The study aimed to investigate the effect of the CD200R1 gene deletion on microglia activation and nigrostriatal dopamine neuron loss in the Parkinson's disease (PD) process. The CRISPR-Cas9 technology was applied to construct the CD200R1^-/- mice. The primary microglia cells of wild-type and CD200R1^-/- mice were cultured and treated with bacterial lipopolysaccharide (LPS). Microglia phagocytosis level was assessed by a fluorescent microsphere phagocytosis assay. PD mouse model was prepared by nigral stereotaxic injection of recombinant adeno-associated virus vector carrying human α-synuclein (α-syn). The changes in the motor behavior of the mice with both genotypes were evaluated by cylinder test, open field test, and rotarod test. Immunohistochemical staining was used to assess the loss of dopamine neurons in substantia nigra. Immunofluorescence staining was used to detect the expression level of CD68 (a key molecule involved in phagocytosis) in microglia. The results showed that CD200R1 deletion markedly enhanced LPS-induced phagocytosis in vitro by the microglial cells. In the mouse model of PD, CD200R1 deletion exacerbated motor behavior impairment and dopamine neuron loss in substantia nigra. Fluorescence intensity analysis results revealed a significant increase in CD68 expression in microglia located in the substantia nigra of CD200R1^-/- mice. The above results suggest that CD200R1 deletion may further activates microglia by promoting microglial phagocytosis, leading to increased loss of the nigrostriatal dopamine neurons in the PD model mice. Therefore, targeting CD200R1 could potentially serve as a novel therapeutic target for the treatment of early-stage PD.
Animals ; Microglia/physiology* ; Mice ; Phagocytosis ; Parkinson Disease/genetics* ; Disease Models, Animal ; Receptors, Cell Surface/physiology* ; Dopaminergic Neurons/pathology* ; Antigens, CD/metabolism* ; Gene Deletion ; Substantia Nigra ; Mice, Inbred C57BL ; Mice, Knockout ; Cells, Cultured ; Male ; alpha-Synuclein ; CD68 Molecule ; Orexin Receptors

Objective To explore the mechanism of lncRNA-BC200 (BC200) targeting the ubiquitination of Beta-site APP cleaving enzyme 1 (BACE1) and regulating the repair of nerve cell injury. Methods Mouse hippocampal neuron cell line HT22 was divided into four groups: control group, oxygen-glucose deprivation/reoxygenation(OGD/R) group, OGD/R+si-NC group and OGD/R+si-BC200 group. In order to further explore the relationship between BC200 and BACE1, HT22 cells were divided into four groups: OGD/R group, OGD/R+si-BC200 group, OGD/R+si-BC200+NC group and OGD/R+si-BC200+ BACE1 group. Twenty male C57BL/6J mice were randomly assigned to the following four groups: control group, middle cerebral artery occlusion (MCAO) group, MCAO+si-BC200 group and MCAO+si-BC200+BACE1 group. The mRNA expression levels of BC200 and BACE1 in cells were measured by real-time quantitative reverse transcription polymerase chain reaction. The expressions of c-caspase-3, B-cell lymphoma 2 (Bcl2), Bcl2 associated X protein(BAX) and BACE1 were detected by western blot, and the apoptotic cells were detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) test. Results Compared with the control group, the activity of HT22 cells in OGD/R group decreased significantly, and the percentage of apoptotic cells increased significantly. Compared with OGD/R+si-NC group, the activity of HT22 cells in OGD/R+si-BC200 group increased significantly, and the percentage of apoptotic cells decreased significantly. Compared with the control group, the expression of BACE1 protein in HT22 cells in OGD/R group was significantly enhanced. Compared with OGD/R+si-NC group, the expression of BACE1 protein in HT22 cells in OGD/R+si-BC200 group decreased significantly. It was observed that after OGD/R treatment, the ubiquitination level of BACE1 decreased significantly and the expression of BACE1 protein increased significantly. After transfection with si-BC200, the ubiquitination level of BACE1 protein increased significantly, while the expression of BACE1 protein decreased significantly. Compared with OGD/R+si-BC200+NC group, the percentage of apoptotic cells, the expression of c-caspase-3 and Bax protein in HT22 cells in OGD/R+si-BC200+BACE1 group increased significantly, and the expression of Bcl2 protein decreased significantly. Compared with the control group, the number of cerebral infarction areas and TUNEL positive cells in MCAO group increased significantly, and the survival number of neurons decreased significantly. Compared with the MCAO group, the number of cerebral infarction areas and TUNEL positive cells in MCAO+si-BC200 group decreased significantly, and the survival number of neurons increased significantly, while the addition of BACE1 reversed the improvement of si-BC200 transfection. Conclusion The combination of BC200 and BACE1 inhibit the ubiquitination of BACE1, and participate in mediating the expression enhancement of BACE1 induced by OGD/R. Specific blocking of BC200/BACE1 axis may be a potential therapeutic target to protect neurons from apoptosis induced by cerebral ischemia/reperfusion.
Animals ; Amyloid Precursor Protein Secretases/genetics* ; RNA, Long Noncoding/physiology* ; Aspartic Acid Endopeptidases/genetics* ; Male ; Neurons/pathology* ; Mice ; Mice, Inbred C57BL ; Apoptosis/genetics* ; Ubiquitination ; Cell Line ; Hippocampus/metabolism* ; bcl-2-Associated X Protein/genetics* ; Caspase 3/genetics* ; Infarction, Middle Cerebral Artery/metabolism*

OBJECTIVES: To investigate the protective effects and underlying mechanisms of Gynostemma pentaphyllum (GP)ethanol extract on motor dysfunction in a mouse model of Parkinson's disease (PD). METHODS: Eighty C57BL/6 male mice were randomly divided into five groups: control group, model group, levodopa group (positive control group), low-dose GP group, and high-dose GP group, with 16 mice per group. The PD model was induced by injection of 6-hydroxydopamine into the substantia nigra pars reticulata of the mice. Two weeks after 6-hydroxydopamine, positive control group received intraperitoneal injection of levodopa 10 mg·kg^－1·d^－1, while low-dose GP and high-dose GP groups received GP extract 100 or 200 mg·kg^－1·d^－1 orally for three weeks. After a 3-week-treatment, the effects of GP on motor dysfunction in 6-hydroxydopamine-induced PD were assessed using open field and CatWalk gait tests, while the effects on muscle strength were evaluated by forelimb grip strength. Immunofluorescence staining was used to detect the number of tyrosine hydroxylase (TH) positive neurons. The levels of dopamine and serotonin in the midbrain were determined by enzyme-linked immunosorbent assay. In addition, Western blotting was performed to detect the expression of mitogen-activated protein kinase (MAPK) family proteins such as p-extracellular signal-regulated kinase (ERK)1/2, p-p38 and p-c-Jun N-terminal kinase (JNK)1/2, and mitochondrial apoptosis pathway proteins such as B-cell lymphoma (Bcl)-2, Bcl-2 associated X protein (Bax), and cleaved-cysteine aspartic acid specific protease (caspase)-3. RESULTS: Behavioral experiments showed that GP significantly improved the spontaneous activity and motor coordination of PD mice (P<0.05). The forelimb grip strength was also increased by GP treatment (P<0.05), compared to the PD model group. In addition, compared with the model group, the number of TH-positive neurons in substantia nigra pars reticulata region, the levels of dopamine and serotonin in midbrain and the expression of p-ERK1/2 were significantly increased by GP treatment (all P<0.05), whereas the expression of p-p38 and p-JNK1/2, the ratio of Bax/Bcl-2 and cleaved-caspase-3/caspase-3 were significantly decreased (all P<0.05). CONCLUSIONS The results indicate that GP might increase dopamine and serotonin levels in the midbrain and promote the survival of dopaminergic neurons in substantia nigra pars reticulata by regulating the expression of phosphorylation of MAPK family proteins and the expression of mitochondrial apoptosis-related proteins, thereby ameliorating motor deficits in PD mice.
Animals ; Mice ; Male ; Gynostemma/chemistry* ; Mice, Inbred C57BL ; Apoptosis/drug effects* ; Plant Extracts/therapeutic use* ; Parkinson Disease/metabolism* ; Disease Models, Animal ; Neurons/pathology*

Neuroendocrine carcinoma (NEC) represents a category of malignant tumors originating from neuroendocrine cells. Given that NEC cells exhibit characteristics of both neural and endocrine cells, they can hijack neuronal signaling pathways and dynamically regulate the expression of neuronal lineage markers during tumor metastasis, thereby constructing a microenvironment conducive to tumor growth and metastasis. Conversely, alterations in the tumor microenvironment can enhance the interactions between neurons and tumor cells, ultimately synergistically promoting the metastasis of NEC. This review highlights recent advancements in the field of cancer neuroscience, uncovering neuronal lineage markers in NEC that facilitate tumor dissemination through mediating crosstalk, bidirectional communication, and synergistic interactions between tumor cells and the nervous system. Consequently, the latest findings in tumor neuroscience have enriched our understanding of the biological mechanisms underlying tumor metastasis, opening new research avenues for a deeper comprehension of the complex biological processes involved in tumor metastasis, particularly brain metastasis. This review provides a comprehensive review of the crosstalk between tumor cells and neural signaling in the metastasis of NEC.
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Humans ; Carcinoma, Neuroendocrine/metabolism* ; Signal Transduction ; Animals ; Neoplasm Metastasis ; Neurons/pathology* ; Tumor Microenvironment ; Cell Communication

OBJECTIVE: To illustrate the role of dehydrocorydaline (DHC) in chronic constriction injury (CCI)-induced neuropathic pain and the underlying mechanism. METHODS: C57BL/6J mice were randomly divided into 3 groups by using a random number table, including sham group (sham operation), CCI group [intrathecal injection of 10% dimethyl sulfoxide (DMSO)], and CCI+DHC group (intrathecal injection of DHC), 8 mice in each group. A CCI mouse model was conducted to induce neuropathic pain through ligating the right common sciatic nerve. On day 14 after CCI modeling or sham operation, mice were intrathecal injected with 5 µL of 10% DMSO or 10 mg/kg DHC (5 µL) into the 5th to 6th lumbar intervertebral space (L5-L6). Pregnant ICR mice were sacrificed for isolating primary spinal neurons on day 14 of embryo development for in vitro experiment. Pain behaviors were evaluated by measuring the paw withdrawal mechanical threshold (PWMT) of mice. Immunofluorescence was used to observe the activation of astrocytes and microglia in mouse spinal cord. Protein expressions of inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), phosphorylation of N-methyl-D-aspartate receptor subunit 2B (p-NR2B), and NR2B in the spinal cord or primary spinal neurons were detected by Western blot. RESULTS: In CCI-induced neuropathic pain model, mice presented significantly decreased PWMT, activation of glial cells, overexpressions of iNOS, TNF-α, IL-6, and higher p-NR2B/NR2B ratio in the spinal cord (P<0.05 or P<0.01), which were all reversed by a single intrathecal injection of DHC (P<0.05 or P<0.01). The p-NR2B/NR2B ratio in primary spinal neurons were also inhibited after DHC treatment (P<0.05). CONCLUSION An intrathecal injection of DHC relieved CCI-induced neuropathic pain in mice by inhibiting the neuroinflammation and neuron hyperactivity.
Animals ; Neuralgia/etiology* ; Mice, Inbred C57BL ; Analgesics/pharmacology* ; Neuroinflammatory Diseases/pathology* ; Constriction ; Male ; Receptors, N-Methyl-D-Aspartate/metabolism* ; Nitric Oxide Synthase Type II/metabolism* ; Mice, Inbred ICR ; Microglia/pathology* ; Spinal Cord/drug effects* ; Female ; Mice ; Tumor Necrosis Factor-alpha/metabolism* ; Disease Models, Animal ; Constriction, Pathologic/complications* ; Interleukin-6/metabolism* ; Astrocytes/metabolism* ; Chronic Disease ; Neurons/metabolism*

OBJECTIVE: To investigate whether Buyang Huanwu Decoction (BYHWD) had a good curative effect on the neuroprotection of red nucleus neurons after spinal cord injury (SCI) and the possible molecular mechanism. METHODS: Ninety male Sprague-Dawley rats were divided into 5 groups (n=18 per group) according to a random number table, including the control, model, low- (12.78 g/kg, BL group), medium- (25.65 g/kg, BM group), and high-dose BYHWD groups (51.30 g/kg, BH group). A rubrospinal tract transection model in rats was established, and different doses of BYHWD were intragastrically administrated for 4 weeks. The forelimb locomotor function was recorded using the spontaneous vertical exploration test. Cyclic adenosine monophosphate (cAMP) level in red nucleus was detected through an enzyme-linked immunosorbent assay. The morphology and number of red nucleus neurons were observed using Nissl's staining and axonal retrograde tracing by Fluoro-Gold (FG). The expression of cAMP-dependent protein kinase A (PKA), nuclear factor kappa-B (NF-κB) p65, and brain-derived neurotrophic factor (BDNF) in red nucleus were detected using immunohistochemistry and quantitative real-time polymerase chain reaction. RESULTS: Compared with the control group, the utilization rate of bilateral forelimbs, unilateral right forelimbs, proportion of FG-labeled positive neurons, cAMP level, protein expressions of PKA and BDNF, and BDNF mRNA expression were significantly decreased in the model group (P<0.01), while NF-κB p65 was increased in the model group (P<0.01). Compared with the model group, the utilization rate of bilateral forelimbs and unilateral right forelimbs were significantly higher in the BL, BM and BH groups (P<0.01), the proportion of FG-labeled positive neurons, cAMP level, protein expressions of PKA and BDNF and BDNF mRNA expression in all BYHWD groups were increased (P<0.05 or P<0.01), while NF-κB p65 were decreased in all BYHWD groups (P<0.05 or P<0.01). CONCLUSIONS BYHWD possesses a sound neuroprotective effect on red nucleus neurons after SCI, and the efficacy was dose-related. The mechanism may be related to regulating the cAMP/PKA/NF-κ B p65 signaling pathway, finally promoting expression of BDNF.
Animals ; Spinal Cord Injuries/pathology* ; Drugs, Chinese Herbal/therapeutic use* ; Rats, Sprague-Dawley ; Male ; Cyclic AMP/metabolism* ; Transcription Factor RelA/metabolism* ; Cyclic AMP-Dependent Protein Kinases/metabolism* ; Signal Transduction/drug effects* ; Brain-Derived Neurotrophic Factor/genetics* ; Red Nucleus/metabolism* ; Recovery of Function/drug effects* ; Neurons/metabolism* ; Rats

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

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*

Hypoxic injury (HI) in the prenatal period often causes neonatal neurological disabilities. Due to the difficulty in obtaining clinical samples, the molecular and cellular mechanisms remain unclear. Here we use vascularized cerebral organoids to investigate the hypoxic injury phenotype and explore the intercellular interactions between vascular and neural tissues under hypoxic conditions. Our results indicate that fused vascularized cerebral organoids exhibit broader hypoxic responses and larger decreases in panels of neural development-related genes when exposed to low oxygen levels compared to single cerebral organoids. Interestingly, vessels also exhibit neural protective effects on T-box brain protein 2⁺ intermediate progenitors (IPs), which are markedly lost in HI cerebral organoids. Furthermore, we identify the role of bone morphogenic protein signaling in protecting IPs. Thus, this study has established an in vitro organoid system that can be used to study the contribution of vessels to brain injury under hypoxic conditions and provides a strategy for the identification of intervention targets.
Organoids/pathology* ; Animals ; Mice ; Hypoxia, Brain/metabolism* ; Brain/blood supply* ; Neurons/metabolism*