1.Electroacupuncture Attenuates Neuroinflammation and Postoperative Cognitive Dysfunction in Aged Rats by Suppressing the cGAS–STING Pathway
Baobao MA ; Shiwen FAN ; Jiaojiao DENG ; Kaihua WEI ; Yan LI ; Jiangwen YIN ; Liping XIE
Experimental Neurobiology 2026;35(1):42-55
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.
2.Chrysanthemum zawadskii Flower Extract Rescues Inflammatory Cognitive Impairment
Yeongwoo CHOI ; Jisun HWANG ; Bohee JANG ; Jiwon PARK ; Inn-Oc HAN ; Eok-Soo OH
Experimental Neurobiology 2026;35(1):29-41
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 CZF, 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 inflammationrelated cognitive deficits.
3.Identification of Cortices with Characteristics of Rhythmic Entrainment and Its Periodicity
Youmin SHIN ; Jii KWON ; June Sic KIM ; Chun Kee CHUNG
Experimental Neurobiology 2026;35(1):17-28
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.
4.Mitochondrial Metabolic Reprogramming of Cortical Neurons by Prenatal Exposure to Corticosterone: A Shift from ATP Synthesis to Membrane Potential Maintenance
Khulan AMARSANAA ; Michidmaa BADARCH ; Hee-Young KIM ; Oh-Bin KWON ; Eun-Bok BAEK ; Eun-A KO ; Sung-Cherl JUNG
Experimental Neurobiology 2026;35(1):1-16
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.
5.Neuroinflammation in Adaptive Immunodeficient Mice with Colitis-like Symptoms
Sung Hee PARK ; Junghwa KANG ; Ji-Young LEE ; Jeong Seon YOON ; Sung Hwan HWANG ; Ji Young LEE ; Deepak Prasad GUPTA ; Il Hyun BAEK ; Ki Jun HAN ; Gyun Jee SONG
Experimental Neurobiology 2025;34(1):34-47
Emerging evidence suggests that systemic inflammation may play a critical role in neurological disorders. Recent studies have shown the connection between inflammatory bowel diseases (IBD) and neurological disorders, revealing a bidirectional relationship through the gut-brain axis.Immunotherapies, such as Treg cells infusion, have been proposed for IBD. However, the role of adaptive immune cells in IBD-induced neuroinflammation remains unclear. In this study, we established an animal model for IBD in mice with severe combined immune-deficient (SCID), an adaptive immune deficiency, to investigate the role of adaptive immune cells in IBD-induced neuroinflammation. Mice were fed 1%, 3%, or 5% dextran sulfate sodium (DSS) for 5 days. We measured body weight, colon length, disease activity index (DAI), and crypt damage. Pro-inflammatory cytokines were measured in the colon, while microglial morphology, neuronal count, and inflammatory cytokines were analyzed in the brain. In the 3% DSS group, colitis symptoms appeared at day 7, with reduced colon length and increased crypt damage showing colitis-like symptoms. By day 21, colon length and crypt damage persisted, while DAI showed recovery. Although colonic inflammation peaked at day 7, no significant increase in inflammatory cytokines or microglial hyperactivation was observed in the brain. By day 21, neuroinflammation was detected, albeit with a slight delay, in the absence of adaptive immune cells. The colitis-induced neuroinflammation model provides insights into the fundamental immune mechanisms of the gut-brain axis and may contribute to developing immune cell therapies for IBD-induced neuroinflammation.
6.Sphingomonas Paucimobilis-derived Extracellular Vesicles Reverse Aβ-induced Dysregulation of Neurotrophic Factors, Mitochondrial Function, and Inflammatory Factors through MeCP2-mediated Mechanism
Eun-Hwa LEE ; Hyejin KWON ; So-Young PARK ; Jin-Young PARK ; Jin-Hwan HONG ; Jae-Won PAENG ; Yoon-Keun KIM ; Pyung-Lim HAN
Experimental Neurobiology 2025;34(1):20-33
Recent studies have shown an increased abundance of Sphingomonas paucimobilis, an aerobic, Gram-negative bacterium with a distinctive cell envelope rich in glycosphingolipids, within the gut microbiome of individuals with Alzheimer Disease (AD). However, the fact that S. paucimobilis is a well-known pathogen associated with nosocomial infections presents a significant challenge in investigating whether its presence in the gut microbiome is detrimental or beneficial, particularly in the context of AD. This study examines the impact of S. paucimobilis-derived extracellular vesicles (Spa-EV) on Aβ-induced pathology in cellular and animal models of AD. Microarray analysis reveals that Spa-EV treatment modulates Aβ42-induced alterations in gene expression in both HT22 neuronal cells and BV2 microglia cells. Among the genes significantly affected by SpaEV, notable examples include Bdnf, Nt3/4, and Trkb, which are key players of neurotrophic signaling; Pgc1α, an upstream regulator of mitochondrial biogenesis; Mecp2 and Sirt1, epigenetic factors that regulate numerous gene expressions; and Il1β, Tnfα, and Nfκb-p65, which are associated with neuroinflammation. Remarkably, Spa-EV effectively reverses Aβ42-induced alteration in the expression of these genes through the upregulation of Mecp2. Furthermore, administration of Spa-EV in Tg-APP/PS1 mice restores the reduced expression of neurotrophic factors, Pgc1α, MeCP2, and Sirt1, while suppressing the increased expression of proinflammatory genes in the brain. Our results indicate that Spa-EV has the potential to reverse Aβ-induced dysregulation of gene expression in neuronal and microglial cells. These alterations encompass those essential for neurotrophic signaling and neuronal plasticity, mitochondrial function, and the regulation of inflammatory processes.
7.Transcriptomic Alteration in the Brain and Gut of Offspring Following Prenatal Exposure to Corticosterone
Eun-A KO ; Tong ZHOU ; Jae-Hong KO ; Sung-Cherl JUNG
Experimental Neurobiology 2025;34(1):9-19
Maternal stress during pregnancy can profoundly affect offspring health, increasing the risk of psychiatric disorders, metabolic diseases, and gastrointestinal problems. In this study, the effects of high prenatal corticosterone exposure on gene expression in the brain and small intestine of rat offspring were investigated via RNA-sequencing analysis. Pregnant rats were divided into two groups: Corti.Moms were injected with corticosterone daily, while Nor.Moms were given saline injections. Their offspring were labeled as Corti.Pups and Nor.Pups, respectively. The brain tissue analysis of Corti.Pups showed that the expression levels of the genes linked to neurodegenerative conditions increased and enhanced mitochondrial biogenesis, possibly due to higher ATP demands. The genes associated with calcium signaling pathways, neuroactive ligand-receptor interactions, and IgA production were also upregulated in the small intestine of Corti.pups. Conversely, the genes related to protein digestion, absorption, and serotonergic and dopaminergic synaptic activities were downregulated. These findings revealed that gene expression patterns in both the brain and intestinal smooth muscle of offspring prenatally exposed to corticosterone were substantially altered. Thus, this study provided valuable insights into the effects of prenatal stress on neurodevelopment and gut function.
8.Combination of Aβ40, Aβ42, and Tau Plasma Levels to Distinguish Amyloid-PET Positive Alzheimer Patients from Normal Controls
Seungyeop BAEK ; Jinny Claire LEE ; Byung Hyun BYUN ; Su Yeon PARK ; Jeong Ho HA ; Kyo Chul LEE ; Seung-Hoon YANG ; Jun-Seok LEE ; Seungpyo HONG ; Gyoonhee HAN ; Sang Moo LIM ; YoungSoo KIM ; Hye Yun KIM
Experimental Neurobiology 2025;34(1):1-8
Alzheimer disease (AD) diagnosis is confirmed using a medley of modalities, such as the detection of amyloid-β (Aβ) neuritic plaques and neurofibrillary tangles with positron electron tomography (PET) or the appraisal of irregularities in cognitive function with examinations. Although these methods have been efficient in confirming AD pathology, the rising demand for earlier intervention during pathogenesis has led researchers to explore the diagnostic potential of fluid biomarkers in cerebrospinal fluid (CSF) and plasma. Since CSF sample collection is invasive and limited in quantity, biomarker detection in plasma has become more attractive and modern advancements in technology has permitted more efficient and accurate analysis of plasma biomolecules. In this study, we found that a composite of standard factors, Aβ40 and total tau levels in plasma, divided by the variation factor, plasma Aβ42 level, provide better correlation with amyloid neuroimaging and neuropsychological test results than a level comparison between total tau and Aβ42 in plasma. We collected EDTA-treated blood plasma samples of 53 subjects, of randomly selected 27 AD patients and 26 normal cognition (NC) individuals, who received amyloid-PET scans for plaque quantification, and measured plasma levels of Aβ40, Aβ42, and total tau with digital enzyme-linked immunosorbent assay (ELISA) in a blinded manner. There was difficulty distinguishing AD patients from controls when analyzing biomarkers independently. However, significant differentiation was observed between the two groups when comparing individual ratios of total-tau×Aβ40/Aβ42. Our results indicate that collectively comparing fluctuations of these fluid biomarkers could aid in monitoring AD pathogenesis.
9.Neuroinflammation in Adaptive Immunodeficient Mice with Colitis-like Symptoms
Sung Hee PARK ; Junghwa KANG ; Ji-Young LEE ; Jeong Seon YOON ; Sung Hwan HWANG ; Ji Young LEE ; Deepak Prasad GUPTA ; Il Hyun BAEK ; Ki Jun HAN ; Gyun Jee SONG
Experimental Neurobiology 2025;34(1):34-47
Emerging evidence suggests that systemic inflammation may play a critical role in neurological disorders. Recent studies have shown the connection between inflammatory bowel diseases (IBD) and neurological disorders, revealing a bidirectional relationship through the gut-brain axis.Immunotherapies, such as Treg cells infusion, have been proposed for IBD. However, the role of adaptive immune cells in IBD-induced neuroinflammation remains unclear. In this study, we established an animal model for IBD in mice with severe combined immune-deficient (SCID), an adaptive immune deficiency, to investigate the role of adaptive immune cells in IBD-induced neuroinflammation. Mice were fed 1%, 3%, or 5% dextran sulfate sodium (DSS) for 5 days. We measured body weight, colon length, disease activity index (DAI), and crypt damage. Pro-inflammatory cytokines were measured in the colon, while microglial morphology, neuronal count, and inflammatory cytokines were analyzed in the brain. In the 3% DSS group, colitis symptoms appeared at day 7, with reduced colon length and increased crypt damage showing colitis-like symptoms. By day 21, colon length and crypt damage persisted, while DAI showed recovery. Although colonic inflammation peaked at day 7, no significant increase in inflammatory cytokines or microglial hyperactivation was observed in the brain. By day 21, neuroinflammation was detected, albeit with a slight delay, in the absence of adaptive immune cells. The colitis-induced neuroinflammation model provides insights into the fundamental immune mechanisms of the gut-brain axis and may contribute to developing immune cell therapies for IBD-induced neuroinflammation.
10.Sphingomonas Paucimobilis-derived Extracellular Vesicles Reverse Aβ-induced Dysregulation of Neurotrophic Factors, Mitochondrial Function, and Inflammatory Factors through MeCP2-mediated Mechanism
Eun-Hwa LEE ; Hyejin KWON ; So-Young PARK ; Jin-Young PARK ; Jin-Hwan HONG ; Jae-Won PAENG ; Yoon-Keun KIM ; Pyung-Lim HAN
Experimental Neurobiology 2025;34(1):20-33
Recent studies have shown an increased abundance of Sphingomonas paucimobilis, an aerobic, Gram-negative bacterium with a distinctive cell envelope rich in glycosphingolipids, within the gut microbiome of individuals with Alzheimer Disease (AD). However, the fact that S. paucimobilis is a well-known pathogen associated with nosocomial infections presents a significant challenge in investigating whether its presence in the gut microbiome is detrimental or beneficial, particularly in the context of AD. This study examines the impact of S. paucimobilis-derived extracellular vesicles (Spa-EV) on Aβ-induced pathology in cellular and animal models of AD. Microarray analysis reveals that Spa-EV treatment modulates Aβ42-induced alterations in gene expression in both HT22 neuronal cells and BV2 microglia cells. Among the genes significantly affected by SpaEV, notable examples include Bdnf, Nt3/4, and Trkb, which are key players of neurotrophic signaling; Pgc1α, an upstream regulator of mitochondrial biogenesis; Mecp2 and Sirt1, epigenetic factors that regulate numerous gene expressions; and Il1β, Tnfα, and Nfκb-p65, which are associated with neuroinflammation. Remarkably, Spa-EV effectively reverses Aβ42-induced alteration in the expression of these genes through the upregulation of Mecp2. Furthermore, administration of Spa-EV in Tg-APP/PS1 mice restores the reduced expression of neurotrophic factors, Pgc1α, MeCP2, and Sirt1, while suppressing the increased expression of proinflammatory genes in the brain. Our results indicate that Spa-EV has the potential to reverse Aβ-induced dysregulation of gene expression in neuronal and microglial cells. These alterations encompass those essential for neurotrophic signaling and neuronal plasticity, mitochondrial function, and the regulation of inflammatory processes.

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