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1.
Proc Natl Acad Sci U S A ; 120(10): e2215290120, 2023 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-36848557

RESUMO

Major Facilitator Superfamily Domain containing 2a (Mfsd2a) is a sodium-dependent lysophosphatidylcholine (LPC) transporter expressed at the blood-brain barrier that constitutes the main pathway by which the brain obtains omega-3 fatty acids, such as docosahexanoic acid. Mfsd2a deficiency in humans results in severe microcephaly, underscoring the importance of LPC transport by Mfsd2a for brain development. Biochemical studies and recent cryo-electron microscopy (cryo-EM) structures of Mfsd2a bound to LPC suggest that Mfsd2a transports LPC via an alternating access mechanism between outward-facing and inward-facing conformational states in which the LPC inverts during transport between the outer and inner leaflet of a membrane. However, direct biochemical evidence of flippase activity by Mfsd2a has not been demonstrated and it is not understood how Mfsd2a could invert LPC between the outer and inner leaflet of the membrane in a sodium-dependent manner. Here, we established a unique in vitro assay using recombinant Mfsd2a reconstituted in liposomes that exploits the ability of Mfsd2a to transport lysophosphatidylserine (LPS) coupled with a small molecule LPS binding fluorophore that allowed for monitoring of directional flipping of the LPS headgroup from the outer to the inner liposome membrane. Using this assay, we demonstrate that Mfsd2a flips LPS from the outer to the inner leaflet of a membrane bilayer in a sodium-dependent manner. Furthermore, using cryo-EM structures as guides together with mutagenesis and a cell-based transport assay, we identify amino acid residues important for Mfsd2a activity that likely constitute substrate interaction domains. These studies provide direct biochemical evidence that Mfsd2a functions as a lysolipid flippase.


Assuntos
Ácidos Graxos Ômega-3 , Simportadores , Humanos , Microscopia Crioeletrônica , Lipopolissacarídeos , Lisofosfatidilcolinas , Aminoácidos , Lipossomos
2.
Plant Physiol ; 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38833579

RESUMO

The asymmetrical distribution of auxin supports high intensity blue light (HBL)-mediated phototropism. Flavonoids, secondary metabolites induced by blue light and TRANSPARENT TESTA GLABRA1 (TTG1), alter auxin transport. However, the role of TTG1 in HBL-induced phototropism in Arabidopsis (Arabidopsis thaliana) remains unclear. We found that TTG1 regulates HBL-mediated phototropism. HBL-induced degradation of CRYPTOCHROME 1 (CRY1) was repressed in ttg1-1, and depletion of CRY1 rescued the phototropic defects of the ttg1-1 mutant. Moreover, overexpression of CRY1 in a cry1 mutant background led to phototropic defects in response to HBL. These results indicated that CRY1 is involved in the regulation of TTG1-mediated phototropism in response to HBL. Further investigation showed that TTG1 physically interacts with CRY1 via its N-terminus and that the added TTG1 promotes the dimerization of CRY1. The interaction between TTG1 and CRY1 may promote HBL-mediated degradation of CRY1. TTG1 also physically interacted with blue light inhibitor of cryptochrome 1 (BIC1) and Light-Response Bric-a-Brack/Tramtrack/Broad 2 (LRB2), and these interactions either inhibited or promoted their interaction with CRY1. Exogenous gibberellins (GA) and auxins, two key plant hormones that crosstalk with CRY1, may confer the recovery of phototropic defects in the ttg1-1 mutant and CRY1-overexpressing plants. Our results revealed that TTG1 participates in the regulation of HBL-induced phototropism by modulating CRY1 levels, which are coordinated with GA or IAA signaling.

3.
PLoS Genet ; 18(9): e1010381, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36126047

RESUMO

Cortical actin, a thin layer of actin network underneath the plasma membranes, plays critical roles in numerous processes, such as cell morphogenesis and migration. Neurons often grow highly branched dendrite morphologies, which is crucial for neural circuit assembly. It is still poorly understood how cortical actin assembly is controlled in dendrites and whether it is critical for dendrite development, maintenance and function. In the present study, we find that knock-out of C. elegans chdp-1, which encodes a cell cortex-localized protein, causes dendrite formation defects in the larval stages and spontaneous dendrite degeneration in adults. Actin assembly in the dendritic growth cones is significantly reduced in the chdp-1 mutants. PVD neurons sense muscle contraction and act as proprioceptors. Loss of chdp-1 abolishes proprioception, which can be rescued by expressing CHDP-1 in the PVD neurons. In the high-ordered branches, loss of chdp-1 also severely affects the microtubule cytoskeleton assembly, intracellular organelle transport and neuropeptide secretion. Interestingly, knock-out of sax-1, which encodes an evolutionary conserved serine/threonine protein kinase, suppresses the defects mentioned above in chdp-1 mutants. Thus, our findings suggest that CHDP-1 and SAX-1 function in an opposing manner in the multi-dendritic neurons to modulate cortical actin assembly, which is critical for dendrite development, maintenance and function.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Actinas/genética , Actinas/metabolismo , Animais , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Dendritos/metabolismo , Proteínas Serina-Treonina Quinases , Células Receptoras Sensoriais/metabolismo , Serina/metabolismo , Treonina/metabolismo
4.
Proc Natl Acad Sci U S A ; 119(40): e2210353119, 2022 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-36161949

RESUMO

The lysosome is central to the degradation of proteins, carbohydrates, and lipids and their salvage back to the cytosol for reutilization. Lysosomal transporters for amino acids, sugars, and cholesterol have been identified, and the metabolic fates of these molecules in the cytoplasm have been elucidated. Remarkably, it is not known whether lysosomal salvage exists for glycerophospholipids, the major constituents of cellular membranes. By using a transport assay screen against orphan lysosomal transporters, we identified the major facilitator superfamily protein Spns1 that is ubiquitously expressed in all tissues as a proton-dependent lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE) transporter, with LPC and LPE being the lysosomal breakdown products of the most abundant eukaryotic phospholipids, phosphatidylcholine and phosphatidylethanolamine, respectively. Spns1 deficiency in cells, zebrafish embryos, and mouse liver resulted in lysosomal accumulation of LPC and LPE species with pathological consequences on lysosomal function. Flux analysis using stable isotope-labeled phospholipid apolipoprotein E nanodiscs targeted to lysosomes showed that LPC was transported out of lysosomes in an Spns1-dependent manner and re-esterified back into the cytoplasmic pools of phosphatidylcholine. Our findings identify a phospholipid salvage pathway from lysosomes to the cytosol that is dependent on Spns1 and critical for maintaining normal lysosomal function.


Assuntos
Lisofosfolipídeos , Proteínas de Membrana Transportadoras , Fosfatidiletanolaminas , Peixe-Zebra , Animais , Lisofosfatidilcolinas/metabolismo , Lisofosfolipídeos/metabolismo , Lisossomos/metabolismo , Proteínas de Membrana , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo , Prótons , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra
5.
Traffic ; 23(3): 140-157, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34994051

RESUMO

The extremely dynamic life cycle of gap junction connections requires highly efficient intracellular trafficking system especially designed for gap junction proteins, but the underlying mechanisms are largely unknown. Here, we identified that the COPII-associated proteins ERGIC2 (ER-Golgi intermediate compartment) and ERGIC3 are specifically required for the efficient intracellular transport of gap junction proteins in both Caenorhabditis elegans and mice. In the absence of Ergic2 or Ergic3, gap junction proteins accumulate in the ER and Golgi apparatus and the size of endogenous gap junction plaques is reduced. Knocking out the Ergic2 or Ergic3 in mice results in heart enlargement and cardiac malfunction accompanied by reduced number and size of connexin 43 (Cx43) gap junctions. Invertebrates' gap junction protein innexins share no sequence similarity with vertebrates' connexins. However, ERGIC2 and ERGIC3 could bind to gap junction proteins in both worms and mice. Characterization of the highly specialized roles of ERGIC2 and ERGIC3 in metazoans reveals how the early secretory pathway could be adapted to facilitate the efficient transport for gap junction proteins in vivo.


Assuntos
Conexinas , Complexo de Golgi , Animais , Conexinas/metabolismo , Junções Comunicantes/metabolismo , Complexo de Golgi/metabolismo , Camundongos , Via Secretória , Proteínas de Transporte Vesicular
6.
Biochem Biophys Res Commun ; 716: 149998, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38692012

RESUMO

The equilibrium between the hypertrophic growth of existing adipocytes and adipogenesis is vital in managing metabolic stability in white adipocytes when faced with overnutrition. Adipogenesis has been established as a key player in combating metabolic irregularities caused by various factors. However, the benefits of increasing adipogenesis-mediated white adipose tissue (WAT) expansion for metabolic health regulation remain uncertain. Our findings reveal an increase in Impdh2 expression during the adipogenesis phase, both in vivo and in vitro. Xmp enhances adipogenic potential by fostering mitotic clonal expansion (MCE). The conditional knockout of Impdh2 in adipocyte progenitor cells(APCs) in adult and aged mice effectively curbs white adipose tissue expansion, ameliorates glucose tolerance, and augments energy expenditure under high-fat diet (HFD). However, no significant difference is observed under normal chow diet (NCD). Concurrently, the knockout of Impdh2 in APCs significantly reduces the count of new adipocytes induced by HFD, without affecting adipocyte size. Mechanistically, Impdh2 regulates the proliferation of APCs during the MCE phase via Xmp. Exogenous Xmp can significantly offset the reduction in adipogenic abilities of APCs due to Impdh2 deficiency. In summary, we discovered that adipogenesis-mediated WAT expansion, induced by overnutrition, also contributes to metabolic abnormalities. Moreover, the pivotal role of Impdh2 in regulating adipogenesis in APCs offers a novel therapeutic approach to combat obesity.


Assuntos
Adipócitos , Adipogenia , Tecido Adiposo Branco , Dieta Hiperlipídica , IMP Desidrogenase , Hipernutrição , Animais , Masculino , Camundongos , Adipócitos/metabolismo , Adipogenia/genética , Tecido Adiposo Branco/metabolismo , Proliferação de Células , Metabolismo Energético/genética , Deleção de Genes , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hipernutrição/metabolismo , Hipernutrição/genética , Células-Tronco/metabolismo , Células-Tronco/citologia , Células-Tronco/patologia , IMP Desidrogenase/genética , IMP Desidrogenase/metabolismo
7.
Clin Exp Immunol ; 215(1): 27-36, 2024 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-37724585

RESUMO

The overlapping of two or more types of neural autoantibodies in one patient has increasingly been documented in recent years. The coexistence of myelin oligodendrocyte glycoprotein (MOG) and N-methyl-d-aspartate receptor (NMDAR) antibodies is most common, which leads to a unique condition known as the MOG antibody and NMDAR antibody overlapping syndrome (MNOS). Here, we have reviewed the pathogenesis, clinical manifestations, paraclinical features, and treatment of MNOS. Forty-nine patients with MNOS were included in this study. They were young males with a median onset age of 23 years. No tumors were observed in the patients, and 24 of them reported prodromal symptoms. The most common clinical presentations were psychiatric symptoms (35/49) and seizures (25/49). Abnormalities on magnetic resonance imaging involved the brainstem (11/49), cerebellum (9/49), and parietal lobe (9/49). Most patients mostly responded to immunotherapy and had a good long-term prognosis. However, the overall recurrence rate of MNOS was higher than that of mono antibody-positive diseases. The existence of concurrent NMDAR antibodies should be suspected in patients with MOG antibody-associated disease having psychiatric symptoms, seizures, movement disorders, or autonomic dysfunction. Similarly, serum MOG antibody testing should be performed when patients with anti-NMDAR encephalitis present with atypical clinical manifestations, such as visual impairment and limb weakness, and neuroradiological findings, such as optic nerve, spinal cord, or infratentorial involvement or meningeal enhancement. Early detection of the syndrome and prompt treatment can be beneficial for these patients, and maintenance immunosuppressive therapy is recommended due to the high overall recurrence rate of the syndrome.


Assuntos
Encefalite Antirreceptor de N-Metil-D-Aspartato , Receptores de N-Metil-D-Aspartato , Humanos , Masculino , Adulto Jovem , Encefalite Antirreceptor de N-Metil-D-Aspartato/diagnóstico , Encefalite Antirreceptor de N-Metil-D-Aspartato/complicações , Autoanticorpos , Glicoproteína Mielina-Oligodendrócito , Convulsões/complicações , Síndrome
8.
EMBO Rep ; 23(3): e52669, 2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-35132760

RESUMO

The size of lipid droplets varies greatly in vivo and is determined by both intrinsic and extrinsic factors. From an RNAi screen in Drosophila, we found that knocking down subunits of COP9 signalosome (CSN) results in enlarged lipid droplets under high-fat, but not normal, conditions. We identified CG2064, a retinol dehydrogenase (RDH) homolog, as the proteasomal degradation target of CSN in regulating lipid droplet size. RDH/CG2064 interacts with the lipid droplet-resident protein Plin2 and the RDH/CG2064-Plin2 axis acts to reduce the overall level and lipid droplet localization of Bmm/ATGL lipase. This axis is important for larval survival under prolonged starvation. Thus, we discovered an RDH-Plin2 axis modulates lipid droplet size.


Assuntos
Drosophila , Lipase , Gotículas Lipídicas , Perilipina-2 , Animais , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Larva/genética , Larva/metabolismo , Lipase/genética , Lipase/metabolismo , Gotículas Lipídicas/metabolismo , Perilipina-2/metabolismo
9.
PLoS Genet ; 17(11): e1009940, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34843479

RESUMO

The UNC-104/KIF1A motor is crucial for axonal transport of synaptic vesicles, but how the UNC-104/KIF1A motor is activated in vivo is not fully understood. Here, we identified point mutations located in the motor domain or the inhibitory CC1 domain, which resulted in gain-of-function alleles of unc-104 that exhibit hyperactive axonal transport and abnormal accumulation of synaptic vesicles. In contrast to the cell body localization of wild type motor, the mutant motors accumulate on neuronal processes. Once on the neuronal process, the mutant motors display dynamic movement similarly to wild type motors. The gain-of-function mutation on the motor domain leads to an active dimeric conformation, releasing the inhibitory CC1 region from the motor domain. Genetically engineered mutations in the motor domain or CC1 of UNC-104, which disrupt the autoinhibitory interface, also led to the gain of function and hyperactivation of axonal transport. Thus, the CC1/motor domain-mediated autoinhibition is crucial for UNC-104/KIF1A-mediated axonal transport in vivo.


Assuntos
Transporte Axonal/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Vesículas Sinápticas/genética , Animais , Caenorhabditis elegans/genética , Mutação com Ganho de Função/genética , Engenharia Genética , Cinesinas/genética , Domínios Proteicos
10.
Zhongguo Zhong Yao Za Zhi ; 49(8): 2197-2209, 2024 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-38812235

RESUMO

This study aims to explore the potential mechanism of action in the intervention of acute lung injury(ALI) based on the blood entry components of Ganke Granules in rats and in conjunction with network pharmacology, molecular docking, and animal experimental validation. The blood entry components of Ganke Granules in rats were imported into the SwissTargetPrediction platform to predict drug targets, and ALI-related targets were collected from the disease database. Intersections were taken, and protein-protein interaction(PPI) networks were constructed to screen the core targets, followed by Gene Ontology(GO) functional and Kyoto encyclopedia of genes and gnomes(KEGG) pathway enrichment analyses. A "blood entry components-target-pathway-disease" network was constructed, and the core components for disease intervention based on their topological parameters were screened. Molecular docking was used to predict the binding ability of the core components to key targets. The key targets of Ganke Granules in the intervention of ALI were verified by the lipopolysaccharide(LPS)-induced ALI mouse model. Through PPI topological parameter analysis, the top six key targets of STAT3, SRC, HSP90AA1, MAPK3, HRAS, and MAPK1 related to ALI were obtained. GO functional analysis showed that it was mainly related to ERK1 and ERK2 cascade, inflammatory response, and response to LPS. KEGG analysis showed that the main enrichment pathways were MAPK, neutrophil extracellular trap(NET) formation, and so on. Six core components(schizantherin B, schisandrin, besigomsin, harpagoside, isotectorigenin, and trachelanthamine) were filtered out by the "blood entry components-target-pathway-disease" network based on the analysis of topological parameters. Molecular docking results showed that the six core components and Tectoridin with the highest content in the granules had a high affinity with the key targets of MAPK3, SRC, MAPK1, and STAT3. In vivo experiment results showed that compared with the model group, Ganke Granules could effectively alleviate LPS-induced histopathological injury in the lungs of mice and reduce the percentage of inflammatory infiltration. The total protein content, nitric oxide(NO) level, myeloperoxidase(MPO) content, tumor necrosis factor-α(TNF-α), gamma interferon(IFN-γ), interleukin-1ß(IL-1ß), interleukin-6(IL-6), vascular endothelial growth factor(VEGF), and chemokine(C-X-C motif) ligand 1(CXCL1) chemokines in bronchoalveolar lavage fluid(BALF) were decreased, and the expression levels of lymphocyte antigen 6G(Ly6G), citrullinated histones 3(Cit-H3), and phosphorylated proteins SRC, ERK1/2, and STAT3 in lung tissue were significantly down-regulated. In conclusion, Ganke Granules could effectively inhibit the inflammatory response of ALI induced by LPS, protect lung tissue, regulate the release of inflammatory factors, and inhibit neutrophil infiltration and NET formation, and the mechanism of action may be related to inhibiting the activation of SRC/ERK1/2/STAT3 signaling pathway.


Assuntos
Lesão Pulmonar Aguda , Medicamentos de Ervas Chinesas , Simulação de Acoplamento Molecular , Farmacologia em Rede , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/metabolismo , Animais , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/química , Camundongos , Ratos , Masculino , Mapas de Interação de Proteínas , Fator de Transcrição STAT3/metabolismo , Fator de Transcrição STAT3/genética , Ratos Sprague-Dawley , Humanos
11.
Clin Exp Immunol ; 211(1): 78-83, 2023 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-36539337

RESUMO

Neuronal surface antibody-mediated autoimmune encephalitis (NSAE) occurs across a wide age range. However, few studies focused on the onset age and their related characteristics. We aimed to explore the age-dependent profile of NSAE. A total of 134 patients with a definite diagnosis of NSAE were retrospectively enrolled from 3 tertiary hospitals between July 2014 and August 2020. Demographic, clinical, therapeutic, and prognostic data were collected and compared between the late- (≥45) and younger-onset (<45) groups. The results showed that 56 (41.8%) patients were classified as late-onset NSAE, and 78 (58.2%) as younger-onset NSAE. There were more males, especially in the late-onset group (P = 0.036). Prodromal symptoms were more common in the younger-onset group (P = 0.004). Among the onset symptoms, more late-onset patients presented as seizures, while more younger-onset patients presented as psychiatric symptoms. Throughout the disease course, the late-onset patients were more likely to have memory dysfunction (P < 0.001), but less likely to have central hypoventilation (P = 0.045). The late-onset patients also had a significantly lower modified Rankin Scale score on admission (P = 0.042), required intensive care unit (ICU) admission less frequently during hospitalization (P = 0.042) and had a shorter hospital stay (P = 0.014). Our study revealed that the late- and younger-onset NSAE had a distinct spectrum of demographic features, presentations, and prognoses. More attention is needed for the younger-onset patients, given a higher disease severity on admission, more frequent requirement for ICU admission and longer length of stay.


Assuntos
Doenças Autoimunes do Sistema Nervoso , Hospitalização , Masculino , Humanos , Estudos Retrospectivos , Prognóstico
12.
BMC Gastroenterol ; 23(1): 33, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36755247

RESUMO

BACKGROUND: Serpin Peptidase Inhibitor 1 (SERPINE1) promotes cancer progression by making it easier for cancer cells to spread to surrounding normal tissue. We expect to understand the prognostic value and regulatory network of SERPINE1 in colon cancer using bioinformatics methods. METHODS: The expression of target gene SERPINE1 in varying cancers was analyzed by the Tumor Immune Estimation Resource (TIMER) database. SERPINE1 expression in Colon Adenocarcinoma and normal tissue samples was assessed by starBase and UALCAN databases. SERPINE1 expression in clinical tissues was assayed using quantitative reverse transcription Polymerase Chain Reaction (qRT-PCR). SERPINE1 expression was detected in colon cancer patients with various clinical features (age, gender, nodal metastasis status, race, stages, and subtype) using analysis of variance. Survival curve was used to analyze the effect of high and low expression of SERPINE1 on the survival time of patients with different clinical phenotypes. Gene Set Enrichment Analysis (GSEA) was conducted on the results of LinkFinder calculation using LinkInterpreter module, which was combined with Pearson correlation analysis to obtain the kinase targets and miRNA targets, transcription factor targets, and corresponding signaling pathways associated with SERPINE1. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed on GSEA result. Finally, Gene Multiple Association Network Integration Algorithm (GeneMANIA) was utilized to establish a network of genes related to the kinases MAPK1, miR-18a, and SRF_Q, and biological functions were analyzed. RESULTS: Based on TIMER, starBase, and UALCAN databases, SERPINE1 was found to be remarkably highly expressed in colon cancer patients, which was further verified by clinical tissue. It was also associated with different clinical features (nodal metastasis status, stages, subtypes). Additionally, survival analysis showed that patients with low expression of SERPINE1 had a longer survival time, suggesting that SERPINE1 was a prognostic risk factor for colon cancer. Pearson correlation analysis revealed that the expression of Integrin Alpha 5 (ITGA5), Matrix Metallopeptidase 19 (MMP19), and ADAM Metallopeptidase with Thrombospondin Type 1 Motif, 4 (ADAMTS4) had the highest correlation with that of SERPINE1. The GSEA results indicated that these genes were mainly enriched in the pathways of RNA expression and kinases. Finally, GeneMANIA analysis was introduced to construct the molecular network of SERPINE1. CONCLUSION: Overall, our bioinformatics analyses comprehensively described the networks involved SERPINE1 in colon cancer and the potentially associated molecular mechanisms.


Assuntos
Adenocarcinoma , Neoplasias do Colo , Serpinas , Humanos , Prognóstico , Neoplasias do Colo/genética , Neoplasias do Colo/patologia , Adenocarcinoma/patologia , Peptídeo Hidrolases , Inibidor 1 de Ativador de Plasminogênio/genética
13.
PLoS Genet ; 16(9): e1008704, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32986702

RESUMO

ER stress occurs in many physiological and pathological conditions. However, how chronic ER stress is alleviated in specific cells in an intact organism is an outstanding question. Here, overexpressing the gap junction protein UNC-9 (Uncoordinated) in C. elegans neurons triggers the Ire1-Xbp1-mediated stress response in an age-dependent and cell-autonomous manner. The p38 MAPK PMK-3 regulates the chronic stress through IRE-1 phosphorylation. Overexpressing gap junction protein also activates autophagy. The insulin pathway functions through autophagy, but not the transcription of genes encoding ER chaperones, to counteract the p38-Ire1-Xbp1-mediated stress response. Together, these results reveal an intricate cellular regulatory network in response to chronic stress in a subset of cells in multicellular organism.


Assuntos
Autofagia/fisiologia , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/citologia , Estresse do Retículo Endoplasmático/fisiologia , Insulina/metabolismo , Neurônios/metabolismo , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Receptor de Insulina/genética , Receptor de Insulina/metabolismo , Estresse Fisiológico , Resposta a Proteínas não Dobradas/fisiologia
14.
Angew Chem Int Ed Engl ; 62(11): e202300553, 2023 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-36655888

RESUMO

Hydride AuI bonds are labile due to the mismatch in electric potential of an oxidizing metal and reducing ligand, and therefore the structure and structure-activity relationships of nanoclusters that contain them are seldom studied. Herein, we report the synthesis and characterization of [Au7 (PPh3 )7 H5 ](SbF6 )2 (abbrev. Au7 H5 2+ ), an Au cluster complex containing five hydride ligands, which decomposed to give [Au8 (PPh3 )7 ]2+ (abbrev. Au8 2+ ) upon exposure to light (300 to 450 nm). The valence state of AuI and H- was verified by density functional theory (DFT) calculations, NMR, UV/Vis and XPS. The two nanoclusters behaved differently in the electrocatalytic CO2 reduction reaction (CO2 RR): Au7 H5 2+ exhibited 98.2 % selectivity for H2 , whereas Au8 2+ was selective for CO (73.5 %). Further DFT calculations showed that the H- ligand inhibited the CO2 RR process compared with the electron-donor H.

15.
Clin Immunol ; 241: 109074, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35809856

RESUMO

The Kelch-like protein 11 antibody-associated paraneoplastic neurological syndrome (KLHL 11-PNS) was first identified in 2019. This novel antibody, targeting the intracellular KLHL 11 antigen, can be detected in serum and cerebrospinal fluid using tissue-based and cell-based assays. It is thought to be a biomarker for a T-cell autoimmunity response. The most likely immunopathogenesis of KLHL 11-PNS appears to be linked to cytotoxic T-cell-mediated neuronal injury and loss. Patients have adult-male predilection, rhombencephalitis (brainstem and / or cerebellar involvement), and a robust oncological correlation with testicular germ cell tumors (predominately seminoma). Brain magnetic resonance imaging demonstrated T2 / fluid-attenuated inversion recovery hyperintensities and atrophy of the temporal lobe, cerebellum, and brainstem. Most patients responded poorly to immunotherapy and oncotherapy and thus had a poor long-term prognosis. We review the literature and provide an update of current knowledge regarding KLHL 11-PNS, including epidemiology, underlying mechanism, clinical presentations, paraclinical and oncological findings, diagnostic workup, and treatment approaches.


Assuntos
Neoplasias Embrionárias de Células Germinativas , Síndromes Paraneoplásicas do Sistema Nervoso , Síndromes Paraneoplásicas , Neoplasias Testiculares , Adulto , Autoanticorpos , Humanos , Masculino , Síndromes Paraneoplásicas do Sistema Nervoso/diagnóstico , Síndromes Paraneoplásicas do Sistema Nervoso/terapia
16.
EMBO J ; 37(17)2018 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-30049710

RESUMO

Seipin, the gene that causes Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2), is important for adipocyte differentiation and lipid homeostasis. Previous studies in Drosophila revealed that Seipin promotes ER calcium homeostasis through the Ca2+-ATPase SERCA, but little is known about the events downstream of perturbed ER calcium homeostasis that lead to decreased lipid storage in Drosophila dSeipin mutants. Here, we show that glycolytic metabolites accumulate and the downstream mitochondrial TCA cycle is impaired in dSeipin mutants. The impaired TCA cycle further leads to a decreased level of citrate, a critical component of lipogenesis. Mechanistically, Seipin/SERCA-mediated ER calcium homeostasis is important for maintaining mitochondrial calcium homeostasis. Reduced mitochondrial calcium in dSeipin mutants affects the TCA cycle and mitochondrial function. The lipid storage defects in dSeipin mutant fat cells can be rescued by replenishing mitochondrial calcium or by restoring the level of citrate through genetic manipulations or supplementation with exogenous metabolites. Together, our results reveal that Seipin promotes adipose tissue lipid storage via calcium-dependent mitochondrial metabolism.


Assuntos
Cálcio/metabolismo , Ciclo do Ácido Cítrico , Proteínas de Drosophila/metabolismo , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Metabolismo dos Lipídeos , Mitocôndrias/metabolismo , Tecido Adiposo/metabolismo , Animais , Proteínas de Drosophila/genética , Drosophila melanogaster , Subunidades gama da Proteína de Ligação ao GTP/genética , Mitocôndrias/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo
17.
Epilepsia ; 63(9): 2173-2191, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35652436

RESUMO

Seizure is one of the manifestations of central nervous system inflammatory demyelinating diseases, which mainly include multiple sclerosis (MS), aquaporin 4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Acute symptomatic seizures secondary to MS/AQP4-NMOSD/MOGAD occur in the acute phase of the diseases, and are more frequent in MOGAD. In contrast, recurrent nonprovoked seizures, mainly attributed to autoimmune-associated epilepsy, occur in the nonacute phase of the diseases. Seizures in MS/AQP4-NMOSD/MOGAD mostly have a focal onset. MS patients with concomitant systemic infections, earlier onset, and greater disease activity are more likely to have seizures, whereas factors such as greater MS severity, the presence of status epilepticus, and cortical damage indicate a greater risk of developing epilepsy. In MOGAD, cerebral cortical encephalitis and acute disseminated encephalomyelitis (ADEM)-like phenotypes (predominately ADEM and multiphasic disseminated encephalomyelitis) indicate a greater seizure risk. Multiple relapses with ADEM-like phenotypes predict epilepsy in pediatrics with MOGAD. Pathophysiologically, acute symptomatic seizures in MS are associated with neuronal hyperexcitability secondary to inflammation and demyelination. Chronic epilepsy in MS is largely due to gliosis, neuronal dysfunction, and synaptic abnormalities. The mainstay of treatment for seizures secondary to MS/AQP4-NMOSD/MOGAD consists of immunotherapy along with antiseizure medications. This critical review discusses the most-updated evidence on epidemiology, clinical correlates, and inflammatory mechanisms underlying seizures and epilepsy in MS/AQP4-NMOSD/MOGAD. Treatment cautions including drug-drug interactions and the impact of treatments on the diseases are outlined. We also highlight pitfalls and challenges in managing such patients and future research perspectives to address unsolved questions.


Assuntos
Epilepsia , Esclerose Múltipla , Neuromielite Óptica , Aquaporina 4 , Autoanticorpos , Criança , Epilepsia/etiologia , Humanos , Esclerose Múltipla/complicações , Glicoproteína Mielina-Oligodendrócito/metabolismo , Neuromielite Óptica/complicações , Convulsões
18.
EMBO Rep ; 21(11): e50214, 2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33034119

RESUMO

Lipid droplets (LDs) are dynamic cytoplasmic organelles present in most eukaryotic cells. The appearance of LDs in neurons is not usually observed under physiological conditions, but is associated with neural diseases. It remains unclear how LD dynamics is regulated in neurons and how the appearance of LDs affects neuronal functions. We discovered that mutations of two key lipolysis genes atgl-1 and lid-1 lead to LD appearance in neurons of Caenorhabditis elegans. This neuronal lipid accumulation protects neurons from hyperactivation-triggered neurodegeneration, with a mild decrease in touch sensation. We also discovered that reduced biosynthesis of polyunsaturated fatty acids (PUFAs) causes similar effects and synergizes with decreased lipolysis. Furthermore, we demonstrated that these changes in lipolysis and PUFA biosynthesis increase PUFA partitioning toward triacylglycerol, and reduced incorporation of PUFAs into phospholipids increases neuronal protection. Together, these results suggest the crucial role of neuronal lipolysis in cell-autonomous regulation of neural functions and neurodegeneration.


Assuntos
Gotículas Lipídicas , Lipólise , Animais , Ácidos Graxos Insaturados/metabolismo , Gotículas Lipídicas/metabolismo , Metabolismo dos Lipídeos/genética , Neurônios , Triglicerídeos
19.
Epilepsy Behav ; 127: 108516, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34991055

RESUMO

OBJECTIVE: We aimed to evaluate the assessment and management of epilepsy with anxiety and depression, and their clinical practice based on a survey. METHODS: A cross-sectional survey of epilepsy health professionals was undertaken in Zhejiang Province using the modified International League Against Epilepsy (ILAE) Psychology Task Force questionnaire. We recorded the characteristics of participants and the practice of screening, referral, and treatment for depression and anxiety disorders. A total of 146 participants joined in the survey, of which 76.0% were neurologists, and 69 participants were the member of the Zhejiang Association Against Epilepsy (ZAAE). RESULTS: This survey revealed that almost all participants (87.7%) agreed that screening for depression and anxiety in patients with epilepsy (PWEs) was very important; however, the frequency of screening was very low (41.1% of participants screened less than 10% of patients, and 34.2% participants screened between 10% and 30% of patients). A higher frequency of screening was reported in the member group and compared with that in the non-member group (P = 0.025). The main barrier to screening was the lack of time during clinic visits: 81.5% participants included screening questions as part of their clinical review. When anxiety/depression was diagnosed, the next step should be to refer patients to a psychiatrist (78.1%). No standardized procedures and lack of mental health specialists trained to assess and/or manage PWEs, were the main barriers to follow-up assessment and management. Lack of appropriately trained mental health specialists was also the main barrier to psychological treatment for depression and anxiety. CONCLUSION: This survey highlighted that epilepsy healthcare professionals in Zhejiang province agreed on the importance of screening for psychiatric comorbidities in PWEs; however, the screening and management were actually insufficient. Certain barriers to screening, referral, and treatment were presented and improvements were recommended.


Assuntos
Depressão , Epilepsia , Ansiedade/diagnóstico , Ansiedade/epidemiologia , Ansiedade/etiologia , Transtornos de Ansiedade , Estudos Transversais , Depressão/diagnóstico , Depressão/epidemiologia , Depressão/etiologia , Epilepsia/complicações , Epilepsia/diagnóstico , Epilepsia/epidemiologia , Humanos , Inquéritos e Questionários
20.
PLoS Genet ; 15(12): e1008548, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31869331

RESUMO

Phosphatidylserine (PS), synthesized in the endoplasmic reticulum (ER) by phosphatidylserine synthase (PSS), is transported to the plasma membrane (PM) and mitochondria through distinct routes. The in vivo functions of PS at different subcellular locations and the coordination between different PS transport routes are not fully understood. Here, we report that Drosophila PSS regulates cell growth, lipid storage and mitochondrial function. In pss RNAi, reduced PS depletes plasma membrane Akt, contributing to cell growth defects; the metabolic shift from phospholipid synthesis to neutral lipid synthesis results in ectopic lipid accumulation; and the reduction of mitochondrial PS impairs mitochondrial protein import and mitochondrial integrity. Importantly, reducing PS transport from the ER to PM by loss of PI4KIIIα partially rescues the mitochondrial defects of pss RNAi. Together, our results uncover a balance between different PS transport routes and reveal that PSS regulates cellular homeostasis through distinct metabolic mechanisms.


Assuntos
CDP-Diacilglicerol-Inositol 3-Fosfatidiltransferase/metabolismo , CDPdiacilglicerol-Serina O-Fosfatidiltransferase/metabolismo , Membrana Celular/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Retículo Endoplasmático/metabolismo , Fosfatidilserinas/metabolismo , Animais , Homeostase , Mitocôndrias/metabolismo , Transporte Proteico , Proteínas Proto-Oncogênicas c-akt/metabolismo
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