Molecular Neurobiology最新文献

CDGSH iron sulfur domain 1 (CISD1) plays important roles in regulating cellular iron and reactive oxygen species (ROS) homeostasis. This study aimed to investigate the effect of CISD1 on neuronal ferroptosis in Alzheimer's disease (AD) cellular models, and the implication of AMPK pathway during this process. CISD1 expression in brain tissues from AD patients and controls was obtained from AlzData public database. HT22 and SH-SY5Y cells were challenged with amyloid-beta (Aβ) to construct AD cellular models. CISD1 or negative-control (NC) overexpression plasmids were transfected into AD cellular models; afterwards, Compound C (an AMPK activator) was added. CISD1 expressions in entorhinal cortex, hippocampus, temporal cortex, and frontal cortex tissues were decreased in AD patients versus controls via AlzData public database analysis. CISD1 expression was also downregulated in AD cellular models versus control cells. Interestingly, cell viability and SLC7A11 and GPX4 expressions were lower, but ROS and Fe²⁺ levels were higher in AD cellular models versus control cells, indicating an enhanced neuronal ferroptosis in AD. Subsequently, CISD1 overexpression plasmids raised cell viability and SLC7A11 and GPX4 expressions, while decreased ROS and Fe²⁺ levels compared with NC overexpression plasmids in AD cellular models. CISD1 overexpression plasmids also facilitated the phosphorylation of AMPK to activate this pathway compared to NC overexpression plasmids. Moreover, the addition of Compound C not only promoted the neuronal ferroptosis, but also attenuated the effect of CISD1 overexpression plasmids on regulating neuronal ferroptosis compared with the absence of Compound C in AD cellular models. Collectively, CISD1 represses neuronal ferroptosis by activating the AMPK pathway in AD cellular models, shedding a light on its potential engagement in the AD pathogenesis.

Aristotelia chilensis (maqui) extracts have garnered interest for their potential bioactivity, yet their specific effects on Alzheimer's disease (AD) pathology remain understudied. This study evaluated the neuroprotective properties of white and black maqui fruit extracts against glutamate-induced excitotoxicity and β-amyloid (Aβ) fibrillogenesis in vitro. Pre-treatment with maqui extracts significantly mitigated glutamate toxicity, increasing cell viability from 26.8% in glutamate-treated cells to 49.9% and 48.8% for white and black maqui, respectively. Furthermore, the extracts reduced Fluorojade C-positive degenerating neurons by up to 86.4% compared to the glutamate control. The extracts also exhibited potent anti-fibrillogenic activity, suppressing Aβ fibril formation by up to 77% in the ThT assay. Electron microscopy confirmed this inhibitory effect by showing a reduction in fibrillar structures. In contrast, neither extract inhibited acetylcholinesterase nor butyrylcholinesterase activity. Together, these results indicate that maqui fruits contain compounds capable of modulating key pathological features of AD in vitro, supporting their potential for further investigation.

Alzheimer's disease (AD) involves progressive neurodegeneration, with abnormal receptor signaling and disrupted cell-cycle activity leading to neuronal loss. Here, we identify a previously unknown mechanism linking β-amyloid (Aβ) exposure to the nuclear translocation of the Insulin-like Growth Factor 1 Receptor (IGF1R) in differentiated SH-SY5Y neuronal cells. The differentiated cholinergic model induced by retinoic acid and BDNF expresses acetylcholinesterase (AChE) and indicates that under amyloidogenic stress, IGF1R may transition from homeostatic membrane and vesicular signaling to a nuclear-centric function. We show that prolonged Aβ treatment causes phosphorylation-dependent nuclear import of IGF1R, confirmed by confocal imaging and biochemical fractionation. IGF1R is conventionally located in the membrane and vesicular membranes; however, under amyloidogenic stress, we show here that it is imported to the nucleus and exerts transcriptional control. The buildup of nuclear IGF1R coincided with increased Cyclin D1 levels and redistribution of neurons into S and G₂ phases, indicating abnormal cell-cycle re-entry. Chromatin immunoprecipitation demonstrated increased IGF1R binding at the CCND1 and JUN promoters after Aβ exposure, suggesting a direct role in gene transcription. Pharmacological blockade of IGF1R phosphorylation by PPP or SUMOylation by Ginkgolic acid significantly reduced Cyclin D1 elevation, implying that both post-translational modifications are involved in receptor nuclear trafficking. Co-immunoprecipitation and confocal imaging identified Nucleophosmin (NPM1) as a putative IGF1R interacting partner, potentially contributing to its nuclear transport and stabilizing receptor-chromatin complexes. These results establish IGF1R as a signaling-transcription connector linking extracellular amyloid stress to nuclear gene regulation, providing a mechanistic explanation for faulty neuronal cell-cycle re-entry in AD. We suggest that abnormal IGF1R-NPM1 interactions contribute to receptor mislocalization and cell-cycle failure, highlighting new targets for therapeutic intervention aimed at receptor trafficking and neuroprotection in Alzheimer's disease.

Growing evidence suggests that spinal cord injury (SCI) can result in chronic brain damage, potentially leading to depression and cognitive deficits. High mobility group box-1 (HMGB1) plays a pivotal role in the pathogenesis of central nervous system (CNS) disorders, yet the mechanism by which SCI induces depression remains unclear. This study aims to explore the key mechanisms by which HMGB1 contributes to depression-like behaviors following SCI. A rat model of SCI-induced depression was established to assess the therapeutic effects of ICM on neurobehavioral outcomes, microglial activation, and neuronal damage. Molecular docking was performed to predict the interaction between ICM and HMGB1. Hippocampal RNA-seq profiled ICM-responsive transcriptional changes, with DEGs identified and KEGG enrichment highlighting TLR4-NF-κB signaling, followed by Western blot validation of selected targets. In vivo, immunofluorescence, Western blotting, qRT-PCR, and ELISA were utilized to evaluate HMGB1 translocation, TLR4-NF-κB pathway activation, and inflammatory cytokine production in the hippocampus. In vitro, a microglia-neuron co-culture system was used to investigate the role of neuronal HMGB1 in microglia-mediated neuroinflammation, with suppression of HMGB1 achieved via ICM pretreatment or siRNA knockdown. Our findings showed that inflachromene (ICM) effectively suppressed microglial activation, thereby reducing hippocampal neuronal injury in the SCI-induced depression model. ICM alleviated neuroinflammatory responses by directly preventing the nuclear-to-cytoplasmic translocation of HMGB1, a critical damage-associated molecular pattern released from injured neurons that triggers microglial activation and inflammatory cytokine expression. Bulk RNA-seq of hippocampal tissue from the Sham, SCI, and SCI + ICM groups revealed significant enrichment of Toll-like receptor and NF-κB signaling pathways following SCI, highlighting the HMGB1-TLR4-NF-κB axis as a central inflammatory mechanism. Consistent with the transcriptomic prediction, both ICM treatment and neuronal HMGB1 knockdown markedly inhibited TLR4-NF-κB signaling, reduced reactive-oxygen-species accumulation, and diminished pro-inflammatory cytokine production in microglia. Notably, the combination of ICM and siHMGB1 produced no additive effect, confirming neuronal HMGB1 as the upstream driver of TLR4-NF-κB-dependent neuroinflammation. SCI-induced release of hippocampal neuronal HMGB1 activates microglial TLR4-NF-κB signaling, driving neuroinflammation and contributing to depressive-like behaviors. Targeting HMGB1 nuclear translocation with ICM represents a promising therapeutic approach for depression following SCI.

Alzheimer's disease (AD) poses a significant global health burden, underscoring the need for early and accessible biomarkers to enable timely diagnosis and intervention. Lipids, which constitute over half of the brain's mass, play essential roles in numerous cellular processes, and their dysregulation has been increasingly implicated in AD pathophysiology. In this study, we performed lipidomic profiling of hippocampal samples derived from individuals at different Braak stages and plasma samples from patients with mild cognitive impairment (MCI), AD, and healthy controls. Parallel analyses were conducted in 5xFAD transgenic mice and wild-type littermates. Our results revealed lipid alterations across central and peripheral compartments in both human subjects and the 5xFAD mouse model. Notably, specific lipid changes identified in particular lipid species at early/mild Braak stages or in MCI persisted into advanced stages of the disease, highlighting the systemic nature of lipid dysregulation in AD and supporting the potential of these lipid signatures as diagnostic and prognostic biomarkers.

Neuroinflammation mediated by microglia is recognized as a critical contributor to Alzheimer's disease (AD) pathogenesis, and P2RY12 maintains microglial homeostasis. MicroRNAs regulate gene expression post-transcriptionally and have been implicated in modulating microglial activation states during AD by affecting inflammatory pathways. This study aimed to investigate the role of miR-548 m in regulating microglial polarization and neuroinflammation in Alzheimer's disease. Male APP/PS1 transgenic and wild-type mice were utilized as animal models alongside cultured microglial cells for in vitro studies. Behavioral assessments, including contextual fear Morris water maze (MWM) and fear conditioning (FC), evaluated cognitive function. Molecular analyses comprised RT-qPCR western blot, and ELISA, as well as dual-luciferase reporter assays to validate miR-548 m and P2RY12 interactions. In vivo modulation of miR-548 m expression was achieved via stereotaxic intracerebral injections of agomir or antagomir oligonucleotides targeting the dentate gyrus. MiR-548 m was significantly upregulated in AD. Overexpression of miR-548 m promoted microglial M1 polarization characterized by increased pro-inflammatory cytokines (TNF-α, IL-6, iNOS, IL-1β) and reduction in M2 anti-inflammatory markers (Arg1, CD206, IL-4, TGF-β). Inhibition of miR-548 m improved spatial learning and memory performance while attenuating microglial activation in vivo. Luciferase reporter assays confirmed that P2RY12 is a direct downstream target suppressed by miR-548 m. And overexpression of miR‑548 m reversed the inflammatory effects induced by P2RY12 overexpression. These findings demonstrate that elevated miR‑548 m exacerbates neuroinflammation through negative regulation of P2RY12 expression, leading to enhanced microglial M1 polarization during AD progression. Targeting the miR‑548 m/P2RY12 axis may provide a novel therapeutic for mitigating AD.

Ischemic stroke is a leading cause of death and disability among youth, with sex-specific differences in risk and outcomes, including post-stroke cognitive impairment. However, the neurodevelopmental factors underlying these pathological states are unclear. This study examined hypoxia-inducible factor-1 alpha (HIF-1α) and brain-derived neurotrophic factor (BDNF) levels in bilateral common carotid artery occlusion/reperfusion (BCCAO/R)-induced ischemic stroke in rats. It focused on post-stroke cognitive decline in male and female adult offspring following BCCAO/R-induced ischemic stroke, after prenatal immune activation (PIA) and late-trimester intermittent maternal hypoxic stress (IMHS). PIA was induced by lipopolysaccharide (0.1 mg/kg, i.p.) injection at gestational day (GD) 15, followed by IMHS exposure from GDs 17 until delivery. Thereafter, offspring (n = 10, male and females) from sham control, LPS-exposed, hypoxia-exposed, and combined LPS + hypoxia group were exposed to BCCAO/R-induced ischemic stroke at postnatal day 90. Neurological deficits and post-stroke cognitive function were assessed using Y-maze and novel-object recognition tests at 1-day and 5-days post-surgery. The prefrontal cortex and striatum, where structural and functional alterations have primarily been described in stroke patients, were isolated for BDNF and HIF-1α ELISA quantification. In female rats, non-spatial working memory was acutely reduced after BCCAO/R-induced stroke following PIA-IMHS exposures, but males were unaffected. Rats co-exposed to LPS + hypoxia show decreased HIF-1α in the male striatum compared to sham or LPS/hypoxia groups. The two-hit factor increased striatal BDNF levels compared with LPS alone. In females' prefrontal cortex, LPS + hypoxia versus controls, but LPS + hypoxia reduces BDNF more than LPS alone, indicating a synergistic and sex-dependent role of PIA and IMHS in stroke vulnerability at adulthood.

Gulf War illness (GWI) affects nearly one-third of US veterans deployed during the 1990-1991 Gulf War (GW) and is characterized by chronic fatigue, neuroinflammation, and gut dysbiosis. Through comprehensive fecal metabolomics sequencing, our lab previously reported the depletion of beneficial metabolites including spermidine in the preclinical GWI mouse model. Spermidine is an endogenously synthesized polyamine known for its anti-inflammatory and mucosal barrier protective effects in various pathological diseases. Given its established role in mitigating intestinal inflammation and maintaining homeostasis, this study investigated the therapeutic potential of spermidine in a persistent (22 weeks) GWI mouse model, with a specific focus on gut-brain axis regulation. Our results demonstrated that spermidine effectively restored both microbial richness and diversity by selectively enriching beneficial bacterial taxa and suppressing growth of opportunistic pathogens, which are otherwise dysregulated following exposure to GW chemicals. Spermidine treatment also improved gut epithelial barrier integrity and reduced epithelial release of high-mobility group box 1 (HMGB1) into systemic circulation. Recent studies on GWI have implicated a critical role of gut-derived damage-associated molecular patterns (DAMPs), particularly HMGB1 in mediating neuroinflammation. Our findings indicate that systemic levels of HMGB1 critically influence the extent of blood-brain barrier (BBB) disruption and subsequent microglial activation. Mechanistically, spermidine activated intestinal aryl hydrocarbon receptor (AhR)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling, which played a role in limiting intestinal HMGB1 release and suppressing downstream receptor for advanced glycation end-product (RAGE)-mediated microglial activation in the brain. In vitro results indicate spermidine promoted AhR/Nrf2 nuclear translocation which reduced LPS-induced HMGB1 release from primary intestinal epithelial cells (IECs), effects abrogated by AhR inhibition. Additionally, we observed that HMGB1 directly induces microglial activation via RAGE receptors in immortalized microglial (IMG) cell lines in a dose-dependent manner. These results demonstrate that spermidine decreases neuroinflammation by modulating gut-brain axis pathophysiology associated with GWI. Together, this study demonstrates the therapeutic role of spermidine in ameliorating systemic and neurological disturbances in GWI.

Blood-brain barrier (BBB) disruption is a major contributor to brain injury following ischemic stroke. However, current endothelial-targeted strategies for BBB protection have shown limited clinical efficacy. Glial cells are essential for maintaining BBB integrity, but the mechanisms underlying glial-mediated BBB dysfunction after ischemic stroke remain poorly defined. Here, we identify microglial oncostatin M (OSM) and astrocytic OSM receptor (OSMR) as critical mediators of BBB disruption following cerebral ischemia-reperfusion. Single-cell RNA sequencing and immunofluorescence analysis revealed selective upregulation of OSMR in astrocytes after transient middle cerebral artery occlusion and reperfusion (MCAO/R) in mice. Astrocyte-specific OSMR knockdown maintained BBB integrity by restoring aquaporin-4 polarity and tight junction protein expression in electron microscopy and dextran leakage assays, thereby reducing infarct volume and improving neurological function. To elucidate the underlying mechanism, cell-cell communication analysis and proximity ligation assays demonstrated a direct and enhanced interaction between microglial OSM and astrocytic OSMR after MCAO/R. Similarly, OSM was markedly upregulated in microglia, and microglia-specific OSM knockout reproduced the protective effects of astrocytic OSMR knockdown, thereby restoring BBB integrity. Collectively, these results support the OSM-OSMR axis as a potential therapeutic target for the preservation of BBB integrity in ischemic stroke.