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Pericytes are one of the main components of the neurovascular unit. They play a critical role in regulating blood flow, blood-brain barrier permeability, neuroinflammation, and neuronal activity. In the central nervous system (CNS), pericytes are classified into three subtypes, that is, ensheathing, mesh, and thin-strand pericytes, based on their distinct morphologies and region-specific distributions. However, whether these three types of pericytes exhibit heterogeneity or homogeneity with regard to membrane properties has been understudied to date. Here, we combined bulk RNA sequencing analysis with electrophysiological methods to demonstrate that the three subtypes of pericytes share similar electrical membrane properties in the CNS, suggesting a homogenous population of neurovascular pericytes in the brain. Furthermore, we identified an inwardly rectifying potassium channel subtype Kir4.1 functionally expressed in pericytes. Electrophysiological patch clamp recordings indicate that Kir4.1 channel currents in pericytes represent a small portion of the K+ macroscopic currents in physiological conditions. However, a significant augmentation of Kir4.1 currents in pericytes was induced when the extracellular K+ was elevated to pathological levels, suggesting pericytes Kir4.1 channels might play an important role as K+ sensors and contribute to K+ homeostasis in local neurovascular networks in pathology.
Assuntos
Pericitos , Canais de Potássio Corretores do Fluxo de Internalização , Encéfalo/metabolismo , Sistema Nervoso Central/metabolismo , Neurônios/metabolismo , Pericitos/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização/genética , Canais de Potássio Corretores do Fluxo de Internalização/metabolismoRESUMO
SAP97 is directly involved in exporting NMDA receptors with a specific subunit composition from the endoplasmic reticulum (ER). Characterization of the interactions between SAP97 and an NMDA receptor splice variant, GluN1-3, and of the effects on forward trafficking revealed that an ER-level interaction blocked the RXR ER-retention motif in the GluN1-3 cytoplasmic C-terminus in the context of both reporter molecules and full-length receptors. Binding of SAP97 to the PDZ-binding domain of GluN1-3 was required, but the blockade of ER-retention was mediated by the SH3-GuK domains coupled with the action of the N-terminus of SAP97. While other domains of SAP97 were involved in forward trafficking of GluN1-3 out of the ER, the SH3 domain was necessary and sufficient to block the ER retention. This is the first direct evidence for the masking of ER-retention signals by PDZ domain-containing proteins, and provides detailed underlying mechanistic requirements. Such a mechanism could be central to modulating the ER exit of receptors into local, non-conventional or conventional, secretory pathways in neurons.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Retículo Endoplasmático/metabolismo , Proteínas de Membrana/metabolismo , Subunidades Proteicas/metabolismo , Receptores de N-Metil-D-Aspartato/química , Receptores de N-Metil-D-Aspartato/metabolismo , Receptores X de Retinoides/metabolismo , Domínios de Homologia de src , Proteínas Adaptadoras de Transdução de Sinal/química , Sequência de Aminoácidos , Animais , Células COS , Membrana Celular/metabolismo , Chlorocebus aethiops , Proteína 1 Homóloga a Discs-Large , Proteínas de Fluorescência Verde/metabolismo , Células HeLa , Humanos , Proteínas de Membrana/química , Modelos Biológicos , Dados de Sequência Molecular , Subunidades Proteicas/química , Relação Estrutura-AtividadeRESUMO
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by a severe decline of memory performance. A widely studied AD mouse model is the APPswe/PSEN1ΔE9 (APP/PS1) strain, as mice exhibit amyloid plaques as well as impaired memory capacities. To test whether restoring synaptic plasticity and decreasing ß-amyloid load by Parkin could represent a potential therapeutic target for AD, we crossed APP/PS1 transgenic mice with transgenic mice overexpressing the ubiquitin ligase Parkin and analyzed offspring properties. Overexpression of Parkin in APP/PS1 transgenic mice restored activity-dependent synaptic plasticity and rescued behavioral abnormalities. Moreover, overexpression of Parkin was associated with down-regulation of APP protein expression, decreased ß-amyloid load and reduced inflammation. Our data suggest that Parkin could be a promising target for AD therapy.
Assuntos
Doença de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Hipocampo/fisiopatologia , Potenciação de Longa Duração , Ubiquitina-Proteína Ligases/metabolismo , Doença de Alzheimer/fisiopatologia , Precursor de Proteína beta-Amiloide/genética , Animais , Córtex Cerebral/metabolismo , Modelos Animais de Doenças , Feminino , Expressão Gênica , Hipocampo/metabolismo , Humanos , Masculino , Aprendizagem em Labirinto , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Sinaptofisina/metabolismo , Transcrição Gênica , Ubiquitina-Proteína Ligases/genética , UbiquitinaçãoRESUMO
This study investigated the impact of chitosan (CH, 1%) and aloe vera gel (AL, 30%) edible coatings on the preservation of blue honeysuckle quality during a 28-day storage at -1 °C. Coating with CH, AL, and CH+AL led to notable enhancements in several key attributes. These included increased firmness, total soluble solids, acidity, pH, and antioxidant capacity (measured through DPPH, ABTS, and FRAP assays), as well as the preservation of primary (ascorbic acid) and secondary metabolites (TPC, TAC, and TFC). The TAC and TFC levels were approximately increased by 280% and 17%, respectively, in coated blue honeysuckle after 28 d compared to uncoated blue honeysuckle. These coatings also resulted in reduced weight loss, respiration rate, color, abscisic acid, ethylene production, and malondialdehyde content. Notably, the CH+AL treatment excelled in preserving secondary metabolites and elevating FRAP-reducing power, demonstrating a remarkable 1.43-fold increase compared to the control after 28 days. Overall, CH+AL exhibited superior effects compared to CH or AL treatment alone, offering a promising strategy for extending the shelf life and preserving the quality of blue honeysuckle during storage.
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Blue honeysuckle seeds are often overlooked by the processing industry, but they are a good source of healthy oil. The composition, volatiles, and antioxidant capacity of blue honeysuckle seeds and seed oil were investigated for the first time. The fatty acid profile of the seed oil was analysed using GC-MS. The seed oil was particularly rich in polyunsaturated fatty acid, especially linoleic acid (71.24 ± 1.64 %). HS-SPME-GC-MS analysis temporarily detected 34 and 37 volatiles in the seeds and seed oil, respectively. Notably, aldehydes were identified as the major contributors to the aroma. The phytosterols, tocopherols, and triglycerides were identified in the seed oil. Interestingly, the total phenolic content and antioxidant capacity of the seeds were found to be much higher than the seed oil. This study evaluates the nutritional profile and value of blue honeysuckle seed oil, and suggests that it can be used as new functional oil.
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BACKGROUND: Stroke is one of the most common neurological diseases in the world and is clinically manifested by transient or permanent brain dysfunction. It has a high mortality and disability rate, which severely affects people's health and diminishes the quality of life. However, there is no efficient treatment that can be considered curative and there are other less well-known theories of pathogenesis. Therefore, it is imperative to gain a full understanding of the pathophysiology of ischemia and to seek new therapeutic strategies. METHODS: We first examined Kir4.1 channel and myelin based protein (MBP) expression in brain tissues from acute ischemic patients by Western blotting. We then established a transient ischemic mouse model (tMCAO) to conduct molecular, cell biological, transmission electron microscopy and pharmacokinetic studies, as well as in Kir4.1 cKO mice. Finally, neuroimaging and behavioral analyses were used to examine whether activation of Kir4.1 channel by luteolin could contribute to neuronal functional recovery in ischemic stroke. FINDINGS: In acute ischemic stroke patients, we first demonstrated that Kir4.1 ion channels were greatly impaired and a severe demyelination of axons occurred in ischemic infarction area of cerebral cortex in these patients. Further evidence showed that the deficits of Kir4.1 channels in NG2 glia led to the myelin loss of axons in a transient ischemic mouse model (tMCAO). Treating ischemic mice with a natural botanical extract, luteolin augmented Kir4.1 channel currents in NG2 glia and consequently promoted remyelination of axons, alleviated the infarction area and ultimately improved motor function in a series of behavioral tests. INTERPRETATION: Targeting Kir4.1 ion channels expressed in NG2 glial cells by luteolin treatment highlights an effective therapeutic strategy for a prompt brain functional recovery in ischemic stroke. FUNDING: This work was supported by grants from the Ministry of Science and Technology China Brain Initiative (2022ZD0204702, to X.T.), the National Natural Science Foundation of China (82271466, 82171279, 31970904 and 31571063), the Program for Professor of Special Appointment (Eastern Scholar for Dr. X.T.) at Shanghai Institutions for Higher Learning (1510000084), Shanghai Pujiang Talent Award (15PJ1404600), Shanghai Municipal Science and Technology Major Project (2018SHZDZX05) and Shanghai Science and Technology Project (17411954000).
Assuntos
AVC Isquêmico , Remielinização , Acidente Vascular Cerebral , Camundongos , Animais , AVC Isquêmico/tratamento farmacológico , AVC Isquêmico/etiologia , AVC Isquêmico/metabolismo , Luteolina/metabolismo , Qualidade de Vida , China , Neuroglia/metabolismo , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/genética , Infarto/metabolismoRESUMO
NG2 glia, also known as oligodendrocyte precursor cells (OPCs), play an important role in proliferation and give rise to myelinating oligodendrocytes during early brain development. In contrast to other glial cell types, the most intriguing aspect of NG2 glia is their ability to directly sense synaptic inputs from neurons. However, whether this synaptic interaction is bidirectional or unidirectional, or its physiological relevance has not yet been clarified. Here, we report that NG2 glia form synaptic complexes with hippocampal interneurons and that selective photostimulation of NG2 glia (expressing channelrhodopsin-2) functionally drives GABA release and enhances inhibitory synaptic transmission onto proximal interneurons in a microcircuit. The mechanism involves GAD67 biosynthesis and VAMP-2 containing vesicular exocytosis. Further, behavioral assays demonstrate that NG2 glia photoactivation triggers anxiety-like behavior in vivo and contributes to chronic social defeat stress.
Assuntos
Ansiedade/psicologia , Hipocampo/patologia , Células Precursoras de Oligodendrócitos/metabolismo , Estresse Psicológico/complicações , Ácido gama-Aminobutírico/metabolismo , Animais , Ansiedade/etiologia , Ansiedade/patologia , Diferenciação Celular , Modelos Animais de Doenças , Exocitose , Glutamato Descarboxilase/biossíntese , Hipocampo/citologia , Humanos , Interneurônios/patologia , Masculino , Camundongos , Camundongos Transgênicos , Técnicas de Patch-Clamp , Derrota Social , Estresse Psicológico/patologia , Estresse Psicológico/psicologia , Sinapses/patologia , Transmissão Sináptica/fisiologia , Proteína 2 Associada à Membrana da Vesícula/metabolismoRESUMO
Classically, endoplasmic reticulum (ER) retention signals in secreted integral membrane proteins impose the requirement to assemble with other cognate subunits to form functional assemblies before they can exit the ER. We report that GluK5 has two ER retention signals in its cytoplasmic C-terminus: an arginine-based signal and a di-leucine motif previously thought to be an endocytic motif. GluK5 assembles with GluK2, but surprisingly GluK2 association does little to block the ER retention signals. We find instead that the ER retention signals are blocked by two proteins involved in intracellular trafficking, SAP97 and CASK. We show that SAP97, in the presence of CASK and the receptor complex, assumes an extended conformation. In the extended conformation, SAP97 makes its SH3 and GuK domains available to bind and sterically mask the ER retention signals in the GluK5 C-terminus. SAP97 and CASK are also necessary for sorting receptor cargoes into the local dendritic secretory pathway in neurons. We show that the ER retention signals of GluK5 play a vital role in sorting the receptor complex in the local dendritic secretory pathway in neurons. These data suggest a new role for ER retention signals in trafficking integral membrane proteins in neurons. SIGNIFICANCE: We present evidence that the ER retention signals in the kainate receptors containing GluK5 impose a requirement for sorting into local dendritic secretory pathways in neurons, as opposed to traversing the somatic Golgi apparatus. There are two ER retention signals in the C-terminus of GluK5. We show that both are blocked by physical association with SAP97 and CASK. The SH3 and GuK domains of SAP97, in the presence of CASK, bind directly to each ER retention signal and form a complex. These results support an entirely new function for ER retention signals in the C-termini of neuronal receptors, such as NMDA and kainate receptors, and define a mechanism for selective entry of receptors into local secretory pathways.
Assuntos
Retículo Endoplasmático/metabolismo , Guanilato Quinases/metabolismo , Receptores de Ácido Caínico/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sequência de Aminoácidos , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Proteína 1 Homóloga a Discs-Large , Complexo de Golgi/metabolismo , Humanos , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Transporte ProteicoRESUMO
The contribution of the inwardly rectifying K+ channel subtype Kir4.1 has been focused mainly on astrocytes, where they play important roles in the maintenance of resting membrane potential, extracellular K+ uptake, and facilitation of glutamate uptake in the central nervous system. Here, we report the role of Kir4.1 channels in NG2-glia during brain development, potassium signaling, and in an ischemic stroke disease model. Kir4.1 channels are widely expressed in NG2-glia during brain development. In the adult mouse hippocampus, Kir4.1 channels in NG2-glia constitute more than 80% of K+ channels inward currents. This large portion of Kir4.1 channel currents exhibits a deficit in NG2-glia as an initial response in a transient ischemic mouse model. Further evidence indicates that Kir4.1 deficits in NG2-glia potentially cause axonal myelin loss in ischemia through the association with oligodendrocyte-specific protein (OSP/Claudin-11), which unravels a potential therapeutic target in the treatment of ischemic stroke.
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BACKGROUND AND PURPOSE: Mild cognitive deficit in early Parkinson's disease (PD) has been widely studied. Here we have examined the effects of memantine in preventing memory deficit in experimental PD models and elucidated some of the underlying mechanisms. EXPERIMENTAL APPROACHES: I.p. injection of 1-methyl-4- phenyl-1,2,3,6-tetrahydro pyridine (MPTP) in C57BL/6 mice was used to produce models of PD. We used behavioural tasks to test memory. In vitro, we used slices of hippocampus, with electrophysiological, Western blotting, real time PCR, elisa and immunochemical techniques. KEY RESULTS: Following MPTP injection, long-term memory was impaired and these changes were prevented by pre-treatment with memantine. In hippocampal slices from MPTP treated mice, long-term potentiation (LTP) -induced by θ burst stimulation (10 bursts, 4 pulses) was decreased, while long-term depression (LTD) induced by low-frequency stimulation (1 Hz, 900 pulses) was enhanced, compared with control values. A single dose of memantine (i.p., 10 mg·kg(-1) ) reversed the decreased LTP and the increased LTD in this PD model. Activity-dependent changes in tyrosine kinase receptor B (TrkB), ERK and brain-derived neurotrophic factor (BDNF) expression were decreased in slices from mice after MPTP treatment. These effects were reversed by pretreatment with memantine. Incubation of slices in vitro with 1-methyl-4-phenylpyridinium (MPP(+) ) decreased depolarization-induced expression of BDNF. This effect was prevented by pretreatment of slices with memantine or with calpain inhibitor III, suggesting the involvement of an overactivated calcium signalling pathway. CONCLUSIONS AND IMPLICATIONS: Memantine should be useful in preventing loss of memory and hippocampal synaptic plasticity in PD models.
Assuntos
1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina , Antiparkinsonianos/farmacologia , Comportamento Animal/efeitos dos fármacos , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Hipocampo/efeitos dos fármacos , Memantina/farmacologia , Glicoproteínas de Membrana/metabolismo , Transtornos da Memória/prevenção & controle , Memória de Longo Prazo/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Transtornos Parkinsonianos/prevenção & controle , Proteínas Tirosina Quinases/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sinapses/efeitos dos fármacos , 1-Metil-4-fenilpiridínio/farmacologia , Animais , Sinalização do Cálcio/efeitos dos fármacos , Modelos Animais de Doenças , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Técnicas In Vitro , Masculino , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/metabolismo , Transtornos da Memória/fisiopatologia , Transtornos da Memória/psicologia , Camundongos Endogâmicos C57BL , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/metabolismo , Transtornos Parkinsonianos/fisiopatologia , Transtornos Parkinsonianos/psicologia , Sinapses/metabolismo , Fatores de TempoRESUMO
RESP18 (Regulated endocrine-specific protein, 18 kDa) was first identified as a dopaminergic drugs-regulated intermediate pituitary transcript. RESP18 protein is a unique endoplasmic reticulum (ER) resident protein. Its functions in the brain especially in the nervous system disorders remain unknown. ER stress (ERS) has been proved to be one of the important pathogenesis of neurodegenerative diseases, including Parkinson's disease (PD). Here, we explored the association of RESP18 and ERS in cell models of PD. Dopaminergic neurotoxin 1-methyl-4-phenyl-pyridinium ion (MPPâº), 6-hydroxydopamine (6-OHDA), and rotenone evoked dramatic MN9D cell death. The transcriptional expressions of RESP18 and two ERS markers--binding immunoglobulin protein/glucose-regulated protein 78 (BiP/GRP78) and CCAAT/enhancer-binding protein homologous protein (CHOP) manifested differential changes in MN9D cells treated with MPPâº, 6-OHDA, and rotenone. The RESP18 protein levels increased in MPP⺠and 6-OHDA-treated cells, but did not change in the cells treated with rotenone, while the protein levels of ER molecular chaperone heat shock protein 90 kDa beta member 1/glucose-regulated protein 94 (HSP90B1/GRP94) and BiP in the cells were up-regulated by MPP⺠and 6-OHDA, respectively. Salubrinal, an ERS inhibitor, significantly reduced MPP⺠and 6-OHDA-induced cell death. Moreover, ERS inducer--thapsigargin and tunicamycin, decreased the expression of RESP18, which is different from the changes of BiP, GRP94, and CHOP. Silencing RESP18 expression with Lenti-shRNA alleviated MPPâº-induced cell death, while over-expression of RESP18 resulted in aggravated cell death induced by MPP⺠and 6-OHDA. Taken together, our results suggest that RESP18 is involved in the cytotoxicity of dopaminergic neurotoxins.
Assuntos
Dopaminérgicos/toxicidade , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/fisiologia , Proteínas do Tecido Nervoso/biossíntese , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Chaperona BiP do Retículo Endoplasmático , Células HEK293 , HumanosRESUMO
Epidemiological and clinico-pathological studies indicate a causal relationship between heart disease and Alzheimer's disease (AD). To learn whether heart disease causes an onset of AD, mice with myocardial infarction (MI) and congestive heart failure (HF) were used to test neuropsychiatric and cognitive behaviors as well as for measurements of AD related protein markers. To this end, adult mice were subjected to ligation of left anterior descending artery (LAD) and about two weeks later high-frequency echocardiography was performed to exam the resulting cardiac structure and function. Three months after successful induction of chronic heart failure (CHF) these mice showed an impairment of learning in the Morris Water Maze task. In addition, the expression of selected molecules, which are involved in ß-amyloid metabolism, apoptosis and inflammation on the level of gene transcription and translation, was altered in CHF mice. Our findings provide a plausible explanation that CHF increases the risk of cognitive impairments and alters cerebral ß-amyloid metabolism. In addition, our data indicate that the cerebral compensatory mechanisms in response to CHF are brain area and gender specific.
Assuntos
Peptídeos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Cognição , Insuficiência Cardíaca/metabolismo , Doença de Alzheimer/etiologia , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/fisiopatologia , Animais , Ansiedade/complicações , Apoptose , Transporte Biológico , Barreira Hematoencefálica/metabolismo , Encéfalo/patologia , Encéfalo/fisiopatologia , Modelos Animais de Doenças , Feminino , Glucose/metabolismo , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/patologia , Insuficiência Cardíaca/fisiopatologia , Aprendizagem , Locomoção , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miocárdio/metabolismo , Miocárdio/patologia , Tomografia por Emissão de Pósitrons , Risco , Caracteres Sexuais , Tomografia Computadorizada por Raios X , Transcrição GênicaRESUMO
Mutations in the parkin gene are currently thought to be the most common cause of recessive familial Parkinsonism. Parkin functions as an E3 ligase to regulate protein turnover, and its function in mitochondrial quality control has been reported recently. Overexpression of parkin has been found to prevent neuronal degeneration under various conditions both in vivo and in vitro. Here, we generated a transgenic mouse model in which expression of wild type parkin was driven by neuron-specific enolase (NSE) promoter. We reported that both young and old parkin transgenic mice exhibited less reduction of striatal TH protein and number of TH positive neurons in the substantia nigra induced by 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (MPTP), compared to wild type littermates. MPTP-induced mitochondrial impairment in the substantia nigra was improved in young parkin transgenic mice. Decreased striatal α-synuclein was demonstrated in old parkin transgenic mice. These results provide reliable evidence from the transgenic mouse model for parkin that overexpression of parkin may attenuate dopaminergic neurodegeneration induced by MPTP through protection of mitochondria and reduction of α-synuclein in the nigrostriatal pathway.