Neurochemical Research最新文献

Stroke is a major cause of mortality and morbidity. It is known to induce gut dysbiosis, which can exacerbate brain injury by increasing systemic inflammation and disrupting the gut-brain axis. This study investigated the effects of probiotics on immunomodulation and brain regeneration in a post-stroke animal model, with a particular focus on gut-brain axis. In this study, Male Wistar rats were divided into three groups: Sham, Ischemia and Ischemia + Probiotic. Focal cerebral ischemia was induced by one-hour middle cerebral artery occlusion (MCAO). The probiotic group received 10⁹ CFU/ml probiotic solution via gavage for 14 days. After 14 days, behavioral outcomes and cerebral infarct volume were assessed. Molecular docking was performed to analyze the binding affinities of probiotic metabolites with TLR4 and FGFR2 which were further validated by RT-PCR gene expression analysis. Serum matrix metalloproteinase-9 activity was evaluated using zymography and oxidative stress was assessed by measuring malondialdehyde, total antioxidant capacity, and nitric oxide levels in the ischemic penumbra. According to the results, the probiotic group showed a significant reduction in infarct volume and improved behavioral deficits. Molecular analysis revealed that probiotics increased nitric oxide levels and total antioxidant capacity while decreasing malondialdehyde levels. Consistent with molecular docking, there was a significant increase in FGFR2 and TLR4 gene expression and matrix metalloproteinase-9 activity. These findings show probiotic supplementation reduces brain damage after stroke, likely via the modulation of FGFR2/TLR4 inflammatory pathway, which could originate from gut microenvironment dysregulation.

The endocannabinoid anandamide (AEA) and the related metabolite oleamide (ODA) have been demonstrated to possess anti-proliferative properties by recruiting apoptotic mechanisms in glioblastoma cells; however, the role of receptors other than the canonical cannabinoid receptors in their pattern of anti-proliferative mechanisms has been poorly investigated. Here, we evaluated the role of mitochondrial function and PPAR-γ membrane receptors in the anti-proliferative mechanisms induced by AEA and ODA in the glioblastoma cell lines C6 and RG2. Cell viability and lipid peroxidation assessments in both cell lines showed antiproliferative and pro-oxidant effects of the tested cannabinoids, respectively, compared to primary astrocyte cultures used as a non-tumor negative control. AEA and ODA also reduced mitochondrial membrane potential in C6, but not in RG2 cells, while impairing mitochondrial Complex I activity in C6. The PPAR-γ receptor antagonist GW9662 showed differential effects on the AEA- and ODA-induced loss of cell viability in both cell lines, as well as in mitochondrial membrane potential. The ontogenetic origin and metabolic differences between RG2 and C6 cell lines may establish differential responses evoked by endogenous cannabinoids and PPAR-γ receptor modulation. Combined, our results demonstrate that AEA and ODA modulate mitochondrial function in glioblastoma cells by inhibiting the activity of mitochondrial Complex 1, which in turn increases markers of oxidative damage and interferes with glioblastoma proliferation.

Graphical Abstract

The endocannabinoids AEA, and its related compound ODA, decrease cell viability and proliferation in C6 and RG2 glioblastoma cells by inducing mitochondrial stress. Depending on the phenotypic and metabolic features of the GB cell line, PPAR-γ receptor can induce anti-proliferative effects mediated by eCB. ODA and AEA exert different mechanisms depending on the cell line; in C6, lipoperoxidation, a decrease in mitochondrial membrane potential, and inhibition of mitochondrial complex I are predominant, while in RG2, sensitivity to PPAR-γ modulation and inhibition of mitochondrial complex I by ODA are more prominent.

The molecular reprogramming of astrocyte gene expression induced by oxygen deprivation is one of the astrocyte-mediated neuroprotective processes relevant to neurodegenerative diseases and various brain injury conditions. The primary oxygen sensor that mediates eukaryotic cells’ adaptive response to changes in oxygen concentration is hypoxia-inducible transcription factor 1 alpha (HIF-1α). Therefore, the astrocyte neuroprotective ability triggered by the activation of HIF-1α downstream effectors has sparked interest in hypoxia mimetics-based treatment approaches as a means to induce adaptive responses without direct hypoxia exposure. Compared to similar studies that evaluated the effect of both oxygen and glucose deprivation for several hours, this study uncovers the reprogramming of astrocyte gene expression patterns after exposure to hypoxia alone for short and relatively long periods of time − 30 min for short-term (ST) and three hours for long-term (LT) hypoxia − as well as following 24 h of reoxygenation induced recovery (RIR). The transcriptional activation of a number of genes, including Pdk1, Mct4, Sirt1, Bcl2, Hsp70, and Sod2, ends rather rapidly, only lasting over the ST-hypoxia. Conversely, during LT-hypoxia, Glut1 and Vegf1 show elevated expression, which is likely due to a positive feedback loop in which secreted Vegf increases both its own and Glut1’s expression. Interestingly, the ST-hypoxia establishes long-lasting variations of gene expression that may be essential for generating an effective neuroprotective response. This is demonstrated by the fact that Mct4 expression continues to be raised during the 24-hour normoxia period that follows the ST-hypoxia, thereby aiding in metabolic adaptation. Therefore, it is reasonable to draw the conclusion that the length of transcriptional activation varies depending on the gene and is associated with the function of the encoded protein.

Ginsenoside Rb1 (GRb1), the major bioactive component of ginseng, exhibits multiple therapeutic effects. However, its neuroprotective role in cerebral ischemia/reperfusion (I/R) injury remains unclear. The neuroprotective effects of GRb1 were investigated using a mouse middle cerebral artery occlusion (MCAO) model and in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) models. GRb1 was administered intraperitoneally to MCAO mice, and the effects on neurological function, brain edema, blood-brain barrier (BBB) integrity, and extracellular matrix (ECM) remodeling were evaluated. In the OGD/R model, tunneling nanotubes (TnTs) formation, oxidative stress, and mitochondrial integrity were evaluated in a co-culture of astrocytes and neurons. GRb1 markedly enhanced neurological function, alleviated brain edema, and maintained BBB integrity in MCAO mice. It also inhibited the expression of matrix metalloproteinases and Granzyme B while increasing Serpina3n, indicating protection of ECM integrity. In OGD/R-treated neurons, GRb1 reduced oxidative stress, restored superoxide dismutase activity, and preserved ATP and mitochondrial DNA. Importantly, GRb1 significantly enhanced TnTs formation, and inhibition of TnTs with cytochalasin B markedly reversed these protective effects, supporting a TnT-dependent mechanism. GRb1 effectively protected against I/R-induced neuronal injury through TnTs-dependent mechanisms, modulating oxidative stress, ECM remodeling, and mitochondrial integrity.

Vascular cognitive impairment (VCI) is a neurological disorder in which chronic cerebral hypoperfusion is one of the common causes, often leading to cognitive and motor dysfunction. Moderate-intensity exercise is a non-pharmacological intervention that promotes long-term, sustainable, and low-risk brain health restoration. However, the multidimensional functional effects and underlying mechanisms of such training remain insufficiently understood. This study aimed to explore how moderate-intensity training relates to improvements in cognitive and gait functions in VCI, with a focus on neurovascular unit (NVU)-related processes and the potential involvement of vasculogenic Sema3G signaling within the hippocampus. Male Sprague–Dawley rats underwent bilateral common carotid artery occlusion (BCAO) surgery to induce VCI, followed by four weeks of moderate-intensity treadmill training in the exercise group. Moderate-intensity training effectively improved memory performance and gait stability in VCI rats. Exercise also corresponded with increased hippocampal Sema3G expression and higher levels of its related intercellular signaling components (Nrp2/PlexinA4). At the neuronal level, exercise was associated with enhanced synaptic marker expression and elevated hippocampal neuronal firing. In terms of immune modulation, exercise shifted microglial phenotypes toward an anti-inflammatory profile, suggesting a more supportive environment for neurovascular repair. Collectively, these findings indicate that moderate-intensity training may influence multiple NVU components, and that the Sema3G/Nrp2/PlexinA4 signaling axis could be one pathway contributing to the observed cognitive and motor benefits in VCI rats. Moderate-intensity exercise may therefore represent a promising approach for mitigating cognitive and motor decline associated with cerebral hypoperfusion.

Pyroptotic inflammation has been shown to contribute to neuronal injury after stroke. Uncoordinated-5 homolog B (UNC5B) is implicated in neuroinflammation, and its downstream kinase death-associated protein kinase 3 (DAPK3) is predicted to interact with mevalonate kinase (MVK). To examine the role of UNC5B in post-stroke pyroptosis, we used a photothrombosis (PT) stroke model in mice and an oxygen-glucose deprivation (OGD) model in BV-2 microglia. Knockdown of Unc5b or Mvk and pharmacological inhibition of DAPK3 were performed, followed by detection of pyroptosis-associated proteins and cell viability. Interactions between DAPK3 and MVK were assessed using transwell coculture and co-immunoprecipitation. PT or OGD induced neuronal injury and increased expression of pyroptosis-related proteins. Knockdown of Unc5b or Mvk in microglia protected neurons by suppressing pyroptosis and disrupting the DAPK3–MVK protein complex. Upregulation of p-MVK was prevented by either Unc5b knockdown or DAPK3 inhibition, whereas DAPK3 upregulation was blocked only by Unc5b knockdown and not by Mvk knockdown. Our results suggest that UNC5B promotes post-stroke microglial pyroptosis in part through the DAPK3/MVK pathway.

Obesity is an escalating global health concern associated with numerous comorbidities, including an elevated risk of neurodegenerative disorders. Status epilepticus, characterized by prolonged and recurrent seizures, leads to neuroinflammation and progressive neuronal cell death. Although obesity is recognized as a comorbidity in epilepsy, its mechanistic contribution to SE pathology remains poorly defined. This study investigated the effects of obesity on SE using leptin-deficient ob/ob mice, a well-established model of metabolic dysfunction. Pilocarpine was used to induce SE, and seizure progression was assessed. Compared to wild-type controls, ob/ob mice exhibited significantly reduced latency to seizure onset and a more rapid progression to SE. Fluoro-Jade B staining revealed markedly increased neuronal death in the CA1 and hilus regions of the hippocampus in ob/ob mice. Concurrently, immunofluorescence staining and western blot analysis showed robust astrocyte activation, evidenced by upregulated glial fibrillary acidic protein (GFAP). Obesity also intensified neuroinflammatory signaling, as evidenced by increased levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), along with increased expression of lipocalin-2 (LCN2) and phosphorylated signal transducer and activator of transcription 3(p-STAT3). Furthermore, necroptosis, a regulated form of cell death mediated by mixed lineage kinase domain-like protein (MLKL), was significantly enhanced in ob/ob mice following SE, as indicated by elevated phosphorylated MLKL (p-MLKL) expression. These results suggest that obesity exacerbated seizure susceptibility and amplifies neuroinflammatory and neurodegenerative processes in SE. This work highlights the LCN2-STAT3-MLKL signaling axis as a potential therapeutic target in obesity-associated seizure disorders and offers new insight into the interplay between systemic metabolism and epileptic brain injury.

Parkinson’s disease is a long-term, progressive condition that affects both movement and other parts of life that aren’t motor-related. Cognitive decline is one of the most impactful non-motor symptoms, as it can seriously affect overall quality of life. Although existing dopamine replacement therapies, including levodopa, mainly focus on alleviating motor symptoms, they do not adequately address issues such as dyskinesia, non-motor deficits, and the need for neuroprotective treatments. This research aimed to explore the neuroprotective properties of levothyroxine (L-T4) in a PD animal model. Female Wistar rats received 6-hydroxydopamine (6-OHDA) into the right medial forebrain bundle (MFB) and were treated with L-T4 (10–100 µg/kg) for 3 weeks. The Morris water maze (MWM), rotarod test, rotational behavior, and analyses of oxidative stress and apoptosis indices were conducted at the end of week 3 after surgery. In this study, L-T4 significantly enhanced learning and memory, improved motor balance and reduced the total number of rotations compared to the 6-OHDA-lesioned group. Biochemical analyses revealed that L-T4 enhanced the activity of superoxide dismutase (SOD) and catalase (CAT). It also lowered levels of lipid peroxidation and reduced the number of neurons dying through apoptosis in the striatum. These effects were seen when compared to the group that received 6-OHDA treatment. It was found that L-T4 treatment mitigated 6-OHDA induced motor and cognitive impairment, likely due to its antioxidant and anti-apoptotic effects. These findings propose that L-T4 may offer neuroprotective benefits for individuals with PD experiencing motor and memory deficits.

Fibronectin (FN1), a vital extracellular matrix protein, has been reported to be elevated in blood and cerebrospinal fluid in epileptic patients exhibiting recent seizure activity. A transcriptomic study from MTLE-HS patients has identified FN1 as a potential gene linked to MTLE. Nonetheless, the function of FN1 and the participation of the FN1/α5β1-Integrin/Src kinase signaling pathway are yet to be fully investigated in both pre-clinical and clinical investigations of TLE. Furthermore, its role in NMDA receptor-mediated hyperexcitability in TLE requires investigation. This study evaluates the contribution of the FN1/α5β1-Integrin/Src kinase axis in facilitating NMDA-induced hyperexcitability in temporal lobe epilepsy. Hippocampal formation and ATL tissues from MTLE-HS patients, as well as acute and chronic Li-pilocarpine TLE rat models, were examined using qRT-PCR, immunoblotting, and ex vivo immunolabeling to evaluate the expression of FN1, α5β1 Integrin, Src kinase, and NMDA receptor subunits. To assess the functions of FN1 and Src in NMDA receptor-induced hyperexcitability, siRNA-mediated knockdown was conducted in TLE rats. Following knockdown, behavioral assessments, molecular studies, and in vivo EEG were employed to examine the FN1/α5β1 Integrin/Src axis in seizure-related hyperexcitability.In MTLE-HS patients and TLE rat models, FN1 and Src kinase showed upregulation in both the hippocampal formation and ATL, together with increased α5β1 Integrin levels in rats. Elevated Src activity was associated with augmented phosphorylation of NMDA receptors. The siRNA-mediated knockdown of FN1 or Src diminished NMDA receptor phosphorylation and markedly reduced seizure activity in TLE animals. Our research suggests that FN1 has a role in MTLE pathophysiology and may regulate NMDAR-mediated hyperexcitability via the FN1/α5β1 Integrin/Src kinase pathway. This pathway regulates seizures via the hippocampal formation and anterior temporal lobe networks. The therapeutic potential of targeting this signaling pathway for epilepsy needs additional investigation.

Epigenetic dysregulation, particularly through histone acetylation dynamics, is critically implicated in sleep deprivation-induced cognitive dysfunction pathogenesis. This study delineates a novel regulatory axis wherein histone deacetylase 2 (HDAC2) deficiency mitigates cognitive deficits, while its upstream transcriptional control mechanisms remain poorly characterized. Through integrative bioinformatics and functional genomics, we identified Yin Yang 1 (YY1) as a direct transcriptional activator of HDAC2. Mechanistic investigations revealed YY1 binds the HDAC2 promoter, enhancing its transcriptional activity. Prefrontal cortical YY1 knockdown in murine models precipitated molecular and neurocognitive improvement, including HDAC2 downregulation, elevated expression of synaptic markers, alongside elevated dendritic spine complexity. These findings position YY1 as a sleep deprivation-responsive epigenetic modulator with intrinsic neuroprotective functionality. Translating these mechanistic insights, we conducted pharmacological screening to identify YY1-reducing therapeutics. Neferine (NEF) emerged as a lead compound, demonstrating dual inhibition of the YY1/HDAC2 axis. In chronic sleep deprivation models, NEF administration rescued synaptic deficits and ameliorated cognitive impairments. Crucially, NEF’s neuroprotective efficacy proved entirely contingent upon intact YY1/HDAC2 signaling, as evidenced by its null effects in HDAC2 conditional knockout models. This study reveals YY1 as a key regulator of HDAC2, identifying the YY1/HDAC2 pathway as a potential therapeutic target for sleep deprivation-induced cognitive deficits.

Graphical Abstract

This investigation establishes YY1 as an essential transcriptional regulator of HDAC2. YY1 directly interacts with the HDAC2 promoter to modulate its expression. Suppression of YY1 in prefrontal cortex leads to decreased HDAC2 levels and alleviates sleep deprivation-induced cognitive deficits in mice. Notably, the compound neferine was found to effectively reduce YY1 protein concentrations in the prefrontal cortex and exert neuroprotective effect sleep deprivation-induced cognitive deficits. These results indicate that the YY1/HDAC2 signaling axis may offer valuable insights for identifying early diagnostic markers and creating novel therapeutic strategies for sleep deprivation-induced cognitive deficits.