Neurochemical Research最新文献

The hippocampus plays an important role in contextual fear-conditioning and exhibits functional specialization along its dorso-ventral axis. The dorsal hippocampus (DH) is primarily involved in spatial and contextual processing, whereas the ventral hippocampus (VH) modulates affective and emotional components of memory. Although these regions are functionally interconnected, their differential neuronal temporal dynamics during contextual fear conditioned (CxFC) memory consolidation and retrieval remain unclear. In this study, we examined the selective engagement and activity-dependent changes during the early phase of CxFC memory consolidation and retrieval in the DH and VH. Mice were subjected to fear-conditioning, and freezing behaviour was assessed during baseline, training, and testing sessions as a measure of fear memory. The levels of Arc and c-Fos proteins in the DH and VH were measured at 0, 1, 3, and 5 h. The freezing response increased significantly during testing compared to the baseline day. The level of Arc and c-Fos proteins significantly increased in the DH but not in the VH during the training and testing days. Arc levels in the DH showed a time-dependent increase, peaking at the 1st hour, and remaining significantly elevated through the 5th hour on conditioning and post-conditioning days, with no corresponding changes observed in the VH. Similarly, c-Fos levels in the DH increased significantly at 1^st, 3^rd, and 5^th hours on both days, with no corresponding changes in the VH. Our results suggest that the DH may play an essential role in mediating the early phase of CxFC memory formation and its subsequent retrieval.

This study probed the mechanism of MARCH6 in endoplasmic reticulum autophagy (ER-phagy) during glioma development by regulating FAM134B stability. MARCH6 and FAM134B expression levels were measured in glioma tissues. A comparative analysis was conducted on the correlation between clinical parameters and FAM134B expression in 46 glioma patients. FAM134B and MARCH6 were knocked down in glioma cells, followed by detection of cell viability and apoptosis, typical ER stress (ERS) markers (PERK, IRE1α, eIF2α, and CHOP), autophagy-related proteins (P62 and LC3B), and autophagosome cytoplasmic accumulation. A mouse glioma model was established for in vivo validation. MARCH6-FAM134B interaction, FAM134B ubiquitination levels, and protein stability were examined. FAM134B expression was high and MARCH6 expression was low in glioma tissues. MARCH6 induced FAM134B protein ubiquitination and degradation, reducing its stability in glioma cells. Knockdown of FAM134B reduced glioma cell survival, inhibited PERK, IRE1α, eIF2α, and CHOP expression, decreased LC3I to LC3II conversion, lowered LC3B fluorescence expression, and reduced the accumulation of autophagosomes with continuous ER structures in the cytoplasm, while enhancing apoptosis and P62 expression. This effect can be reversed by knocking down MARCH6. In vivo, FAM134B knockdown suppressed tumorigenesis in mice. MARCH6 exerts a repressive effect on ERS responses and ER-phagy in glioma cells by destabilizing FAM134B.

Epilepsy is a complex neurological disorder shaped by oxidative stress, imbalances in trace elements, and psychological distress, yet the mechanisms linking these factors to seizure severity and psychiatric outcomes remain poorly understood. This study investigated their interplay through clinical, biochemical, and in silico approaches. A cross sectional analysis was conducted on 200 epilepsy patients and 200 controls with comparable age and sex distributions. Psychological distress was measured using the Depression Anxiety Stress Scale-21 (DASS-21). Serum levels of copper (Cu²⁺), zinc (Zn²⁺), selenium (Se^2-), iron (Fe²⁺), chromium (Cr³⁺), and magnesium (Mg²) were quantified via atomic absorption spectrophotometry, while oxidative stress markers malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were assessed by ELISA. Hierarchical regression identified predictors of stress and anxiety, and molecular docking was employed to evaluate interactions of Cu²⁺, Zn²⁺, Se^2-, and MDA with SOD. Results revealed that epilepsy patients had significantly higher stress, anxiety, depression, Cu²⁺, and MDA levels, along with reduced Zn²⁺, Se^2-, SOD, and GSH. Regression analyses indicated that Cu²⁺ and MDA were positive predictors of psychological distress, while Zn²⁺, Se^2-, and SOD exerted protective effects. Docking studies demonstrated strong binding of Cu²⁺ and MDA to SOD, potentially impairing its activity, whereas Zn²⁺ and Se^2- promoted stabilization of antioxidant defenses. These findings suggest that trace element dysregulation and oxidative stress contribute to both seizure pathology and psychiatric comorbidities, reinforcing a cycle of neuronal excitatory imbalance, and psychological vulnerability. Integrating antioxidant based therapies and trace element correction with mental health monitoring may improve personalized management of epilepsy. This study is distinctive in combining clinical, biochemical, psychological, and molecular docking analyses to unravel the synergistic effects of trace elements and oxidative stress on epilepsy outcomes.

Chronic post-surgical pain (CPSP) in rats is characterized by persistent mechanical allodynia and spinal neuronal hypersensitivity. Astrocyte-derived L-lactate, a key modulator of neuronal excitability and synaptic plasticity, was herein investigated for its role in CPSP development following skin/muscle incision and retraction (SMIR). SMIR triggered long-lasting mechanical allodynia, concomitantly with astrocyte activation and elevated L-lactate levels in the spinal dorsal horn. Blockage of glycogenolysis by 4-dideoxy-1,4-imino-D-arabinitol (DAB), inhibition of carbonic anhydrase (CA) by acetazolamide or inhibition of soluble adenylyl cyclase (sAC) by bithionol prevented SMIR-induced mechanical allodynia and reduced spinal dorsal horn L-lactate levels, implicating a critical role of astrocyte-derived lactate in CPSP development and maintenance. Chemogenetic inhibition of spinal astrocyte suppressed mechanical allodynia and decreased L-lactate accumulation in the dorsal horn. Notably, exogenous L-lactate enhanced the firing rate of spinal lamina Ⅰ-II neurons but failed to alter excitatory synaptic transmission, suggesting a selective role for L-lactate in modulating spinal neuronal intrinsic excitability. Mechanistically, SMIR elevated plasma glucocorticoid levels, while adrenalectomy (ADX) abolished both SMIR- induced mechanical allodynia and spinal lactate elevation. Collectively, these findings indicate that glucocorticoid receptor signaling drives astrocytic L-lactate release in spinal dorsal horn following SMIR, which promotes spinal neuronal hyperexcitability and contributes to CPSP pathogenesis.

Conversion of microglia to a branching state is considered a potential strategy to ameliorate neuroinflammation. Inhibition of histone deacetylases (HDACs) may convert microglia to a branching state and thus prevent neuroinflammation. Drugs that inhibit HDACs could be used to alleviate neuroinflammation. Here, we hypothesize that 4-phenylbutyric acid (4-PBA), an HDAC inhibitor, could shift microglia to an anti-inflammatory phenotype by promoting microglial process elongation. As expected, our results showed that 4-PBA induced reversible elongation of branching processes in primary cultured mouse microglia and in microglia in the prefrontal cortex of mice. Pretreatment with 4-PBA also prevented lipopolysaccharide (LPS)-induced shortening of branching processes in microglia under both in vitro and ex vivo conditions, LPS-induced pro-inflammatory responses in cultured microglia and prefrontal cortex, and LPS-induced sickness behavior in mice. Short-term incubation with 4-PBA led to a significant increase in phosphorylation levels of protein kinase B (Akt) in cultured microglia. 4-PBA did not induce microglial process elongation in vitro or ex vivo when cultured microglia or mice were treated with the Akt signaling inhibitor LY294002, suggesting that the pro-elongation effect of 4-PBA on microglial processes require activation of Akt signaling. Moreover, 4-PBA did not prevent LPS-induced inflammatory responses in cultured microglia and prefrontal cortex or LPS-induced sickness behaviors when cultured microglia or mice were treated with LY294002. Altogether, these results indicate that 4-PBA induces microglial process elongation in an Akt-dependent manner, which may underlie the anti-neuroinflammatory properties of 4-PBA.

Glioblastoma (GB) is the most aggressive and lethal primary brain tumor, characterized by high proliferative, migratory, and invasive capacities, as well as marked resistance to apoptosis. Despite standard therapy with temozolomide (TMZ), prognosis remains poor, underscoring the need for novel therapeutic strategies. In this study, we investigated the antitumor potential of centratherin, a sesquiterpene lactone, in established GB cell lines and patient-derived GB cells (GBM02, GBM95). Centratherin significantly reduced cell viability in a dose-dependent manner, with IC50 values varying across GB cells, while exhibiting no cytotoxicity to healthy human astrocytes. Functional assays revealed that centratherin impairs cell proliferation, migration, and invasion, and alters cytoskeletal architecture, as evidenced by morphological changes, reduced actin and tubulin organization. Additionally, centratherin induced double-strand DNA breaks, increased γH2AX levels, and triggered cell death predominantly via necrosis, as demonstrated by LIVE/DEAD staining, Annexin V/PI flow cytometry, and ultrastructural analysis. Notably, this cytotoxic effect did not involve necroptosis, as RIP1 expression and Nec-1 sensitivity were unchanged. Furthermore, centratherin failed to sensitize GB cells to TMZ, suggesting distinct mechanisms of action, in spite of its remarked effect on inducing cell death in GB cancer stem-like cells. Overall, our findings highlight centratherin as a promising selective cytotoxic agent against GB, capable of inducing cell death and disrupting key malignant phenotypes, which may be advantageous for GB treatment.

Alzheimer's disease (AD), a major neurodegenerative disorder, lacks effective early diagnostic and therapeutic strategies. This study aimed to investigate the diagnostic utility of Long non-coding RNAs HLA Complex Group 18 ( HCG18) in AD and elucidate its molecular mechanisms in neuronal injury. Eighty-three AD patients and 83 healthy controls (HC) were enrolled. Serum samples were analyzed for HCG18 expression using qRT-PCR and cerebrospinal fluid (CSF) samples were analyzed for AD biomarkers by ELISA. Diagnostic performance was assessed using ROC analysis. Aβ1-42-treated HT22 cells (Immortalized murine hippocampal neuronal-like cell line) were employed to model neuronal injury, with HCG18 knockdown and miR-425-3p inhibition experiments conducted to validate functional interactions. HT22 cell apoptosis, oxidative stress markers (SOD, GSH-Px, MDA, ROS), and HCG18/miR-425-3p interactions were evaluated through flow cytometry, biochemical assays, and dual-luciferase reporter systems. Serum HCG18 levels were significantly elevated in AD patients compared to HC (P < 0.001), exhibiting strong diagnostic accuracy (AUC = 0.889). HCG18 expression correlated negatively with CSF Aβ1-42 (r=-0.709) and MMSE scores (r=-0.657), but positively with t-tau (r = 0.591) and p-tau181 (r = 0.582). In Aβ1-42-treated HT22 cells, HCG18 knockdown reduced apoptosis, suppressed ROS, and normalized oxidative stress markers. Mechanistically, HCG18 directly bound to and acted as a molecular sponge for miR-425-3p, sequestering its function; the downregulation of miR-425-3p mediated by a synthetic inhibitor reversed the protective effects of HCG18 silencing. HCG18 serves as a potential non-invasive biomarker for AD, exacerbating neuronal injury via sponging miR-425-3p to disrupt redox balance. Targeting the HCG18/miR-425-3p axis may offer new therapeutic strategies for AD.

Microglia are crucial in ischemic brain injury (IBI). Modulating microglial autophagy and inhibiting ferroptosis via miR-122 targeting G9a may mitigate disease progression. This study investigated whether miR-122 attenuates IBI progression by targeting G9a to promote microglial autophagy and inhibit ferroptosis. In vivo, a transient middle cerebral artery occlusion (tMCAO) rat model received intracerebroventricular injections of agomiR-122 for miR-122 overexpression or AAV-G9a for G9a overexpression to assess miR-122/G9a roles in autophagy and ferroptosis. In vitro, oxygen-glucose deprivation/reperfusion (OGD/R)-treated BV2 cells were transfected with miR-122 mimic, oe-G9a, and treated with rapamycin (RA) or ferrostatin-1 (Fer-1) to delineate the miR-122/G9a-autophagy-ferroptosis axis. A microglia-hippocampal neuronal cell transwell co-culture system assessed HT22 viability to confirm miR-122-mediated neuroprotection via G9a inhibition. In vivo, miR-122 ameliorated neurological deficits and attenuated brain injury in tMCAO rats by negatively regulating G9a. This was accompanied by enhanced autophagy (e.g., increased LC3-II/I ratio) and suppression of ferroptosis (e.g., upregulation of GPX4) and inflammatory responses. In vitro, agomiR-122 in OGD/R-injured BV2 cells promoted cell viability and autophagy, while inhibiting ferroptosis. These effects were reversed by AAV-G9a but rescued upon treatment with RA or Fer-1. Moreover, in a BV2-HT22 co-culture system, agomiR-122 in microglia conferred neuroprotection, an effect that was abolished by G9a upregulation. MiR-122 ameliorates IBI by targeting G9a to enhance microglial autophagy and suppress ferroptosis, offering mechanistic insights and novel therapeutic targets.