Experimental Neurobiology最新文献

Postoperative cognitive dysfunction (POCD) is a clinically significant complication in elderly patients, largely driven by surgery-induced neuroinflammation. The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway, a crucial regulator of innate immunity, has been implicated in neuroinflammatory activation. This study investigated whether electroacupuncture (EA) improves POCD by modulating this pathway in aged rats. Aged male Sprague-Dawley rats were subjected to sevoflurane anesthesia and splenectomy to establish a POCD model. Animals were divided into sham, POCD, POCD+EA, and POCD+EA+cGAS inhibitor groups. The EA groups received stimulation at Baihui (Governor Vessel 20 (GV20)), Neiguan (Pericardium 6 (PC6)), and Zusanli (Stomach 36 (ST36)) acupoints. Cognitive function was evaluated using the Morris water maze, while hippocampal expression of cGAS-STING pathway components and downstream effectors-interferon regulatory factor 3 (IRF3), nuclear factor kappa B (NF-κB), and interleukin-1 beta (IL-1β)-was assessed by Western blot. Cellular localization was determined by immunofluorescence staining. Compared with the Sham group, rats in the POCD group showed significant impairments in spatial memory, accompanied by upregulated protein expression of cGAS, STING, NF-κB, IRF3, and IL-1β in the hippocampus. Upon pathway activation, cGAS and STING proteins were predominantly co-localized with neurons, and their fluorescence intensity in the hippocampus was markedly increased. These behavioral deficits and molecular alterations were partially reversed in both the POCD+EA and POCD+EA+inhibitor groups. Electroacupuncture alleviates POCD in aged rats by inhibiting hippocampal cGAS-STING pathway activation and reducing neuroinflammation, suggesting a promising non-pharmacological strategy for POCD management.

In Alzheimer's disease (AD), persistent microglial neuroinflammation and the poor brain exposure and durability of current therapies underscore the need for new, long-acting treatments. We developed a non-viral gene therapy that suppresses microglial Toll-like receptor 2 (TLR2) signaling using poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with a plasmid encoding the anti-TLR2 single-chain variable fragment (scFv33). Following intra-cisterna magna delivery, PLGA NPs exhibited microglia-biased uptake and enabled brain-wide transgene expression in mice. In 5xFAD mice, a single administration of scFv33 NPs improved recognition memory in the novel object recognition (NOR) assay, outperforming 8 weeks of weekly recombinant scFv33-Fc dosing. Histology showed selective reduction of small hippocampal Aβ plaques and a shift toward a ramified microglial morphology, indicative of reduced activation. In primary neuron-microglia co-culture, scFv33 reduced microglial hypertrophy, restored process complexity, and enhanced Aβ phagocytosis. Together, these data indicate that sustained, local expression of an anti-TLR2 scFv via a clinically translatable PLGA platform recalibrates microglial state and preferentially limits early-stage plaque accumulation, yielding cognitive benefit after a single dose.

Chrysanthemum zawadskii flower ethanol extract (CZ-F) was evaluated for its neuroprotective potential against inflammation-associated cognitive impairment. To assess its anti-inflammatory properties, we first conducted in vitro studies using LPS-stimulated BV2 microglial cells. CZ-F demonstrated strong antioxidant activity with IC₅₀ values of 186.04 μg/ml (DPPH) and 94.56 μg/ml (ABTS), suppressed the production of reactive oxygen species and nitric oxide, and downregulated the expression of iNOS and IL-1β, likely via inhibiting the NF-κB signaling pathway. CZ-F also decreased inflammation-induced acetylcholinesterase (AChE) expression and directly inhibited AChE activity. Among the constituents of CZ-F, quercetin and luteolin exhibited the strongest anti-inflammatory and antioxidant effects, while linarin most potently inhibited AChE activity. In an in vivo zebrafish model, CZ-F treatment ameliorated learning and memory impairments induced by sleep deprivation. These findings suggest that CZ-F can attenuate neuroinflammation and modulate cholinergic dysfunction, providing a potential therapeutic approach for inflammation-related cognitive deficits.

Glioblastoma (GBM) remains fatal despite maximal surgical resection, temozolomide chemotherapy, and radiotherapy. Within the GBM microenvironment, tumor-educated microglia and astrocytes adopt immunoregulatory-like STAT3-high and ARG1/TGF-β-high phenotypes, respectively, which shield GBM cells from adaptive immune attack. In this review, we examine emerging adjuvant strategies designed to molecularly reprogram glial cells toward pro-inflammatory C3-high and IFN/NF-κB-high states, amplifying antitumor immunity. First, we summarize key aspects of GBM pathobiology and identify why conventional treatments fail to achieve durable control. Next, we dissect the signaling networks that govern glial phase states, including NF-κB, STAT3, IRF3, NLRP3, and cGAS-STING axes. We then provide a mechanism-centric analysis of pattern-recognition receptor (PRR) agonists, inflammasome modulators, and cyclic-dinucleotide STING agonists, integrating quantitative preclinical data with early clinical trial results. For each adjuvant, we distinguish between direct astrocytic engagement and indirect cytokine-mediated reprogramming. Modulation of glial phase states holds considerable promise for enhancing personalized vaccine efficacy and for converting immunologically "cold" GBM into a T cell-inflamed tumor. Consequently, targeting glial cell phase modulation is a highly attractive strategy for GBM immunotherapy, with the potential to maximize therapeutic benefit. Despite advances in chemo-, radio-, and checkpoint-blockade therapies, the immunosuppressive tumor microenvironment (TME) of GBM and its failure to establish memory immunity limit their impact. Tumor-polarized astrocytes and microglia form a barrier to effective T cell-mediated attack. Emerging evidence shows that redirecting glia toward pro-inflammatory phenotypes can recondition the TME, creating a more permissive landscape for immunotherapy. This review highlights glial phase reprogramming as a promising immunoadjuvant approach, emphasizing molecular circuits, synthetic modulators, and translational prospects.

Spinocerebellar ataxia type 3 (SCA3) is an autosomal-dominant neurodegenerative disorder caused by an expanded polyglutamine repeat in the ataxin-3 gene. The resulting mutant ataxin-3 protein forms intraneuronal inclusions that lead to neurodegeneration in the cerebellum and other brain regions. This study aimed to develop a novel nonhuman primate model of SCA3 to address the limitations of existing knock-in and transgenic models using an adeno-associated virus (AAV) to deliver the mutant gene. AAV viral vectors carrying mutant ataxin-3 were stereotaxically injected into the cerebellum of monkeys. The animals were monitored over an 8-week period, during which behavioral and neuroimaging assessments were conducted. This was followed by a detailed pathological examination. The AAV vector successfully spread throughout the cerebellum, and the expression of mutant ataxin-3 was confirmed. Neuroimaging revealed a reduction in N-acetylaspartate (NAA) levels, whereas histological analysis showed significant damage to the Purkinje cell layer. Notably, the monkeys exhibited sleep disturbances, a prodromal symptom commonly observed in human patients with SCA3. AAV-mediated delivery of mutant ataxin-3 can effectively replicate the key pathological and clinical features of SCA3 in primates. This approach offers a promising new model for studying disease mechanisms and evaluating potential therapies.

Early-life stress (ELS) is a major contributor to neurodevelopmental vulnerability, particularly within the dentate gyrus (DG), where oxidative burden and microglial activation disrupt adult neurogenesis. Here, we examined whether N-acetylcysteine (NAC), a cysteine prodrug and glutathione precursor, could counteract impaired neurogenesis induced by neonatal maternal separation (NMS). Adolescent NAC administration restored the number of Ki67⁺ proliferating progenitors and DCX⁺ immature neurons in the DG of NMS rats, accompanied by reduced reactive oxygen species, suppressed iNOS induction, and attenuated microglial activation. NAC also normalized EAAC1 expression, indicating enhanced neuronal antioxidant capacity. Notably, NAC rescued diminished neurogenesis in EAAC1 knockout mice, demonstrating its efficacy under both stress-induced and transporter-deficient redox imbalance. These findings identify NAC as a potent modulator of hippocampal neuroplasticity, acting through the restoration of redox and inflammatory homeostasis, and support its potential as an early therapeutic strategy to mitigate long-lasting neurodevelopmental consequences of ELS.

The ability to cope with changing environments is critical for healthy functioning, yet this flexibility is impaired in many neuropsychiatric disorders. However, neural mechanisms underlying flexible behavior remain elusive. Here, we report that oscillatory dynamics in the medial prefrontal cortex (mPFC) support learning to flexibly overcome established behavioral bias. Mice performed a delayed non-match-to-sample task that required trial-by-trial adjustment of arm choice strategy despite persistent arm bias. Decoding analysis of delay-period local field potentials (LFPs) and single-unit activities revealed evolving neural representations across trials as mice adapted to the task. Notably, mPFC neurons modulated by theta (4~12 Hz) bursts selectively encoded upcoming choice information after acquiring the new rule. In contrast, beta (12~30 Hz) bursts correlated with perseverative behavior and appeared to inhibit theta-modulated neuronal firing in mice showing adaptive behavior. These theta and beta bursts were temporally separated over the delay period, reflecting a dynamic gating mechanism. Thus, beta bursts shape neuronal ensembles that are modulated by theta bursts to facilitate flexible learning. This dynamic interaction provides a mechanistic basis for cognitive flexibility and provides insights into cognitive rigidity seen in neuropsychiatric disorders such as schizophrenia and autism.

Listening to rhythmic patterns leads to neural entrainment to beat and meter periodicities. The debate over whether entrainment is a mere reflection of external stimuli, or an inherent intrinsic response persists. The objective of this study was to ascertain whether there are cerebral cortices, which satisfy 3 distinct features of intrinsic entrainment; first, the ability to sustain neural oscillations even in random beat omission; second, a requisite latency period for the build-up before initiating a response to rhythmic stimuli; and third, the persistence of these neural oscillations gradually recedes following the cessation of the stimulus. In 27 patients with medically intractable epilepsy, electrocorticography data were obtained with 2- or 3-beat sound stimulations with random omissions. We found that there are cortices which satisfy all three requirements of intrinsic entrainment. The cortices synchronized with beat were in Brodmann areas (BA) 21, and 22, whereas the cortices synchronized with meter corresponded to BA3, 6, 9, 22, 40, and 44. We showed that entrainment is an intrinsic response, with distinct neural processing for beat and meter. These insights advance our understanding of neural entrainment to beat and meter periodicities.

Mitochondrial bioenergetics plays a fundamental role in neuronal development and function. Prenatal exposure to corticosterone in rats (Corti. Pup) has previously been shown to cause delayed neurodevelopment and synaptic plasticity deficits, showing attention deficit hyperactivity disorder (ADHD) - like behaviors. However, the underlying mitochondrial metabolic adaptations remain unclear. This study investigated mitochondrial function and metabolic remodeling in prefrontal cortex neurons of Corti.Pups, focusing on oxidative phosphorylation, calcium handling, and redox balance. We assessed neuronal viability, reactive oxygen species (ROS) production, and oxygen consumption rate (OCR) through experiments conducted in both neuron-glia co-culture and neuron-only conditions. Furthermore, we evaluated electron transport chain (ETC) activity, mitochondrial membrane potential (MMP), and mitochondrial Ca²⁺ uptake in purified isolated mitochondria. In results, Corti.Pup neurons exhibited increased vulnerability to glutamate-induced excitotoxicity in the absence of glial support. Despite reduced ROS production, these neurons showed elevated mitochondrial OCR and proton leak, coupled with decreased non-mitochondrial OCR and ETC complex activity. Surprisingly, MMP remained elevated despite ETC dysfunction, and mitochondrial Ca²⁺ uptake was suppressed. These features indicate mitochondrial metabolic reprogramming, prioritizing MMP maintenance over ATP synthesis. The observed mitochondrial inefficiency and compensatory adaptations may impair energy production, contributing to delayed neuronal development in Corti.Pups. These findings suggest that mitochondrial dysfunction and metabolic remodeling play central roles in the pathogenesis of neurodevelopmental disorders such as ADHD.

Dynamic facial expressions carry a wide range of signals, encompassing emotional but also more conversational content important for social interaction, for which the dynamic aspect is crucial. Likewise, we know from previous behavioral and neuroimaging studies that processing of emotional stimuli changes across aging - little, however, is known about how age may impact brain activity for dynamic facial expressions. To address this open issue, here we used two cohorts of older and younger adults (total N=77) within a whole-brain MVPA decoding paradigm in fMRI. We used a range of dynamic and conversational expressions as stimuli shown with a foil task in the scanner and had participants rate these post-scanning in terms of their affective content along 12 dimensions (including valence and arousal). The behavioral ratings were used to cluster the facial expressions and the resulting similarity matrix was used in a searchlight decoding paradigm to identify common areas. Using robust bootstrap analyses, we identified the insula as a common brain region able to decode the wide range of emotional and conversational dynamic facial expressions for both participants groups. We also discuss additional brain areas specific to the younger group. Our study adds to the growing literature on neural processing of dynamic expressions in the context of aging.