Neurochemical Research最新文献

Alzheimer’s disease (AD) is characterized by amyloid-β (Aβ) deposition, chronic neuroinflammation, and dysregulation of the cAMP/PKA/CREB pathway that impairs synaptic plasticity. PF-04957325 (PF), a selective PDE8B inhibitor, elevates intracellular cAMP; however, its systems-level effects and mechanisms in Aβ-driven AD are unclear. Here, we evaluate PF in an Aβ1–42 mouse model and delineate its modulation of cAMP/PKA/CREB and TLR4/MyD88/NF-κB signaling. An AD model was induced by intracerebroventricular injection of Aβ1–42, followed by oral PF administration (0.1 mg/kg/day). Cognitive performance was evaluated with the Morris water maze. Hippocampal pathology, Aβ burden, and apoptosis were assessed by H&E, immunohistochemistry, and TUNEL assays. IL-1β and IL-6 were measured by ELISA in hippocampal tissue and BV2 supernatants. Western blotting quantified APP, p-tau, and pathway proteins. BV2 cells and si-PDE8B served to validate mechanisms in vitro. PF significantly shortened escape latency (p < 0.01) and increased both platform crossings and target-quadrant dwell time (p < 0.01). It alleviated hippocampal neuronal injury, reduced Aβ burden, and decreased TUNEL-positive cells. Molecularly, PF elevated cAMP and increased p-PKA/PKA and p-CREB/CREB ratios (p < 0.01), while decreasing TLR4, MyD88, and p-NF-κB p65/NF-κB p65 (p < 0.01). PF also lowered IL-1β and IL-6 levels in hippocampal tissue and BV2 supernatants (both p < 0.01). In vitro, 300 nM PF phenocopied PDE8B knockdown, restoring cAMP/PKA/CREB activity and suppressing TLR4/MyD88/NF-κB activation. PF exerts dual protective effects by activating cAMP/PKA/CREB to enhance synaptic plasticity and survival, while inhibiting TLR4/MyD88/NF-κB to mitigate neuroinflammation. These findings highlight PDE8B inhibition as a promising therapeutic strategy for AD.

Neuroinflammation and tau pathology are central drivers of Alzheimer’s disease (AD) progression, necessitating multi-target therapeutic strategies. Here, we evaluated the efficacy and mechanisms of 0242, a novel small-molecule derivative optimized from the berberine scaffold. In lipopolysaccharide (LPS)-stimulated BV-2 microglia, 0242 treatment significantly inhibited cell activation and nitric oxide release without cytotoxicity, while downregulating the mRNA levels of pro-inflammatory cytokines IL-1β and TNF-α. Transcriptomic profiling revealed that 0242 modulated LPS-induced inflammatory gene signatures by enriched core signaling cascades, including NF-κB, TLR, and JAK-STAT and upregulating cytoprotective genes such as ceruloplasmin (Cp) and Bcl2a1b. In vivo, oral administration of 0242 attenuated hippocampal astrocyte and microglial activation in an LPS-induced acute neuroinflammatory mouse model. Furthermore, in female P301S tau transgenic mice, 0242 treatment significantly improved spontaneous locomotor activity and recognition memory. Histological and biochemical analyses confirmed that 0242 suppressed hippocampal glial activation and reduced total tau protein levels in the prefrontal cortex. Collectively, these findings suggest that 0242 may exert potent anti-neuroinflammatory effects by modulating multiple immune signaling cascades and uniquely alleviates tau pathology in AD.

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With the acceleration of global aging, Alzheimer’s disease (AD) poses a significant public health challenge, and effective treatments are still lacking. Neuroinflammation, particularly microglia-mediated inflammation, plays a central role in AD pathogenesis, with the Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathway being a key regulator. The histone deacetylase inhibitor (HDACi) Vorinostat (SAHA) has shown anti-inflammatory and neuroprotective potential in preclinical studies. Given the significant sex differences in AD incidence, pathology, and treatment response, this study aimed to systematically investigate the effects of SAHA on lipopolysaccharide (LPS)-induced neuroinflammation and cognitive dysfunction, analyzing its sex-specific effects and underlying mechanisms. An LPS-induced neuroinflammation model was established in male and female C57BL/6 mice via intraperitoneal injection (1 mg/kg) for 7 consecutive days, followed by SAHA (50 mg/kg) gavage intervention for 23 days. Cognitive function was assessed using Y-maze, novel object recognition, and passive avoidance tests. Hippocampal pathology was analyzed via hematoxylin-eosin (HE) staining and Nissl staining. Western blot and quantitative PCR (qPCR) were used to detect hippocampal expression of the TLR4/TRAF6/IKKα/NF-κB pathway, inflammatory factors (IL-6, IL-1β, TNF-α, iNOS), and neuroplasticity-related proteins (BDNF, p-CREB). In vitro experiments using LPS-stimulated BV2 microglia validated SAHA’s anti-inflammatory mechanisms via CCK-8, Griess assay, qPCR, and Western blot. Results showed that LPS treatment significantly activated the TLR4/TRAF6/IKKα/NF-κB pathway, upregulated hippocampal pro-inflammatory factors, caused neuronal damage, and impaired learning and memory; these effects appeared more pronounced in female mice, though this observation is exploratory and requires cautious interpretation. SAHA treatment markedly alleviated LPS-induced inflammation, neuropathology, and cognitive deficits. Notably, SAHA appeared to produce differential effects across sexes: female mice showed potentially stronger and more comprehensive improvements in cognitive recovery, downregulation of inflammatory factors, and upregulation of BDNF and p-CREB compared to males, suggesting a possible sexually dimorphic response. In vitro experiments further confirmed that SAHA significantly reduced inflammation in LPS-stimulated BV2 microglia by inhibiting the TLR4/TRAF6/IKKα/NF-κB pathway. In conclusion, this study demonstrates that SAHA exerts neuroprotective effects by inhibiting the TLR4/NF-κB pathway, thereby improving cognitive impairment, and may have a more pronounced protective effect in females. These findings suggest SAHA is a promising drug for treating neuroinflammation-induced cognitive dysfunction and highlight the importance of considering sex as a biological variable in epigenetic therapy for precision medicine.

Microglia-mediated neuroinflammation is closely associated with the pathogenesis of epilepsy. Mammalian sterile-20-like kinase 4 (MST4) has been suggested a regulator of inflammation. However, the effect of MST4 on microglia neuroinflammation in epilepsy remains unclear. A pilocarpine-induced rat epilepsy model was constructed and a lipopolysaccharide (LPS)-stimulated microglia cell model was applied in the current research. Knockdown or overexpression of MST4 was established using lentivirus transfection. Electroencephalograph (EEG) was employed to measure brain activities of rats. The protein and mRNA expressions were detected using western blot and qRT-PCR, respectively. Immunofluorescent staining was conducted to detect the distribution of the proteins. TUNEL staining was performed to evaluate cell apoptosis. The protein interaction was evaluated with Co-IP assay. Our results showed that MST4 and nuclear PKM2 expressions were increased in epileptic rats compared to control and colocalized with microglia. MST4 overexpression inhibited microglia activation, the release of TNF-α and IL-1β, and improved neuronal apoptosis in epileptic rats. Furthermore, MST4 interacted with PKM2 and regulated PKM2 nuclear translocation. Inhibiting PKM2 nuclear translocation by TEPP-46 reversed the promoting effect of MST4 knockdown on microglia neuroinflammation. In summary, our study demonstrated that MST4 alleviated microglia-mediated neuroinflammation in epilepsy, and the mechanism of MST4-mediated anti-neuroinflammatory effects may be associated with the inhibition of PKM2 nuclear translocation.

Accumulating evidence suggests that pharmacological restoration of microglial homeostasis in the hippocampus may be a promising strategy for treating depression. In this study, we evaluated whether gardiquimod (GDQ), a selective Toll-like receptor 7 (TLR7) agonist, produces antidepressant effects in mice subjected to chronic unpredictable stress (CUS). A single intraperitoneal injection of GDQ at 1 or 1.5 mg/kg, but not 0.5 mg/kg, improved depression-related behaviors within 5 h of administration. Time-course analyses showed that the antidepressant efficacy of GDQ (1.5 mg/kg) appeared between 5 and 8 h, persisted for up to 7 days, and diminished by 14 days after a single dose. Notably, a second GDQ injection at 14 days restored the behavioral improvements, indicating sustained responsiveness to the drug. Mechanistically, the antidepressant effects of GDQ were abolished by both pharmacological inhibition (minocycline) and genetic depletion (PLX3397) of microglia, highlighting the necessity of these cells. Furthermore, GDQ reversed the CUS-induced reduction in brain-derived neurotrophic factor (BDNF) protein levels in the dentate gyrus in a microglia-dependent manner. The critical role of BDNF signaling was confirmed by three complementary approaches: intra-hippocampal infusion of a BDNF-neutralizing antibody, genetic disruption of activity-dependent BDNF release via the Val68Met knock-in mutation, and pharmacological blockade of the TrkB receptor with K252a. Each intervention abolished the behavioral effects of GDQ. Together, these findings identify GDQ as a promising candidate for antidepressant development and highlight the restoration of microglia-supported BDNF signaling in the dentate gyrus as a key mechanism underlying TLR7-mediated mood regulation.

Early-life stress (ELS), such as maternal separation, has been associated with neuronal apoptosis and impaired hippocampal function in rodent models. This study investigated the long-term effects of two ELS paradigms—unpredictable maternal separation (MS) and MS combined with unpredictable maternal stress (MSUS)—on the hippocampal mRNA expression of proapoptotic (Bax, Tp53 and Casp3) and prosurvival (Bcl2) genes in offspring, both in vivo and in a complementary in vitro neuronal culture model. The study included three groups (Control, MS and MSUS groups), with ELS applied from postnatal days 1 to 14 to BALB/c mice. For the in vitro experiments, total RNA from the MSUS hippocampus was nucleofected at different concentrations into healthy mouse hippocampal cells, followed by 3D neuronal cell culture using N-heptyl-D-galactonamide (GalC7) hydrogels. Quantitative real-time PCR was used to assess gene expression, which was analyzed via the comparative Ct method (2^−ΔΔCt). This study revealed that Bax mRNA expression was significantly lower in the MS group than in the control group, whereas both the MS and MSUS groups presented significant increases in Bcl2 mRNA expression. In addition, the expression ratio of Bcl2/Bax was significantly greater in the MS and MSUS groups. No significant differences in Tp53 or Casp3 mRNA expression levels were detected between the groups. Although the in vitro mRNA expression levels were not significantly different, the mRNA expression ratio of Bcl2/Bax reached equilibrium as the concentration of total RNA nucleofected increased. Our results suggested that, in response to ELS, hippocampal cells adapt to prioritize survival over apoptosis.

To investigate the regulatory effects of cryptotanshinone (CTS) on the biological behavior of glioma cells and its underlying molecular mechanisms, with a particular focus on the role of the epidermal growth factor receptor/reactive oxygen species (EGFR/ROS) pathway in ferroptosis-mediated antitumor activity. Glioma cell behaviors were monitored through Cell Counting Kit-8 (CCK-8), colony formation, wound healing, and Transwell assays. Intracellular and tumor tissue levels of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), ferrous iron (Fe²⁺), glutathione/glutathione disulfide (GSH/GSSG) ratio, and malondialdehyde (MDA) were assessed. Glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), acyl-CoA synthetase long-chain family member 4 (ACSL4), epidermal growth factor receptor (EGFR), and Ki67 expression was examined using western blotting and immunohistochemistry. Network pharmacology and molecular docking were employed to predict potential cryptotanshinone targets. An in vivo glioma model was created by implanting tumor cells into nude mice. CTS inhibited glioma cell malignant phenotype, while promoting ROS accumulation, MMP loss, Fe²⁺ elevation, and GSH depletion. CTS also modulated ferroptosis-associated molecules, characterized by downregulation of GPX4 and SLC7A11 and upregulation of ACSL4. EGFR was identified as a central target, which was experimentally validated to mediate the antitumor and ferroptosis-inducing effects of CTS. In vivo, CTS suppressed tumor growth and activated ferroptosis, whereas EGFR overexpression partially reversed these protective effects. CTS induces ferroptosis in glioma cells by inhibiting EGFR and enhancing ROS signaling, thereby suppressing tumor proliferation and invasion.

Autism is a multifactorial neurodevelopmental disorder characterized by social deficits, stereotypical behaviour, and neurotransmitter imbalance. This study evaluated the neuroprotective potential of Puerarin (PUN) and Magnesium Acetyl Taurate (MGAT) in a propionic acid (PPNA)-induced rat model of autism. PPNA was administered intracerebroventricularly for 11 consecutive days to induce autism-like features, followed by a 44-day treatment period with PUN (300 mg/kg, i.p.) and MGAT (500 mg/kg, p.o.). A comprehensive assessment was conducted, including behavioural analysis, biochemical and molecular evaluations, cerebrospinal fluid and plasma profiling, and histopathology. Treatment with PUN and MGAT, particularly in combination, improved behavioural outcomes, restored neurotransmitter balance, reduced neuroinflammation and apoptotic signaling, and attenuated activation of the glutaminase–glutamate/NMDAR and MAPK pathways (C-JNK, ERK1/2, P38 MAPK). Additionally, treatment increased magnesium levels and PSD-95 expression, indicating significant neuroprotection. These findings support the potential of PUN and MGAT as a multitarget therapeutic strategy for autism and warrant further translational investigation.

Brain inflammation is increasingly recognized as a critical contributor to seizure generation and neuronal hyperexcitability. Among proinflammatory mediators, interleukin-1β (IL-1β) has been implicated in epileptogenesis; however, its acute temporal dynamics during seizure initiation remain poorly characterized because of limitations in conventional sampling approaches. In this study, we investigated the minute-by-minute intracerebral dynamics of IL-1β in a rat model of acute epileptiform activity induced by 4-aminopyridine (4-AP) and compared it with that induced by a classical inflammatory stimulus, lipopolysaccharide (LPS). Adult male Wistar rats (10–12 weeks old) were implanted with a push-pull guide cannula in the right lateral ventricle and electrodes over the ipsilateral and contralateral cortices to enable simultaneous cerebrospinal fluid (CSF) sampling and electroencephalographic (EEG) recordings. IL-1β concentrations were quantified at one-minute resolution using a nanodot blot immunodetection method, while epileptiform activity was assessed through EEG amplitude analysis and discharge train identification. Intraventricular administration of 4-AP (75 mM) induced robust epileptiform activity accompanied by a rapid and transient surge in IL-1β levels, reaching a peak concentration of 199 ± 28 ng/mL within 14 min (p < 0.05 vs. NaCl) and closely coinciding with the onset of epileptiform discharges. In contrast, intraventricular administration of LPS (25 µg/µL) elicited a delayed and sustained increase in IL-1β which was statistically significant at 240 and 300 min post-administration and did not induce epileptiform activity during the evaluated period. Although cumulative IL-1β exposure was comparable between 4-AP and LPS groups, their temporal profiles were markedly distinct. These findings demonstrate that acute epileptiform activity is associated with a rapid release of IL-1β that temporally coincides with seizure-like events, supporting a role for early cytokine signaling in seizure initiation. Moreover, this study highlights the importance of minute-resolution approaches for identifying neuroinflammatory processes that are otherwise obscured by conventional sampling strategies.