Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
FASEB J ; 38(20): e70111, 2024 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-39436109

RESUMO

The neurons of the melanocortin system regulate feeding and energy homeostasis through a combination of electrical and endocrine mechanisms. However, the molecular basis for this functional heterogeneity is poorly understood. Here, a voltage-gated potassium (Kv+) channel named KCNB1 (alias Kv2.1) forms stable complexes with the leptin receptor (LepR) in a subset of hypothalamic neurons including proopiomelanocortin (POMC) expressing neurons of the Arcuate nucleus (ARHPOMC). Mice lacking functional KCNB1 channels (NULL mice) have less adipose tissue and circulating leptin than WT animals and are insensitive to anorexic stimuli induced by leptin administration. NULL mice produce aberrant amounts of POMC at any developmental stage. Canonical LepR-STAT3 signaling-which underlies POMC production-is impaired, whereas non-canonical insulin receptor substrate PI3K/Akt/FOXO1 and ERK signaling are constitutively upregulated in NULL hypothalami. The levels of proto-oncogene c-Fos-that provides an indirect measure of neuronal activity-are higher in arcuate NULL neurons compared to WT and most importantly do not increase in the former upon leptin stimulation. Hence, a Kv channel provides a molecular link between neuronal excitability and endocrine function in hypothalamic neurons.


Assuntos
Hipotálamo , Leptina , Camundongos Knockout , Neurônios , Pró-Opiomelanocortina , Receptores para Leptina , Canais de Potássio Shab , Animais , Camundongos , Neurônios/metabolismo , Receptores para Leptina/metabolismo , Receptores para Leptina/genética , Hipotálamo/metabolismo , Leptina/metabolismo , Pró-Opiomelanocortina/metabolismo , Canais de Potássio Shab/metabolismo , Canais de Potássio Shab/genética , Transdução de Sinais , Masculino , Núcleo Arqueado do Hipotálamo/metabolismo , Fator de Transcrição STAT3/metabolismo , Camundongos Endogâmicos C57BL , Melanocortinas/metabolismo
2.
Mol Biol Rep ; 51(1): 560, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38643284

RESUMO

BACKGROUND: Zygotic genome activation (ZGA) is an important event in the early embryo development, and human embryo developmental arrest has been highly correlated with ZGA failure in clinical studies. Although a few studies have linked maternal factors to mammalian ZGA, more studies are needed to fully elucidate the maternal factors that are involved in ZGA. METHODS AND RESULTS: In this study, we utilized published single-cell RNA sequencing data from a Dux-mediated mouse embryonic stem cell to induce a 2-cell-like transition state and selected potential drivers for the transition according to an RNA velocity analysis. CONCLUSIONS: An overlap of potential candidate markers of 2-cell-like-cells identified in this research with markers generated by various data sets suggests that Trim75 is a potential driver of minor ZGA and may recruit EP300 and establish H3K27ac in the gene body of minor ZGA genes, thereby contributing to mammalian preimplantation embryo development.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Zigoto , Animais , Humanos , Camundongos , Embrião de Mamíferos , Desenvolvimento Embrionário/genética , Genoma/genética , Zigoto/metabolismo
3.
J Biol Chem ; 297(1): 100873, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34126070

RESUMO

Macroautophagy dysregulation is implicated in multiple neurological disorders, such as Parkinson's disease. While autophagy pathways are heavily researched in heterologous cells and neurons, regulation of autophagy in the astrocyte, the most abundant cell type in the mammalian brain, is less well understood. Missense mutations in the Synj1 gene encoding Synaptojanin1 (Synj1), a neuron-enriched lipid phosphatase, have been linked to Parkinsonism with seizures. Our previous study showed that the Synj1 haploinsufficient (Synj1+/-) mouse exhibits age-dependent autophagy impairment in multiple brain regions. Here, we used cultured astrocytes from Synj1-deficient mice to investigate its role in astrocyte autophagy. We report that Synj1 is expressed in low levels in astrocytes and represses basal autophagosome formation. We demonstrate using cellular imaging that Synj1-deficient astrocytes exhibit hyperactive autophagosome formation, represented by an increase in the size and number of GFP-microtubule-associated protein 1A/1B-light chain 3 structures. Interestingly, Synj1 deficiency is also associated with an impairment in stress-induced autophagy clearance. We show, for the first time, that the Parkinsonism-associated R839C mutation impacts autophagy in astrocytes. The impact of this mutation on the phosphatase function of Synj1 resulted in elevated basal autophagosome formation that mimics Synj1 deletion. We found that the membrane expression of the astrocyte-specific glucose transporter GluT-1 was reduced in Synj1-deficient astrocytes. Consistently, AMP-activated protein kinase activity was elevated, suggesting altered glucose sensing in Synj1-deficient astrocytes. Expressing exogenous GluT-1 in Synj1-deficient astrocytes reversed the autophagy impairment, supporting a role for Synj1 in regulating astrocyte autophagy via disrupting glucose-sensing pathways. Thus, our work suggests a novel mechanism for Synj1-related Parkinsonism involving astrocyte dysfunction.


Assuntos
Astrócitos/metabolismo , Autofagossomos/metabolismo , Proteínas do Tecido Nervoso/genética , Doença de Parkinson/genética , Monoéster Fosfórico Hidrolases/genética , Quinases Proteína-Quinases Ativadas por AMP , Animais , Autofagia , Células Cultivadas , Camundongos , Proteínas Associadas aos Microtúbulos/metabolismo , Mutação de Sentido Incorreto , Proteínas do Tecido Nervoso/deficiência , Proteínas do Tecido Nervoso/metabolismo , Monoéster Fosfórico Hidrolases/deficiência , Monoéster Fosfórico Hidrolases/metabolismo , Proteínas Quinases/metabolismo , Regulação para Cima
4.
Hum Mol Genet ; 29(14): 2300-2312, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32356558

RESUMO

Synaptojanin1 (synj1) is a phosphoinositide phosphatase with dual SAC1 and 5'-phosphatase enzymatic activities in regulating phospholipid signaling. The brain-enriched isoform has been shown to participate in synaptic vesicle (SV) recycling. More recently, recessive human mutations were identified in the two phosphatase domains of SYNJ1, including R258Q, R459P and R839C, which are linked to rare forms of early-onset Parkinsonism. We now demonstrate that Synj1 heterozygous deletion (Synj1+/-), which is associated with an impaired 5'-phosphatase activity, also leads to Parkinson's disease (PD)-like pathologies in mice. We report that male Synj1+/- mice display age-dependent motor function abnormalities as well as alpha-synuclein accumulation, impaired autophagy and dopaminergic terminal degeneration. Synj1+/- mice contain elevated 5'-phosphatase substrate, PI(4,5)P2, particularly in the midbrain neurons. Moreover, pharmacological elevation of membrane PI(4,5)P2 in cultured neurons impairs SV endocytosis, specifically in midbrain neurons, and further exacerbates SV trafficking defects in Synj1+/- midbrain neurons. We demonstrate down-regulation of SYNJ1 transcript in a subset of sporadic PD brains, implicating a potential role of Synj1 deficiency in the decline of dopaminergic function during aging.


Assuntos
Proteínas do Tecido Nervoso/genética , Doença de Parkinson/genética , Monoéster Fosfórico Hidrolases/genética , alfa-Sinucleína/genética , Animais , Autofagia/genética , Modelos Animais de Doenças , Dopamina/genética , Dopamina/metabolismo , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/patologia , Endocitose/genética , Haploinsuficiência/genética , Humanos , Mesencéfalo/metabolismo , Mesencéfalo/patologia , Camundongos , Doença de Parkinson/patologia , Deleção de Sequência/genética
5.
BMC Plant Biol ; 21(1): 426, 2021 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-34537013

RESUMO

BACKGROUND: Reproduction in most flowering plants may be limited because of the decreased visitation or activity of pollinators in fragmented habitats. Hedysarum scoparium Fisch. et Mey. is an arid region shrub with ecological importance. We explored the pollen limitation and seed set of Hedysarum scoparium in fragmented and restored environments, and examined whether pollen limitation is a significant limiting factor for seed set. We also compared floral traits and pollinator visitation between both habitats, and we determined the difference of floral traits and pollinators influenced reproductive success in Hedysarum scoparium. RESULTS: Our results indicated that supplementation with pollen significantly increased seed set per flower, which is pollen-limited in this species. Furthermore, there was greater seed set of the hand cross-pollination group in the restored habitat compared to the fragmented environment. More visits by Apis mellifera were recorded in the restored habitats, which may explain the difference in seed production between the fragmented and restored habitats. CONCLUSIONS: In this study, a positive association between pollinator visitation frequency and open flower number was observed. The findings of this study are important for experimentally quantifying the effects of floral traits and pollinators on plant reproductive success in different habitats.


Assuntos
Fabaceae/fisiologia , Flores/fisiologia , Pólen/fisiologia , Animais , China , Ecossistema , Polinização , Sementes/crescimento & desenvolvimento
6.
Neurobiol Dis ; 122: 64-71, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-29723605

RESUMO

Parkinson's disease (PD) is a debilitating neurodegenerative disorder that profoundly affects one's motor functions. The disease is characterized pathologically by denervation of dopaminergic (DAergic) nigrostriatal terminal and degeneration of DAergic neurons in the substantia nigra par compacta (SNpc); however, the precise molecular mechanism underlying disease pathogenesis remains poorly understood. Animal studies in both toxin-induced and genetic PD models suggest that presynaptic impairments may underlie the early stage of DA depletion and neurodegeneration (reviewed in Schirinzi, T., et al. 2016). Supporting this notion, human genetic studies and genomic analysis have identified an increasing number of PD risk variants that are associated with synaptic vesicle (SV) trafficking, regulation of synaptic function and autophagy/lysosomal system (Chang, D., et al. 2017, reviewed in Trinh, J. & Farrer, M. 2013; Singleton, A.B., et al. 2013). Although the precise mechanism for autophagy regulation in neurons is currently unclear, many studies demonstrate that autophagosomes form at the presynaptic terminal (Maday, S. & Holzbaur, E.L. 2014; Vanhauwaert, R., et al. 2017; reviewed in Yue, Z. 2007). Growing evidence has revealed overlapping genes involved in both SV recycling and autophagy, suggesting that the two membrane trafficking processes are inter-connected. Here we will review emergent evidence linking SV endocytic genes and autophagy genes at the presynaptic terminal. We will discuss their potential relevance to PD pathogenesis.


Assuntos
Autofagia/fisiologia , Doença de Parkinson/metabolismo , Terminações Pré-Sinápticas/metabolismo , Vesículas Sinápticas/metabolismo , Animais , Endocitose/fisiologia , Humanos
7.
J Neurosci ; 37(47): 11366-11376, 2017 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-29054882

RESUMO

Parkinson's disease (PD) is characterized pathologically by the selective loss of substantia nigra (SN) dopaminergic (DAergic) neurons. Recent evidence has suggested a role of LRRK2, linked to the most frequent familial PD, in regulating synaptic vesicle (SV) trafficking. However, the mechanism whereby LRRK2 mutants contribute to nigral vulnerability remains unclear. Here we show that the most common PD mutation LRRK2 G2019S impairs SV endocytosis in ventral midbrain (MB) neurons, including DA neurons, and the slowed endocytosis can be rescued by inhibition of LRRK2 kinase activity. A similar endocytic defect, however, was not observed in LRRK2 mutant neurons from the neocortex (hereafter, cortical neurons) or the hippocampus, suggesting a brain region-specific vulnerability to the G2019S mutation. Additionally, we found MB-specific impairment of SV endocytosis in neurons carrying heterozygous deletion of SYNJ1 (PARK20), a gene that is associated with recessive Parkinsonism. Combining SYNJ1+/- and LRRK2 G2019S does not exacerbate SV endocytosis but impairs sustained exocytosis in MB neurons and alters specific motor functions of 1-year-old male mice. Interestingly, we show that LRRK2 directly phosphorylates synaptojanin1 in vitro, resulting in the disruption of endophilin-synaptojanin1 interaction required for SV endocytosis. Our work suggests a merge of LRRK2 and SYNJ1 pathogenic pathways in deregulating SV trafficking in MB neurons as an underlying molecular mechanism of early PD pathogenesis.SIGNIFICANCE STATEMENT Understanding midbrain dopaminergic (DAergic) neuron-selective vulnerability in PD is essential for the development of targeted therapeutics. We report, for the first time, a nerve terminal impairment in SV trafficking selectively in MB neurons but not cortical neurons caused by two PARK genes: LRRK2 (PARK8) and SYNJ1 (PARK20). We demonstrate that the enhanced kinase activity resulting from the most frequent G2019S mutation in LRRK2 is the key to this impairment. We provide evidence suggesting that LRRK2 G2019S and SYNJ1 loss of function share a similar pathogenic pathway in deregulating DAergic neuron SV endocytosis and that they play additive roles in facilitating each other's pathogenic functions in PD.


Assuntos
Neurônios Dopaminérgicos/metabolismo , Endocitose , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Mesencéfalo/metabolismo , Doença de Parkinson/genética , Vesículas Sinápticas/metabolismo , Animais , Mutação com Ganho de Função , Deleção de Genes , Células HEK293 , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Masculino , Mesencéfalo/citologia , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Doença de Parkinson/metabolismo , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/metabolismo
8.
J Biol Chem ; 290(37): 22593-601, 2015 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-26224632

RESUMO

A long standing question in synaptic physiology is how neurotransmitter-filled vesicles are rebuilt after exocytosis. Among the first steps in this process is the endocytic retrieval of the transmembrane proteins that are enriched in synaptic vesicles (SVs). At least six types of transmembrane proteins must be recovered, but the rules for how this multiple cargo selection is accomplished are poorly understood. Among these SV cargos is the vesicular glutamate transporter (vGlut). We show here that vGlut1 has a strong influence on the kinetics of retrieval of half of the known SV cargos and that specifically impairing the endocytosis of vGlut1 in turn slows down other SV cargos, demonstrating that cargo retrieval is a collective cargo-driven process. Finally, we demonstrate that different cargos can be retrieved in the same synapse with different kinetics, suggesting that additional post-endocytic sorting steps likely occur in the nerve terminal.


Assuntos
Região CA1 Hipocampal/metabolismo , Região CA3 Hipocampal/metabolismo , Endocitose/fisiologia , Vesículas Sinápticas/metabolismo , Proteína Vesicular 1 de Transporte de Glutamato/metabolismo , Animais , Região CA1 Hipocampal/citologia , Região CA3 Hipocampal/citologia , Células Cultivadas , Transporte Proteico/fisiologia , Ratos , Ratos Sprague-Dawley
9.
STAR Protoc ; 5(4): 103358, 2024 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-39368094

RESUMO

Surface availability of the dopamine (DA) transporter (DAT) critically influences DA transmission. Here, we present a protocol that describes the preparation of mouse ventral midbrain neurons, the expression of a new optical sensor, DAT-pHluorin, and the utilization of this sensor to analyze the surface availability of DAT in live neurons via fluorescent microscopy. This approach allows quantitative measures of basal surface DAT fraction under genetic backgrounds of interest and live trafficking of DAT in response to psychoactive substances. For complete details on the use and execution of this protocol, please refer to Saenz et al.1.

10.
Front Behav Neurosci ; 18: 1359225, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39050701

RESUMO

The synaptojanin-1 (SYNJ1) gene is known to be important for dopamine-related disorders. Recent evidence has demonstrated that Synj1 deficient mice (Synj1 +/-) have impairments in dopaminergic synaptic vesicular recycling. However, less is known about how Synj1 deficits affect the mesolimbic system, reward processing, and motivated behavior. To examine the role of the Synj1 gene in motivated behavior, we subjected male and female Synj1 +/- and Synj1 +/+ mice to a battery of behavioral tests evaluating hedonic responses, effortful responding, and responses to psychomotor stimulants. We observed that Synj1 +/- mice exhibit few differences in reward processing and motivated behavior, with normal hedonic responses and motivated responding for sucrose. However, male but not female Synj1 +/- demonstrated an attenuated conditioned place preference for cocaine that could not be attributed to deficits in spatial memory. To further understand the dopamine signaling underlying the attenuated response to cocaine in these mutant mice, we recorded nucleus accumbens dopamine in response to cocaine and observed that Synj1 +/- male and female mice took longer to reach peak dopamine release following experimenter-administered cocaine. However, female mice also showed slower decay in accumbens dopamine that appear to be linked to differences in cocaine-induced DAT responses. These findings demonstrate that SYNJ1 deficiencies result in abnormal mesolimbic DA signaling which has not previously been demonstrated. Our work also highlights the need to develop targeted therapeutics capable of restoring deficits in DAT function, which may be effective for reversing the pathologies associated with Synj1 mutations.

11.
NPJ Parkinsons Dis ; 10(1): 148, 2024 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-39117637

RESUMO

Missense mutations of PARK20/SYNJ1 (synaptojanin1/Synj1) were found in complex forms of familial Parkinsonism. However, the Synj1-regulated molecular and cellular changes associated with dopaminergic dysfunction remain unknown. We now report a fast depletion of evoked dopamine and impaired maintenance of the axonal dopamine transporter (DAT) in the Synj1 haploinsufficient (Synj1+/-) neurons. While Synj1 has been traditionally known to facilitate the endocytosis of synaptic vesicles, we provide in vitro and in vivo evidence demonstrating that Synj1 haploinsufficiency results in an increase of total DAT but a reduction of the surface DAT. Synj1+/- neurons exhibit maladaptive DAT trafficking, which could contribute to the altered DA release. We showed that the loss of surface DAT is associated with the impaired 5'-phosphatase activity and the hyperactive PI(4,5)P2-PKCß pathway downstream of Synj1 deficiency. Thus, our findings provided important mechanistic insight for Synj1-regulated DAT trafficking integral to dysfunctional DA signaling, which might be relevant to early Parkinsonism.

12.
Res Sq ; 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38559229

RESUMO

Missense mutations of PARK20/SYNJ1 (synaptojanin1/Synj1) have been linked to complex forms of familial parkinsonism, however, the molecular and cellular changes associated with dopaminergic dysfunction remains unknown. We now report fast depletion of evoked dopamine (DA) and altered maintenance of the axonal dopamine transporter (DAT) in the Synj1+/- neurons. While Synj1 has been traditionally known to facilitate the endocytosis of synaptic vesicles, we demonstrated that axons of cultured Synj1+/- neurons exhibit an increase of total DAT but a reduction of the surface DAT, which could be exacerbated by neuronal activity. We revealed that the loss of surface DAT is specifically associated with the impaired 5'-phosphatase activity of Synj1 and the hyperactive downstream PI(4,5)P2-PKCß pathway. Thus, our findings provided important mechanistic insight for Synj1-regulated DAT trafficking integral to dysfunctional DA signaling in early parkinsonism.

13.
J Pediatr Endocrinol Metab ; 36(8): 798-802, 2023 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-37283093

RESUMO

OBJECTIVES: The 12q14 microdeletion syndrome is a rare genetic condition characterized by intrauterine growth restriction, proportionate short stature, failure to thrive, and intellectual disability. Few reports have discussed the therapeutic aspect of patients with 12q14 microdeletion syndrome. Herein, we report the first case of 12q14 microdeletion patient treated with rhGH without growth hormone deficiency. CASE PRESENTATION: The patient presented with feeding difficulties during infancy, failure to thrive, intellectual disability and subtle dysmorphic facial features. The patient first visited the clinic at 5 years and 3 months, his height was 91.4 cm (-4.9 SD) and weight 10.0 kg (-2.86 SD). The growth hormone level was within the normal range. Bone radiological testing revealed no significant abnormalities. Genetic analysis identified a 6.97 Mb deletion at the chromosome 12q14.1-q14.3 region in the proband. Recombinant human growth hormone therapy was initiated, which lasted for 12 months, and the new height was 101.0 cm (-4.0 SD) and weight 12.0 kg (-3.6 SD). CONCLUSIONS: This report first showed that patient with 12q14 microdeletion, although without growth hormone deficiency, can benefit from human growth hormone therapy.


Assuntos
Transtornos Cromossômicos , Nanismo , Hormônio do Crescimento Humano , Hipopituitarismo , Deficiência Intelectual , Criança , Feminino , Humanos , Deleção Cromossômica , Transtornos Cromossômicos/genética , Nanismo/genética , População do Leste Asiático , Insuficiência de Crescimento , Hormônio do Crescimento Humano/uso terapêutico , Hormônio do Crescimento Humano/genética , Hipopituitarismo/genética , Deficiência Intelectual/tratamento farmacológico , Deficiência Intelectual/genética
14.
Orthop Surg ; 15(4): 1117-1125, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36794302

RESUMO

OBJECTIVE: Ankle arthroscope is the preferred tool for ankle surgeons to treat ankle impingement. However, there is no relevant report on how to improve the accuracy of arthroscopic osteotomy through preoperative planning. The aims of this study were to investigate a novel method to obtain the bone morphology in anterior and posterior ankle bony impingement through computed tomography (CT) calculation model, use this method to guide surgical decision-making, and compare the postoperative efficacy and actual bone cutting volume with conventional surgery. METHODS: This retrospective cohort study includes 32 consecutive cases with anterior and posterior ankle bony impingement by arthroscopy from January 2017 to December 2019. Mimics software was utilized to calculate the bony morphology and measure the volume of the osteophytes by two trained software engineers. The patients were divided into the precise group (n = 15) and the conventional group (n = 17) according to whether obtain and quantify the osteophytes' morphology with CT based calculation model preoperative. All patients were evaluated clinically using visual analog scale (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) score, active dorsiflexion and plantarflexion angle before and after surgery at both 3 months and 12 months postoperatively. We obtained the shape and volume of bone cutting through Boolean calculation. Clinical outcomes and radiological data were compared between the two groups. RESULTS: The VAS score, AOFAS score, active dorsiflexion angle and plantarflexion angle were significantly improved in both groups postoperatively. In comparison of the VAS score, AOFAS score, and active dorsiflexion angle, the precise group were higher than the conventional group in the follow-up at 3 and 12 months postoperatively with statistical difference. The difference between the virtual bone cutting volume and the actual bone cutting volume of the anterior edge of distal tibia in the conventional group and precise group were 244.20 ± 147.66 mm3 and 76.53 ± 168.51 mm3 , respectively, there was statistical difference between the two groups (t = -2.927, p = 0.011). CONCLUSION: Using a novel method of obtaining and quantifying the bony morphology with CT-based calculation model for anterior and posterior ankle bony impingement can help guide surgical decision-making preoperatively and assist precise bone cutting during the operation, which can improve the efficacy and evaluate the accuracy of osteotomy postoperatively.


Assuntos
Articulação do Tornozelo , Artropatias , Procedimentos Ortopédicos , Osteófito , Articulação do Tornozelo/diagnóstico por imagem , Estudos de Coortes , Artropatias/diagnóstico por imagem , Artropatias/cirurgia , Osteófito/diagnóstico por imagem , Osteófito/cirurgia , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade
15.
eNeuro ; 10(5)2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37072173

RESUMO

The accumulation of α-synuclein (α-syn)-enriched protein aggregates is thought to arise from dysfunction in degradation systems within the brain. Recently, missense mutations of SYNJ1 encoding the SAC1 and 5'-phosphatase domains have been found in families with hereditary early-onset Parkinsonism. Previous studies showed that Synj1 haploinsufficiency (Synj1+/-) leads to accumulation of the autophagy substrate p62 and pathologic α-syn proteins in the midbrain (MB) and striatum of aged mice. In this study, we aim to investigate the neuronal degradation pathway using the Synj1+/- MB culture from mouse pups of mixed sex as a model. Our data show that GFP-LC3 puncta formation and cumulative mKeima puncta formation are unaltered at baseline in Synj1+/- MB neurons. However, GFP-LAMP1 puncta is reduced with a similar decrease in endogenous proteins, including lysosomal-associated membrane protein (LAMP)1, LAMP2, and LAMP2A. The LAMP1 vesicles are hyperacidified with enhanced enzymatic activity in Synj1+/- MB neurons. Using a combination of light and electron microscopy (EM), we show that endolysosomal changes are primarily associated with a lack of SAC1 activity. Consistently, expressing the SYNJ1 R258Q mutant in N2a cells reduces the lysosome number. Interestingly, the endolysosomal defects in Synj1+/- neurons does not impact the clearance of exogenously expressed wild-type (WT) α-syn; however, the clearance of α-syn A53T was impaired in the axons of Synj1+/- MB neurons. Taken together, our results suggest axonal vulnerability to endolysosomal defects in Synj1-deficient MB neurons.


Assuntos
Mesencéfalo , Neurônios , Animais , Camundongos , Mesencéfalo/metabolismo , Neurônios/metabolismo , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/metabolismo , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo , Lisossomos/metabolismo , Autofagia/fisiologia
16.
iScience ; 26(1): 105782, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36594015

RESUMO

Cocaine acts by inhibiting plasma membrane dopamine transporter (DAT) function and altering its surface expression. The precise manner and mechanism by which cocaine regulates DAT trafficking, especially at neuronal processes, are poorly understood. In this study, we engineered and validated the use of DAT-pHluorin for studying DAT localization and its dynamic trafficking at neuronal processes of cultured mouse midbrain neurons. We demonstrate that unlike neuronal soma and dendrites, which contain a majority of the DATs in weakly acidic intracellular compartments, axonal DATs at both shafts and boutons are primarily (75%) localized to the plasma membrane, whereas large varicosities contain abundant intracellular DAT within acidic intracellular structures. We also demonstrate that cocaine exposure leads to a Synaptojanin1-sensitive DAT internalization process followed by membrane reinsertion that lasts for days. Thus, our study reveals the previously unknown dynamics and molecular regulation for cocaine-regulated DAT trafficking in neuronal processes.

17.
Int J Biol Macromol ; 242(Pt 2): 124912, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37207750

RESUMO

Flexible supercapacitors are an important portable energy storage but suffer from low capacitance, inability to stretch, etc. Therefore, flexible supercapacitors must achieve higher capacitance, energy density, and mechanical robustness to expand the applications. Herein, a hydrogel electrode with excellent mechanical strength was created by simulating the collagen fiber network and proteoglycan in cartilage using silk nanofiber (SNF) network and polyvinyl alcohol (PVA). The Young's modulus and breaking strength of the hydrogel electrode increased by 205 % and 91 % compared with PVA hydrogel owing to the enhanced effect of the bionic structure, respectively, which are 1.22 MPa and 1.3 MPa. The fracture energy and fatigue threshold reached 1813.5 J/m2 and 1585.2 J/m2, respectively. The SNF network effectively connected carbon nanotubes (CNTs) and polypyrrole (PPy) in series, affording a capacitance of 13.62 F/cm2 and energy density of 1.2098 mWh/cm2. This capacitance is the highest among currently reported PVA hydrogel capacitors, which can maintain >95.2 % after 3000 charge-discharge cycles. This capacitance Notably, the cartilage-like structure endowed the supercapacitor with high resilience; thus, the capacitance remained >92.1 % under 150 % deformation and >93.35 % after repeated stretching (3000 times), which was far superior to that of other PVA-based supercapacitors. Overall, this effective bionic strategy can endow supercapacitors with ultrahigh capacitance and effectively ensure the mechanical reliability of flexible supercapacitors, which will help expand the applications of supercapacitors.


Assuntos
Nanofibras , Nanotubos de Carbono , Hidrogéis , Polímeros , Reprodutibilidade dos Testes , Pirróis
18.
Int J Biol Macromol ; 253(Pt 2): 126730, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37678699

RESUMO

Hydrogels are attractive materials with structures and functional properties similar to biological tissues and widely used in biomedical engineering. However, traditional synthetic hydrogels possess poor mechanical strength, and their applications are limited. Herein, a multidimensional material design method is developed; it includes the in situ gelation of silk fabric and nacre-inspired layer-by-layer assembly, which is used to prepare silk fibroin (SF) hydrogels. The in situ gelation method of silk fabric introduces a directionally ordered fabric network in a silk substrate, considerably enhancing the strength of hydrogels. Based on the nacre structure, the layer-by-layer assembly method enables silk hydrogels to break through the size limit and increase the thickness, realizing the longitudinal extension of the hydrogels. The application of the combined biomineralization and hot pressing method can effectively reduce interface defects and improve the interaction between organic and inorganic interfaces. The multidimensional material design method helps increase the strength (287.78 MPa), toughness (18.43 MJ m-3), and fracture energy (50.58 kJ m-2) of SF hydrogels; these hydrogels can weigh 2000 times their own weight. Therefore, SF hydrogels designed using the aforementioned combined method can realize the combination of strength and toughness and be used in biological tissue engineering and structural materials.


Assuntos
Fibroínas , Nácar , Fibroínas/química , Hidrogéis/química , Biomineralização , Nanopartículas em Multicamadas , Seda/química
19.
Artigo em Inglês | MEDLINE | ID: mdl-37905186

RESUMO

Background: Microglia are closely linked to Alzheimer's disease (AD) many years ago; however, the pathological mechanisms of AD remain unclear. The purpose of this study was to determine whether leptin affected microglia in the hippocampus of young and aged male APP/PS1 mice. Objective: In a transgenic model of AD, we investigated the association between intraperitoneal injection of leptin and microglia. Methods: We intraperitoneal injection of leptin (1mg/kg) every day for one week and analyzed inflammatory markers in microglia in the hippocampus of adult (6 months) and aged (12 months) APP/PS1 mice. Results: In all leptin treatment group, the brain Aß levels were decrease. We found increased levels of IL-1ß, IL-6 and microglial activation in the hippocampus of adult mice. Using aged mice as an experimental model for chronic neuroinflammation and leptin resistance, the number of Iba-1+ microglia and the levels of IL-1ß/IL-6 in the hippocampus were greatly increased as compared to the adult. But between the leptin treatment and un-treatment, there were no difference. Conclusion: Leptin signaling would regulate the activation of microglia and the release of inflammatory factors, but it is not the only underlying mechanism in the neuroprotective effects of AD pathogenesis.

20.
Prog Neurobiol ; 231: 102530, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37739206

RESUMO

Different dopaminergic (DA) neuronal subgroups exhibit distinct vulnerability to stress, while the underlying mechanisms are elusive. Here we report that the transient receptor potential melastatin 2 (TRPM2) channel is preferentially expressed in vulnerable DA neuronal subgroups, which correlates positively with aging in Parkinson's Disease (PD) patients. Overexpression of human TRPM2 in the DA neurons of C. elegans resulted in selective death of ADE but not CEP neurons in aged worms. Mechanistically, TRPM2 activation mediates FZO-1/CED-9-dependent mitochondrial hyperfusion and mitochondrial permeability transition (MPT), leading to ADE death. In mice, TRPM2 knockout reduced vulnerable substantia nigra pars compacta (SNc) DA neuronal death induced by stress. Moreover, the TRPM2-mediated vulnerable DA neuronal death pathway is conserved from C. elegans to toxin-treated mice model and PD patient iPSC-derived DA neurons. The vulnerable SNc DA neuronal loss is the major symptom and cause of PD, and therefore the TRPM2-mediated pathway serves as a promising therapeutic target against PD.


Assuntos
Proteínas de Caenorhabditis elegans , Doença de Parkinson , Canais de Cátion TRPM , Humanos , Camundongos , Animais , Idoso , Cálcio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Canais de Cátion TRPM/metabolismo , Caenorhabditis elegans/metabolismo , Neurônios Dopaminérgicos/metabolismo , Doença de Parkinson/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA