Search Results (554)

Cerebellar climbing fiber–Purkinje cell (CF–PC) long-term depression (LTD) plays a critical role in motor learning and is modulated by locus coeruleus (LC) noradrenergic afferents via distinct adrenergic receptor (AR) subtypes. Nevertheless, the mechanisms underlying LC noradrenergic neuron-mediated regulation of CF–PC LTD remain poorly understood. Here, we investigated the effects of chemogenetic activation of LC noradrenergic afferents on CF–PC LTD in cerebellar slices from dopamine β-hydroxylase (DBH)-Cre mice using electrophysiology, glutamate sensor imaging, immunofluorescence and pharmacological approaches. Tetanic stimulation (5 Hz) of CFs induced CF–PC LTD under control conditions, and this LTD was enhanced by chemogenetic activation of LC noradrenergic afferents. Blockade of group I metabotropic glutamate receptors (mGluR1) abolished LTD under control conditions, whereas chemogenetic activation of LC noradrenergic afferents triggered a novel form of CF–PC LTD accompanied by an increased N2/N1 ratio. With mGluR1 blocked, chemogenetic activation of LC noradrenergic afferents failed to trigger the novel CF–PC LTD following blockade of α₂-AR or α₂A-AR, but not α₂B-AR or α₂C-AR. Importantly, chemogenetic activation of LC noradrenergic afferents triggered LTD of glutamate fluorescence at CF terminals, which was abolished by blockade of α_2-AR or α₂A-AR, but not α₂B-AR or α₂C-AR. Notably, inhibition of either cyclin-dependent kinase 5 (CDK5) or presynaptic, but not postsynaptic, protein kinase A (PKA) completely abolished the CF–PC LTD triggered by chemogenetic activation of LC noradrenergic afferents in mouse cerebellar slices. Immunofluorescence results showed robust α₂A-AR expression throughout the cerebellar molecular layer, with intense signals along PC dendrites and clear colocalization with vesicular glutamate transporter 2 (vGluT2) at cerebellar CF terminals. These results indicate that activation of LC noradrenergic afferents potentiates CF–PC LTD by triggering Glu-LTD at CF terminals through the α₂A-AR/CDK5/PKA signaling cascade in the mouse cerebellar cortex. Full article

Background/Objectives: The non-neuronal cardiac cholinergic system (NNCCS) is known to synthesize ACh independently of the parasympathetic nervous system, thereby regulating cardiac homeostasis, which includes sustainability of energy metabolism, anti-inflammatory and anti-ischemic properties, electrical stability, and mitochondrial calcium handling. Given these beneficial functions of NNCCS, we were prompted to search for an inducer. One such inducer is SNPiP, a novel low-molecular-weight chemical compound developed by us. SNPiP accelerates ACh synthesis in the heart via cGMP elevation and, intriguingly, enhances diastolic function, increasing cardiac output and end-systolic pressure without elevating heart rate. However, the pharmacokinetics of SNPiP remain unknown, which led us to conduct the present study. Methods and Results: We found that the half-life of SNPiP in the blood was extremely short, similar to that of a nitric oxide (NO) donor, S-nitroso-N-acetyl-DL-penicillamine. This short half-life is caused by the rapid distribution of SNPiP into organs, including the heart, kidney, and liver. In addition, once transferred into blood cells, SNPiP itself became stable and remained intact for up to 1 h. Moreover, the short half-life was partly explained by the rapid degradation of SNPiP and concomitant loss of the nitroso group in the blood. Notably, when rats were treated with SNPiP, NO levels in the heart elevated bimodally: immediately after administration and again about 12 h later, coinciding with the previous report of NNCCS upregulation and accelerated ACh synthesis with NO production. Importantly, our previous transcriptome analysis of SNPiP-treated hearts supports these findings, as it revealed upregulation of diastolic function-related genes and proteins. Conclusions: Collectively, these results clarify the pharmacokinetics of SNPiP and demonstrate that, despite a shorter half-life, SNPiP is efficiently distributed to the heart, where it confers beneficial effects through induction of NNCCS. Full article

Background and Objectives: Cornerstone therapies for metastatic prostate cancer include androgen deprivation and androgen receptor pathway inhibition, but cognitive impairment is a recognized, life-altering potential adverse effect of this treatment. Abiraterone acetate (AA), an androgen receptor pathway and CYP17A1 inhibitor, suppresses androgen synthesis and may contribute to cognitive changes. This cell culture-based study uses the BE(2)M17 human male neuroblastoma model to investigate AA-induced alterations in gene and protein expression that may underlie cognitive decline, laying the foundation for a mechanistic investigation aimed at identifying molecular targets to mitigate cognitive impairment in men with prostate cancer receiving androgen-directed therapies. Materials and Methods: BE(2)M17 cells were pretreated for 12 h with dihydrotestosterone (DHT; 5 nM) or vehicle control, then exposed to AA (0, 5, 10 µM, 24 h). RNA and protein were analyzed by qRT-PCR and Western blot for markers of amyloid processing, neuronal health, and mitochondrial function. Results: AA significantly altered multiple neurobiological markers. BACE1 mRNA increased in DHT + 10 µM AA compared to control and DHT alone (p = 0.0416 and p = 0.0118). However, BACE1 protein decreased in 10 µM AA + DHT versus DHT alone (p = 0.0132). Immunoblot revealed reduced amyloid precursor protein (APP) in 10 µM AA versus control (p = 0.0057) and 10 µM versus 5 µM (p = 0.0263). APP was reduced in 10 µM AA + DHT versus control (p = 0.0015) and versus DHT alone (p = 0.0467). LRP1 and BDNF were significantly reduced with 10 µM AA versus 5 µM AA (p = 0.0092 and p = 0.0081), while synaptophysin decreased in 10 µM AA + DHT versus DHT alone (p = 0.0049). BDNF also declined in 10 µM AA + DHT compared to 5 µM AA + DHT (p = 0.0301). PGC1α mRNA increased in AA + DHT versus DHT alone (p = 0.0332). MitoTracker analysis showed reduced fluorescence with 5 µM AA alone but increased fluorescence with 5 µM AA + DHT relative to control and DHT (p = 0.0019; p < 0.0001), while 10 µM AA + DHT reduced fluorescence compared to 5 µM AA + DHT (p = 0.0003). Conclusions: AA, alone or combined with DHT, disrupts key pathways involved in neuronal health, amyloid processing, and mitochondrial function. These findings suggest a potential mechanistic link between AA treatment and cognitive impairment. Full article

Epidemiological investigations have indicated that females are particularly susceptible to perfluorooctane sulfonate (PFOS)-induced cognitive impairment, yet the mechanisms underlying this sex-specific vulnerability remain obscure. Estrogen and estrogen receptor β (ERβ) signaling are essential for female brain function, but their role in PFOS-induced neurotoxicity has not been explored. We therefore hypothesized that disruption of astrocyte-derived estrogen–ERβ signaling, leading to downregulation of N-myc downstream-regulated gene 2 (NDRG2) and subsequent synaptic dysfunction, contributes to PFOS-induced neurotoxicity in females. Female rats were exposed to PFOS for 30 days, followed by behavioral tests and hippocampal analysis. PC12 cells were treated with astrocyte-conditioned medium (ACM) to assess synaptic injury. Molecular docking was further performed to predict the binding affinity between PFOS and ERβ. In vivo, PFOS exposure impaired cognitive performance and caused hippocampal dysfunction, accompanied by decreased levels of estradiol (E2), aromatase (AROM), ERβ, N-myc downstream regulated gene 2 (NDRG2), and AMPA receptors (AMPARs), together with increased glial fibrillary acidic protein (GFAP) and Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) in the hippocampus. In vitro, PFOS-exposed C6 cells showed reduced E2, AROM, ERβ, and NDRG2, along with elevated GFAP and extracellular glutamate concentration. PC12 cells treated with PFOS-ACM exhibited decreased synaptophysin (SYP), postsynaptic density protein 95 (PSD-95), and AMPARs, as well as increased CaMKII, indicative of synaptic injury. Pretreatment with E2 or the ERβ agonist diarylpropionitrile (DPN) could reverse these molecular alterations and mitigate neuronal dysfunction. Molecular docking revealed a strong binding affinity between PFOS and ERβ. Collectively, these findings support our hypothesis that PFOS impairs cognitive function in female rats by disrupting astrocyte-derived estrogen–ERβ–NDRG2 signaling, with NDRG2 as a potential downstream effector. This provides a mechanistic basis for the heightened female susceptibility to PFOS neurotoxicity and highlighting ERβ as a potential therapeutic target. Full article

The hormonal vitamin D metabolite, 1,25-dihydroxyvitamin D (1,25D), produced primarily in the kidney, acts in numerous end-organs via the nuclear vitamin D receptor (VDR) to trigger molecular events that orchestrate bone mineral homeostasis, immune responsiveness, and aspects of behavior. Tyrosine hydroxylase (TH) encodes a neuronally expressed enzyme that catalyzes the initial, rate-limiting step in the production of several catecholamine neurotransmitters and hormones, including dopamine, norepinephrine, and epinephrine. Herein we report that TH mRNA is significantly induced (2.5-fold) and NURR1 mRNA is induced 9.3-fold by 10 nM 1,25D in differentiated human SH-SY5Y neuroblastoma cells. Similar results were observed in human U87 glioblastoma cells (TH, 2.6-fold; NURR1, 3.6-fold). Comparative analysis of TH gene promoter-proximal sequences from human, mouse, and rat identifies candidate NURR1-responsive elements (NBREs) at the following positions: −35, −855, −1470, and −2343 bp in the human gene; −34 and −961 bp in the mouse gene; and −34, −350, and −873 bp in the rat gene, consistent with NURR1 acting as a recurring regulatory factor at TH promoters across mammalian species. Furthermore, by interrogating VDR ChIP-seq/cistrome datasets, we identified candidate vitamin D-responsive elements (VDREs) at the human NURR1 locus that provide a plausible genomic framework for direct regulation of NURR1 by 1,25D/VDR. We propose that 1,25D-liganded VDR acts as a primary inducer of NURR1, which in turn secondarily activates expression of the TH gene, thereby defining a transcriptional route through which 1,25D/VDR signaling may influence TH-linked dopaminergic gene programs. Retinoid X receptor (RXR) may facilitate both NURR1-dependent and -independent potentiation of TH transcription because the rexinoid, bexarotene, significantly enhances TH mRNA in human U87 cells, either alone (2.0-fold) or in combination with 1,25D (4.1-fold). In addition, bexarotene and its novel analogs, A41 and A55, induce NURR1 mRNA expression in U87 cells by 2.8-, 3.1-, and 4.8-fold, respectively, with A55 outperforming the parent compound at matched concentration. Because Parkinson’s disease is characterized by the selective degeneration of dopaminergic neurons and impaired NURR1-dependent transcriptional programs, our findings identify a 1,25D/VDR–NURR1–RXR transcriptional axis as a previously underappreciated regulatory framework for studying TH gene expression and dopaminergic gene regulation in Parkinson’s disease-relevant neural contexts. Full article

Little is known about how nicotinic signalling in human astrocytes may contribute to the functional neurotoxicity of compounds related to tobacco alkaloids and neonicotinoid pesticides. We generated a single-cell Ca²⁺-imaging assay in induced pluripotent stem cell (iPSC)-derived astrocytes, and profiled functional expressions of some neurotoxicologically relevant receptors. Responses to pharmacological tool compounds indicated the expression of nicotinic, muscarinic, purinergic, glutamatergic receptors and voltage-gated Na⁺/Ca²⁺ channels. Closer investigation of the nicotinic system, e.g., using the alpha7 nicotinic acetylcholine receptor (nAChR)-selective positive allosteric modulator PNU-120596 and alpha7-preferring agonist (AR-R17779) demonstrated that Ca²⁺ signals elicited by nicotine and neonicotinoids are dominated by alpha7 nAChRs and depend on the downstream activation of L-type Ca²⁺ channels and tetrodotoxin-sensitive Na⁺ channels. Crosstalk of nAChR activation/desensitization was not observed for the inflammatory response elicited by TNF or for activation of glutamatergic or purinergic signalling. However, pre-stimulation of nAChR by neonicotinoids significantly blunted the response to the neurotransmitter acetylcholine. Comparative experiments in the human neuronal cultures (LUHMES cells) revealed similar potency ranges and pharmacological fingerprints for several neonicotinoids and their human-relevant metabolites descyanothiacloprid and desnitroimidacloprid. The pesticide metabolites showed a high potency, compared with their respective parent compounds. After this basic system characterization, the hitherto data-poor pesticides cycloxaprid and flupyradifurone were comparatively profiled in astrocytic and neuronal test systems. They showed the typical features of alpha7 nAChR agonists. The disruption of cholinergic signalling in astrocytes suggests that neonicotinoids affect not only neurons in human brains. Therefore, future neurotoxicity screening approaches may need to consider astrocyte toxicity. Full article

High homocysteine levels are a key risk factor for cognitive impairment, a major public health concern in aging societies. Although betaine is known to reduce Hcy levels, its effects on hyperhomocysteinemia (hHcy)-induced cognitive impairment and the underlying mechanisms remain unclear. Here, we established an hHcy-induced cognitive impairment mouse model by feeding mice a high-methionine diet for 8 weeks, followed by betaine supplementation for 14 days. Betaine treatment attenuated hHcy-induced cognitive impairment. This improvement was accompanied by alleviation of neuropathological alterations and enhancement of antioxidant capacity. Notably, betaine suppressed reactive oxygen species (ROS) accumulation, neuronal apoptosis, and Tau hyperphosphorylation at Ser396 and Thr231 in both mouse hippocampus and HT-22 cells. Mechanistically, betaine-induced activation of the PI3K/AKT/GSK-3β pathway was effectively blocked by the PI3K inhibitor LY294002. Notably, treatment with the ROS scavenger N-acetylcysteine (NAC) alone phenocopied this activation, suggesting that ROS functions as an upstream regulator of this signaling cascade. Collectively, our data demonstrate that betaine attenuates hHcy-induced cognitive impairment by suppressing oxidative stress-driven apoptosis and Tau pathology through modulation of the PI3K/AKT/GSK-3β signaling pathway. These findings suggest that betaine may hold promise for further preclinical and clinical studies, although long-term efficacy and safety evaluations remain necessary. Full article

Ferroptosis has emerged as a critical mechanism linking iron dysregulation, oxidative stress, and neurodegeneration in amyloid-associated pathologies. Building on our previous work, which identified compound 20 as a promising antioxidant and neuroprotective agent, the present study investigates the molecular mechanisms underlying its protective activity against amyloid-induced ferroptosis in human neuroblastoma SH-SY5Y cells exposed to Aβ(25–35). Compound 20 (3-(((4-hydroxybenzyl)(methyl)amino)methyl)-1-methyl-N-(2-(piperazin-1-yl)ethyl)-1H-indole-5-carboxamide) markedly counteracted Aβ(25–35)-induced ferroptotic damage by restoring intracellular glutathione levels, depleting the labile iron pool, and suppressing lipid peroxidation. In parallel, the compound significantly rescued mitochondrial membrane potential and attenuated endoplasmic reticulum (ER) expansion associated with ER stress, thereby preserving cellular homeostasis under oxidative challenge. These protective effects were further corroborated by real-time PCR analysis, which revealed the modulation of key genes involved in the oxidative stress response, endoplasmic reticulum stress, and inflammatory pathways. To gain a systems-level insight into these mechanisms, untargeted ¹H-NMR metabolomic profiling was performed. This analysis confirmed the activation of antioxidant pathways and disclosed a significant modulation of energy metabolism and GABA-related pathways, both of which are closely linked to redox balance and neuronal resilience. Overall, these findings demonstrate that compound 20 drives metabolic reprogramming that orchestrates its multifactorial protective effect against Aβ(25–35)-induced ferroptosis by coordinating antioxidant defense, iron homeostasis, and ER stress mitigation. Full article

Background/Objectives. Parkinson’s disease (PD) is a multifactorial neurodegenerative disorder characterized by dopaminergic neuron loss, α-synuclein pathology, neuroinflammation, and cognitive decline. Synaptamide (N-Docosahexaenoylethanolamine (DHEA)) is an endogenous lipid mediator with documented anti-inflammatory and neurogenic properties, but its effects in PD models remain unexplored. This study aimed to evaluate the neuroprotective potential of synaptamide in a subchronic MPTP-induced mouse model of PD. Methods. Male C57BL/6 mice received MPTP (30 mg/kg/day, i.p., 5 days) with or without synaptamide (10 mg/kg/day, s.c., 13 days). Behavioral tests (open field, Y-maze, elevated plus maze, novel object recognition (NOR)) were performed, followed by immunohistochemical analysis of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra, and Western blotting for α-synuclein, p-α-synuclein, TH, and IL1β in brain homogenates and serum. In vitro Neuro-2a cells were co-treated with MPP⁺ (100 µM) and synaptamide (0.1–10 µM) for cytotoxicity assessment (MTS assay). Results. Synaptamide (10 µM) significantly attenuated MPP⁺-induced cytotoxicity in Neuro-2a cells. In vivo, MPTP caused a marked loss of TH⁺-neurons in the substantia nigra, which was prevented by synaptamide treatment. Importantly, this subchronic MPTP model recapitulates early biochemical alterations (e.g., α-synuclein phosphorylation at Ser129) rather than mature Lewy body pathology, a limitation that should be considered when interpreting these findings. Although no motor deficits or anxiety-like behavior were observed, the NOR test revealed MPTP-induced long-term memory impairment, which was fully restored by synaptamide. Conclusions. These findings suggest that synaptamide may exert effects on pathological processes associated with PD, warranting further investigation into its potential role in combination or supportive therapy for this disease. Full article

Neurodegeneration and oxidative stress are central drivers of immune-mediated neuropathies. Capsaicin, the active ingredient in chili pepper and a direct agonist of the transient receptor potential vanilloid (TRPV1) channel, is used clinically to treat neuropathic pain. We previously demonstrated immunomodulatory and antioxidative effects of capsaicin in experimental autoimmune neuritis in vivo and Schwann cells (SC) in vitro. However, the molecular mechanisms underlying the maintenance of axonal integrity in dorsal root ganglion (DRG) and SC homeostasis remain unclear. In this study, we described the effects of capsaicin on DRG and SC in vitro under both naïve and S-Nitroso-N-acetyl-DL-penicillamine (SNAP)-induced oxidative stress conditions. Capsaicin induced an upregulation of the antioxidative cascade involving Nrf2, Ho-1, and Nqo1 in naïve DRG neurons and restored axonal growth under preventive and therapeutic settings. Preventive treatment enhanced catalase expression, whereas treatment increased regeneration-associated Gap43 and Atf3. Inhibition of TRPV1 with capsazepine partly attenuated the protective effect of axonal outgrowth, indicating TRPV1-mediated neuroprotection. In SC, capsaicin increased mitochondrial ATP production and spare respiratory capacity, inducing a transient Nrf2-dependent antioxidant response. Capsaicin suppressed expression of myelination markers under basal conditions but promoted expression of myelination- and repair-associated markers under oxidative stress. The findings support capsaicin as a regulator of neuronal and Schwann cell oxidative stress adaptation. Full article

Background: The glucocorticoid receptor NR3C1 exhibits antiepileptic properties, but the mechanisms governing its stability during epileptogenesis remain elusive. This study investigated whether the E3 ubiquitin ligase TRIM8 regulates neuronal hyperexcitability and epileptic activity by modulating NR3C1. Methods: We established an in vivo epilepsy model via intrahippocampal kainic acid (KA) injection and an in vitro epileptiform model using Mg²⁺-free artificial cerebrospinal fluid in primary hippocampal neurons. The roles of TRIM8 and NR3C1 were assessed using in vivo and in vitro gain- and loss-of-function approaches, alongside co-immunoprecipitation, Western blotting, immunofluorescence and whole-cell patch-clamp recording. Results: TRIM8 is significantly upregulated in hippocampal and temporal lobe neurons in epileptic mice. TRIM8 was markedly upregulated in the hippocampal neurons of epileptic mice, inversely correlating with NR3C1 levels. Mechanistically, TRIM8 interacted with NR3C1, promoting its polyubiquitination and proteasomal degradation. This TRIM8-mediated NR3C1 reduction enhanced the phosphorylation of AMPA receptor (AMPAR) subunits GluR1 (Ser831) and GluR2 (Ser880) without affecting total receptor expression. In vitro, TRIM8 overexpression exacerbated calcium dysregulation, neuronal injury, and AMPAR phosphorylation; crucially, concurrent NR3C1 overexpression rescued these effects. In vivo, knockdown of TRIM8 significantly reduced seizure frequency, prolonged the latency to the first Stage III seizure, shortened average seizure duration, and decreased total seizure burden in KA-induced epileptic mice. Electrophysiologically, TRIM8 overexpression significantly increased the frequency of spontaneous action potentials and amplitudes of spontaneous excitatory postsynaptic currents under Mg²⁺-free conditions. Furthermore, in vivo knockdown of TRIM8 attenuated KA-induced seizure severity, restored NR3C1 protein stability, and suppressed aberrant AMPAR phosphorylation in the hippocampus. Triple immunofluorescence staining showed that KA-induced epilepsy increased TRIM8 but decreased NR3C1 immunoreactivity in NeuN⁺ hippocampal neurons, and TRIM8 knockdown reversed these changes. Conclusions: TRIM8 acts as a critical driver of epileptiform activity by targeting NR3C1 for degradation, thereby disinhibiting AMPAR phosphorylation and enhancing network hyperexcitability. The TRIM8-NR3C1-AMPAR axis emerges as a previously unrecognized molecular pathway in epileptogenesis, highlighting its potential as a promising therapeutic target for epilepsy. Full article

Accumulation of aggregated amyloid beta (Aβ) species is a defining pathological hallmark of Alzheimer’s disease and is associated with extensive neuronal structural abnormalities. Mild cognitive impairment (MCI), a transitional stage between normal aging and the onset of dementia, is thought to represent an early phase of this pathological continuum. Studies at the cellular level suggest that the conditions impair the maintenance of established neuronal processes/networks and restrict their capacity for elongation or re-elongation. They may also attenuate the activation and process extension of quiescent neural progenitor or stem-like cells. These early cellular changes precede overt neurodegeneration in neural tissue and are likely to contribute to cognitive decline. They highlight the importance of in vitro models for identifying molecular targets involved in recovery from disease. In this study, we investigated the effects of aggregated Aβ (25–35) on neuronal process elongation and associated intracellular events in the N1E-115 cell line, a widely used model of neuronal differentiation. Addition of aggregated Aβ to cultured N1E-115 cells attenuated process elongation in a concentration-dependent manner. This morphological impairment was accompanied by decreased expression of neuronal differentiation markers. In contrast, at the half-maximal inhibitory concentration for process elongation, long-term cultured cells did not exhibit apparent process retraction or degenerative morphology. This mild but progressive impairment, without extensive cell death, is consistent with the cellular features of early-stage conditions rather than advanced Alzheimer’s pathologies. Similar results were observed in primary cortical neurons. Aβ also decreased the level of GTP-bound Ras and phosphorylation of the downstream mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK). Furthermore, treatment with hesperetin, a bioactive flavonoid compound, recovered the Aβ-induced inhibition of neuronal process elongation. Hesperetin also restored Ras and MAPK/ERK states, suggesting that its effects are associated, at least in part, with modulation of signaling through Ras and MAPK/ERK. Our findings suggest that hesperetin may serve as a useful molecular probe for modulating early cellular responses associated with Alzheimer’s disease-related pathology. This in vitro model might serve as a useful platform for investigating the molecular target candidates involved in recovery from nervous system disorders. Full article

Neonatal hyperoxia induces oxidative stress that disrupts neurodevelopmental processes. While dexmedetomidine (DEX) exhibits acute neuroprotective properties, its long-term impact on developmental trajectories during recovery remains incompletely understood. This study examined whether a single neonatal dose of DEX modulates hippocampal neurogenesis following hyperoxia across defined postnatal stages. Six-day-old Wistar rats were exposed to 80% oxygen for 24 h and evaluated at postnatal days (P) 9, 11, and 14 after recovery in room air. Mechanistically, hyperoxia permanently triggered apoptotic cascades, evidenced by sustained transcript upregulation and increased histological apoptosis and cell loss across the cortex and hippocampus, while disrupting the hippocampal progenitor niche, suppressing key differentiation factors (Sox2, Tbr2, Prox1, Calb1) and altering mature NeuN expression. Likewise, markers for autophagy (Atg5/12, Beclin1), neurotrophins (BDNF, NGF, NT3), and plasticity markers (Nrp1, Sem3a) showed reduced expression. Proactive treatment with DEX (5 µg/kg) significantly reversed these detrimental patterns. First, DEX elicited a robust antioxidant response (Nrf2, SOD1, SOD3 induction). Second, DEX effectively suppressed hyperoxia-induced programmed cell death and tissue degeneration up to P14. Crucially, this dual protection sustained the neurogenic niche, safeguarding autophagy processes as well as neurotrophic and neuronal plasticity mediators, while showing excellent safety under normoxia. In conclusion, a single dose of DEX mitigates acute oxygen injury and exhibits beneficial, stage-specific effects within hippocampal neurogenic niches during the postnatal phase, highlighting its potential to preserve neurodevelopmental trajectories. Full article

Accurately quantifying the expression of individual transcript isoforms remains a formidable challenge, especially in contexts such as neurodegenerative diseases and cancers, which are characterized by high isoform diversity. The present study introduces a junction-based method, named differential splicing frequency analysis (DSFA), which enables more sensitive detection of differential splicing using RNA-seq data. Unlike the existing exon-, isoform-, and event-based methods, DSFA quantifies splice junction usage. We applied DSFA to Alzheimer’s disease (AD)-associated genes through large-scale RNA-seq data mining. The present study is the first to establish that the APP770-, APP751-, APP695-, and APP752-encoding isoforms represent major isoforms of the APP gene. Three important findings are: (1) the APP752-encoding isoform exhibits immune cell specificity; (2) the relative proportion of the APP752-encoding isoform increases during the differentiation of induced pluripotent stem cells (iPSCs) into microglia, akin to the increase in relative proportion of the APP695-encoding isoform during iPSC differentiation into neurons; and (3) the APP751-encoding isoform predominates in both cancer and immune cells. Additionally, we identified APP/58417N and App/52804N as differentially expressed splice junctions in humans and mice, respectively. Through over-expression of U1 snRNA in human embryonic stem cell (hESC)-derived neurons, we found that U1 snRNA over-expression decreases the usage of APP/58417N in neurons, similar to the effects observed in AD samples. Our research highlights that the major isoforms of a gene can differ markedly in their expression across tissue and cell types. Full article

Objective: Cerebral ischemia/reperfusion (I/R) injury triggers oxidative stress, neuroinflammation, neuronal degeneration, and white matter damage not only in directly affected cerebral regions but also in remote brain areas such as the cerebellum. Skimmianine, a naturally occurring furoquinoline alkaloid, has been reported to possess antioxidant and anti-inflammatory properties. This study investigated the protective effects of skimmianine pretreatment against secondary cerebellar injury following experimental cerebral I/R. Materials and Methods: Thirty-two female Wistar rats were randomly assigned to sham, Skimmianine, I/R, and I/R + Skimmianine groups (n = 8/group). Cerebral I/R was induced by transient middle cerebral artery occlusion for 60 min followed by 23 h reperfusion. Skimmianine (40 mg/kg/day, intraperitoneally) was administered for 14 days before ischemia induction. Oxidative stress markers, neuroinflammatory mediators, histopathological alterations, behavioral outcomes, and ultrastructural changes were evaluated. In addition, network pharmacology and molecular docking analyses were performed to explore potential molecular mechanisms. Results: Cerebral I/R significantly decreased TAS levels compared with sham (0.89 ± 0.15 vs. 1.52 ± 0.18 mmol Trolox Eq/L) and increased TOS (15.60 ± 3.03 vs. 6.80 ± 1.41 µmol H₂O₂ Eq/L), OSI (17.48 ± 0.50 vs. 4.43 ± 0.47), TNF-α (68.4 ± 10.2 vs. 18.6 ± 4.4 pg/mL), Iba1 (41.3 ± 9.7 vs. 11.7 ± 1.6 pg/mL), and GFAP levels (334.5 ± 12.5 vs. 87.7 ± 9.5 ng/mL; all p < 0.001). I/R also impaired motor performance, as shown by increased beam crossing time (11.7 ± 2.2 vs. 4.8 ± 0.7 s) and grid foot fault rate (18.6 ± 4.0% vs. 3.4 ± 1.1%). Skimmianine pretreatment significantly improved these alterations, increasing TAS to 1.29 ± 0.20 mmol Trolox Eq/L and reducing TOS, OSI, TNF-α, Iba1, and GFAP levels to 9.20 ± 2.04, 7.07 ± 0.47, 34.9 ± 7.4, 24.2 ± 6.9, and 237.0 ± 7.9, respectively, compared with the untreated I/R group. Histopathological scores for Purkinje cell loss, edema, vascular congestion, and TNF-α expression were also significantly reduced by skimmianine. Quantitative TEM analysis showed that I/R reduced myelin thickness (0.29 ± 0.05 vs. 0.53 ± 0.07 µm), increased G-ratio values (0.75 ± 0.05 vs. 0.63 ± 0.04), and increased vacuolized fibers (24.70 ± 4.20% vs. 3.20 ± 1.10%), whereas skimmianine partially restored myelin thickness (0.42 ± 0.07 µm), reduced the G-ratio (0.68 ± 0.05), and decreased vacuolized fibers (11.20 ± 2.80%; p < 0.05 vs. I/R). Molecular docking demonstrated favorable binding between skimmianine and TNF-α, with a predicted binding energy of −6.953 kcal/mol. Conclusions: These findings indicate that skimmianine exerts neuroprotective effects against secondary cerebellar injury following cerebral I/R through coordinated modulation of oxidative stress, systemic neuroinflammatory responses, astroglial injury-associated pathways, and inflammation-related mechanisms. Full article