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Netrin-G2 is a membrane-anchored protein and is known to play critical roles in neuronal circuit development and synaptic organization. In this study, we identify compound heterozygous mutations of c.547delC, p.(Arg183Alafs*186) and c.605G>A, p.(Trp202*) in NTNG2 causing a syndrome exhibiting developmental delay, intellectual disability, hypotonia, and facial dysmorphism. To elucidate the underlying cellular and molecular mechanisms, CRISPR-Cas9 technology is employed to generate a knock-in mouse model expressing the R183Afs and W202X mutations. We report that the Ntng2R183Afs/W202X mice exhibit hypotonia and impaired learning and memory. We find that levels of CaMKII and p-GluA1Ser831 are decreased and excitatory postsynaptic transmission and long-term potentiation are impaired. To increase the activity of CaMKII, the mutant mice have received intraperitoneal injections of DCP-LA, a CaMKII agonist, and show improved cognitive function. Together, our findings reveal molecular mechanisms of how NTNG2 deficiency leads to impairments of cognitive ability and synaptic plasticity.
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Leucine-rich glioma-inactivated protein 1 (LGI1), a secretory protein in the brain, plays a critical role in myelination; dysfunction of this protein leads to hypomyelination and white matter abnormalities (WMAs). Here, we hypothesized that LGI1 may regulate myelination through binding to an unidentified receptor on the membrane of oligodendrocytes (OLs). To search for this hypothetic receptor, we analyzed LGI1 binding proteins through LGI1-3 × FLAG affinity chromatography with mouse brain lysates followed by mass spectrometry. An OL-specific membrane protein, the oligodendrocytic myelin paranodal and inner loop protein (OPALIN), was identified. Conditional knockout (cKO) of OPALIN in the OL lineage caused hypomyelination and WMAs, phenocopying LGI1 deficiency in mice. Biochemical analysis revealed the downregulation of Sox10 and Olig2, transcription factors critical for OL differentiation, further confirming the impaired OL maturation in Opalin cKO mice. Moreover, virus-mediated re-expression of OPALIN successfully restored myelination in Opalin cKO mice. In contrast, re-expression of LGI1-unbound OPALIN_K23A/D26A failed to reverse the hypomyelination phenotype. In conclusion, our study demonstrated that OPALIN on the OL membrane serves as an LGI1 receptor, highlighting the importance of the LGI1/OPALIN complex in orchestrating OL differentiation and myelination.
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Diferenciação Celular , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos Knockout , Oligodendroglia , Animais , Oligodendroglia/metabolismo , Oligodendroglia/citologia , Camundongos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Bainha de Mielina/metabolismo , Proteínas da Mielina/metabolismo , Proteínas da Mielina/genéticaRESUMO
BACKGROUND: Proteasome assembly chaperone 3 (PSMG3), a subunit of proteasome, has been found to be associated with lung cancer. However, the role of PSMG3 in other cancers has not been elucidated. The objective of this study was to explore the immune role of PSMG3 in pan-cancer and confirm the oncogenic significance in liver hepatocellular carcinoma (LIHC). METHODS: We examined the differential expression of PSMG3 across various cancer types using data from The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) databases. We investigated the prognostic value of PSMG3 and examined its relationship with tumor mutation burden (TMB), microsatellite instability (MSI), and immune infiltration. The functional enrichment analysis was performed to explore the potential molecular mechanism of PSMG3. To elucidate the biological function of PSMG3, we conducted in vitro experiments using liver cancer cell lines. RESULTS: PSMG3 was highly expressed in most cancers. The high PSMG3 expression value of PSMG3 was closely related to poor prognosis. We observed correlations between PSMG3 and TMB, and MSI immune infiltration. PSMG3 may be involved in metabolic reprogramming, cell cycle, and PPAR pathways. The over-expression of PSMG3 promoted the proliferation, migration, and invasion capabilities of liver cancer cells. CONCLUSION: Our study demonstrated that PSMG3 was a pivotal oncogene in multiple cancers. PSMG3 contributed to the progression and immune infiltration in pan-cancer, especially in LIHC.
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This study investigates whether exercise as a strategy for improving physical fitness at sea level also offers comparable benefits in the unique context of high altitudes (HA), considering the physiological challenges of hypoxic conditions. Overall, 121 lowlanders who had lived on the Tibetan Plateau for >2 years and were still living at HA during the measurements were randomly classified into four groups. Each individual of the low-intensity (LI), moderate-intensity (MI), and high-intensity (HI) groups performed 20 sessions of aerobic exercise at HA (3680 m) over 4 weeks, while the control group (CG) did not undergo any intervention. Physiological responses before and after the intervention were observed. The LI and MI groups experienced significant improvement in cardiopulmonary fitness (0.27 and 0.35 L/min increases in peak oxygen uptake [ V Ë $\dot{\mathrm{V}}$ O2peak], both p < 0.05) after exercise intervention, while the hematocrit (HCT) remained unchanged (p > 0.05). However, HI exercise was less efficient for cardiopulmonary fitness of lowlanders (0.02 L/min decrease in V Ë $\dot{\mathrm{V}}$ O2peak, p > 0.05), whereas both the HCT (1.74 %, p < 0.001) and glomerular filtration rate (18.41 mL/min, p < 0.001) increased with HI intervention. Therefore, LI and MI aerobic exercise, rather than HI, can help lowlanders in Tibet become more acclimated to the HA by increasing cardiopulmonary function and counteracting erythrocytosis.
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Aclimatação , Altitude , Aptidão Cardiorrespiratória , Exercício Físico , Consumo de Oxigênio , Humanos , Tibet , Exercício Físico/fisiologia , Masculino , Adulto , Aclimatação/fisiologia , Consumo de Oxigênio/fisiologia , Aptidão Cardiorrespiratória/fisiologia , Feminino , Hematócrito , Adulto Jovem , Taxa de Filtração Glomerular/fisiologia , Aptidão Física/fisiologia , Frequência Cardíaca/fisiologiaRESUMO
Ageing increases susceptibility to neurodegenerative disorders, such as Alzheimer's disease (AD). Serum levels of sclerostin, an osteocyte-derived Wnt-ß-catenin signalling antagonist, increase with age and inhibit osteoblastogenesis. As Wnt-ß-catenin signalling acts as a protective mechanism for memory, we hypothesize that osteocyte-derived sclerostin can impact cognitive function under pathological conditions. Here we show that osteocyte-derived sclerostin can cross the blood-brain barrier of old mice, where it can dysregulate Wnt-ß-catenin signalling. Gain-of-function and loss-of-function experiments show that abnormally elevated osteocyte-derived sclerostin impairs synaptic plasticity and memory in old mice of both sexes. Mechanistically, sclerostin increases amyloid ß (Aß) production through ß-catenin-ß-secretase 1 (BACE1) signalling, indicating a functional role for sclerostin in AD. Accordingly, high sclerostin levels in patients with AD of both sexes are associated with severe cognitive impairment, which is in line with the acceleration of Αß production in an AD mouse model with bone-specific overexpression of sclerostin. Thus, we demonstrate osteocyte-derived sclerostin-mediated bone-brain crosstalk, which could serve as a target for developing therapeutic interventions against AD.
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Doença de Alzheimer , Humanos , Masculino , Feminino , Camundongos , Animais , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/uso terapêutico , Secretases da Proteína Precursora do Amiloide/metabolismo , Secretases da Proteína Precursora do Amiloide/uso terapêutico , Osteócitos/metabolismo , Osteócitos/patologia , beta Catenina/metabolismo , beta Catenina/uso terapêutico , Ácido Aspártico Endopeptidases/metabolismo , Ácido Aspártico Endopeptidases/uso terapêutico , Via de Sinalização Wnt , Cognição , EnvelhecimentoRESUMO
In recent years, tumor catalytic therapy based on nanozymes has attracted widespread attention. However, its application is limited by the tumor hypoxic microenvironment (TME). In this study, we developed oxygen-supplying magnetic bead nanozymes that integrate hemoglobin and encapsulate the photosensitizer curcumin, demonstrating reactive oxygen species (ROS)-induced synergistic breast cancer therapy. Fe3O4 magnetic bead-mediated catalytic dynamic therapy (CDT) generates hydroxyl radicals (ËOH) through the Fenton reaction in the tumor microenvironment. The Hb-encapsulated Fe3O4 magnetic beads can be co-loaded with the photosensitizer/chemotherapeutic agent curcumin (cur), resulting in Fe3O4-Hb@cur. Under hypoxic conditions, oxygen molecules are released from Fe3O4-Hb@cur to overcome the TME hypoxia, resulting in comprehensive effects favoring anti-tumor responses. Upon near-infrared (NIR) irradiation, Fe3O4-Hb@cur activates the surrounding molecular oxygen to generate a certain amount of singlet oxygen (1O2), which is utilized for photodynamic therapy (PDT) in cancer treatment. Meanwhile, we validated that the O2 carried by Hb significantly enhances the intracellular ROS level, intensifying the catalytic therapy mediated by Fe3O4 magnetic beads and inflicting lethal damage to cancer cells, effectively inhibiting tumor growth. Therefore, significant in vivo synergistic therapeutic effects can be achieved through catalytic-photodynamic combination therapy.
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Neoplasias da Mama , Curcumina , Neoplasias , Fotoquimioterapia , Humanos , Feminino , Neoplasias da Mama/tratamento farmacológico , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Oxigênio , Espécies Reativas de Oxigênio/farmacologia , Curcumina/farmacologia , Curcumina/uso terapêutico , Linhagem Celular Tumoral , Fotoquimioterapia/métodos , Neoplasias/tratamento farmacológico , Hipóxia , Fenômenos Magnéticos , Microambiente Tumoral , Peróxido de Hidrogênio/uso terapêuticoRESUMO
The emergence of acute ischemic stroke (AIS) induced cardiovascular dysfunctions as a bidirectional interaction has gained paramount importance in understanding the intricate relationship between the brain and heart. Post AIS, the ensuing cardiovascular dysfunctions encompass a spectrum of complications, including heart attack, congestive heart failure, systolic or diastolic dysfunction, arrhythmias, electrocardiographic anomalies, hemodynamic instability, cardiac arrest, among others, all of which are correlated with adverse outcomes and mortality. Mounting evidence underscores the intimate crosstalk between the heart and the brain, facilitated by intricate physiological and neurohumoral complex networks. The primary pathophysiological mechanisms contributing to these severe cardiac complications involve the hypothalamic-pituitary-adrenal (HPA) axis, sympathetic and parasympathetic hyperactivity, immune and inflammatory responses, and gut dysbiosis, collectively shaping the stroke-related brain-heart axis. Ongoing research endeavors are concentrated on devising strategies to prevent AIS-induced cardiovascular dysfunctions. Notably, labetalol, nicardipine, and nitroprusside are recommended for hypertension control, while ß-blockers are employed to avert chronic remodeling and address arrhythmias. However, despite these therapeutic interventions, therapeutic targets remain elusive, necessitating further investigations into this complex challenge. This review aims to delineate the state-of-the-art pathophysiological mechanisms in AIS through preclinical and clinical research, unraveling their intricate interplay within the brain-heart axis, and offering pragmatic suggestions for managing AIS-induced cardiovascular dysfunctions.
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AVC Isquêmico , Infarto do Miocárdio , Acidente Vascular Cerebral , Humanos , Coração , Acidente Vascular Cerebral/complicações , EncéfaloRESUMO
Ketamine exhibits rapid and sustained antidepressant effects. As decreased myelination has been linked to depression pathology, changes in myelination may be a pivotal mechanism underlying ketamine's long-lasting antidepressant effects. Although ketamine has a long-lasting facilitating effect on myelination, the precise roles of myelination in ketamine's sustained antidepressant effects remain unknown. In this study, we employed spatial transcriptomics (ST) to examine ketamine's lasting effects in the medial prefrontal cortex (mPFC) and hippocampus of mice subjected to chronic social defeat stress and identified several differentially expressed myelin-related genes. Ketamine's ability to restore impaired myelination in the brain by promoting the differentiation of oligodendrocyte precursor cells (OPCs) into mature oligodendrocytes was demonstrated. Moreover, we showed that inhibiting the expression of myelin-associated oligodendrocytic basic protein (Mobp) blocked ketamine's long-lasting antidepressant effects. We also illustrated that α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) signaling mediated ketamine's facilitation on myelination. In addition, we found that the (R)-stereoisomer of ketamine showed stronger effects on myelination than (S)-ketamine, which may explain its longer-lasting antidepressant effects. These findings reveal novel mechanisms underlying the sustained antidepressant effects of ketamine and the differences in antidepressant effects between (R)-ketamine and (S)-ketamine, providing new insights into the role of myelination in antidepressant mechanisms.
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OBJECTIVE: Rare variants of CCNK (cyclin K) give rise to a syndrome with intellectual disability. The purpose of this study was to describe the genotype-phenotype spectrum of CCNK-related syndrome and the underlying molecular mechanisms of pathogenesis. METHODS: We identified a number of de novo CCNK variants in unrelated patients. We generated patient-induced pluripotent stem cells (iPSCs) and neural progenitor cells (NPCs) as disease models. In addition, we constructed NPC-specific Ccnk knockout (KO) mice and performed molecular and morphological analyses. RESULTS: We identified 2 new patients harboring CCNK missense variants and followed-up 3 previous reported patients, which constitute the largest patient population analysis of the disease. We demonstrate that both the patient-derived NPC models and the Ccnk KO mouse displayed deficient NPC proliferation and enhanced apoptotic cell death. RNA sequencing analyses of these NPC models uncovered transcriptomic signatures unique to CCNK-related syndrome, revealing significant changes in genes, including WNT5A, critical for progenitor proliferation and cell death. Further, to confirm WNT5A's role, we conducted rescue experiments using NPC and mouse models. We found that a Wnt5a inhibitor significantly increased proliferation and reduced apoptosis in NPCs derived from patients with CCNK-related syndrome and NPCs in the developing cortex of Ccnk KO mice. INTERPRETATION: We discussed the genotype-phenotype relationship of CCNK-related syndrome. Importantly, we demonstrated that CCNK plays critical roles in NPC proliferation and NPC apoptosis in vivo and in vitro. Together, our study highlights that Wnt5a may serve as a promising therapeutic target for the disease intervention. ANN NEUROL 2023;94:1136-1154.
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Deficiência Intelectual , Células-Tronco Neurais , Camundongos , Animais , Humanos , Células-Tronco Neurais/metabolismo , Transdução de Sinais/genética , Ciclinas/metabolismo , ApoptoseRESUMO
Real-time studies of biomarkers for neurological disorders present significant opportunities for diagnosing and treating related diseases, and fluorescent probes offer a promising approach to brain imaging. However, intracerebral fluorescence imaging is often limited by blood-brain barrier permeability and penetration depth. Moreover, only very few probes have rapid intracerebral metabolic properties, which are critical for in vivo imaging. Here, we developed a novel class of fluorescent dyes with two-photon excitation and near-infrared (NIR) emission (920/705 nm). The representative WAPP-4 probe exhibits a large Stokes shift (Δλ = 324 nm in ethanol) and excellent blood-brain barrier permeability. Notably, using WAPP-4, we achieved in vivo 3D dynamic imaging of Aß plaques in the brains of living mice with Alzheimer's disease (AD). In addition, super-resolution imaging showed that WAPP-4 could effectively characterize the distribution and shape of Aß plaques in isolated brain slices. This study demonstrates that newly developed fluorescent dyes with large Stokes shifts and blood-brain barrier permeability enable real-time imaging of amyloid plaques, which will contribute to the development of other valuable tools for near-infrared imaging and super-resolution imaging in the brain.
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Técnicas Biossensoriais , Corantes Fluorescentes , Animais , Camundongos , Placa Amiloide/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Barreira Hematoencefálica , Cloreto de PolivinilaRESUMO
METTL7A is a protein-coding gene expected to be associated with methylation, and its expression disorder is associated with a range of diseases. However, few research have been carried out to explore the relationship between METTL7A and tumor malignant phenotype as well as the involvement potential mechanism. We conducted our research via a combination of silico analysis and molecular biology techniques to investigate the biological function of METTL7A in the progression of cancer. Gene expression and clinical information were extracted from the TCGA database to explore expression variation and prognostic value of METTL7A. In vitro, CCK8, transwell, wound healing and colony formation assays were conducted to explore the biological functions of METT7A in cancer cell. GSEA was performed to explore the signaling pathway involved in METTL7A and validated via western blotting. In conclusion, METTL7A was downregulated in most cancer tissues and its low expression was associated with shorter overall survival. In melanoma, METTL7A downregulation was associated with poorer clinical staging, lower levels of TIL infiltration, higher IC50 levels of chemotherapeutic agents, and poorer immunotherapy outcomes. QPCR results confirm that METTL7A is down-regulated in melanoma cells. Cell function assays showed that METTL7A knockdown promoted proliferation, invasion, migration and clone formation of melanoma cells. Mechanistic studies showed that METTL7A inhibits tumorigenicity through the p53 signaling pathway. Meanwhile, METTL7A is also a potential immune regulatory factor.
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Melanoma , Metiltransferases , Proteína Supressora de Tumor p53 , Humanos , Linhagem Celular Tumoral , Melanoma/genética , Transdução de Sinais/genética , Transcriptoma , Proteína Supressora de Tumor p53/genética , Metiltransferases/genéticaRESUMO
In 2019 and 2020, 70 paddy and 70 brown rice samples were collected from South China and Southwest China, wherein the residues of 15 target pesticides were investigated. A gas chromatography-mass spectrometry (GC-MS) method was established for the simultaneous detection of 15 pesticides, which achieved good linear relationship with limits of detection (LODs) of 0.10-4.00 µg kg-1. The average recoveries and relative standard deviations (RSD) were satisfied for the pesticide residues detection. Analysis results showed that the detection rates of 15 typical pesticides in paddy and brown rice were 0%-12.9% and 0%-1.4%, respectively. None of the 15 pesticides exceed their maximum residue limit (MRL) stipulated by China. The pesticide with the highest detection rate and concentration was chlorpyrifos. This study can provide data support for the control of pesticide residues in rice and the realisation of the improving the efficiency of pesticide and fertiliser while reducing their application.
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Oryza , Resíduos de Praguicidas , Praguicidas , Resíduos de Praguicidas/análise , Oryza/química , Contaminação de Alimentos/análise , Praguicidas/análise , Cromatografia Gasosa-Espectrometria de Massas/métodosRESUMO
The prenylation of proteins is involved in a variety of biological functions. However, it remains unknown whether it plays an important role in the morphogenesis of the cerebellum. To address this question, we generated a mouse model, in which the geranylgeranyl pyrophosphate synthase (Ggps1) gene is inactivated in neural progenitor cells in the developing cerebellum. We report that conditional knockout (cKO) of Ggps1 leads to severe ataxia and deficient locomotion. To identify the underlying mechanisms, we completed a series of cellular and molecular experiments. First, our morphological analysis revealed significantly decreased population of granule cell progenitors (GCPs) and impaired proliferation of GCPs in the developing cerebellum of Ggps1 cKO mice. Second, our molecular analysis showed increased expression of p21, an important cell cycle regulator in Ggps1 cKO mice. Together, this study highlights a critical role of Ggpps-dependent protein prenylation in the proliferation of cerebellar GCPs during cerebellar development.
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Células-Tronco Neurais , Prenilação de Proteína , Camundongos , Animais , Cerebelo , Ataxia , Proliferação de Células , Camundongos KnockoutRESUMO
Background: The histologically complete resection (CR) rate of small rectal neuroendocrine tumors (RNETs) is unsatisfactory at the first endoscopy. Risk factors and clinical outcomes associated with incomplete resection (IR) have not been explicitly elucidated. This study aims to explore the relevant factors of IR. Methods: This retrospective study reviewed patients with small RNETs (≤10 mm) in eight centers from January 2013 to December 2021. Clinicopathological characteristics and clinical outcomes were compared between the CR and IR groups, and the polypectomy and advanced treatment groups. Results: Of the 326 patients included, 83 (25.5%) were diagnosed with IR. Polypectomy (odds ratio [OR] = 16.86), a central depression (OR = 7.50), and treatment in the early period (OR = 2.60) were closely associated with IR. Further analysis revealed that an atypical hyperemic appearance (OR = 7.49) and treatment in the early period (OR = 2.54) were significantly associated with the inappropriate use of polypectomy (both P < 0.05). In addition, a total of 265 (81.3%) were followed up with a median follow-up period of 30.9 months. No death, metastasis, or recurrence was found during the follow-up period. Conclusions: Polypectomy, a central depression, and treatment in the early period were risk factors for IR. Further, an atypical hyperemic appearance and treatment in the early period were significant predisposing factors for inappropriate choice of polypectomy. For histologically incompletely resected small RNETs, follow-up may be a safe and feasible alternative to rigorous salvage therapy.
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Developing rapid and non-invasive diagnostics for Helicobacter pylori (HP) is imperative to prevent associated diseases such as stomach gastritis, ulcers, and cancers. Owing to HP strain heterogeneity, not all HP-infected individuals incur side effects. Cytotoxin-associated gene A (CagA), and vacuolating cytotoxin A (VacA) genes predominantly drive HP pathogenicity. Therefore, diagnosing CagA and VacA genotypes could alert active infection and decide suitable therapeutics. We report an enhanced LbCas12a trans-cleavage activity with extended reporters and reductants (CEXTRAR) for early detection of HP. We demonstrate that extended ssDNA reporter acts as an excellent signal amplifier, making it a potential alternative substrate for LbCas12a collateral activity. Through a systematic investigation of various buffer components, we demonstrate that reductants improve LbCas12a trans-cleavage activity. Overall, our novel reporter and optimal buffer increased the trans-cleavage activity to an order of 16-fold, achieving picomolar sensitivity (171 pM) without target pre-amplification. Integrated with loop-mediated isothermal amplification (LAMP), CEXTRAR successfully attained attomolar sensitivity for HP detection using real-time fluorescence (43 and 96 aM), in-tube fluorescence readouts (430 and 960 aM), and lateral flow (4.3 and 9.6 aM) for CagA and VacA, respectively. We also demonstrate a rapid 2-min Triton X-100 lysis for clinical sample analysis, which could provide clinicians with actionable information for rapid diagnosis. CEXTRAR could potentially spot the 13C urea breath test false-negatives. For the first time, our study unveils an experimental outlook to manipulate reporters and reconsider precise cysteine substitution via protein engineering for Cas variants with enhanced catalytic activities for use in diagnostics and genetic engineering.
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Técnicas Biossensoriais , Infecções por Helicobacter , Helicobacter pylori , Úlcera Péptica , Neoplasias Gástricas , Humanos , Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/genética , Helicobacter pylori/genética , Helicobacter pylori/metabolismo , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/genética , Substâncias Redutoras , Sistemas CRISPR-Cas , Detecção Precoce de Câncer , Úlcera Péptica/diagnóstico , Úlcera Péptica/genética , Genótipo , Citotoxinas/genética , Infecções por Helicobacter/diagnóstico , Infecções por Helicobacter/genética , Infecções por Helicobacter/metabolismoRESUMO
[This retracts the article DOI: 10.1016/j.omtn.2019.02.022.].
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Eucommia ulmoides, a precious Chinese herbal medicine, lack of studies on the detection of its pesticide residues. A simple sample preparation based on the solid-phase extraction (SPE) procedure was established for the analysis of 16 kinds of pesticides in Eucommia ulmoides by gas chromatography mass spectrometry (GC-MS) with selective ion monitoring mode. Here, the type and volume of extraction solvent and eluent, the kinds of sorbents in SPE Cleanert column, were optimized. Under the optimal conditions, a good linear relationship was obtained in the range of 0.005 to 5.0 mg/L with correlation coefficient (r) higher than 0.9990, and the average recoveries (AR) of 16 pesticides ranged from 79.6 to 109.2% at the spiking levels of 0.01, 0.1, and 0.5 mg/kg. The relative standard deviations (RSD) were 0.78 to 9.56% (n = 6). The results show that the established method can not only fully meet the analytical requirements of various pesticides in Eucommia ulmoides, but also have the potential to be applied in the detection of pesticide residues in others Chinese herbal medicine.
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Medicamentos de Ervas Chinesas , Eucommiaceae , Resíduos de Praguicidas , Praguicidas , Medicamentos de Ervas Chinesas/análise , Monitoramento Ambiental , Cromatografia Gasosa-Espectrometria de Massas/métodos , Resíduos de Praguicidas/análise , Praguicidas/análise , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodosRESUMO
It has been shown that PP2A is critical for apoptosis in neural progenitor cells. However, it remains unknown whether PP2A is required for neuronal survival. To address this question, we generated forebrain-specific Ppp2cα knockout (KO) mice. We show that Ppp2cα KO mice display robust neuronal apoptosis and inflammatory responses in the postnatal cortex. Previous evidence has revealed that PD98059 is a potent ERK inhibitor and may protect the brain against cell death after cardiac arrest. To study whether PD98059 may have any effects on Ppp2cα KO mice, the latter was treated with this inhibitor. We demonstrated that the total number of cleaved caspase3 positive (+) cells in the cortex was significantly reduced in Ppp2cα KO mice treated with PD98059 compared with those without PD98059 treatment. We observed that the total number of IBA1+ cells in the cortex was significantly decreased in Ppp2cα KO mice treated with PD98059. Mechanistic analysis reveals that deletion of PP2Aca causes DNA damage, which may be attenuated by PD98059. Together, this study suggests that inhibition of ERK may be an effective strategy to reduce cell death in brain diseases with abnormal neuronal apoptosis.
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Neurônios , Prosencéfalo , Animais , Apoptose , Morte Celular , Camundongos , Camundongos Knockout , Neurônios/metabolismoRESUMO
AIMS: Abundant recent evidence has shown that 3-phosphoinositide-dependent protein kinase 1 (PDK1) is activated in Alzheimer's disease (AD). However, it remains unknown whether inhibition of PDK1 in neurons may affect AD-like pathology in animal models of AD. Here, we aim to examine the effects of specific inactivation of neuronal PDK1 on pathology and behaviour in 5×FAD mice and to identify the underlying molecular mechanisms. METHODS: The Cre-loxP system was employed to generate Pdk1 cKO/5×FAD mice, in which PDK1 is inactivated in excitatory neurons in the adult forebrain. Cellular and behavioural techniques were used to examine plaque burden, inflammatory responses and spatial working memory in mice. Biochemical and molecular analyses were conducted to investigate relevant mechanisms. RESULTS: First, Aß deposition was massively decreased and gliosis was highly attenuated in Pdk1 cKO/5×FAD mice compared with 5×FAD mice. Second, memory deficits were significantly improved in Pdk1 cKO/5×FAD mice. Third, APP levels were notably decreased in Pdk1 cKO/5×FAD mice. Fourth, mammalian target of rapamycin (mTOR) signalling and ribosome biogenesis were reduced in Pdk1 cKO/5×FAD mice. CONCLUSIONS: Neuron-specific deletion of PDK1 robustly ameliorates AD-like pathology and improves spatial working memory in 5×FAD mice. We propose that genetic approach to inhibit PDK1 may be an effective strategy to slow AD.