Search Results (218)

Background: Hippocampal neurogenesis in the dentate gyrus persists into adulthood and plays a crucial role in learning and memory. Early-life exposure to low-dose propofol has been reported to enhance neural development in rodent models, but detailed mechanisms remain unclear. To address this gap, we aimed to investigate how low-dose propofol alters neurogenic lineage differentiation, transcriptional programs, and underlying molecular mechanisms within the early postnatal hippocampal neurogenic niche. Results: We conducted an in-depth re-analysis of a published single-nucleus RNA-sequencing (snRNA-seq) dataset from hippocampal tissue of postnatal day 10 (PND10) mice, collected 3 days after low-dose propofol treatment. Uniform Manifold Approximation and Projection (UMAP)-based clustering revealed twelve major cell types, including a population of Ntng1⁺Fxyd7⁺Pcp1⁺ immature pyramidal neurons (imPYR), lacking the mature markers Meis2 and Spock1. Trajectory analysis revealed two neurogenic lineages (granule and pyramidal) and indicated that propofol biases progenitor fate commitment towards the granule lineage. CellChat analysis demonstrated that propofol enhances Neurexin (Nrxn) signaling to neural progenitor cells, suggesting increased synaptic adhesion and maturation. Differential expression analysis (|log₂FC| ≥ 0.26, adjusted p < 0.01) followed by pathway enrichment revealed that propofol upregulates neurogenic maturation pathways—including synaptogenesis, synaptic transmission, dendritic morphogenesis, and memory-related processes—specifically within neural intermediate progenitor cells (nIPC). Conclusions: Together, these findings delineate a coordinated transcriptional and intercellular mechanism by which low-dose propofol reprograms hippocampal neurogenesis during early postnatal development, highlighting progenitor-specific and synapse-oriented processes that may underlie its cognitive-enhancing effects. Full article

Adult neurogenesis is well established in canonical niches—the dentate gyrus and the subventricular zone, where aerobic exercise reliably enhances progenitor proliferation, survival, and synaptic integration via increased cerebral blood flow, neurotrophins (e.g., BDNF, IGF-1), neurotransmitter regulation, and reduced neuroinflammation. Nutraceuticals (e.g., polyphenols, omega-3, creatine, vitamins) further support neuroplasticity and neuronal survival through convergent trophic, anti-inflammatory, and metabolic pathways. By contrast, the hypothalamus, a metabolically pivotal, non-canonical niche, remains comparatively understudied. Here, we synthesize anatomical and functional features of hypothalamic neural stem cells, primarily tanycytes (α1, α2, β1, β2), which line the third ventricle and differentially contribute to neuronal activity regulation, metabolic signaling, and cerebrospinal fluid–portal vasculature coupling, thereby linking neurogenesis to endocrine control. Notably, tanycytes can form neurospheres in vitro, enabling mechanistic interrogation. Although evidence for adult hypothalamic neurogenesis in humans is debated due to methodological constraints, animal data suggest potential relevance to disorders characterized by neuronal loss, metabolic dysregulation, and impaired neuroendocrine function. We propose that an integrative framework is timely: exercise and diet likely interact in the hypothalamic niche through shared mediators (BDNF, IGF-1, CNTF, GPR40) and exercise-derived signals (e.g., lactate, IL-6) that may be complemented by defined nutraceuticals. Yet critical uncertainties persist, including the extent of bona fide hypothalamic neurogenesis, nucleus-specific responses (arcuate nucleus, paraventricular nucleus, ventromedial hypothalamic nucleus), and the mechanistic integration of lifestyle signals in this region. To address these gaps, we outline actionable priorities: (i) single-cell and lineage-tracing studies of tanycyte subtypes under distinct training modalities (aerobic, high-intensity interval training, resistance); (ii) combinatorial interventions pairing structured exercise with nutraceuticals to test synergy on progenitor dynamics and inflammation; and (iii) multi-omics and translational studies to identify biomarkers and establish clinical relevance. Clarifying these interactions will determine whether lifestyle and supplementation strategies can synergistically modulate hypothalamic neurogenesis and inform therapies for neurological, neuropsychiatric, and metabolic disorders. Full article

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by amyloid-β (Aβ) accumulation, synaptic dysfunction, and cognitive decline. Current pharmacological treatments provide only symptomatic relief without altering disease progression. Photobiomodulation therapy (PBMT), a light-based intervention, has shown neuroprotective potential, although its exact neurobiological mechanisms in AD pathogenesis remain obscure. In this study, we investigated the effects of PBMT using a 660 nm wavelength light-emitting diode (LED) in 5xFAD transgenic mouse, a well-established model of early-onset AD. Mice were subjected to once daily PBMT sessions over a defined treatment period and outcomes were assessed through immunohistochemical analysis of hippocampal regions (CA1, CA2, CA3, and dentate gyrus) alongside behavioral testing using the Y-maze spontaneous alternation task. PBMT significantly reduced Aβ plaque load across hippocampal regions, accompanied by improved preservation of neuronal morphology. Furthermore, PBMT significantly upregulated SIRT1 expression, a critical regulator of synaptic plasticity and memory processes. Behaviorally, PBMT-treated mice displayed enhanced spatial working memory compared with controls, indicating a functional benefit linked to the observed molecular and structural changes. These findings suggest that 660 nm PBMT attenuates hallmark AD pathology, promotes neuroprotective pathways, and improves cognition, highlighting its potential as a disease-modifying therapy that warrants further preclinical and clinical investigation. Full article

Background/Objectives: Understanding the diverse neuron types within the hippocampal formation is essential for advancing our knowledge of its fundamental roles in learning and memory. Hippocampome.org serves as a comprehensive, evidence-based knowledge repository that integrates morphological, electrophysiological, and molecular features of neurons across the rodent dentate gyrus, CA3, CA2, CA1, subiculum, and entorhinal cortex. In addition to these core properties, this open access resource includes detailed information on synaptic connectivity, signal propagation, and plasticity, facilitating sophisticated modeling of hippocampal circuits. A distinguishing feature of Hippocampome.org is its emphasis on quantitative, literature-backed data that can help constrain and validate spiking neural network simulations via an interactive web interface. Methods: To assess and enhance its utility to the neuroscience community, we integrated Google Analytics (GA) into the platform to monitor user behavior, identify high-impact content, and evaluate geographic reach. Results: GA data provided valuable page view metrics, revealing usage trends, frequently accessed neuron properties, and the progressive adoption of new functionalities. Conclusions: These insights directly inform iterative development, particularly in the design of a robust Application Programming Interface (API) to support programmatic access. Ultimately, the integration of GA empowers data-driven optimization of this public resource to better serve the global neuroscience community. Full article

Background: Traumatic brain injury (TBI) disrupts hippocampal neurogenesis and dendritic structure. Objective: The objective was to assess whether fractal and multifractal analyses can sensitively quantify dendritic complexity changes in newly formed dentate gyrus neurons following TBI and hyperbaric oxygen therapy (HBO). Methods: Adult rats underwent sham surgery with HBO (SHBO), lesion-induced TBI (L), or lesion-induced TBI with HBO (LHBO). Dendritic morphology was evaluated using Euclidean, monofractal, and multifractal metrics. Results: Lesioned animals exhibited marked reductions in dendritic complexity across multiple metrics compared to both HBO-treated groups. HBO treatment partially restored complexity to near-sham levels, with multifractal spectra revealing subtle structural differences between SHBO and LHBO. Conclusions: Fractal and multifractal analyses provide sensitive tools for detecting TBI-induced morphological changes and therapeutic effects. Our findings support HBO as a potential neuroprotective intervention and demonstrate the utility of mathematical modeling in evaluating therapeutic efficacy in neurotrauma. Full article

Brain pathophysiology in Down syndrome (DS), the most common genetic cause of intellectual disability, has traditionally been considered a consequence of neuronal dysfunction. However, although it is well documented that astrocytes play a critical role in brain homeostasis, synaptic regulation, and neuronal support, and their malfunction has been associated with the onset and progression of different neurological disorders, only a few studies have addressed whether astrocyte dysfunction can contribute to the DS pathophysiology. Astrocytes are increased in number and size, and show increased levels of expression of astroglial markers like S100β and GFAP. In this study, we detected a region-specific increase in astrocyte population in CA1 and, to a lesser extent, in the dentate gyrus. Single-nucleus transcriptomic profiling identified markers associated with reactive astroglia, synaptic transmission, and neuroinflammation in trisomic astrocytes. Functional analysis revealed abnormal Ca²⁺ oscillations in trisomic astrocytes and impaired astrocyte-to-neuron communication in CA1, the most affected subregion, leading to astrocyte-mediated excitatory synaptic depression. Our findings demonstrate that astrocytes play an active and critical role in the pathophysiology of DS, not only as reactive responders to neuronal injury but as key contributors to the disease process itself. This astrocytic dysfunction presents a region-specific distribution within the hippocampus, suggesting localized vulnerability and complex glial involvement in DS-related neuropathology. Full article

The purpose of this work was to study the effects of lactoferrin (Lf) on acute (days 3 and 15) and early-delayed (day 30) changes in the dentate gyrus of mouse hippocampus caused by whole-body gamma-irradiation. Male C57BL/6 mice received Lf (4 mg per mouse, i.p. injection) immediately after whole-body gamma-irradiation at a dose of 7.5 Gy from a ⁶⁰Co source. The effect of Lf on mouse behavior was evaluated using “Open field” and “Elevated plus-maze” tests. The proportion of cells with DNA replication was determined by 5-ethynyl-2′-deoxyuridine incorporation (thymidine analog) and detected by a click reaction with azide Alexa Fluor 568. Lf treatment increased animal survival during the experiment (30 days), compensated for radiation-induced body weight loss, and prevented suppression of motor and exploratory activities. A pronounced anti-radiation effect of Lf on mouse brain cells has been demonstrated. A single injection of the protein allowed preserving 2-fold more proliferating cells and immature neurons in the dentate gyrus of the hippocampus of irradiated animals during the acute period of post-radiation injury development. Full article

Forty per cent of major depression patients are resistant to antidepressant medication. Thus, it is necessary to search for alternative treatments. Melatonin (N-acetyl-5-hydroxytryptamine) enhances neurogenesis and neuronal survival in the adult mouse hippocampal dentate gyrus. Additionally, melatonin stimulates the activity of Ca²⁺/Calmodulin-dependent Kinase II (CaMKII), promoting dendrite formation and neurogenic processes in human olfactory neuronal precursors and rat organotypic cultures. Similarly, ketamine, an N-methyl-D-aspartate receptor (NMDAR) antagonist, modulates CaMKII activity. Importantly, co-treatment of low doses of ketamine (10⁻⁷ M) in combination with melatonin (10⁻⁷ M) produces additive effects on neurogenic responses in olfactory neuronal precursors. Importantly, enhanced neurogenic responses are produced by conventional antidepressants like ISSRs. The goal of this study was to investigate whether hippocampal CaMKII participates in the signaling pathway elicited by combining doses of melatonin with ketamine acutely administered to mice, 30 min before being subjected to the forced swimming test. The results showed that melatonin, in conjunction with ketamine, significantly enhances CaMKII activation and changes its subcellular distribution in the dentate gyrus of the hippocampus. Remarkably, melatonin causes nuclear translocation of the active form of CaMKII. Luzindole, a non-selective MT₁ and MT₂ receptor antagonist, abolished these effects, suggesting that CaMKII is downstream of the melatonin receptor pathway that causes the antidepressant-like effects. These findings provide molecular insights into the combined effects of melatonin and ketamine on neuronal plasticity-related signaling pathways and pave the way for combating depression using combination therapy. Full article

Developmental exposure to polybrominated diphenyl ethers (PBDEs), which are commonly used as flame retardants, results in irreversible cognitive impairments. Postnatal hippocampal neurogenesis, which occurs in the subgranular zone (SGZ) of the dentate gyrus, is critical for neuronal circuits and plasticity. Wnt7a-Frizzled5 (FZD5) is essential for both neurogenesis and synapse formation; moreover, Wnt signaling participates in PBDE neurotoxicity and also contributes to the neuroprotective effects of melatonin. Therefore, we investigated the impacts of perinatal decabromodiphenyl ether (BDE-209) exposure on hippocampal neurogenesis and synaptogenesis in juvenile rats through BrdU injection and Golgi staining, as well as the alleviation of melatonin pretreatment. Additionally, we identified the structural basis of Wnt7a and two compounds via molecular docking. The hippocampal neural progenitor pool (Sox2+BrdU+ and Sox2+GFAP+cells), immature neurons (DCX+) differentiated from neuroblasts, and the survival of mature neurons (NeuN+) in the dentate gyrus were inhibited. Moreover, in BDE-209-exposed offspring rats, it was observed that dendritic branching and spine density were reduced, alongside the long-lasting suppression of the Wnt7a-FZD5/β-catenin pathway and targeted genes (Prox1, Neurod1, Neurogin2, Dlg4, and Netrin1) expression. Melatonin alleviated BDE-209-disrupted memory, along with hippocampal neurogenesis and dendritogenesis, for which the restoration of Wnt7a-FZD5 signaling may be beneficial. This study suggested that melatonin could represent a potential intervention for the cognitive deficits induced by PBDEs. Full article

The intranasal delivery of exogenous mitochondria is a potential therapy for Parkinson’s disease (PD). The regulatory mechanisms and effectiveness in genetic models remains uncertain, as well as the impact of modulating the mitochondrial permeability transition pore (mPTP) in grafts. Utilizing UQCRC1 (p.Tyr314Ser) knock-in mice, and a cellular model, this study validated the transplantation of mitochondria with or without cyclosporin A (CsA) preloading as a method to treat mitochondrial dysfunction and improve disease progression through intranasal delivery. Liver-derived mitochondria were labeled with bromodeoxyuridine (BrdU), incubated with CsA to inhibit mPTP opening, and were administered weekly via the nasal route to 6-month-old mice for six months. Both treatment groups showed significant locomotor improvements in open-field tests. PET imaging showed increased striatal tracer uptake, indicating enhanced dopamine synthesis capacity. The immunohistochemical analysis revealed increased neuron survival in the dentate gyrus, a higher number of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra (SN) and striatum (ST), and a thicker granule cell layer. In SN neurons, the function of mitochondrial complex III was reinstated. Additionally, the CsA-accumulated mitochondria reduced more proinflammatory cytokine levels, yet their therapeutic effectiveness was similar to that of unmodified mitochondria. External mitochondria were detected in multiple brain areas through BrdU tracking, showing a 3.6-fold increase in the ST compared to the SN. In the ST, about 47% of TH-positive neurons incorporated exogenous mitochondria compared to 8% in the SN. Notably, GFAP-labeled striatal astrocytes (ASTs) also displayed external mitochondria, while MBP-labeled striatal oligodendrocytes (OLs) did not. On the other hand, fewer ASTs and increased OLs were noted, along with lower S100β levels, indicating reduced reactive gliosis and a more supportive environment for OLs. Intranasally, mitochondrial transplantation showed neuroprotective effects in genetic PD, validating a noninvasive therapeutic approach. This supports mitochondrial recovery and is linked to anti-inflammatory responses and glial modulation. Full article

The adult rodent hippocampus is capable of maintaining its capacity to generate new neurons in the subgranular zone (SGZ) of the dentate gyrus (DG). Interestingly, proliferative cells have also been described in the hilus. The involvement of the hilar neurogenesis process in hippocampal physiology is unknown. Thyroid hormones (THs) are necessary for the survival of postmitotic progenitor cells, neuroblasts, and immature granule neurons in the SGZ. In contrast, evidence concerning the role of THs in the hilar neurogenesis process is limited. The present study characterized the mitotic activity, cell survival, and neuronal differentiation of hilar neurogenesis under physiological and hypothyroid conditions and compared them with those of the granular layer (GL) and the SGZ of the DG in adult Wistar rats. We found that, under physiological conditions, the hilus harbors fewer proliferative cells than the neurogenic zone (GL/SGZ) does, with a rate of cell survival of 18.9% and a rate of differentiation into granular neurons of 19%. Interestingly, hypothyroidism provokes decreased cell proliferation and an increased rate of cell survival without affecting neuronal differentiation. These effects induced by hypothyroidism in the hilus were different or inclusive, contrary to those observed in the neurogenic zone. Full article

Perioperative neurocognitive disorder (PND) is a concern following anesthesia, particularly in individuals at risk for Alzheimer’s disease (AD). This study compared the cognitive and pathological effects of propofol and remimazolam in a mouse model with AD following surgery. Five-month-old male ApoE4-KI mice underwent abdominal surgery under either propofol (170 mg/kg) or remimazolam (85 mg/kg) anesthesia. Cognitive function was assessed using the Morris water maze and Y-maze, and neuronal apoptosis and amyloid-beta (Aβ) deposition in the CA3 and dentate gyrus (DG) of the hippocampus were evaluated preoperatively and at 2, 4, and 7 days postoperatively. Both groups showed similar postoperative cognitive functions, with increased relative escape latency at day 2 and decreased relative spontaneous alternation at days 4 and 7. However, the neuropathological analysis revealed that propofol-induced significantly more neuronal death in the CA3 (days 4 and 7) and DG (days 2, 4, and 7), and greater Aβ accumulation in the CA3 (days 2 and 4) and DG (days 2 and 7) compared to remimazolam (p < 0.05). Propofol was associated with more pronounced neuropathologic changes in the hippocampus compared to remimazolam. These findings suggest remimazolam may be a safer anesthetic for patients at risk for neurodegenerative disorders, as it is associated with less severe hippocampal pathology, which is characteristic of AD. Full article

Oxidative stress and membrane damage are believed to be principally involved in the pathogenesis of epilepsy. This study aimed to assess the effects of phenosanic acid (PA), an antioxidant and membrane protector, in acute pentylenetetrazole and chronic lithium–pilocarpine seizure models in male Wistar rats. PA was administered acutely (ip, 120 mg/kg BW ip, or 240 mg/kg BW per os) or chronically (80 mg/kg BW/day per os). Indices of free radical oxidation, the hypothalamo–pituitary–adrenocortical axis, and the nitrergic system were assessed in blood and brain regions. Morphological analysis of the hippocampus was performed in the lithium–pilocarpine model. PA exerted an acute anti-seizure effect in the pentylenetetrazole model. In the lithium–pilocarpine model, acute PA treatment decreased the death rate and corticosterone levels in the neocortex and brainstem. In contrast, the level of free radical oxidation products reacting with thiobarbituric acid declined in the brain stem in response to chronic PA treatment. In the lithium–pilocarpine model, the neuronal density in the dentate gyrus was elevated, and the proliferating cell nuclear antigen positive (PCNA+) cell counts in the subgranular zone did not differ between groups. Doublecortin positive (DCX+) cell count was significantly increased after chronic PA treatment. PA-induced reduction in mortality in the lithium–pilocarpine epilepsy model may be partially mediated by decreasing the lipid peroxidation and corticosterone levels in different brain regions. Chronic PA treatment may affect adult hippocampal neurogenesis by either prolonging the action of factors that increase neurogenesis after status epilepticus or by slowing down the neuronal differentiation rate. These data suggest that PA may be a disease-modifying AED able to hamper epileptogenesis. Full article

Endosomal dysfunction is one of the earliest cellular signs in Alzheimer’s disease. Tumor susceptibility gene 101 protein (TSG101) is a component of the endosomal sorting complex required for transport (ESCRT)-I, which plays a key role in sorting ubiquitinated cell surface proteins and lipids onto intraluminal vesicles of multivesicular bodies for trafficking to lysosomes or autophagosomes for degradation, or to the plasma membrane for exosomal secretion. TSG101-dependent trafficking has been implicated in the propagation and spread of misfolded proteins associated with neurodegenerative diseases. We used transgenesis mice to study the in vivo consequences of disrupting TSG101-dependent trafficking in adult neurons. Mice lacking Tsg101 in forebrain neurons (Tsg101^ck2-null) showed rapid loss of hippocampal neurons and progressive forebrain atrophy. Astrogliosis was apparent in the dentate gyrus within 1 week of deleting Tsg101, followed by apoptosis of hippocampal CA3 neurons and accumulation of the autophagy adapter P62/SQSTM1 and ubiquitinated proteins. Failure to detect lipidated LC3 indicated autophagy was impaired rather than upregulated. Endosomal markers (RAB5 and RAB7) and amyloid protein also accumulated in hippocampal neurons of Tsg101^ck2-null mice. Our data establish a critical role for TSG101 in neuronal survival and demonstrate the importance of the in vivo assessment of gene and protein functions. Full article

Background: The pathogenesis of neuropsychiatric lupus erythematosus (NPSLE) is very complex and is associated with neuroinflammation and blood–brain barrier compromise. Experimental investigations of NPSLE have classically relied on spontaneous models. Recently, TLR7 agonist-induced lupus has been shown to exhibit similar neuropsychiatric manifestations to spontaneous ones. Cinnamon is a widespread spice and natural flavoring agent. It has been proven to modulate vascular endothelial tight junctions, neuroinflammation, and autoimmunity pathways, but it has never been tested in relation to lupus. Hypothesis/Purpose: In this pilot study, we aimed to explore the disease-modifying effect of Cinnamomum cassia on NPSLE in a TLR7 agonist-induced model. Study Design: An experimental design was followed in this study. Methods: Lupus was induced in C57BL/6J female mice via the direct application of imiquimod, a TLR7 agonist (5% imiquimod cream, 1.25 mg three times weekly), to the skin. Mice were divided into five groups (n = 8 per group): a sham group (S), a sham group supplemented with cinnamon (SC), an imiquimod-treated group (L), an imiquimod-treated group supplemented with cinnamon starting from induction (LC), and an imiquimod-treated group supplemented with cinnamon beginning two weeks prior to induction (CLC). This protocol was followed for six consecutive weeks. Cinnamomum cassia powder was administered orally at 200 mg/kg, 5 days per week. Results: Behavioral alterations were significantly ameliorated in the CLC group compared to lupus mice. Neuronal shrinkage and nuclear chromatin condensation were visible in the hippocampal cornu ammonis and dentate gyrus zones of lupus mice, with an increased expression of TLR7 and NLRP3, versus significantly less neurodegeneration and TLR7 and NLRP3 expression in the CLC group. In addition, the expression of the blood–brain barrier endothelial cell tight junction proteins claudin-1, occludin, and ZO-1 was abnormally modified in lupus mice and was restored in the CLC group. Moreover, while the cell–cell border delocalization of claudin-1 was documented in cultured blood–brain barrier endothelial cells treated with the plasma of lupus mice to a punctate intracytoplasmic fluorescence pattern, only cells treated with the plasma of the CLC group exhibited a complete reversal of this redistribution of claudin-1. Finally, cinnamaldehyde seemed to interact with TLR7 at multiple sites. Conclusions:Cinnamomum cassia seems to alleviate the pathogenesis of NPSLE. Supplementation with Cinnamomum cassia could be of great interest to modulate the activity and severity of the disease. Full article