acid levels were significantly lower in patients with encephalitis compared to those with meningitis (p = 0.012209). Follow-up analyses showed fluctuations in the levels of O-phosphoethanolamine, succinic acid, and L-proline in the encephalitis group, and pyruvic acid in the meningitis group. TBEV-infection of hMNs increased the production of SAM, FBP1 and PEP in a time-dependent manner. Depletion of the metabolites with characterised pharmacological inhibitors led to a concentration-dependent attenuation of virus growth, validating the identified changes as key mediators of TBEV infection. CONCLUSIONS: Our findings reveal that the neurological disease outcome of TBEV infection is associated with specific and dynamic metabolic signatures in the cerebrospinal fluid. We describe a new in vitro model for in-depth studies of TBEV-induced neuropathogenesis, in which the depletion of identified metabolites limits virus infection. Collectively, this reveals new biomarkers that can differentiate and predict TBEV-associated neurological disease. Additionally, we have identified novel therapeutic targets with the potential to significantly improve patient outcomes and deepen our understanding of TBEV pathogenesis.

• MeSH
• Cytokines cerebrospinal fluid   MeSH
• Adult MeSH
• Encephalitis, Tick-Borne * cerebrospinal fluid   metabolism   MeSH
• Cells, Cultured MeSH
• Middle Aged MeSH
• Humans MeSH
• Metabolome * physiology   MeSH
• Metabolomics MeSH
• Young Adult MeSH
• Neurons * metabolism   virology   MeSH
• Aged MeSH
• Encephalitis Viruses, Tick-Borne * MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

Spinal cord injury (SCI) results in paralysis, driven partly by widespread glutamate-induced secondary excitotoxic neuronal cell death in and around the injury site. While there is no curative treatment, the standard of care often requires interventive decompression surgery and repair of the damaged dura mater close to the injury locus using dural substitutes. Such intervention provides an opportunity for early and local delivery of therapeutics directly to the injured cord via a drug-loaded synthetic dural substitute for localized pharmacological therapy. Riluzole, a glutamate-release inhibitor, has shown neuroprotective potential in patients with traumatic SCI, and therefore, this study aimed to develop an electrospun riluzole-loaded synthetic dural substitute patch suitable for the treatment of glutamate-induced injury in neurons. A glutamate-induced excitotoxicity was optimized in SH-SY5Y cells by exploring the effect of glutamate concentration and exposure duration. The most effective timing for administering riluzole was found to be at the onset of glutamate release as this helped to limit extended periods of glutamate-induced excitotoxic cell death. Riluzole-loaded patches were prepared by using blend electrospinning. Physicochemical characterization of the patches showed the successful encapsulation of riluzole within polycaprolactone fibers. A drug release study showed an initial burst release of riluzole within the first 24 h, followed by a sustained release of the drug over 52 days to up to approximately 400 μg released for the highest loading of riluzole within fiber patches. Finally, riluzole eluted from electrospun fibers remained pharmacologically active and was capable of counteracting glutamate-induced excitotoxicity in SH-SY5Y cells, suggesting the clinical potential of riluzole-loaded dural substitutes in counteracting the effects of secondary injury in the injured spinal cord.

• MeSH
• Drug Implants MeSH
• Glutamic Acid metabolism   MeSH
• Humans MeSH
• Cell Line, Tumor MeSH
• Neurons drug effects   MeSH
• Neuroprotective Agents * administration & dosage   chemistry   pharmacology   MeSH
• Polyesters chemistry   MeSH
• Spinal Cord Injuries * drug therapy   MeSH
• Riluzole * administration & dosage   chemistry   pharmacology   MeSH
• Drug Liberation MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Full recovery from spinal cord injury requires axon regeneration to re-establish motor and sensory pathways. In mammals, the failure of sensory and motor axon regeneration has many causes intrinsic and extrinsic to neurons, amongst which is the lack of adhesion molecules needed to interact with the damaged spinal cord. This study addressed this limitation by expressing the integrin adhesion molecule α9, along with its activator kindlin-1, in sensory neurons via adeno-associated viral (AAV) vectors. This enabled sensory axons to regenerate through spinal cord injuries and extend to the brainstem, restoring sensory pathways, touch sensation and sensory behaviours. One of the integrin ligands in the injured spinal cord is tenascin-C, which serves as a substrate for α9β1 integrin, a key receptor in developmental axon guidance. However, the adult PNS and CNS neurons lack this receptor. Sensory neurons were transduced with α9 integrin (which pairs with endogenous β1 to form a α9β1 tenascin receptor) together with the integrin activator kindlin-1. Regeneration from sensory neurons transduced with α9integrin and kindlin-1 was examined after C4 and after T10 dorsal column lesions with C6,7 and L4,5 sensory ganglia injected with AAV1 vectors. In animals treated with α9 integrin and kindlin-1, sensory axons regenerated through tenascin-C-expressing connective tissue strands and bridges across the lesions and then re-entered the CNS tissue. Many axons regenerated rostrally to the level of the medulla. Axons grew through the dorsal grey matter rather than their normal pathway the dorsal columns. Growth was slow, axons taking 12 weeks to grow from T10 to the medulla, a distance of 4-5 cm. Functional recovery was confirmed through cFos activation in neurons rostral to the injury after nerve stimulation and VGLUT1/2 staining indicating new synapse formation above the lesion. Behavioural recovery was seen in both heat and mechanical sensation, as well as tape removal tests. This approach demonstrates the potential of integrin-based therapies for long distance sensory axon regeneration and functional recovery following thoracic and partial recovery after cervical spinal cord injury.

• MeSH
• Axons MeSH
• Dependovirus genetics   MeSH
• Genetic Vectors MeSH
• Rats MeSH
• Disease Models, Animal MeSH
• Mice MeSH
• Sensory Receptor Cells * metabolism   physiology   pathology   MeSH
• Recovery of Function physiology   MeSH
• Spinal Cord Injuries * pathology   physiopathology   metabolism   MeSH
• Rats, Sprague-Dawley MeSH
• Nerve Tissue Proteins metabolism   genetics   MeSH
• Nerve Regeneration * physiology   MeSH
• Tenascin metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Alterations in the excitability of dorsal root ganglion (DRG) neurons are critical in the pathogenesis of acute and chronic pain. Neurotransmitter release from the terminals of DRG neurons is regulated by cannabinoid receptor 1 (CB1) and transient receptor potential vanilloid 1 (TRPV1), both activated by anandamide (AEA). In our experiments, the AEA precursor N-arachidonoylphosphatidylethanolamine (20:4-NAPE) was used to study the modulation of nociceptive DRG neurons excitability using K+-evoked Ca2+ transients. Intrathecal administration was used to evaluate in vivo effects. Application of 20:4-NAPE at lower concentrations (10 nM - 1 μM) decreased the excitability of DRG neurons, whereas the higher (10 μM) increased it. Both effects of 20:4-NAPE were blocked by the N-acylphosphatidylethanolamine phospholipase D (NAPE-PLD) inhibitor LEI-401. Similarly, lower concentrations of externally applied AEA (1 nM - 10 nM) inhibited DRG neurons, whereas higher concentration (100 nM) did not change it. High AEA concentration (10 μM) evoked Ca2+ transients dependent on TRPV1 activation in separate experiments. Inhibition of the CB1 receptor by PF514273 (400 nM) prevented the 20:4-NAPE- and AEA-induced inhibition, whereas TRPV1 inhibition by SB366791 (1 μM) prevented the increased DRG neuron excitability. In behavioral tests, lower 20:4-NAPE concentration caused hyposensitivity, while higher evoked mechanical allodynia. Intrathecal LEI-401 prevented both in vivo effects of 20:4-NAPE. These results highlight anti- and pro-nociceptive effects of 20:4-NAPE mediated by CB1 and TRPV1 in concentration-dependent manner. Our study underscores the complexity of endocannabinoid signaling in pain transmission modulation and highlights 20:4-NAPE as a potential therapeutic target, offering new insights for developing analgesic strategies.

• MeSH
• Endocannabinoids pharmacology   metabolism   MeSH
• Phosphatidylethanolamines * pharmacology   MeSH
• Phospholipase D * metabolism   antagonists & inhibitors   MeSH
• TRPV Cation Channels metabolism   MeSH
• Rats MeSH
• Arachidonic Acids * pharmacology   MeSH
• Neurons * drug effects   metabolism   MeSH
• Polyunsaturated Alkamides pharmacology   MeSH
• Rats, Sprague-Dawley MeSH
• Receptor, Cannabinoid, CB1 metabolism   MeSH
• Ganglia, Spinal * drug effects   metabolism   cytology   MeSH
• Calcium metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH