NeuroMolecular Medicine最新文献

Pain and depression frequently are comorbid and have common mechanisms such as monoamine depletion, inflammation, and oxidative stress. Hence, this study aimed to investigate the effects of bioactive coumarin on reserpine induced pain-depression dyad in mice. Mechanical allodynia, depressive-like behavior, and cognitive deficits were induced by reserpine (0.5 mg/kg, subcutaneously, once daily on days 1-3) in male BALB/c mice. Scopoletin (50 mg/kg, p.o.) or gabapentin (10 mg/kg, p.o.) was given twice daily (at 9:00 am and 5:00 pm) for 5 days. For days 1-3, the initial daily dose of scopoletin or gabapentin was given 30 min before reserpine injection, with the second dose at the evening. Control animals, which received vehicle, were given 0.1% CMC. Behavioural tests (Electronic von Frey (eVF) test, Pressure Application Measurement (PAM) test) (Forced Swim Test (FST) and Morris Water Maze (MWM) test) were performed on day 4 and 6, and tissue collection was conducted on day 6 for biochemical analyses (cytokines (TNF-α and IL-1β), neurotransmitters (Serotonin, Norepinephrine, and Glutamate), MAO-A activity, GSH, TBARS). Paw withdrawal thresholds (eVF day 4: F(3,20) = 28.75, p < 0.001; PAM: F(3,20) = 35.17, p < 0.001) were markedly diminished and immobility time in FST (F(3,20) = 29.11, p < 0.001) was notably prolonged by reserpine. Moreover, it impaired the spatial memory (MWM: F(3,20) = 30.56, p < 0.001), and increased the serum TNF-α and IL-1β (F(3,20) = 24.32 and 18.50, respectively; p < 0.01), the brain MAO-A activity (F(3,20) = 16.83, p < 0.01), glutamate and TBARS (F(3,20) = 25.11, p < 0.001; F(3,20) = 19.76, p < 0.01), and decreased the brain serotonin, norepinephrine and GSH (p < 0.01-0.001). Supplementation with scopoletin markedly retarded deficits in behavior (eVF and PAL, p < 0.001; FST, p < 0.001; MWM, p < 0.001) and biochemistry (reduction of UG [TNF-α, IL-1β], MAO-A activity and glutamate level along with restoration of monoamine and antioxidant status, p < 0.05-0.001). Scopoletin is a promising candidate drug for comorbid pain and depression due to its significant counteracting effects on reserpine-induced behavioral and biochemical alterations.

Although researchers began to unravel the potential significance of Runt-related transcription factor 2 (RUNX2) in some of neurological diseases, the role of RUNX2 in ischemic stroke remained unclear. Blood samples and clinical information were collected from stroke patients and control subjects. Besides, middle cerebral artery occlusion (MCAO) mice model and astrocytes oxygen-glucose deprivation/reperfusion (OGD/R) were established to simulate the pathological process of stroke in vivo and in vitro. Loss-of-function assay was used to assess the effect of RUNX2 on astrocytes function. HE staining and Nissl staining were used to examine the histopathological changes of brain tissues in mice. TTC staining was used to measure the cerebral infarct volume in mice. Morri's water maze test, the corner turn test, and the balance beam test were performed to evaluate neurobehavioral performances of mice. The results showed that the expression and serum content of RUNX2 were upregulated in stroke patients and mice. Knocking-down RUNX2 inhibited OGD/R-induced increases of proliferation and migration, while reversed the decrease of apoptosis in astrocytes. Moreover, RUNX2 knockdown also suppressed the inflammatory response in OGD/R-treated astrocytes and promoted the conversion of the reactive astrocyte phenotype from A1 to A2. The serum mRNA expression and level of RUNX2 were both notably increased in patients with cerebral edema. RUNX2 knockdown weakened cerebral edema and swelling of astrocytes. The results of HE staining and Nissl staining suggested that RUNX2 knockdown notably improved neuronal damage in the brain tissues of MCAO mice and also improved the injured performance of MCAO stroke mice in the behavioral test. In conclusion, RUNX2 expression was upregulated during the pathological progression of ischemic stroke. Furthermore, the knockdown of RUNX2 alleviated OGD/R-induced astrocytes activation and swelling, while inhibiting the polarization and inflammatory response in astrocytes. More importantly, RUNX2 interference also improved neuronal damage, cerebral edema, and neurobehavioral performances of MCAO mice.

Spinal Cord Injury (SCI) is a severe disorder of the central nervous system, typically caused by trauma or disease, which significantly impacts the quality of life of affected individuals. Secondary inflammation following spinal cord injury is a critical factor influencing prognosis, making the exploration of the inflammatory microenvironment crucial for the treatment of SCI. Xanthoxylin, a small organic molecule extracted from plants, has demonstrated notable anti-inflammatory effects. To investigate the role of Xanthoxylin in spinal cord injury, we initially employed Hoechst staining and flow cytometry, revealing that Xanthoxylin reduces neuronal apoptosis. Subsequently, through Western blot, immunofluorescence, and qPCR, we discovered that Xanthoxylin promotes the polarization of microglia from the M1 inflammatory phenotype to the M2 anti-inflammatory phenotype. Furthermore, transcriptome sequencing identified differential expression in the NF-κB pathway, which was corroborated by Western blot analysis. Finally, animal experiments were conducted to further validate the therapeutic effects of Xanthoxylin on spinal cord injury in mice. These results suggest that Xanthoxylin has a significant therapeutic effect on SCI in mice. Overall, our study is the first to demonstrate the therapeutic effect of Xanthoxylin on SCI and provides a scientific exploration of its underlying mechanisms, offering new directions for pharmacological treatment of spinal cord injury.

Rett syndrome (RTT), a severe neurodevelopmental disorder primarily affecting girls, is commonly caused by MECP2 loss-of-function mutations. Key symptoms include motor impairments, typical hand stereotypies and intellectual disability. Moreover, although not thoroughly studied, anxiety, heightened stress sensitivity, and aberrant pain perception are also an important component of the RTT phenotype. Emerging evidence suggests that early-life stress (ELS) worsens Mecp2-related phenotypic alterations in mice. Microglia, the resident immune cells within the central nervous system, play a critical role in RTT pathophysiology, yet the combined impact of ELS and Mecp2 deficiency on microglia has not been studied. Previously, we observed reduced activation of the periaqueductal grey (PAG, a cerebral structure involved in pain modulation, autonomic control, and defensive behaviours) in Mecp2-heterozygous (Mecp2-het) mice after thermal stimulation. Here, we investigated the impact of ELS on microglia morphology in the PAG under Mecp2 deficiency. To this end, we analysed microglia in the PAG of presymptomatic Mecp2-het mice previously subjected to maternal separation (MS) as a model of ELS, alongside corresponding control animals. Brain sections were immunolabelled for IBA1, a pan-microglial marker. Microglial cells within the PAG were evaluated for expression levels, morphological characteristics, and fractal properties. While global PAG analyses showed minimal differences, subdivision-specific analyses revealed significant microglial alterations. These findings suggest that ELS exacerbates Mecp2-related neurodevelopmental deficits, impairing microglia in a region-specific manner. Our data points to a microglial failure to morphologically adapt, rather than overt structural loss, in the PAG that may underlie some of the neurological dysfunctions observed in RTT.

The bisbenzylisoquinoline alkaloid dauricine (DAU) is known for its neuroprotective effects in animals. This study investigates the memory-enhancing effects of DAU in Swiss albino mice using both in vivo and in silico approaches, focusing on its interaction with the D2 dopamine (DOP) receptor. Behavioral tests, including marble burying, dust removal, and trained swimming, were used to assess cognitive performance, anxiety, and motor coordination. Molecular docking studies revealed that DAU binds strongly to the D2 DOP receptor (6CM4 protein), with a binding affinity of - 7.9 kcal/mol, forming significant hydrogen and hydrophobic bonds. Additionally, the pharmacokinetics and toxicity profiles of DAU were also evaluated. In vivo results showed that DAU improved behavioral performance in a dose-dependent manner, with the DAU-10 group showing significant (p < 0.05) enhancement compared to the control and standard groups. The DAU-10 + DOP-22 combination group also showed remarkable results compared to the standard alone. Pharmacokinetics and toxicity profiles were also assessed, revealing favorable properties but some concerns regarding mutagenicity and immunotoxicity. These findings suggest that DAU, especially when combined with D2 DOP receptor agonists, holds significant potential for memory enhancement and warrants further investigation.

Tauopathies, including Alzheimer's disease and frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17), are characterized by the aberrant aggregation of tau protein into neurofibrillary tangles. Despite extensive studies on tau aggregation, the mechanisms of tau misfolding and propagation remain incompletely understood. In this study, we utilize the SPAM (S320F/P301S) tau transgenic mouse model, which expresses 0N4R human tau with two FTDP-17 mutations, to investigate the biochemical properties and seeding potential of misfolded tau from these mice. Sarkosyl extraction and ultracentrifugation were employed to isolate detergent-insoluble tau aggregates (SPAM-tau) from aged SPAM mice. These aggregates were then tested for their prion-type seeding activity in an established HEK293T cell model comparing the induced aggregation of wild-type and mutant forms of human and murine tau. Our results show that SPAM-tau exhibits distinct and vigorous prion-like seeding properties, inducing the aggregation of human and murine tau homologues with the formation of amyloidogenic (Thioflavin S-positive) inclusions. Importantly, SPAM-tau aggregates can facilitate the prion-type misfolding of wild-type and mutant forms of human and mouse tau. We demonstrated that these induced tau aggregates are able to be further transmitted in passaging studies. Furthermore, SPAM-tau preferentially templated 4R tau isoforms, sharing strain-like seeding properties with insoluble tau derived from the brains of individuals with progressive supranuclear palsy (PSP-tau). In summary, these findings enhance our understanding of tau aggregation and propagation, suggesting that SPAM-tau may serve as a valuable tool for studying tauopathies and evaluating potential therapeutic strategies aimed at halting tau misfolding and propagation.

In the human brain, the nigrostriatal pathway regulates motor functions, and its selective deterioration leads to the onset of Parkinson's disease (PD), a neurodegenerative disorder characterized by motor dysfunction and significant disability. The A9 neurons, a subgroup of ventral mesencephalic dopaminergic (DA) neurons, form the nigrostriatal pathway that emerges from the nigral region and innervates into the striatum. These DA neurons exhibit extensive and arborized axonal terminals projecting into the dorsal striatum. This review examines the distinct molecular determinants underlying the development, projection pattern, survival, maintenance, and vulnerability of A9 neurons, distinguishing them from other ventral midbrain DA subgroups such as A8 and A10. Key transcription factors (e.g., Lmx1a/b, FoxA2, Pitx3), signaling cascade pathways (e.g., Sonic Hedgehog, Wnt/β-catenin), and molecular markers (e.g., Aldh1a1, GIRK2, ANT2) are discussed in detail. A comparative assessment of the electrophysiology, cytoarchitecture, energy demand, and antioxidant reserves of A9 DA neurons versus the neighboring ventral mesencephalic DA subgroups elucidates the role of intrinsic determinants in susceptibility and selective degeneration in PD. The unique susceptibility of A9 cells to redox imbalance, neuronal inflammation, and mitochondrial dysfunction is also explored. Furthermore, recent advancements in stem cell-based approaches for generating A9-like neurons and their application in cell transplantation therapies for PD are discussed. Current challenges, including integration and long-term survival of transplanted neurons, are highlighted alongside prospects of cell replacement therapy. By evaluating the molecular biology of A9 neurons, this review aims to understand PD pathology and develop strategies for novel therapeutic approaches.

The chronic administration of D-galactose (D-gal) is widely used to model brain senescence in rodents. However, the effects of prolonged oral exposure of D-gal on the neuroinflammatory cytokines in rats remain poorly characterized. Therefore, we administered D-gal (100 mg/kg) in male Wistar rats aged 3-4 months, via oral gavage once a day for 1, 2, 4, 6, or 8 weeks. Cytokine and neurotrophin levels were analyzed using the ELISA method. D-gal administrations for 4, 6, and 8 weeks significantly increased interleukin -1β (IL-1β), tumor necrosis factor-alpha (TNF-α), and interleukin-4 (IL-4) levels in the frontal cortex and hippocampus. In addition, 4, 6, and 8 weeks of D-gal administration significantly increased interleukin-10 (IL-10) levels in the frontal cortex; however, in the hippocampus, only 6 and 8 weeks of D-gal administration significantly increased the IL-10 levels. In terms of neurotrophin levels, our results demonstrated that 1 week of D-gal administration significantly increased Brain-derived Neurotrophic Factor (BDNF) and Nerve Growth Factor (NGF) in the hippocampus. In the frontal cortex, D-gal increased BDNF levels when administered for 1 and 2 weeks and increased NGF levels when administered for only 2 weeks. However, we observed a reduction of BDNF, NGF, and Glial cell line-derived Neurotrophic Factor (GDNF) levels after 6 and 8 weeks of D-gal treatment in the frontal cortex. Moreover, GDNF levels also were reduced after 4 weeks of D-gal administration. These findings suggest that oral D-gal exposure disrupts the balance of cytokines and neurotrophins, which may be an essential mechanism in brain aging and neurodegenerative processes.

Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder for which there are currently no curative therapies. Therefore, the need for innovative treatments for this illness is critical. The glucosylceramidase beta 1 (GBA1) and leucine-rich repeated kinase 2 (LRRK2) genes have been postulated as potential genetically defined drug targets. We report for the first time that the LRRK2 inhibitor PF-06447475 (PF-475) not only restores GCase enzyme activity, but also increases mitochondrial membrane potential, significantly decreases DJ-1 Cys106-SO₃, reduces lysosome accumulation, and diminishes cleaved caspase-3 (CC3) in GBA1 K198E fibroblasts. Furthermore, in addition to a significant reduction in p-Ser935 LRRK2 kinase, we found that PF-475 reduced p-Thr73 RAB 10 and p-Ser129 α-Syn in mutant skin fibroblasts. In addition, we found that the GCase activator GCA (NCGC00188758) increased GCase activity and decreased lysosomal accumulation, but did not affect p-Ser935 LRRK2, ∆Ψm, p-Ser129 α-Syn, DJ-1 Cys106-SO₃, or CC3 in K198E GBA1 fibroblasts. The GCase inhibitor conduritol-β-epoxide (CBE), used as an internal control, significantly reduced GCase and left the other pathological markers largely unaltered in GBA1 K198E, but reduced GCase and increased the accumulation of lysosomes only in WT GBA1 fibroblasts. Taken together, these results suggest that LRRK2 is a critical signaling kinase in the pathogenic mechanism associated with the lysosomal GBA1/GCase K198E variant. Our findings suggest that the use of LRRK2 inhibitors in PD patients with GBA1 mutations, such as K198E, may be effective in reversing GBA1/GCase deficiency, autophagy impairment, oxidative stress, and neuronal death.

Organophosphate insecticides like malathion, though less toxic than other compounds in the same class, remain a significant public health concern due to their widespread use and potential neurotoxic effects. Prolonged exposure to malathion can lead to environmental contamination and neurobehavioral issues such as anxiety, depression, and cognitive impairment, mediated through cholinergic and non-cholinergic pathways. Cynodon dactylon (L.), a medicinal herb renowned in traditional and Ayurvedic medicine, exhibits anti-inflammatory, antioxidant, anti-diabetic, and neuroprotective properties. Evidence suggests that it can mitigate neurotoxicity and improve brain antioxidant status in rodent models. Therefore, this study explored the protective effects of the hydro-alcoholic extract of Cynodon dactylon (HAECD) on malathion-induced neurotoxicity, emphasizing its impact on behavior, biochemistry, and brain structure. Forty-two Swiss mice were randomly assigned to six groups, each containing seven mice. One group received normal saline (control), while another was given malathion (100 mg/kg, orally). Three groups received HAECD (250, 500, or 1000 mg/kg daily) alongside malathion, and the final group received only HAECD (1000 mg/kg, orally). Behavioral tests, including the elevated plus maze, light-dark test, and Morris water maze to assess the anxiety-depression-like behaviors, and cognitive function. Biochemical analyses measured acetylcholinesterase activity, lipid peroxidation, antioxidant enzymes (superoxide dismutase and catalase), and brain-derived neurotrophic factor (BDNF). Inflammatory markers and hippocampal histopathology were also examined. Results indicated that HAECD significantly alleviated anxiety and cognitive dysfunction while reducing oxidative stress markers, restoring antioxidant enzyme levels, and modulating brain-derived neurotrophic factor and inflammatory responses. These findings highlight the potential of HAECD in protecting the brain from malathion-induced neurotoxicity.