OBJECTIVES: To investigate the effect of monotropein on motor function recovery of mice with spinal cord injury (SCI) and explore the underlying mechanism. METHODS: Forty-five adult female C57BL/6 mice were randomized equally into sham operation group, SCI group, and SCI group with daily intraperitoneal monotropein injection. The mice in the former two groups received daily saline injections. Motor function of the mice was evaluated using BMS scores, slant plate test, and footprint analyses. Pathological changes and neuronal counts in the spinal cord were observed using HE, LFB, and Nissl staining. The biological functions of monotropein were explored using GO and KEGG enrichment analyses. NeuN/cleaved caspase-3 immunofluorescence assay and Western blotting were used to detect neuronal apoptosis in the spinal cord of the mice. In cultured HT22 cells, the effect of monotropein on TNF-α-induced cell apoptosis was evaluated using TUNEL staining and Western blotting. In monotropein-treated HT22 cells and SCI mice, the changes in the PI3K/AKT pathway were examined, and the effect of a PI3K/AKT pathway activator (IGF-1) on HT22 cell apoptosis and motor function recovery of SCI mice were observed. RESULTS: SCI mice with monotropein treatment showed significantly improved motor functions with reduced SCI areas and increased myelin retention and neuron counts in the spinal cord. Bioinformatics analysis suggested a role of PI3K/AKT signaling pathway in mediating the anti-apoptotic effects of monotropein. In SCI mice, monotropein obviously reduced apoptotic neurons, decreased expressions of cleaved caspase-3 and Bax and increased Bcl-2 expression in the spinal cord. In HT22 cells, monotropein significantly inhibited TNF-α-induced apoptosis and PI3K/AKT pathway activation. Treatment with IGF-1 obviously increased apoptosis of HT22 cells and exacerbated locomotor dysfunction in SCI mice. CONCLUSIONS Monotropein promotes motor function recovery in SCI mice by reducing neuronal apoptosis possibly by inhibiting the PI3K/AKT signaling pathway.
Animals ; Spinal Cord Injuries/metabolism* ; Apoptosis/drug effects* ; Signal Transduction/drug effects* ; Mice, Inbred C57BL ; Mice ; Proto-Oncogene Proteins c-akt/metabolism* ; Female ; Phosphatidylinositol 3-Kinases/metabolism* ; Neurons/pathology* ; Recovery of Function

OBJECTIVES: To explore whether the antioxidant axis Nrf2/HO-1 is involved in the regulation of hippocampus injury induced by cypermethrin and its underlying mechanism. METHODS: Ten-week-old C57BL/6 mice were randomly divided into control group and cypermethrin exposure groups with low, medium, and high exposure levels. After 21 days of oral gavage of corn oil (control) or cypermethrin, the levels of MDA, T-SOD, GSH-Px and CAT in the hippocampus of the mice were examined to evaluate the oxidative stress levels. HE staining was used to observe morphological changes of the hippocampal neurons. Western blotting, immunofluorescence staining and RT-qPCR were employed to detect the protein expressions and mRNA expression of Nrf2 and HO-1 and HO-1. RESULTS: Subacute oral exposure to cypermethrin significantly increased MDA level, decreased the activities of antioxidant enzymes T-SOD, GSH-Px and CAT, and induced neuronal damage in the CA1 and CA3 regions in the hippocampus of C57BL/6 mice. Cypermethrin exposure also caused Nrf2 protein translocation from the cytoplasm to the nucleus, accompanied by upregulated expression levels of the key antioxidant factor Nrf2 and its downstream target kinase HO-1. CONCLUSIONS Cypermethrin exposure dose-dependently causes oxidative damage in the hippocampus of C57BL/6 mice, which is regulated by the Nrf2/HO-1 antioxidant pathway.
Animals ; Pyrethrins/toxicity* ; NF-E2-Related Factor 2/metabolism* ; Hippocampus/cytology* ; Mice, Inbred C57BL ; Mice ; Oxidative Stress/drug effects* ; Neurons/pathology* ; Heme Oxygenase-1/metabolism* ; Signal Transduction ; Membrane Proteins

OBJECTIVES: To explore the effects of cannabidiol on endoplasmic reticulum stress and neuronal apoptosis in rats with multiple concussions (MCC). METHODS: SD rats were randomized into sham group, MCC group, 1% tween20 (TW) treatment group, and low-dose (10 mg/kg) and high-dose (40 mg/kg) cannabidiol treatment groups. In all but the sham group, MCC models were established using a metal pendulum percussion device, after which the rats received daily intraperitoneal injections of the corresponding agents for 2 weeks. The expressions of PERK, eIF2α, ATF4, CHOP, TRIB3, p-Akt and pro-caspase-3 in the brain tissue of the rats were detected with qRT-PCR, Western blotting and immunofluorescence staining. The core targets of cannabidiol in treatment of traumatic brain injury (TBI) were identified by network pharmacology analysis, and molecular docking was carried out to simulate the interaction of cannabidiol with the factors related to endoplasmic reticulum stress and apoptosis. RESULTS: Compared with the sham-operated rats, the rat models of MCC showed significantly increased mRNA expressions of PERK, eIF2α and CHOP and protein expressions of PERK, eIF2α, ATF4, CHOP, TRIB3, p-AKT and pro-caspase-3 in the cerebral cortex. CBD treatment, especially at the high dose, obviously increased the expression of p-Akt and lowered the expression levels of the other factors tested in the rat models. Network pharmacology analysis indicated interactions of the core targets of CBD with the factors related to endoplasmic reticulum stress and TBI, and molecular docking study showed a high binding energy of CBD with multiple factors pertaining to endoplasmic reticulum stress and apoptosis. CONCLUSIONS MCC induce endoplasmic reticulum stress and apoptosis in rat brain tissues, for which CBD, especially at a high dose, provides neuroprotective effects by inhibiting endoplasmic reticulum stress and cell apoptosis.
Animals ; Endoplasmic Reticulum Stress/drug effects* ; Apoptosis/drug effects* ; Rats, Sprague-Dawley ; Activating Transcription Factor 4/metabolism* ; Transcription Factor CHOP/metabolism* ; Rats ; Eukaryotic Initiation Factor-2/metabolism* ; Signal Transduction/drug effects* ; eIF-2 Kinase/metabolism* ; Cannabidiol/pharmacology* ; Neurons/metabolism* ; Brain Concussion/metabolism* ; Male ; Molecular Docking Simulation

OBJECTIVES: To investigate the subcellular localization and biological functions of transmembrane protein 240 (TMEM240). METHODS: NCBI BLAST and TMHMM bioinformatics software were used for protein sequence analysis and prediction of transmembrane domain of TMEM240. Brain tissues from male C57BL/6 mice (18-20 days old) were examined for distribution of TMEM240 using in situ hybridization, and qPCR and Western blotting were used to detect TMEM240 expression in different mouse tissues and in cortical neurons at different time points (n=3). In the in vitro experiment, HepG2 and Neuro-2a cells were transfected with plasmids for overexpression of TMEM240, and subcellular localization of TMEM240 was analyzed using cell imaging. In primary cultures of cortical neurons isolated from C57BL/6 mice, TMEM240 expression and its biological functions were investigated using qPCR, Western blotting, and immunofluorescence staining. RESULTS: Human and mouse TMEM240 proteins share a 97.69% similarity in the protein sequences, and both are transmembrane proteins with two transmembrane domains. TMEM240 mRNA and protein were highly expressed in mouse brain tissues and cortical neurons. In isolated mouse cortical neurons, TMEM240 expression reached the peak level after primary culture for 9 days and distributed in scattered spots within the cells. In HepG2 cells, TMEM240 was characterized as intracellular membrane structures and showed 80% colocalization with peroxisomes. In Neuro-2a cells, TMEM240 overexpression caused significant enhancement of the expressions of Rho GDP dissociation inhibitor β (ARHGDIB) at both the mRNA and protein levels. CONCLUSIONS TMEM240 is a novel intracellular subcellular structure specifically expressed in neurons with significant potential for targeted cellular function regulation.
Animals ; Humans ; Mice ; Peroxisomes/metabolism* ; Membrane Proteins/genetics* ; Mice, Inbred C57BL ; Neurons/metabolism* ; Male ; rho-Specific Guanine Nucleotide Dissociation Inhibitors ; Hep G2 Cells ; Brain/metabolism*

Autism Spectrum Disorders (ASDs) are reported as a group of neurodevelopmental disorders. The structural changes of brain regions including the hippocampus were widely reported in autistic patients and mouse models with dysfunction of ASD risk genes, but the underlying mechanisms are not fully understood. Here, we report that deletion of Trio, a high-susceptibility gene of ASDs, causes a postnatal dentate gyrus (DG) hypoplasia with a zigzagged suprapyramidal blade, and the Trio-deficient mice display autism-like behaviors. The impaired morphogenesis of DG is mainly caused by disturbing the postnatal distribution of postmitotic granule cells (GCs), which further results in a migration deficit of neural progenitors. Furthermore, we reveal that Trio plays different roles in various excitatory neural cells by spatial transcriptomic sequencing, especially the role of regulating the migration of postmitotic GCs. In summary, our findings provide evidence of cellular mechanisms that Trio is involved in postnatal DG morphogenesis.
Animals ; Dentate Gyrus/metabolism* ; Mice ; Morphogenesis/physiology* ; Neurons/pathology* ; Cell Movement ; Mice, Inbred C57BL ; Autism Spectrum Disorder/pathology* ; Mice, Knockout ; Neural Stem Cells ; Male ; Neurogenesis ; Autistic Disorder/genetics*

Stromal interaction molecules (STIM)s are Ca²⁺ sensors in internal Ca²⁺ stores of the endoplasmic reticulum. They activate the store-operated Ca²⁺ channels, which are the main source of Ca²⁺ entry in non-excitable cells. Moreover, STIM proteins interact with other Ca²⁺ channel subunits and active transporters, making STIMs an important intermediate molecule in orchestrating a wide variety of Ca²⁺ influxes into excitable cells. Nevertheless, little is known about the role of STIM proteins in brain functioning. Being involved in many signaling pathways, STIMs replenish internal Ca²⁺ stores in neurons and mediate synaptic transmission and neuronal excitability. Ca²⁺ dyshomeostasis is a signature of many pathological conditions of the brain, including neurodegenerative diseases, injuries, stroke, and epilepsy. STIMs play a role in these disturbances not only by supporting abnormal store-operated Ca²⁺ entry but also by regulating Ca²⁺ influx through other channels. Here, we review the present knowledge of STIMs in neurons and their involvement in brain pathology.
Neurons/metabolism* ; Animals ; Humans ; Calcium/metabolism* ; Stromal Interaction Molecules/metabolism* ; Calcium Signaling/physiology* ; Calcium Channels/metabolism* ; Brain/metabolism*

The oxytocin receptor (OXTR) has garnered increasing attention for its role in regulating both mature behaviors and brain development. It has been established that OXTR mediates a range of effects that are region-specific or period-specific. However, the current studies of OXTR expression patterns in mice only provide limited help due to limitations in resolution. Therefore, our objective was to generate a comprehensive, high-resolution spatiotemporal expression map of Oxtr mRNA across the entire developing mouse brain. We applied RNAscope in situ hybridization to investigate the spatiotemporal expression pattern of Oxtr in the brains of male mice at six distinct postnatal developmental stages (P7, P14, P21, P28, P42, P56). We provide detailed descriptions of Oxtr expression patterns in key brain regions, including the cortex, basal forebrain, hippocampus, and amygdaloid complex, with a focus on the precise localization of Oxtr⁺ cells and the variance of expression between different neurons. Furthermore, we identified some neuronal populations with high Oxtr expression levels that have been little studied, including glutamatergic neurons in the ventral dentate gyrus, Vgat⁺Oxtr⁺ cells in the basal forebrain, and GABAergic neurons in layers 4/5 of the cortex. Our study provides a novel perspective for understanding the distribution of Oxtr and encourages further investigations into its functions.
Animals ; Receptors, Oxytocin/metabolism* ; Male ; Brain/growth & development* ; Mice ; Mice, Inbred C57BL ; Neurons/metabolism* ; Single-Cell Analysis ; Gene Expression Regulation, Developmental ; RNA, Messenger/metabolism* ; Animals, Newborn

The ventral anterior (VA) nucleus of the thalamus is a major target of the basal ganglia and is closely associated with the pathogenesis of Parkinson's disease (PD). Notably, the VA receives direct innervation from the hypothalamic histaminergic system. However, its role in PD remains unknown. Here, we assessed the contribution of histamine to VA neuronal activity and PD motor deficits. Functional magnetic resonance imaging showed reduced VA activity in PD patients. Optogenetic activation of VA neurons or histaminergic afferents significantly alleviated motor deficits in 6-OHDA-induced PD rats. Furthermore, histamine excited VA neurons via H1 and H2 receptors and their coupled hyperpolarization-activated cyclic nucleotide-gated channels, inward-rectifier K⁺ channels, or Ca²⁺-activated K⁺ channels. These results demonstrate that histaminergic afferents actively compensate for Parkinsonian motor deficits by biasing VA activity. These findings suggest that targeting VA histamine receptors and downstream ion channels may be a potential therapeutic strategy for PD motor dysfunction.
Animals ; Histamine/metabolism* ; Male ; Oxidopamine/toxicity* ; Rats ; Ventral Thalamic Nuclei/physiopathology* ; Rats, Sprague-Dawley ; Disease Models, Animal ; Parkinson Disease/metabolism* ; Neurons/physiology* ; Humans ; Optogenetics

In the face of constantly changing environments, the central nervous system (CNS) rapidly and accurately calculates the body's needs, regulates feeding behavior, and maintains energy homeostasis. The arcuate nucleus of the hypothalamus (ARC) plays a key role in this process, serving as a critical brain region for detecting nutrition-related hormones and regulating appetite and energy homeostasis. Agouti-related protein (AgRP)/neuropeptide Y (NPY) neurons in the ARC are core elements that interact with other brain regions through a complex appetite-regulating network to comprehensively control energy homeostasis. In this review, we explore the discovery and research progress of AgRP neurons in regulating feeding and energy metabolism. In addition, recent advances in terms of feeding behavior and energy homeostasis, along with the redundant neural mechanisms involved in energy metabolism, are discussed. Finally, the challenges and opportunities in the field of neural regulation of feeding and energy metabolism are briefly discussed.
Energy Metabolism/physiology* ; Animals ; Humans ; Hypothalamus/metabolism* ; Neurons/metabolism* ; Feeding Behavior/physiology* ; Brain Stem/metabolism* ; Agouti-Related Protein/metabolism* ; Homeostasis/physiology* ; Neuropeptide Y/metabolism*

During the hyperacute phase of intracerebral hemorrhage (ICH), the mass effect and blood components mechanically lead to brain damage and neurotoxicity. Our findings revealed that the mass effect and transferrin precipitate neuronal oxidative stress and iron uptake, culminating in ferroptosis in neurons. M6A (N6-methyladenosine) modification, the most prevalent mRNA modification, plays a critical role in various cell death pathways. The Fto (fat mass and obesity-associated protein) demethylase has been implicated in numerous signaling pathways of neurological diseases by modulating m6A mRNA levels. Regulation of Fto protein levels in neurons effectively mitigated mass effect-induced neuronal ferroptosis. Applying nanopore direct RNA sequencing, we identified voltage-dependent anion channel 3 (Vdac3) as a potential target associated with ferroptosis. Fto influenced neuronal ferroptosis by regulating the m6A methylation of Vdac3 mRNA. These findings elucidate the intricate interplay between Fto, Vdac3, m6A methylation, and ferroptosis in neurons during the hyperacute phase post-ICH and suggest novel therapeutic strategies for ICH.
Ferroptosis/physiology* ; Alpha-Ketoglutarate-Dependent Dioxygenase FTO/genetics* ; Animals ; Neurons/metabolism* ; Transferrin/pharmacology* ; Mice ; Methylation ; Mice, Inbred C57BL ; Adenosine/metabolism* ; RNA, Messenger/metabolism* ; Male ; Oxidative Stress/physiology*