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1.
Chem Soc Rev ; 53(7): 3350-3383, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38406832

RESUMO

Super-resolution imaging has rapidly emerged as an optical microscopy technique, offering advantages of high optical resolution over the past two decades; achieving improved imaging resolution requires significant efforts in developing super-resolution imaging agents characterized by high brightness, high contrast and high sensitivity to fluorescence switching. Apart from technical requirements in optical systems and algorithms, super-resolution imaging relies on fluorescent dyes with special photophysical or photochemical properties. The concept of aggregation-induced emission (AIE) was proposed in 2001, coinciding with unprecedented advancements and innovations in super-resolution imaging technology. AIE probes offer many advantages, including high brightness in the aggregated state, low background signal, a larger Stokes shift, ultra-high photostability, and excellent biocompatibility, making them highly promising for applications in super-resolution imaging. In this review, we summarize the progress in implementation methods and provide insights into the mechanism of AIE-based super-resolution imaging, including fluorescence switching resulting from photochemically-converted aggregation-induced emission, electrostatically controlled aggregation-induced emission and specific binding-regulated aggregation-induced emission. Particularly, the aggregation-induced emission principle has been proposed to achieve spontaneous fluorescence switching, expanding the selection and application scenarios of super-resolution imaging probes. By combining the aggregation-induced emission principle and specific molecular design, we offer some comprehensive insights to facilitate the applications of AIEgens (AIE-active molecules) in super-resolution imaging.

2.
Nano Lett ; 24(36): 11187-11193, 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39141575

RESUMO

Antiferromagnets (AFMs) are ideal materials to boost neuromorphic computing toward the ultrahigh speed and ultracompact integration regime. However, developing a suitable AFM neuromorphic memory remains an aspirational but challenging goal. In this work, we construct such a memory based on the CoO/Pt heterostructure, in which the collinear insulating AFM CoO shows a strong perpendicular anisotropy facilitating its electrical readout and writing. Utilizing the unique nonlinear response and bipolar fading memory properties of the device, we demonstrate a multidimensional reservoir computing beyond the traditional binary paradigm. These results are expected to pave the way toward next-generation fast and massive neuromorphic computing.

3.
J Neurosci ; 43(36): 6230-6248, 2023 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-37474308

RESUMO

Synaptic vesicle (SV) endocytosis is a critical and well-regulated process for the maintenance of neurotransmission. We previously reported that synaptotagmin-11 (Syt11), an essential non-Ca2+-binding Syt associated with brain diseases, inhibits neuronal endocytosis (Wang et al., 2016). Here, we found that Syt11 deficiency caused accelerated SV endocytosis and vesicle recycling under sustained stimulation and led to the abnormal membrane partition of synaptic proteins in mouse hippocampal boutons of either sex. Furthermore, our study revealed that Syt11 has direct but Ca2+-independent binding with endophilin A1 (EndoA1), a membrane curvature sensor and endocytic protein recruiter, with high affinity. EndoA1-knockdown significantly reversed Syt11-KO phenotype, identifying EndoA1 as a main inhibitory target of Syt11 during SV endocytosis. The N-terminus of EndoA1 and the C2B domain of Syt11 were responsible for this interaction. A peptide (amino acids 314-336) derived from the Syt11 C2B efficiently blocked Syt11-EndoA1 binding both in vitro and in vivo Application of this peptide inhibited SV endocytosis in WT hippocampal neurons but not in EndoA1-knockdown neurons. Moreover, intracellular application of this peptide in mouse calyx of Held terminals of either sex effectively hampered both fast and slow SV endocytosis at physiological temperature. We thus propose that Syt11 ensures the precision of protein retrieval during SV endocytosis by inhibiting EndoA1 function at neuronal terminals.SIGNIFICANCE STATEMENT Endocytosis is a key stage of synaptic vesicle (SV) recycling. SV endocytosis retrieves vesicular membrane and protein components precisely to support sustained neurotransmission. However, the molecular mechanisms underlying the regulation of SV endocytosis remain elusive. Here, we reported that Syt11-KO accelerated SV endocytosis and impaired membrane partition of synaptic proteins. EndoA1 was identified as a main inhibitory target of Syt11 during SV endocytosis. Our study reveals a novel inhibitory mechanism of SV endocytosis in preventing hyperactivation of endocytosis, potentially safeguarding the recycling of synaptic proteins during sustained neurotransmission.


Assuntos
Transmissão Sináptica , Vesículas Sinápticas , Animais , Camundongos , Endocitose , Neurônios/fisiologia , Transmissão Sináptica/fisiologia , Vesículas Sinápticas/metabolismo , Sinaptotagminas/genética , Sinaptotagminas/metabolismo
4.
Nat Chem Biol ; 18(12): 1351-1360, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36396954

RESUMO

The landscape of cell-surface signaling is formidably complex. Robust tools capable of manipulating the spatiotemporal distribution of cell-surface proteins (CSPs) for dissecting signaling are in high demand. Some CSPs are regulated via multivalency-driven liquid-liquid phase separation (LLPS). Employing the robustness and versatility of LLPS, we decided to engineer LLPS-based tools for precisely manipulating CSPs. We generated membrane-tethering LLPS systems by fusing multivalent modular phase-separation scaffold pairs with CSP binders. Phase separation of the scaffold pairs, concomitant compartmentalization of CSPs on membranes, and cluster-dependent signaling outputs of CSPs require membrane recruitment of one or both scaffolds. We also engineered orthogonal phase-separation systems to segregate CSPs into mutually exclusive compartments. The engineered phase-separation systems can robustly cluster individual CSPs, co-cluster two or more CSPs, or segregate different CSPs into distinct compartments on cell surfaces. These tools will enable the dissection of complicated cell-signaling landscapes with high precision.


Assuntos
Proteínas de Membrana , Transdução de Sinais , Membrana Celular/metabolismo , Proteínas de Membrana/metabolismo
5.
Biochem J ; 480(22): 1805-1816, 2023 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-37905668

RESUMO

Staphylococcal nuclease Tudor domain containing 1 (SND1) protein is an oncogene that 'reads' methylarginine marks through its Tudor domain. Specifically, it recognizes methylation marks deposited by protein arginine methyltransferase 5 (PRMT5), which is also known to promote tumorigenesis. Although SND1 can drive hepatocellular carcinoma (HCC), it is unclear whether the SND1 Tudor domain is needed to promote HCC. We sought to identify the biological role of the SND1 Tudor domain in normal and tumorigenic settings by developing two genetically engineered SND1 mouse models, an Snd1 knockout (Snd1 KO) and an Snd1 Tudor domain-mutated (Snd1 KI) mouse, whose mutant SND1 can no longer recognize PRMT5-catalyzed methylarginine marks. Quantitative PCR analysis of normal, KO, and KI liver samples revealed a role for the SND1 Tudor domain in regulating the expression of genes encoding major acute phase proteins, which could provide mechanistic insight into SND1 function in a tumor setting. Prior studies indicated that ectopic overexpression of SND1 in the mouse liver dramatically accelerates the development of diethylnitrosamine (DEN)-induced HCC. Thus, we tested the combined effects of DEN and SND1 loss or mutation on the development of HCC. We found that both Snd1 KO and Snd1 KI mice were partially protected against malignant tumor development following exposure to DEN. These results support the development of small molecule inhibitors that target the SND1 Tudor domain or the use of upstream PRMT5 inhibitors, as novel treatments for HCC.


Assuntos
Carcinoma Hepatocelular , Endonucleases , Neoplasias Hepáticas , Animais , Camundongos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Endonucleases/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Proteínas Nucleares/metabolismo , Fatores de Transcrição , Predisposição Genética para Doença
6.
Proc Natl Acad Sci U S A ; 118(4)2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33483420

RESUMO

RNA helicases play roles in various essential biological processes such as RNA splicing and editing. Recent in vitro studies show that RNA helicases are involved in immune responses toward viruses, serving as viral RNA sensors or immune signaling adaptors. However, there is still a lack of in vivo data to support the tissue- or cell-specific function of RNA helicases owing to the lethality of mice with complete knockout of RNA helicases; further, there is a lack of evidence about the antibacterial role of helicases. Here, we investigated the in vivo role of Dhx15 in intestinal antibacterial responses by generating mice that were intestinal epithelial cell (IEC)-specific deficient for Dhx15 (Dhx15 f/f Villin1-cre, Dhx15ΔIEC). These mice are susceptible to infection with enteric bacteria Citrobacter rodentium (C. rod), owing to impaired α-defensin production by Paneth cells. Moreover, mice with Paneth cell-specific depletion of Dhx15 (Dhx15 f/f Defensinα6-cre, Dhx15ΔPaneth) are more susceptible to DSS (dextran sodium sulfate)-induced colitis, which phenocopy Dhx15ΔIEC mice, due to the dysbiosis of the intestinal microbiota. In humans, reduced protein levels of Dhx15 are found in ulcerative colitis (UC) patients. Taken together, our findings identify a key regulator of Wnt-induced α-defensins in Paneth cells and offer insights into its role in the antimicrobial response as well as intestinal inflammation.


Assuntos
Colite/imunologia , Defensinas/genética , Infecções por Enterobacteriaceae/imunologia , Celulas de Paneth/imunologia , RNA Helicases/genética , Via de Sinalização Wnt , Animais , Citrobacter rodentium/imunologia , Citrobacter rodentium/patogenicidade , Colite/induzido quimicamente , Colite/genética , Colite/patologia , Defensinas/imunologia , Sulfato de Dextrana/administração & dosagem , Infecções por Enterobacteriaceae/genética , Infecções por Enterobacteriaceae/microbiologia , Infecções por Enterobacteriaceae/patologia , Microbioma Gastrointestinal/imunologia , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Transgênicos , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/imunologia , Celulas de Paneth/microbiologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/imunologia , RNA Helicases/imunologia
7.
Biochem Soc Trans ; 51(2): 725-734, 2023 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-37013969

RESUMO

Arginine methylation is a ubiquitous and relatively stable post-translational modification (PTM) that occurs in three types: monomethylarginine (MMA), asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA). Methylarginine marks are catalyzed by members of the protein arginine methyltransferases (PRMTs) family of enzymes. Substrates for arginine methylation are found in most cellular compartments, with RNA-binding proteins forming the majority of PRMT targets. Arginine methylation often occurs in intrinsically disordered regions of proteins, which impacts biological processes like protein-protein interactions and phase separation, to modulate gene transcription, mRNA splicing and signal transduction. With regards to protein-protein interactions, the major 'readers' of methylarginine marks are Tudor domain-containing proteins, although additional domain types and unique protein folds have also recently been identified as methylarginine readers. Here, we will assess the current 'state-of-the-art' in the arginine methylation reader field. We will focus on the biological functions of the Tudor domain-containing methylarginine readers and address other domains and complexes that sense methylarginine marks.


Assuntos
Processamento de Proteína Pós-Traducional , Proteínas de Ligação a RNA , Arginina/química , Arginina/genética , Arginina/metabolismo , Metilação , Proteína-Arginina N-Metiltransferases/química , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Proteínas de Ligação a RNA/metabolismo
8.
Methods ; 200: 80-86, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34107353

RESUMO

Arginine methylation is a prevalent posttranslational modification which is deposited by a family of protein arginine methyltransferases (PRMTs), and is found in three different forms in mammalian cells: monomethylarginine (MMA), asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA). Pan-methylarginine antibodies are critical for identifying proteins that are methylated on arginine residues, and are also used for evaluating signaling pathways that modulate this methyltransferase activity. Although good pan-MMA, -ADMA and -SDMA antibodies have been developed over the years, there is still room for improvement. Here we use a novel antigen approach, which involves the separation of short methylated motifs with inert polyethylene glycol (PEG) linkers, to generate a set of pan antibodies to the full range of methylarginine marks. Using these antibodies, we observed substrate scavenging by PRMT1, when PRMT5 activity is blocked. Specifically, we find that the splicing factor SmD1 displays increased ADMA levels upon PRMT5 inhibitor treatment. Furthermore, when the catalysis of both SDMA and ADMA is blocked with small molecule inhibitors, we demonstrate that SmD1 and SMN no longer interact. This could partially explain the synergistic effect of PRMT5 and type I PRMT inhibition on RNA splicing and cancer cell growth.


Assuntos
Polietilenoglicóis , Proteína-Arginina N-Metiltransferases , Animais , Anticorpos/genética , Arginina/metabolismo , Mamíferos/metabolismo , Metilação , Processamento de Proteína Pós-Traducional , Proteína-Arginina N-Metiltransferases/metabolismo
9.
J Neurochem ; 159(4): 729-741, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34599505

RESUMO

Recent work has revealed that spontaneous release plays critical roles in the central nervous system, but how it is regulated remains elusive. Here, we report that synaptotagmin-11 (Syt11), a Ca2+ -independent Syt isoform associated with schizophrenia and Parkinson's disease, suppressed spontaneous release. Syt11-knockout hippocampal neurons showed an increased frequency of miniature excitatory post-synaptic currents while over-expression of Syt11 inversely decreased the frequency. Neither knockout nor over-expression of Syt11 affected the average amplitude, suggesting the pre-synaptic regulation of spontaneous neurotransmission by Syt11. Glutathione S-transferase pull-down, co-immunoprecipitation, and affinity-purification experiments demonstrated a direct interaction of Syt11 with vps10p-tail-interactor-1a (vti1a), a non-canonical SNARE protein that maintains spontaneous release. Importantly, knockdown of vti1a reversed the phenotype of Syt11 knockout, identifying vti1a as the main target of Syt11 inhibition. Domain analysis revealed that the C2A domain of Syt11 bound vti1a with high affinity. Consistently, expression of the C2A domain alone rescued the phenotype of elevated spontaneous release in Syt11-knockout neurons similar to the full-length protein. Altogether, our results suggest that Syt11 inhibits vti1a-containing vesicles during spontaneous release.


Assuntos
Proteínas Qb-SNARE/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos , Sinaptotagminas/farmacologia , Animais , Fenômenos Eletrofisiológicos , Potenciais Pós-Sinápticos Excitadores , Técnicas de Introdução de Genes , Hipocampo/patologia , Imunoprecipitação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/patologia , Cultura Primária de Células
10.
FASEB J ; 34(2): 2609-2624, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31908017

RESUMO

Caveolae play crucial roles in intracellular membrane trafficking and mechanosensation. In this study, we report that synaptotagmin-11 (Syt11), a synaptotagmin isoform associated with Parkinson's disease and schizophrenia, regulates both caveolae-mediated endocytosis and the caveolar response to mechanical stimuli in astrocytes. Syt11-knockout (KO) accelerated caveolae-mediated endocytosis. Interestingly, the caveolar structures on the cell surface were markedly fewer in the absence of Syt11. Caveolar disassembly in response to hypoosmotic stimuli and astrocyte swelling were both impaired in Syt11-KO astrocytes. Live imaging revealed that Syt11 left caveolar structures before cavin1 during hypoosmotic stress and returned earlier than cavin1 after isoosmotic recovery. Chronic hypoosmotic stress led to proteasome-mediated Syt11 degradation. In addition, Syt11-KO increased the turnover of cavin1 and EH domain-containing protein 2 (EHD2), accompanied by compromised membrane integrity, suggesting a mechanoprotective role of Syt11. Direct interactions between Syt11 and cavin1 and EHD2, but not caveolin-1, are found. Altogether, we propose that Syt11 stabilizes caveolar structures on the cell surface of astrocytes and regulates caveolar functions under physiological and pathological conditions through cavin1 and EHD2.


Assuntos
Astrócitos/metabolismo , Cavéolas/metabolismo , Endocitose/fisiologia , Estresse Mecânico , Sinaptotagminas/metabolismo , Animais , Membrana Celular/metabolismo , Camundongos Transgênicos , Domínios Proteicos/fisiologia , Sinaptotagminas/genética
11.
J Am Chem Soc ; 142(16): 7497-7505, 2020 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-32223234

RESUMO

A water-soluble probe, TPA-1OH, with aggregation-induced emission activity is synthesized and used for expedient real-time fluorescence in situ visualization of latent fingerprints (LFPs). A TPA-1OH aqueous solution exhibits nonfluorescence in pure water while strong fluorescence upon molecular aggregation induced by addition of poor solvent. Fluorescence images of LFPs on a variety of substrates, including rough surfaces such as walls, bricks, and paper, are developed under 405 nm light, by soaking in or spraying with a TPA-1OH aqueous solution (30 µM) without any necessity of organic cosolvents and post-treatment steps. The probe is noncytotoxic at a concentration lower than 50 µM. The development process of LFPs is demonstrated by real-time fluorescence in situ imaging. The exponential relationship between the relative fluorescence intensity and time is deduced from the fitting curve. The LFP images developed by TPA-1OH are evident and intact enough to allow that the level 1-3 details are displayed and analyzed. Noteworthily, the level 3 details of LFPs such as the fingerprint ridge width and the characteristics of the sweat pores are evidently visible under fluorescence microscopy. Even the nanoscopic details exceeding level 3 are visualized under super-resolution microscopy with sub-50 nm optical resolution.

12.
Biol Reprod ; 103(5): 1085-1098, 2020 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-32776126

RESUMO

Women with polycystic ovary syndrome (PCOS) are characterized by endocrine disorders accompanied by a decline in oocyte quality. In this study, we generated a PCOS mice model by hypodermic injection of dehydroepiandrosterone, and metformin was used as a positive control drug to study the effect of pachymic acid (PA) on endocrine and oocyte quality in PCOS mice. Compared with the model group, the mice treated with PA showed the following changes (slower weight gain, improved abnormal metabolism; increased development potential of GV oocytes, reduced number of abnormal MII oocytes, and damaged embryos; lower expression of ovarian-related genes in ovarian tissue and pro-inflammatory cytokines in adipose tissue). All these aspects show similar effects on metformin. Most notably, PA is superior to metformin in improving inflammation of adipose tissue and mitochondrial abnormalities. It is suggested that PA has the similar effect with metformin, which can improve the endocrine environment and oocyte quality of PCOS mice. These findings suggest that PA has the similar effect with metformin, which can improve the endocrine environment and oocyte quality of PCOS mice.


Assuntos
Oócitos/efeitos dos fármacos , Ovário/efeitos dos fármacos , Síndrome do Ovário Policístico/metabolismo , Triterpenos/farmacologia , Animais , Desidroepiandrosterona , Modelos Animais de Doenças , Feminino , Metformina/farmacologia , Camundongos , Oócitos/metabolismo , Ovário/metabolismo , Síndrome do Ovário Policístico/induzido quimicamente
13.
Bioconjug Chem ; 31(10): 2303-2311, 2020 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-33002360

RESUMO

Protein misfolding and denaturation, represented by amyloid fibrillation, are associated with many diseases. However, as a general chemical biological process, the dynamic structure information on amyloid fibrillation has not been demonstrated categorically. Herein, hen egg white lysozyme (HEWL) was used as the model protein of interest to realize in situ nanoscale imaging of protein fibrillation process using the fluorophores with aggregation-induced emission (AIE) activity. The AIE-active fluorophores exhibit the reversible capability of association and dissociation with ß-sheet structure and thus dynamic binding-induced emission, which causes the spontaneous switching of fluorescence. The entire HEWL denaturation process induced by sodium dodecyl sulfate (SDS) at ambient conditions was demonstrated in detail by using two AIE-active fluorophores (TPE-NaSO3 and PD-BZ-OH) through reversible electrostatic interaction and specific labeling between AIE probes and ß-sheet structures of amyloid fibrils, respectively. The results indicate that PD-BZ-OH is more specific AIE probe for amyloid fibrils than TPE-NaSO3. In comparison, the SEM and TEM results show the same denaturation process of protein fibrillation induced by SDS at different concentrations. The static super-resolution imaging of amyloid fibrils is performed with a resolution of 35 nm using PD-BZ-OH aqueous solution without additional auxiliary conditions. The dynamic evolution process of HEWL amyloid fibrillation is in situ visualized through super-resolution fluorescent microscopy with nanoscale resolution. Both static and dynamic super-resolution imaging of amyloid fibrillation provides detailed nanoscale structure information exceeding 50 nm resolution, which is of great significance in the exploration of amyloid fibrillation and related diseases.


Assuntos
Amiloide/química , Muramidase/química , Agregados Proteicos , Amiloide/ultraestrutura , Animais , Galinhas , Citrulinação , Clara de Ovo/química , Conformação Proteica em Folha beta
14.
Nano Lett ; 19(9): 6377-6384, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31381355

RESUMO

The low Coulombic efficiency and hazardous dendrite growth hinder the adoption of lithium anode in high-energy density batteries. Herein, we report a lithium metal-carbon nanotube (Li-CNT) composite as an alternative to the long-term untamed lithium electrode to address the critical issues associated with the lithium anode in Li-O2 batteries, where the lithium metal is impregnated in a porous carbon nanotube microsphere matrix (CNTm) and surface-passivated with a self-assembled monolayer of octadecylphosphonic acid as a tailor-designed solid electrolyte interphase (SEI). The high specific surface area of the Li-CNT composite reduces the local current density and thus suppresses the lithium dendrite formation upon cycling. Moreover, the tailor-designed SEI effectively separates the Li-CNT composite from the electrolyte solution and prevents the latter's further decomposition. When the Li-CNT composite anode is coupled with another CNTm-based O2 cathode, the reversibility and cycle life of the resultant Li-O2 batteries are drastically elevated.

15.
J Cell Physiol ; 234(8): 13820-13831, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30644094

RESUMO

Recently, graphene nanomaterials have attracted tremendous attention and have been utilized in various fields because of their excellent mechanical, thermal, chemical, optical properties, and good biocompatibility, especially in biomedical aspects. However, there is a concern that the unique characteristics of nanomaterials may have undesirable effects. Therefore, in this study, we sought to systematically investigate the effects of graphene quantum dots (GQDs) on the maturation of mouse oocytes and development of the offspring via in vitro and in vivo studies. In vitro, we found that the first polar body extrusion rate in the high dosage exposure groups (1.0-1.5 mg/ml) 2 decreased significantly and the failure of spindle migration and actin cap formation after GQDs exposure was observed. The underlying mechanisms might be associated with reactive oxygen species accumulation and DNA damage. Moreover, transmission electron microscope studies showed that GQDs may have been internalized into oocytes, tending to accumulate in the nucleus and severely affecting mitochondrial morphology, which included swollen and vacuolated mitochondria accompanied by cristae alteration with a lower amount of dense mitochondrial matrix. In vivo, when pregnant mice were exposed to GQDs at 8.5 days of gestation (GD, 8.5), we found that high dosage of GQD exposure (30 mg/kg) significantly affected mean fetal length; however, all the second generation of female mice grew up normal, attained sexual maturity, and gave birth to a healthy offspring after mating with a healthy male mouse. The results presented in this study are important for the future investigation of GQDs for the biomedical applications.


Assuntos
Desenvolvimento Embrionário/efeitos dos fármacos , Grafite/farmacologia , Oócitos/citologia , Pontos Quânticos/química , Actinas/metabolismo , Animais , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Feminino , Feto/efeitos dos fármacos , Feto/embriologia , Masculino , Metáfase/efeitos dos fármacos , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/ultraestrutura , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Oócitos/ultraestrutura , Pontos Quânticos/ultraestrutura , Espécies Reativas de Oxigênio/metabolismo , Fuso Acromático/efeitos dos fármacos , Fuso Acromático/metabolismo , Difração de Raios X
16.
Mol Pharm ; 16(2): 779-785, 2019 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-30604617

RESUMO

Oncolytic viral therapy is an attractive novel strategy for cancer therapy. As a natural alphavirus, oncolytic virus M1 is able to infect and kill various zinc finger antiviral protein (ZAP)-deficient tumor cells selectively, while leaving normal cells undamaged. However, M1 can trigger the production of neutralizing antibodies that dramatically weaken its antitumor effect. In order to attenuate immunogenicity of the therapeutic M1 virus, we encapsulated it into liposomes (referred to as M-LPO) using the thin-film hydration method. The effect of anti-M1 neutralizing antibody on M-LPO was examined in LoVo and Hep 3B cell lines. In the absence of neutralizing antibodies, treating cells with naked M1, blank liposomes (LPO), M-LPO, or a simple mixture of M1 and liposomes (LPO+M1) inhibited cell growth. In the presence of neutralizing antibodies, only M-LPO inhibited cell growth. After intravenous administration, M-LPO reduced the production of the M1-neutralizing antibody and the corresponding immune response. Analysis of the M-LPO uptake by cells was examined by confocal microscopy using M1 labeled with FITC and liposomal shells labeled with RhB. The results suggest that M1 may be released from liposomes before or after M-LPO internalization. Taken together, our results suggest that encapsulating oncolytic virus M1 in liposomes may reduce intrinsic viral immunogenicity for improved anticancer therapy.


Assuntos
Lipossomos/química , Vírus Oncolíticos/fisiologia , Animais , Anticorpos Neutralizantes/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/fisiologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Terapia Viral Oncolítica/métodos , Vírus Oncolíticos/química
17.
Cell Mol Life Sci ; 74(16): 2917-2927, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28361181

RESUMO

In chemical synapses, action potentials evoke synaptic vesicle fusion with the presynaptic membrane at the active zone to release neurotransmitter. Synaptic vesicle endocytosis (SVE) then follows exocytosis to recapture vesicle proteins and lipid components for recycling and the maintenance of membrane homeostasis. Therefore, SVE plays an essential role during neurotransmission and is one of the most precisely regulated biological processes. Four modes of SVE have been characterized and both positive and negative regulators have been identified. However, our understanding of SVE regulation remains unclear, especially the identity of negative regulators and their mechanisms of action. Here, we review the current knowledge of proteins that function as inhibitors of SVE and their modes of action in different forms of endocytosis. We also propose possible physiological roles of such negative regulation. We believe that a better understanding of SVE regulation, especially the inhibitory mechanisms, will shed light on neurotransmission in health and disease.


Assuntos
Endocitose , Mapas de Interação de Proteínas , Vesículas Sinápticas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Calcineurina/metabolismo , Calpaína/metabolismo , Quinase 5 Dependente de Ciclina/metabolismo , Humanos , Sinapses/metabolismo , Transmissão Sináptica , Sinaptotagminas/metabolismo , Temperatura
18.
Glia ; 65(10): 1656-1667, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28686317

RESUMO

Cytokine secretion and phagocytosis are key functions of activated microglia. However, the molecular mechanisms underlying their regulation in microglia remain largely unknown. Here, we report that synaptotagmin-11 (Syt11), a non-Ca2+ -binding Syt implicated in Parkinson disease and schizophrenia, inhibits cytokine secretion and phagocytosis in microglia. We found Syt11 expression in microglia in brain slices and primary microglia. Interestingly, Syt11-knockdown (KD) increased cytokine secretion and NO release in primary microglia both in the absence and presence of lipopolysaccharide. NF-κB was activated in untreated KD microglia together with enhanced synthesis of IL-6, TNF-α, IL-1ß, and iNOS. When the release capacity was assessed by the ratio of extracellular to intracellular levels, only the IL-6 and TNF-α secretion capacity was increased in Syt11-KD cells, suggesting that Syt11 specifically regulates conventional secretion. Consistently, Syt11 localized to the trans-Golgi network and recycling endosomes. In addition, Syt11 was recruited to phagosomes and its deficiency enhanced microglial phagocytosis. All the KD phenotypes were rescued by expression of an shRNA-resistant Syt11, while overexpression of Syt11 suppressed cytokine secretion and phagocytosis. Importantly, Syt11 also inhibited microglial phagocytosis of α-synuclein fibrils, supporting its association with Parkinson disease. Taken together, we propose that Syt11 suppresses microglial activation under both physiological and pathological conditions through the inhibition of cytokine secretion and phagocytosis.


Assuntos
Citocinas/metabolismo , Regulação da Expressão Gênica/genética , Microglia/efeitos dos fármacos , Microglia/metabolismo , Fagocitose/efeitos dos fármacos , Sinaptotagminas/metabolismo , Animais , Animais Recém-Nascidos , Encéfalo/citologia , Células Cultivadas , Regulação da Expressão Gênica/efeitos dos fármacos , Técnicas In Vitro , Lipopolissacarídeos/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transfecção , alfa-Sinucleína/metabolismo
19.
Appl Opt ; 56(35): 9809-9813, 2017 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-29240129

RESUMO

We demonstrate a tunable single-longitudinal-mode Ho:YAG laser pumped by a 1.13 µm diode. With two intracavity Fabry-Perot etalons, the maximum single-longitudinal-mode output power of 102 mW at 2129.6 nm is obtained. The wavelength is tuned from 2119.7 to 2131.5 nm by precisely rotating two etalons. The measured beam quality factors M2 are 1.29 and 1.28 in the x and y directions, respectively.

20.
Mol Reprod Dev ; 83(9): 768-779, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27434785

RESUMO

Methoxychlor (MXC) is used worldwide against insects and other pests. This organochlorine pesticide acts as a xenoestrogen, promotes oxidative stress, and is considered cytotoxic and genotoxic, causing abortions and stillbirths in females. Mechanistically related estrogens and oxidants affect oocyte meiosis, so we investigated the effects of MXC on mouse oocyte meiotic maturation. Our results showed that maturation rates of MXC-treated oocytes were lower than those of controls, which was due to abnormal spindle morphologies and DNA double-strand breaks, as confirmed by increased γ-H2AX foci. Our findings also suggest that MXC may affect oocyte quality by causing the accumulation of superoxide radicals and other reactive oxygen species, aberrant mitochondrial distribution, decreased mitochondrial membrane potential, and increased lipid peroxidation. Thus, exposure to MXC negatively affects oocyte meiotic maturation, primarily through impairments in cellular ROS metabolism. Mol. Reprod. Dev. 83: 768-779, 2016 © 2016 Wiley Periodicals, Inc.


Assuntos
Quebras de DNA de Cadeia Dupla , Meiose/efeitos dos fármacos , Metoxicloro/efeitos adversos , Oócitos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Superóxidos/metabolismo , Animais , Feminino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Metoxicloro/farmacologia , Camundongos , Camundongos Endogâmicos ICR , Oócitos/patologia
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