Molecular Neurobiology最新文献

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.

The gastrointestinal system is of particular importance in radiation biodosimetry because of its constant cell renewal and sensitivity to radiation-induced injury. It has been reported that total abdominal irradiation causes distant cognitive defects in a mouse model. In this study, we demonstrated that metformin alleviated the cognitive dysfunction caused by total abdominal irradiation. No neuropathological changes were observed in hippocampal tissues in control, irradiated, and irradiated plus metformin-treated groups. However, we found that metformin treatment improved the expression of brain-derived neurotrophic factor and the phosphorylation level of cAMP response element-binding in the hippocampus from irradiated mice. Furthermore, our results revealed that metformin treatment reduced the expression of miR-34a-5p, which targets the brain-derived neurotrophic factor mRNA, in the small intestine, peripheral blood, and hippocampus. More importantly, injection of miR-34a-5p agomir inhibited the enhancement effects of metformin on the cognitive defects induced by total abdominal irradiation, as well as the enhanced expression of BNDF and the phosphorylation level of cAMP response element-binding in the hippocampus. Thus, our results provide alternative strategies for the treatment of total abdominal irradiation-induced distant cognitive impairment using metformin and further confirmed that miR-34a-5p is a potential drug target to reduce the cognitive defects caused by total abdominal irradiation.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-β (Aβ) plaques and widespread neuroinflammation. Atractylenolide III (AT-III), the primary active compound in Atractylodes macrocephala Koidz, has shown various health-promoting effects, including antioxidant properties and neuroprotection. However, the anti-AD molecular mechanism of AT-III remains to be further investigated. FAD^4T mice were treated with AT-III for 4 weeks, and the neuroprotective effect of AT-III was subsequently evaluated by cognitive performance, histopathology, transcriptomic profiling, and 16S rRNA sequencing. SH-SY5Y cells were also used to verify the roles of AT-III on the AMPK/GSK3β/Nrf2/HO-1 pathway. AT-III significantly improved cognitive function, evidenced by a decreased escape latency and increased number of platform crossings in the Morris water maze (MWM) test and an increased alternation ratio in the Y-maze test. Histological analysis revealed that AT-III alleviated neuronal loss, reduced apoptosis and glial activation, and reduced Aβ deposition in the hippocampus. Biochemical assessments indicated that AT-III decreased oxidative stress and reduced neuroinflammation. Additionally, AT-III improved the diversity of the gut microbiota, including an increase in Ileibacterium and a decrease in Candidatus_Saccharimonas. Mechanistically, AT-III activated the AMPK/GSK3β/Nrf2/HO-1 signaling pathway both in vivo and in vitro. We further confirmed that AT-III significantly ameliorates Aβ_1-42-induced cytotoxicity, excessive ROS production, and apoptosis in SH-SY5Y cells. However, the protective effects of AT-III were partially abolished by Compound C (an AMPK inhibitor). Our study demonstrates that AT-III mitigated neurodegenerative damage in AD by suppressing microglial activation and neuroinflammation through the AMPK/GSK3β/Nrf2/HO-1 signaling, which suggests that AT-III might be a novel therapeutic strategy for the inhibition of AD.

Diabetes-related cognitive dysfunction (DCD) represents a significant complication of diabetes mellitus, yet its underlying molecular mechanisms remain incompletely elucidated. In this study, we aimed to investigate the potential role of nuclear receptor coactivator 3 (NCOA3) in DCD pathogenesis using both conditional knockout (cKO) and lentivirus-mediated overexpression mouse models. Diabetes was induced through combined high-fat diet feeding and low-dose streptozotocin (STZ) administration. Comprehensive behavioral assessments, including novel object recognition test (NORT), Y-maze, and contextual fear conditioning (CFC), were performed alongside molecular analyses of NCOA3/AGO2 expression and downstream targets. Our results suggested a significant downregulation of NCOA3 expression in cortical and hippocampal tissues of diabetic mice. Genetic ablation of NCOA3 in forebrain excitatory neurons markedly appeared to exacerbate hippocampus-dependent cognitive deficits, while targeted hippocampal NCOA3 overexpression effectively ameliorated these impairments. At the mechanistic level, NCOA3 deficiency was associated with reduced protein levels of AGO2, along with downregulation of the synaptic markers synaptophysin (SYP) and postsynaptic density protein 95 (PSD-95). In vitro studies using primary neuronal cultures indicated that high glucose treatment similarly reduced the expression of both NCOA3 and AGO2, while pharmacological inhibition or genetic knockdown of NCOA3 was found to significantly upregulate miR-138-5p levels. These findings collectively suggested a potential regulatory axis wherein NCOA3 is associated with synaptic plasticity via AGO2/miR-138-5p signaling, providing insights into DCD pathogenesis.

Preeclampsia (PE) is a pregnancy-specific hypertension with signs of other organ dysfunction. Despite its unclear mechanism, current data suggest the role of neuroinflammation in blood pressure dysregulation in PE. Considering the role of toll-like receptor 4 (TLR4) in various inflammatory conditions, we hypothesized that centrally expressed TLR4 may promote PE and that its inhibition, with pyridostigmine (PYR), may attenuate this condition in rats. Changes in TLR4 expression in the paraventricular nucleus (PVN) of reduced uterine perfusion pressure (RUPP) were assessed, as well as TLR4 sensitivity. The effect of PYR, at an oral dose of 20 mg/kg/day, on TLR4 signaling in RUPP or lipopolysaccharides (LPS, 5 µg/kg)-infused pregnant rats was assessed. On gestation day 19, mean arterial pressure (MAP) was recorded under urethane anesthesia, and PVN samples were collected and subsequently processed. Placental ischemia increased MAP (p < 0.05), TLR4 expression (p < 0.05) in RUPP, and TLR4 sensitivity in RUPP + LPS rats. LPS infusion elevated MAP to a greater extent in RUPP (37.1 ± 3.5 mmHg) compared to Sham (13.2 ± 6.5 mmHg) (p < 0.01) after 1 h. Such an effect of LPS was associated with increased expression of c-Fos (p < 0.01) in the PVN. PYR significantly reduced MAP in RUPP and LPS-treated dams, as well as TLR4 signaling proteins, ROS, TNF-α, and IL-1β in the PVN. In conclusion, placental ischemia-increased MAP is associated with high TLR4 expression in the PVN and increased TLR4 sensitivity, and PYR could attenuate TLR4 signaling in the PVN, thereby reducing blood pressure.

Intracerebral hemorrhage (ICH) incidence increases with age, and neuronal mitochondrial dysfunction and apoptosis post-ICH contribute to severe secondary brain injury. It is of paramount importance to explore molecular targets for protecting against brain injury after ICH. UBA52, a ubiquitin precursor protein, was found to be upregulated in brain tissues of ICH mice. Intracerebral injection of adeno-associated virus type 9 overexpressing UBA52 (AAV9-UBA52) alleviated neurological deficits and brain edema in ICH mice. In vitro and in vivo experiments demonstrated that UBA52 overexpression reduced hemin or ICH-induced apoptosis, reflected in decreased TUNEL-positive cells and reduced caspase-3 and caspase-9 levels. The augmentation of fluorescence intensity in Mitotracker labeling and the reduction of fluorescence intensity in JC-1 staining suggested that UBA52 overexpression mitigated hemin-induced mitochondrial damage. This was further evidenced by increased cellular ATP content and elevated cytochrome c levels located in mitochondria. In vivo findings showed that UBA52 overexpression reduced the quantity of degenerative neurons. UBA52 and NeuN co-localization verified its direct protective effect on neurons. IP-LC/MS and Co-IP assays identified Daxx as a UBA52-interacting protein, with UBA52 promoting Daxx ubiquitination and degradation. Rescue experiments showed Daxx overexpression abolished the protective effect of UBA52 against hemin-induced apoptosis and mitochondrial dysfunction. Collectively, this study demonstrated that UBA52 ameliorates ICH-induced secondary brain injury by promoting Daxx ubiquitination/degradation to inhibit neuronal apoptosis and mitochondrial damage, suggesting UBA52 as a potential protective target for ICH therapy.

Neurodegenerative diseases, including multiple sclerosis, Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis, are characterized by progressive neuronal loss and are frequently linked to metal dysregulation, oxidative stress, and immune dysfunction. Metallothioneins (MTs), a family of cysteine-rich, metal-binding proteins, are critical in maintaining metal homeostasis, mitigating oxidative damage, and modulating immune responses, functions highly relevant in these pathologies. MTs regulate essential metals like copper and iron by preventing their participation in harmful redox reactions and control zinc availability for enzymatic and signaling processes. They also detoxify neurotoxic metal(oid)s such as cadmium, mercury, lead, and arsenic, thereby reducing their adverse neurological and immunological effects. In autoimmune neurodegeneration, MTs modulate pro- and anti-inflammatory cytokines (e.g., IL-6, TNF-α, IL-10) and influence immune cell activity, particularly microglia and T cells, which are central to neuroinflammation and autoimmunity. Through these mechanisms, MTs play a dual role in sustaining immune homeostasis and counteracting oxidative stress. Their capacity to integrate metal regulation with immune modulation positions them as promising therapeutic targets, with preclinical and some clinical evidence supporting strategies to enhance MT expression or develop MT-mimetic agents to address both metal dysregulation and immune imbalance. Additionally, MTs show emerging utility as biomarkers, as alterations in MT isoform expression and metal-bound complexes in biofluids have been associated with disease onset, progression, and therapeutic response in specific neurodegenerative conditions. This article reviews the multifaceted roles of MTs in neurodegenerative diseases, emphasizing their function in metal and immune regulation and their emerging potential as therapeutic targets and clinical biomarkers.

Depression is a widespread neuropsychiatric disorder with the current therapeutic approaches achieving only suboptimal efficacy. Neferine is the main bioactive component of Nelumbinis plumula with multiple pharmacological functions. This study sought to investigate the antidepressant activity of neferine and elucidate its underlying mechanisms. Network pharmacology analysis was performed to uncover the molecular targets and pathways involved in neferine's antidepressant effects. The interaction of neferine with the core target was demonstrated by molecular docking and molecular dynamics simulation. The mouse model of depression triggered by chronic corticosterone (CORT) administration was utilized to validate the impact of neferine on core targets and pathways. We found that neferine remarkably attenuated CORT-induced depressive-like behaviors in mice. A total of 178 overlapping targets were acquired through the intersection of neferine and depression-related genes. The protein-protein interaction (PPI) network analysis revealed nine pivotal hub genes, namely AKT1, TNF, ESR1, PPARG, JUN, HIF1A, CASP3, NFKB1, and MMP9. Functional enrichment analysis indicated that these targets predominantly mapped to the TNF signaling pathway in depression. Molecular docking and molecular dynamics simulation showed that neferine has strong binding stability with PPARγ, a key molecule involved in regulating the TNF pathway. The results of animal experiments found that a PPARγ antagonist abolished neferine-induced alleviation of depressive-like behaviors. Moreover, neferine suppressed TNF/NF-κB pathway activation and attenuated neuronal loss in the hippocampus, potentially through activating PPARγ. Collectively, our study suggested that neferine produced antidepressant effects by suppressing hippocampal inflammation and neuronal loss through inhibiting the TNF/NF-κB signaling pathway. These preclinical evidence laid a foundation for further exploring the role of neferine in treating depression.

The transcription factor Nurr1 (NR4A2) serves as an essential element in dopaminergic neuron development since it functions predominantly in the substantia nigra, which becomes severely affected during Parkinson's disease (PD) and Alzheimer's disease (AD). Nurr1 regulates dopamine synthesis, survival-promoting, and oxidative stress genes that affect mitochondrial formation. Nurr1 binds to PGC-1α, allowing for mitochondrial activity regulation. This relationship supports mitochondrial biogenesis. Post-translational changes, including phosphorylation and acetylation, modify Nurr1 transcriptional regulation in order to enhance its ability to regulate mitochondrial genes. The assessment examines Nurr1's involvement in dopaminergic neuron development and mitochondrial formation while showing its role in reducing oxidative damage for an extensive understanding of its neurological disease functionality. Nurr1 serves as a therapeutic candidate for analysis, while the review explores obstacles and potential paths for using Nurr1-based treatments against Parkinson's disease alongside Alzheimer's disease and other neurodegenerative disorders. The extensive research utilized multiple databases, PubMed, Scopus, Medline, and EMBASE, with keywords "Nurr1," "NR4A2," "Neurodegenerative disorders," "Mitochondrial biogenesis," "Oxidative stress," "Parkinson's disease," "Alzheimer's disease," and "Therapeutic target." The analysis examined published research regarding Nurr1-mediated control of dopaminergic function and survival and mitigation of neurological and mitochondrial deficits within the past decade. Nurr1's interactions with important co-regulators like PGCα, its post-translational changes, and its effects on neuroinflammation have also received particular focus. In neurodegenerative illnesses, mitochondrial dysfunction adds to neuronal damage. Nurr1's regulation of mitochondrial biogenesis helps recover mitochondrial function, alleviate oxidative stress, and sustain neuronal survival. Dysregulation of Nurr1 expression is connected to decreased mitochondrial activity and accelerated neurodegeneration.