Molecular Neurobiology最新文献

Glutamate-mediated excitotoxicity leads to mitochondrial dysfunction, apoptosis, and neuronal cell death. This study aims to investigate whether NPY2 receptors (NPY2R) and NPY5 receptors (NPY5R) enhance the effects of Apelin-13/APJ signaling pathways as modulatory cofactors in the neuroprotection provided by Apelin-13 against excitotoxic damage and in the prevention of learning-memory disorders. D-Glutamic acid-induced excitotoxicity was established in 42 male Sprague-Dawley rats (6-8 weeks, 200-250 g). Animals were randomly divided into six groups (n = 7); Control (C; 0.9% NaCl, i.p), D-Glutamic Acid (G; 4 mg/kg, i.p), Apelin-13 (A; 300 µg/kg, i.p), D-Glutamic Acid + Apelin-13 (GA), D-Glutamic Acid + Apelin-13 + NPY2R antagonist (GAN2; 1,5 mg/kg, i.p) and D-Glutamic Acid + Apelin-13 + NPY5R antagonist (GAN5; 1,5 mg/kg, i.p). Locomotor activity were evaluated with the Open Field (OFT), short/long-term memory and learning performance, allocentric-egocentric orientation were assesed with novel object recognition (NORT) and Morris water maze (MWM) tests. All parameters were normalized to the C group, and statistical significance between groups was assesed. In group G, a significant decrease (p < 0.001) in Extracellular Signal Regulatory Kinase (ERK1/2) and Protein Kinase B-1 (AKT-1) levels and an increase (p < 0.001) in Caspase-3 were observed. Oxidative parameters increased in the G and GAN2 groups. Antioxidant parameters were also elevated in GA and GAN5, similar to C and A groups. An increase in MWM latency to the target quadrant (p < 0.001) and a decrease in NORT discrimination index (p < 0.001) were found in the G and GAN2 groups compare to the C and A. Histochemical staining scores showed that the protection of Apelin-13 was mediated by NPY2R. In GAN2, blocking NPY2R reduces Apelin-13's neuroprotection, which is sustained only via NPY5R with limited effect. In GAN5, Apelin-13's protection was enhanced through NPY2R, as shown with NPY5R blockade. Accordingly, Apelin-13 exerts its neuroprotective effects primarily through NPY2R, its modulatory influence via NPY5R appears to be comparatively limited.

Cerebral ischemia-reperfusion (I/R) injury remains a major challenge in patients with ischemic stroke undergoing endovascular thrombectomy (EVT). Although selective intraarterial hypothermia has shown neuroprotective potential, its therapeutic efficacy is limited, highlighting the need for effective pharmacological adjuncts. This study investigated whether combining intracarotid hypothermia with Shenmai could synergistically enhance neuroprotection against cerebral I/R injury. Cold Shenmai (4 °C) or saline was infused into rat brain. Systemic toxicity was assessed by body weight, serum biochemistry, organ morphology, and indices. Brain toxicity was evaluated with 2,3,5-triphenyltetrazolium chloride (TTC), hematoxylin and eosin (H&E), and Fluoro-Jade B (FJB) staining. Cerebral I/R injury was induced by middle cerebral artery occlusion (MCAO). Neuroprotection was assessed by TTC staining, neurological deficit score, rotarod, adhesive removal, and by H&E, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and Nissl staining. RNA sequencing explored mechanisms. Inflammatory cytokines were quantified by quantitative real-time polymerase chain reaction (qRT-PCR), while extracellular signal-regulated kinase (ERK) and nuclear factor kappa-B (NF-κB) signaling were examined by Western blot and immunofluorescence. The ERK inhibitor PD98059 verified mechanistic contributions. Cold Shenmai infusion showed no evidence of systemic or cerebral toxicity. Compared with cold saline, it significantly reduced infarct volume, improved neurological function and behavioral outcomes, and attenuated neuronal damage. Transcriptomic analysis revealed downregulation of pro-inflammatory pathways and reduced expression of microglial activation-related signaling. Mechanistically, cold Shenmai enhanced ERK1/2 phosphorylation, which was associated with reduced microglial marker expression and suppressed NF-κB P65 nuclear translocation. Importantly, these protective effects were markedly attenuated by the ERK1/2 inhibitor PD98059, indicating that ERK signaling plays a critical role in mediating the anti-inflammatory and neuroprotective effects of cold Shenmai during cerebral I/R injury. Intracarotid Shenmai with hypothermia synergistically attenuates cerebral I/R injury through ERK-mediated anti-inflammatory effects, including reduced microglial activation markers. These findings provide mechanistic preclinical evidence supporting Shenmai as an effective pharmacological adjunct to intraarterial hypothermia and suggest a promising therapeutic approach for mitigating reperfusion injury following EVT in acute ischemic stroke.

Hearing loss is a prevalent global health problem that most often arises from aging, noise exposure, ototoxic insults, or genetic defects. In addition to its well‑recognized social and economic burden, mounting evidence links hearing loss to neurological disorders such as Alzheimer's disease and dementia, underscoring the urgent need for effective curative strategies. Progress in regenerative therapies has been hindered by the limited capacity of mammalian auditory hair cells to regenerate, making a deep understanding of the underlying molecular pathology essential. The mechanistic target of rapamycin (mTOR), a master regulator of cell growth, metabolism, autophagy, and aging, has recently emerged as a key player in both auditory and neurological disorders. In this review, we summarize the current knowledge on how mTOR signaling shapes auditory cellular physiology, contributes to hearing disorder pathogenesis, and offers novel therapeutic entry points. We further explored the possibility that dysregulated mTOR activity may represent a missing mechanistic link between hearing loss and broader neurological disease processes.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, one of the most common types of dementia, accompanying severe learning and memory dysfunctions. In AD brains, the misfolded aggregation and deposits of amyloid-β (Aβ) and tau are frequently observed before the cognitive symptom onset; thus, trials for alleviation of these lesions are considered commensurate strategies with AD treatment. Additionally, increasing evidence suggests that misfolded and aggregated proteins induce the activation of microglia and astrocytes by the release of the inflammatory mediators via the activation of the inflammatory signaling cascade, which consequently contributes to AD pathogenesis. Here, we investigated the therapeutic potential of fucoxanthin, a compound derived from the microalgae Phaeodactylum tricornutum, in mitigating AD pathologies. Fucoxanthin was shown to inhibit the aggregation of Aβ and tau, converting their aggregates to monomeric forms. In the brain of APP/PS1 transgenic mice, fucoxanthin administration significantly reduced the levels of Aβ plaques and hyperphosphorylated tau and further ameliorated cognitive impairments by inhibiting the activation of microglia and astrocytes. Notably, fucoxanthin effectively regulated Aβ-induced NLRP3 inflammasome activation in astrocytes, reducing neuroinflammation associated with AD. Thus, our findings showing the multifaceted therapeutic mode of action of fucoxanthin against AD provide that fucoxanthin would have promising roles in the strategies of AD treatment.

Type 2 diabetes mellitus (T2DM) is a systemic metabolic disorder increasingly implicated in central nervous system (CNS) dysfunction, yet the molecular substrates underlying diabetes-induced dopaminergic (DAergic) dysregulation remain poorly defined. This study evaluated region-specific alterations in DAergic neurotransmission within the hippocampus, striatum, and prefrontal cortex, and their association with social behavioral deficits in diabetic mice. According to the weight and age of the animal, two groups were designated as the control group and the diabetes group. The control group was designated as group 1, and the diabetic group was designated as group 2. In group 2, diabetes was caused by injecting 50 mg/kg of streptozotocin for five consecutive days in them. The behavioural tests were performed after eight weeks of inducing diabetes. On the 60th day, from the striatum, hippocampus, and cortex, total RNA was taken out after the dissection. Real-time polymerase chain reaction was used to carry out expression analysis. STZ-induced diabetic mice showed normal sociability and social novelty preference but exhibited a marked decline in social recognition memory, indicating selective impairment of long-term social cognition. Region-specific dysregulation of dopaminergic signaling was evident, particularly in the striatum and cortex. These transcriptional alterations likely represent compensatory neuroadaptive mechanisms responding to oxidative and neuronal stress induced by diabetes, suggesting that T2DM-driven dopaminergic imbalance contributes to cognitive and neurobehavioral dysfunction. T2DM induces differential dysregulation of dopaminergic signaling across cortical and subcortical regions, contributing to selective deficits in social cognition. These findings highlight potential therapeutic targets for mitigating diabetes-associated neurobehavioral dysfunction.

Emerging evidence suggests that chronic infections may contribute to neurodegenerative diseases such as Alzheimer's disease (AD). One such infection is caused by Borrelia burgdorferi sensu lato (Bbsl), the spirochete complex responsible for Lyme disease, which can invade the central nervous system (CNS) and trigger Lyme neuroborreliosis (LNB). Bbsl infection is associated with persistent neuroinflammatory responses and immune evasion mechanisms, which may contribute to long-term neurological sequelae in a subset of patients. Neuroinflammation is increasingly recognized as a contributing factor in AD pathogenesis. This review examines proposed mechanistic overlaps between LNB and AD, focusing on the role of Bbsl-induced neuroinflammation driving amyloid-beta (Aβ) accumulation and tau pathology. We summarize evidence from in vitro, in vivo, and postmortem studies reporting assay-dependent co-localization of Borrelia with hallmark AD pathology in selected cases, alongside epidemiological studies that yield mixed results. While some studies suggest an association between Bbsl exposure and neurodegenerative risk, others report no clear correlation. Overall, current evidence indicates only an association, and a causal relationship between Bbsl infection and AD has not been established. Understanding this potential link may inform future mechanistic studies, biomarker development, and preventive strategies targeting chronic infection-driven neuroinflammation to address the hypothesis.

Mitochondria are essential drivers of neuronal growth, differentiation, and overall brain development. Synthetic cannabinoids (SCs) have been shown to enhance neurite outgrowth in NG108-15 neuroblastoma x glioma cells through CB1 receptor activation, while disrupting mitochondrial function. Here, we demonstrated first-hand the impact of biologically-relevant concentrations (< 1μM) of ADB-FUBINACA (an SC commonly identified in drug seizures) on mitochondrial morphology and dynamics (i.e., fusion, fission and mobility) during the neurodifferentiation of NG108-15 cells. Our findings revealed that, during NG108-15 neurodifferentiation, ADB-FUBINACA reduced the mean mitochondrial area and perimeter by around 10%, while increasing mitochondrial circularity, and decreasing network branching and interconnectivity. Specifically, branch length per mitochondrion and branch junctions declined by 17 and 25% in the neurons' soma at the end of NG108-15 differentiation (after 72 h). Moreover, 1 nM and 1 µM ADB-FUBINACA markedly decreased the levels of mitochondrial fusion markers (Opa1 and Mfn2) and increased the levels of fission markers Drp1 and Fis1 at the same time point. The percentage of motile mitochondria in neurites also decreased at 72 h, while average speed and total run length per mobile mitochondrion remained unaffected, resulting in an accumulation of stationary mitochondria which may be important, for example, to support neurite extension. Collectively, these findings suggest that while ADB-FUBINACA promotes mitochondrial accumulation in neurites, potentially supporting the energy demands of developing neurites and influencing neurite outgrowth, in the long-term, the fragmentation of the mitochondrial network in the soma may compromise the maintenance of neurites, in terms of energy requirements.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by dopaminergic neuron loss and mitochondrial dysfunction. Recent studies implicate the histone acetyltransferase GCN5 in regulating mitochondrial homeostasis and oxidative stress. This study investigated the therapeutic potential of GCN5 silencing via systemically administered siRNA-loaded niosomes in a rotenone-induced rat model of PD. Niosomes were prepared using the thin-film hydration method, and the most effective siRNA sequence was selected through real time quantitative PCR (RT-qPCR) and immunofluorescence in primary mesencephalic neurons. Adult male rats were divided into four groups (n = 24/group), and PD was induced with rotenone (2 mg/kg/day, s.c., for 35 days). Behavioral assessments, biochemical analyses, IVIS imaging, histopathology, immunohistochemistry, and RT-qPCR were conducted. IVIS confirmed brain accumulation of siRNA-niosomes within 3-5 h post-injection. GCN5 siRNA treatment significantly improved locomotor activity (p < 0.05), decreased MDA levels (p < 0.05), and restored SOD and dopamine levels (p < 0.05). Molecular findings showed decreased GCN5 and mitochondrial fission-related gene Drp-1 expression, increased expression of mitophagy and biogenesis markers (↑Parkin, ↑PINK1, ↑Mfn2, ↑PGC-1α), elevated TH expression, and reduced α-synuclein accumulation. Histological analysis revealed preserved midbrain cytoarchitecture and reduced neuronal damage. In conclusion, these findings highlight that epigenetic silencing of GCN5 via siRNA-loaded niosomal delivery provides neuroprotection in PD by modulating the expression of genes involved in mitochondrial dynamics, offering preclinical support for its development as a novel therapeutic strategy.

α-Synuclein has been the center of focus in understanding synucleinopathies such as Parkinson's disease, amyotrophic lateral sclerosis, multiple system atrophy, dementia with Lewy bodies, for decades. Most researches focus on its pathology. However, its physiological function remains elusive, especially in olfactory system, one of the original sites to find α-synuclein accumulation in Parkinson's disease. In the present study, α-synuclein knockout (KO) mice were employed to study its physiological function. KO mice exhibited olfaction impairment with cell apoptosis in olfactory bulb. To identify molecules underlying olfactory dysfunction, we employed proteomics based on isobaric tags for relative and absolute quantification (iTRAQ). 188 differentially expressed proteins were identified between KO mice and its littermate control of wildtype mice. Bioinformatic analysis highlighted Phosphatidyl-inositol-3-kinase (PI3K) pathway. Hence, we examined its activation and found that both PI3K and its downstream, protein kinase B(AKT) is hyperactivated with α-synuclein deficiency. Mammalian target of Rapamycin (mTOR), a switch of autophagy, was activated followed by uncoordinated 51-like kinase 1, the autophagy initiator, inhibition. The specific substrate of autophagy, P62 was accumulated, indicating that autophagy was blocked. This blockade of autophagy led to Caspase 8 mediated apoptosis characterized by an increased ratio of B-cell lymphoma-2 (BCL-2)-associated X protein (BAX) to BCL-2 (BAX/BCL-2), reduced mitochondrial complex I activity, and decreased mitochondrial membrane potential. To summarize, α-synuclein played roles in maintaining the normal structure and function of olfactory system. α-Synuclein deletion induced Caspase 8 mediated apoptosis due to the defective autophagy by PI3K/mTOR hyperactivation.

Temporal lobe epilepsy (TLE), one of the most prevalent focal epilepsies, is characterized by aberrant neuron and glial activation, yet the mechanisms driving microglia-astrocyte crosstalk remain elusive. To address this, we performed integrative single-nucleus RNA sequencing (snRNA-seq) analysis on surgically resected human brain tissue samples from a discovery cohort (4 TLE patients vs 4 controls) and a validation cohort (7 focal epilepsy cases vs the same controls). Using Seurat-based clustering, we identified 9 major cell types and further subclustered microglia and astrocytes. Cell-cell communication, gene regulatory networks, and pseudotime analysis were employed to explore the molecular mechanisms of microglia-astrocyte interactions. Results revealed significant expansion of both activated microglial and activated astrocytic subpopulations in TLE patients versus controls. The SPP1-CD44 axis emerged as the dominant pathway mediating their crosstalk, with reactive microglia as primary SPP1 senders and reactive astrocytes as CD44 receivers. The upstream regulators of SPP1-CD44 axis were subsequently explored, and 9 transcription factors (TFs) were identified as key regulators in reactive microglia. Pseudotime analysis further revealed a CD44-associated phenotypic shift from homeostatic to reactive astrocytes, characterized by progressive loss of synaptic regulatory functions and concurrent acquisition of neurotoxic properties during disease progression. Collectively, our multi-cohort snRNA-seq study reveals the SPP1-CD44 axis as a key mediator of neuroinflammatory pathology in TLE, linking microglial activation to astrocytic dysfunction. These findings broaden therapeutic strategies beyond neuronal targets, underscoring glial modulation as a promising adjunctive approach for epilepsy treatment.