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1.
Mol Cell ; 83(12): 2045-2058.e9, 2023 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-37192628

RESUMEN

Mitophagy plays an important role in mitochondrial homeostasis by selective degradation of mitochondria. During mitophagy, mitochondria should be fragmented to allow engulfment within autophagosomes, whose capacity is exceeded by the typical mitochondria mass. However, the known mitochondrial fission factors, dynamin-related proteins Dnm1 in yeasts and DNM1L/Drp1 in mammals, are dispensable for mitophagy. Here, we identify Atg44 as a mitochondrial fission factor that is essential for mitophagy in yeasts, and we therefore term Atg44 and its orthologous proteins mitofissin. In mitofissin-deficient cells, a part of the mitochondria is recognized by the mitophagy machinery as cargo but cannot be enwrapped by the autophagosome precursor, the phagophore, due to a lack of mitochondrial fission. Furthermore, we show that mitofissin directly binds to lipid membranes and brings about lipid membrane fragility to facilitate membrane fission. Taken together, we propose that mitofissin acts directly on lipid membranes to drive mitochondrial fission required for mitophagy.


Asunto(s)
Autofagia , Mitofagia , Animales , Dinámicas Mitocondriales , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Mitocondrias/genética , Mitocondrias/metabolismo , Dinaminas/genética , Dinaminas/metabolismo , Lípidos , Mamíferos/metabolismo
2.
EMBO J ; 43(4): 568-594, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38263333

RESUMEN

Comprehensive analysis of cellular dynamics during the process of morphogenesis is fundamental to understanding the principles of animal development. Despite recent advancements in light microscopy, how successive cell shape changes lead to complex three-dimensional tissue morphogenesis is still largely unresolved. Using in vivo live imaging of Drosophila wing development, we have studied unique cellular structures comprising a microtubule-based membrane protrusion network. This network, which we name here the Interplanar Amida Network (IPAN), links the two wing epithelium leaflets. Initially, the IPAN sustains cell-cell contacts between the two layers of the wing epithelium through basal protrusions. Subsequent disassembly of the IPAN involves loss of these contacts, with concomitant degeneration of aligned microtubules. These processes are both autonomously and non-autonomously required for mitosis, leading to coordinated tissue proliferation between two wing epithelia. Our findings further reveal that a microtubule organization switch from non-centrosomal to centrosomal microtubule-organizing centers (MTOCs) at the G2/M transition leads to disassembly of non-centrosomal microtubule-derived IPAN protrusions. These findings exemplify how cell shape change-mediated loss of inter-tissue contacts results in 3D tissue morphogenesis.


Asunto(s)
Drosophila , Microtúbulos , Animales , Microtúbulos/metabolismo , Epitelio/metabolismo , Centro Organizador de los Microtúbulos/metabolismo , Morfogénesis
3.
EMBO J ; 42(18): e112305, 2023 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-37609947

RESUMEN

Nanog and Oct4 are core transcription factors that form part of a gene regulatory network to regulate hundreds of target genes for pluripotency maintenance in mouse embryonic stem cells (ESCs). To understand their function in the pluripotency maintenance, we visualised and quantified the dynamics of single molecules of Nanog and Oct4 in a mouse ESCs during pluripotency loss. Interestingly, Nanog interacted longer with its target loci upon reduced expression or at the onset of differentiation, suggesting a feedback mechanism to maintain the pluripotent state. The expression level and interaction time of Nanog and Oct4 correlate with their fluctuation and interaction frequency, respectively, which in turn depend on the ESC differentiation status. The DNA viscoelasticity near the Oct4 target locus remained flexible during differentiation, supporting its role either in chromatin opening or a preferred binding to uncondensed chromatin regions. Based on these results, we propose a new negative feedback mechanism for pluripotency maintenance via the DNA condensation state-dependent interplay of Nanog and Oct4.


Asunto(s)
Células Madre Embrionarias de Ratones , Imagen Individual de Molécula , Animales , Ratones , Retroalimentación , Cromatina/genética , Diferenciación Celular
4.
Nat Methods ; 21(4): 648-656, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38036853

RESUMEN

Although StayGold is a bright and highly photostable fluorescent protein, its propensity for obligate dimer formation may hinder applications in molecular fusion and membrane targeting. To attain monovalent as well as bright and photostable labeling, we engineered tandem dimers of StayGold to promote dispersibility. On the basis of the crystal structure of this fluorescent protein, we disrupted the dimerization to generate a monomeric variant that offers improved photostability and brightness compared to StayGold. We applied the new monovalent StayGold tools to live-cell imaging experiments using spinning-disk laser-scanning confocal microscopy or structured illumination microscopy. We achieved cell-wide, high-spatiotemporal resolution and sustained imaging of dynamic subcellular events, including the targeting of endogenous condensin I to mitotic chromosomes, the movement of the Golgi apparatus and its membranous derivatives along microtubule networks, the distribution of cortical filamentous actin and the remolding of cristae membranes within mobile mitochondria.


Asunto(s)
Aparato de Golgi , Mitocondrias , Mitocondrias/química , Aparato de Golgi/metabolismo , Microtúbulos/metabolismo , Microscopía Confocal/métodos
5.
Nature ; 578(7794): 301-305, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-32025038

RESUMEN

Many biomolecules undergo liquid-liquid phase separation to form liquid-like condensates that mediate diverse cellular functions1,2. Autophagy is able to degrade such condensates using autophagosomes-double-membrane structures that are synthesized de novo at the pre-autophagosomal structure (PAS) in yeast3-5. Whereas Atg proteins that associate with the PAS have been characterized, the physicochemical and functional properties of the PAS remain unclear owing to its small size and fragility. Here we show that the PAS is in fact a liquid-like condensate of Atg proteins. The autophagy-initiating Atg1 complex undergoes phase separation to form liquid droplets in vitro, and point mutations or phosphorylation that inhibit phase separation impair PAS formation in vivo. In vitro experiments show that Atg1-complex droplets can be tethered to membranes via specific protein-protein interactions, explaining the vacuolar membrane localization of the PAS in vivo. We propose that phase separation has a critical, active role in autophagy, whereby it organizes the autophagy machinery at the PAS.


Asunto(s)
Autofagosomas/química , Autofagosomas/metabolismo , Saccharomyces cerevisiae/citología , Saccharomyces cerevisiae/metabolismo , Proteínas Adaptadoras Transductoras de Señales/química , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Autofagia , Proteínas Relacionadas con la Autofagia/química , Proteínas Relacionadas con la Autofagia/genética , Proteínas Relacionadas con la Autofagia/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/química , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Complejos Multiproteicos/química , Complejos Multiproteicos/genética , Complejos Multiproteicos/metabolismo , Fosforilación , Mutación Puntual , Unión Proteica , Proteínas Quinasas/química , Proteínas Quinasas/genética , Proteínas Quinasas/metabolismo , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Vacuolas/metabolismo
6.
Ann Neurol ; 95(2): 338-346, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37807081

RESUMEN

OBJECTIVE: Atrial fibrillation (AF) detected after insular stroke might arise from autonomic and inflammatory mechanisms triggered by insular damage, and be associated with a low embolic risk. We assessed the association of the timing of AF detection and insular involvement with the risk of embolic events after acute ischemic stroke. METHODS: Acute ischemic stroke patients with AF who underwent brain magnetic resonance imaging at baseline were enrolled. Patients were classified according to the timing of AF detection (AF detected after stroke [AFDAS] or known AF [KAF]) and insular involvement. The primary outcome was embolic events defined as recurrent ischemic stroke, transient ischemic attack, and systemic embolism within 90 days. RESULTS: Of 1,548 patients, 360 had AFDAS with insular cortex lesions (+I), 409 had AFDAS without insular cortex lesions (-I), 349 had KAF+I, and 430 had KAF-I. Cumulative incidence rates of embolic events at 90 days in patients with AFDAS+I, AFDAS-I, KAF+I, and KAF-I were 0.8%, 3.5%, 4.9%, and 3.3%, respectively. Patients with AFDAS-I (adjusted hazard ratio 5.04, 95% confidence interval 1.43-17.75), KAF+I (6.18, 1.78-21.46), and KAF-I (5.26, 1.48-18.69) had a significantly higher risk of embolic events than those with AFDAS+I. INTERPRETATION: Acute ischemic stroke patients with AFDAS and insular cortex lesions had a lower risk of embolic events than those who had AFDAS without insular cortex lesions or those with KAF, regardless of insular involvement. ANN NEUROL 2024;95:338-346.


Asunto(s)
Fibrilación Atrial , Isquemia Encefálica , Embolia , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Accidente Cerebrovascular Isquémico/complicaciones , Fibrilación Atrial/complicaciones , Fibrilación Atrial/diagnóstico , Isquemia Encefálica/complicaciones , Isquemia Encefálica/diagnóstico por imagen , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/epidemiología , Embolia/complicaciones , Embolia/diagnóstico por imagen , Factores de Riesgo
7.
Ann Neurol ; 95(4): 774-787, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38146238

RESUMEN

OBJECTIVE: This study was undertaken to determine the excess risk of antithrombotic-related bleeding due to cerebral small vessel disease (SVD) burden. METHODS: In this observational, prospective cohort study, patients with cerebrovascular or cardiovascular diseases taking oral antithrombotic agents were enrolled from 52 hospitals across Japan between 2016 and 2019. Baseline multimodal magnetic resonance imaging acquired under prespecified conditions was assessed by a central diagnostic radiology committee to calculate total SVD score. The primary outcome was major bleeding. Secondary outcomes included bleeding at each site and ischemic events. RESULTS: Of the analyzed 5,250 patients (1,736 women; median age = 73 years, 9,933 patient-years of follow-up), antiplatelets and anticoagulants were administered at baseline in 3,948 and 1,565, respectively. Median SVD score was 2 (interquartile range = 1-3). Incidence rate of major bleeding was 0.39 (per 100 patinet-years) in score 0, 0.56 in score 1, 0.91 in score 2, 1.35 in score 3, and 2.24 in score 4 (adjusted hazard ratio [aHR] for score 4 vs 0 = 5.47, 95% confidence interval [CI] = 2.26-13.23), that of intracranial hemorrhage was 0.11, 0.33, 0.58, 0.99, and 1.06, respectively (aHR = 9.29, 95% CI = 1.99-43.35), and that of ischemic event was 1.82, 2.27, 3.04, 3.91, and 4.07, respectively (aHR = 1.76, 95% CI = 1.08-2.86). In addition, extracranial major bleeding (aHR = 3.43, 95% CI = 1.13-10.38) and gastrointestinal bleeding (aHR = 2.54, 95% CI = 1.02-6.35) significantly increased in SVD score 4 compared to score 0. INTERPRETATION: Total SVD score was predictive for intracranial hemorrhage and probably for extracranial bleeding, suggesting the broader clinical relevance of cerebral SVD as a marker for safe implementation of antithrombotic therapy. ANN NEUROL 2024;95:774-787.


Asunto(s)
Enfermedades de los Pequeños Vasos Cerebrales , Accidente Cerebrovascular , Anciano , Femenino , Humanos , Anticoagulantes , Enfermedades de los Pequeños Vasos Cerebrales/epidemiología , Fibrinolíticos/efectos adversos , Hemorragia , Hemorragias Intracraneales/inducido químicamente , Hemorragias Intracraneales/epidemiología , Estudios Prospectivos , Accidente Cerebrovascular/epidemiología , Masculino
8.
Mol Cell ; 67(2): 282-293.e7, 2017 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-28712725

RESUMEN

The eukaryotic genome is organized within cells as chromatin. For proper information output, higher-order chromatin structures can be regulated dynamically. How such structures form and behave in various cellular processes remains unclear. Here, by combining super-resolution imaging (photoactivated localization microscopy [PALM]) and single-nucleosome tracking, we developed a nuclear imaging system to visualize the higher-order structures along with their dynamics in live mammalian cells. We demonstrated that nucleosomes form compact domains with a peak diameter of ∼160 nm and move coherently in live cells. The heterochromatin-rich regions showed more domains and less movement. With cell differentiation, the domains became more apparent, with reduced dynamics. Furthermore, various perturbation experiments indicated that they are organized by a combination of factors, including cohesin and nucleosome-nucleosome interactions. Notably, we observed the domains during mitosis, suggesting that they act as building blocks of chromosomes and may serve as information units throughout the cell cycle.


Asunto(s)
Ensamble y Desensamble de Cromatina , Heterocromatina/metabolismo , Microscopía por Video/métodos , Mitosis , Nucleosomas/metabolismo , Animales , Proteínas de Ciclo Celular/metabolismo , Diferenciación Celular , Proteínas Cromosómicas no Histona/metabolismo , Cromosomas Humanos , Células HCT116 , Células HeLa , Heterocromatina/química , Humanos , Ratones , Movimiento (Física) , Conformación de Ácido Nucleico , Nucleosomas/química , Conformación Proteica , Interferencia de ARN , Relación Estructura-Actividad , Factores de Tiempo , Transcripción Genética , Transfección , Cohesinas
9.
Nucleic Acids Res ; 51(12): 6190-6207, 2023 07 07.
Artículo en Inglés | MEDLINE | ID: mdl-37178005

RESUMEN

Heterochromatin is a key architectural feature of eukaryotic chromosomes critical for cell type-specific gene expression and genome stability. In the mammalian nucleus, heterochromatin segregates from transcriptionally active genomic regions and exists in large, condensed, and inactive nuclear compartments. However, the mechanisms underlying the spatial organization of heterochromatin need to be better understood. Histone H3 lysine 9 trimethylation (H3K9me3) and lysine 27 trimethylation (H3K27me3) are two major epigenetic modifications that enrich constitutive and facultative heterochromatin, respectively. Mammals have at least five H3K9 methyltransferases (SUV39H1, SUV39H2, SETDB1, G9a and GLP) and two H3K27 methyltransferases (EZH1 and EZH2). In this study, we addressed the role of H3K9 and H3K27 methylation in heterochromatin organization using a combination of mutant cells for five H3K9 methyltransferases and an EZH1/2 dual inhibitor, DS3201. We showed that H3K27me3, which is normally segregated from H3K9me3, was redistributed to regions targeted by H3K9me3 after the loss of H3K9 methylation and that the loss of both H3K9 and H3K27 methylation resulted in impaired condensation and spatial organization of heterochromatin. Our data demonstrate that the H3K27me3 pathway safeguards heterochromatin organization after the loss of H3K9 methylation in mammalian cells.


Asunto(s)
Epigénesis Genética , Heterocromatina , Animales , Heterocromatina/genética , Histonas/metabolismo , Lisina/metabolismo , Mamíferos/genética , Metilación , Histona Metiltransferasas/metabolismo
10.
Dev Dyn ; 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38984461

RESUMEN

BACKGROUND: Mouse nodal immotile cilia mechanically sense the bending direction for left-right (L-R) determination and activate the left-side-specific signaling cascade, leading to increased Nodal activity. Asymmetric distribution of Pkd2, a crucial channel for L-R determination, on immotile cilia has been reported recently. However, the causal relationship between the asymmetric Pkd2 distribution and direction-dependent flow sensing is not well understood. Furthermore, the underlying molecular mechanism directing this asymmetric Pkd2 distribution remains unclear. RESULTS: The effects of several recombinant proteins and inhibitors on the Pkd2 distribution were analyzed using super-resolution microscopy. Notably, bone morphogenetic protein 4 (BMP4) affected the Pkd2 distribution. Additionally, three-dimensional manipulation of nodal immotile cilia using optical tweezers revealed that excess BMP4 caused defects in the mechanosensing ability of the cilia. CONCLUSIONS: Experimental data together with model calculations suggest that BMP4 regulates the asymmetric distribution of Pkd2 in nodal immotile cilia, thereby affecting the ability of these cilia to sense the bending direction for L-R determination. This study, for the first time, provides insight into the relationship between the asymmetric protein distribution in cilia and their function.

11.
Biophys J ; 2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-38459696

RESUMEN

ATP synthase, a crucial enzyme for cellular bioenergetics, operates via the coordinated coupling of an FO motor, which presents variable symmetry, and a tripartite F1 motor. Despite extensive research, the understanding of their coupling dynamics, especially with non-10-fold symmetrical FO motors, remains incomplete. This study investigates the coupling patterns between eightfold and ninefold FO motors and the constant threefold F1 motor using coarse-grained molecular dynamics simulations. We unveil that in the case of a ninefold FO motor, a 3-3-3 motion is most likely to occur, whereas a 3-3-2 motion predominates with an eightfold FO motor. Furthermore, our findings propose a revised model for the coupling method, elucidating that the pathways' energy usage is primarily influenced by F1 rotation and conformational changes hindered by the b-subunits. Our results present a crucial step toward comprehending the energy landscape and mechanisms governing ATP synthase operation.

12.
Nat Mater ; 22(12): 1564-1570, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37903925

RESUMEN

Cosmic large-scale structures, animal flocks and living tissues can be considered non-equilibrium organized systems created by dissipative processes. Replicating such properties in artificial systems is still difficult. Herein we report a dissipative network formation process in a dilute polymer-water mixture that leads to percolation-induced gel-gel phase separation. The dilute system, which forms a monophase structure at the percolation threshold, spontaneously separates into two co-continuous gel phases with a submillimetre scale (a dilute-percolated gel) during the deswelling process after the completion of the gelation reaction. The dilute-percolated gel, which contains 99% water, exhibits unexpected hydrophobicity and induces the development of adipose-like tissues in subcutaneous tissues. These findings support the development of dissipative structures with advanced functionalities for distinct applications, ranging from physical chemistry to tissue engineering.


Asunto(s)
Polímeros , Animales , Geles/química , Polímeros/química , Interacciones Hidrofóbicas e Hidrofílicas , Agua/química
13.
PLoS Genet ; 17(8): e1009727, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34407079

RESUMEN

Vps13 family proteins are proposed to function in bulk lipid transfer between membranes, but little is known about their regulation. During sporulation of Saccharomyces cerevisiae, Vps13 localizes to the prospore membrane (PSM) via the Spo71-Spo73 adaptor complex. We previously reported that loss of any of these proteins causes PSM extension and subsequent sporulation defects, yet their precise function remains unclear. Here, we performed a genetic screen and identified genes coding for a fragment of phosphatidylinositol (PI) 4-kinase catalytic subunit and PI 4-kinase noncatalytic subunit as multicopy suppressors of spo73Δ. Further genetic and cytological analyses revealed that lowering PI4P levels in the PSM rescues the spo73Δ defects. Furthermore, overexpression of VPS13 and lowering PI4P levels synergistically rescued the defect of a spo71Δ spo73Δ double mutant, suggesting that PI4P might regulate Vps13 function. In addition, we show that an N-terminal fragment of Vps13 has affinity for the endoplasmic reticulum (ER), and ER-plasma membrane (PM) tethers localize along the PSM in a manner dependent on Vps13 and the adaptor complex. These observations suggest that Vps13 and the adaptor complex recruit ER-PM tethers to ER-PSM contact sites. Our analysis revealed that involvement of a phosphoinositide, PI4P, in regulation of Vps13, and also suggest that distinct contact site proteins function cooperatively to promote de novo membrane formation.


Asunto(s)
1-Fosfatidilinositol 4-Quinasa/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Esporas Fúngicas/genética , 1-Fosfatidilinositol 4-Quinasa/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Portadoras/genética , Membrana Celular/metabolismo , Retículo Endoplásmico/metabolismo , Membranas/metabolismo , Membranas Mitocondriales/metabolismo , Transporte de Proteínas , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética
14.
Angew Chem Int Ed Engl ; 63(15): e202400711, 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38315771

RESUMEN

The development of near-infrared (NIR) fluorophores that have both excellent chemical stability and photostability, as well as efficient cell permeability, is highly demanded. In this study, we present phospha-rhodamine (POR) dyes which display significantly improved performance for protein labeling. This is achieved by incorporating a 2-carboxy-3-benzothiophenyl group at the 9-position of the xanthene scaffold. The resulting cis and trans isomers were successfully isolated and structurally characterized using X-ray diffraction. The HaloTag ligand conjugates of the two isomers exhibited different staining abilities in live cells. While the cis isomer showed non-specific accumulation on the organelle membranes, the trans isomer selectively labeled the HaloTag-fused proteins, enabling the long-term imaging of cell division and the 5-color imaging of cell organelles. Molecular dynamics simulations of the HaloTag ligand conjugates within the lipid membrane suggested that the cis isomer is more prone to forming oligomers in the membrane. In contrast, the oligomerization of the trans isomer is effectively suppressed by its interaction with the lipid molecules. By taking advantage of the superior labeling performance of the trans isomer and its NIR-emissive properties, multi-color time-lapse super-resolution 3D imaging, namely super-resolution 5D-imaging, of the interconnected network between the endoplasmic reticulum and microtubules was achieved in living cells.


Asunto(s)
Colorantes Fluorescentes , Orgánulos , Rodaminas , Ligandos , Colorantes Fluorescentes/química , Orgánulos/metabolismo , Proteínas , Microscopía Fluorescente/métodos , Lípidos
15.
J Biol Chem ; 298(7): 102090, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35654143

RESUMEN

Invadopodia on cancer cells play crucial roles in tumor invasion and metastasis by degrading and remodeling the surrounding extracellular matrices and driving cell migration in complex 3D environments. Previous studies have indicated that microtubules (MTs) play a crucial role in elongation of invadopodia, but not their formation, probably by regulating delivery of membrane and secretory proteins within invadopodia. However, the identity of the responsible MT-based molecular motors and their regulation has been elusive. Here, we show that KIF1C, a member of kinesin-3 family, is localized to the tips of invadopodia and is required for their elongation and the invasion of cancer cells. We also found that c-Src phosphorylates tyrosine residues within the stalk domain of KIF1C, thereby enhancing its association with tyrosine phosphatase PTPD1, that in turn activates MT-binding ability of KIF1C, probably by relieving the autoinhibitory interaction between its motor and stalk domains. These findings shed new insights into how c-Src signaling is coupled to the MT-dependent dynamic nature of invadopodia and also advance our understanding of the mechanism of KIF1C activation through release of its autoinhibition.


Asunto(s)
Genes src , Cinesinas , Invasividad Neoplásica , Podosomas , Línea Celular Tumoral , Humanos , Cinesinas/genética , Microtúbulos/metabolismo , Fosforilación , Podosomas/metabolismo , Proteínas Tirosina Fosfatasas no Receptoras , Tirosina/metabolismo
16.
Stroke ; 54(3): 697-705, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36734235

RESUMEN

BACKGROUND: The effectiveness of long-term dual antiplatelet therapy (DAPT) to prevent recurrent strokes in patients with lacunar stroke remains unclarified. Therefore, this study aimed to compare and to elucidate the safety and effectiveness of DAPT and single antiplatelet therapy (SAPT) in preventing recurrence in chronic lacunar stroke. METHODS: CSPS.com (Cilostazol Stroke Prevention Study for Antiplatelet Combination) was a prospective, multicenter, randomized controlled trial. In this prespecified subanalysis, 925 patients (mean age, 69.5 years; 69.4% men) with lacunar stroke were selected from 1884 patients with high-risk noncardioembolic stroke, enrolled in the CSPS.com trial after 8 to 180 days following stroke. Patients were randomly assigned to receive either SAPT or DAPT using cilostazol and were followed for 0.5 to 3.5 years. The primary efficacy outcome was the first recurrence of ischemic stroke. The safety outcomes were severe or life-threatening bleeding. RESULTS: The DAPT group receiving cilostazol and either aspirin or clopidogrel and SAPT group receiving aspirin or clopidogrel alone comprised 464 (50.2%) and 461 (49.8%) patients, respectively. Ischemic stroke occurred in 12 of 464 patients (1.84 per 100 patient-years) in the DAPT group and 31 of 461 patients (4.42 per 100 patient-years) in the SAPT group, during follow-up. After adjusting for multiple potential confounding factors, ischemic stroke risk was significantly lower in the DAPT group than in the SAPT group (hazard ratio, 0.43 [95% CI, 0.22-0.84]). The rate of severe or life-threatening hemorrhage did not differ significantly between the groups (2 patients [0.31 per 100 patient-years] versus 6 patients [0.86 per 100 patient-years] in the DAPT and SAPT groups, respectively; hazard ratio, 0.36 [95% CI, 0.07-1.81]). CONCLUSIONS: In patients with lacunar stroke, DAPT using cilostazol had significant benefits in reducing recurrent ischemic stroke incidence compared with SAPT without increasing the risk of severe or life-threatening bleeding. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01995370. URL: https://www.umin.ac.jp/ctr; Unique identifier: UMIN000012180.


Asunto(s)
Accidente Vascular Cerebral Lacunar , Accidente Cerebrovascular , Masculino , Humanos , Anciano , Femenino , Inhibidores de Agregación Plaquetaria/efectos adversos , Cilostazol/uso terapéutico , Clopidogrel/uso terapéutico , Prevención Secundaria , Accidente Vascular Cerebral Lacunar/tratamiento farmacológico , Accidente Vascular Cerebral Lacunar/epidemiología , Accidente Vascular Cerebral Lacunar/prevención & control , Estudios Prospectivos , Quimioterapia Combinada , Aspirina/uso terapéutico , Accidente Cerebrovascular/tratamiento farmacológico , Accidente Cerebrovascular/epidemiología , Accidente Cerebrovascular/prevención & control , Hemorragia/inducido químicamente
17.
J Immunol ; 206(1): 154-163, 2021 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-33219146

RESUMEN

Viral RNA in the cytoplasm of mammalian host cells is recognized by retinoic acid-inducible protein-I-like receptors (RLRs), which localize to cytoplasmic stress granules (SGs). Activated RLRs associate with the mitochondrial adaptor protein IPS-1, which activates antiviral host defense mechanisms, including type I IFN induction. It has remained unclear, however, how RLRs in SGs and IPS-1 in the mitochondrial outer membrane associate physically and engage in information transfer. In this study, we show that NUDT21, an RNA-binding protein that regulates alternative transcript polyadenylation, physically associates with IPS-1 and mediates its localization to SGs in response to transfection with polyinosinic-polycytidylic acid [poly(I:C)], a mimic of viral dsRNA. We found that despite its well-established function in the nucleus, a fraction of NUDT21 localizes to mitochondria in resting cells and becomes localized to SGs in response to poly(I:C) transfection. NUDT21 was also found to be required for efficient type I IFN induction in response to viral infection in both human HeLa cells and mouse macrophage cell line RAW264.7 cells. Our results together indicate that NUDT21 links RLRs in SGs to mitochondrial IPS-1 and thereby activates host defense responses to viral infection.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Infecciones por Cardiovirus/metabolismo , Factor de Especificidad de Desdoblamiento y Poliadenilación/metabolismo , Proteína 58 DEAD Box/metabolismo , Virus de la Encefalomiocarditis/fisiología , Mitocondrias/metabolismo , Enfermedad de Newcastle/metabolismo , Virus de la Enfermedad de Newcastle/fisiología , Receptores Inmunológicos/metabolismo , Vesículas Secretoras/metabolismo , Animales , Factor de Especificidad de Desdoblamiento y Poliadenilación/genética , Regulación de la Expresión Génica , Células HEK293 , Células HeLa , Humanos , Interferón Tipo I/genética , Interferón Tipo I/metabolismo , Ratones , Poli I-C/inmunología , Transporte de Proteínas , Células RAW 264.7 , ARN Interferente Pequeño/genética , ARN Viral/inmunología , Estrés Fisiológico
18.
Acta Radiol ; 64(2): 769-775, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35466686

RESUMEN

BACKGROUND: Moyamoya disease (MMD) and non-MMD have different pathogenesis, clinical presentation, and treatment policy. PURPOSE: To identify differences in hemodynamics between MMD and non-MMD using intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT). MATERIAL AND METHODS: Patients who had undergone 99mTc-ECD or 123I-IMP SPECT, and IVIM imaging were retrospectively studied. IVIM imaging was acquired using six different b-values. Cerebral blood flow ratio (CBFR) in the basal ganglia was calculated using a standardized volume-of-interest template. The cerebellum was used as a reference region. IVIM perfusion fraction (f) was obtained using a two-step fitting algorithm. Elliptical regions of interest were placed in bilateral basal ganglia on the IVIM f map. Patients were classified into MMD and non-MMD groups. The correlation between CBFR and mean IVIM f (fmean) in the basal ganglia was evaluated using Spearman's rank correlation coefficient. RESULTS: In total, 20 patients with MMD and 28 non-MMD patients were analyzed. No significant differences in fmean were observed among MMD, affected hemisphere with non-MMD (non-MMDaff), and unaffected hemispheres with non-MMD (non-MMDunaff). A negative correlation was seen between fmean and CBFR in the MMD group (r = -0.40, P = 0.0108), but not in the non-MMD group (non-MMDaff, r = 0.07, P = 0.69; non-MMDunaff, r = -0.22, P = 0.29). No significant differences were found among MMD and non-MMD patients, irrespective of SPECT tracers. CONCLUSION: The combination of IVIM MRI and SPECT appears to allow non-invasive identification of differences in hemodynamics between MMD and non-MMD.


Asunto(s)
Imagen de Difusión por Resonancia Magnética , Imagen por Resonancia Magnética , Humanos , Imagen de Difusión por Resonancia Magnética/métodos , Estudios Retrospectivos , Imagen por Resonancia Magnética/métodos , Movimiento (Física) , Tomografía Computarizada de Emisión de Fotón Único , Ganglios Basales/diagnóstico por imagen
19.
J Stroke Cerebrovasc Dis ; 32(6): 107087, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36972640

RESUMEN

A 63-year-old man was admitted to our stroke center with brain infarction in the left posterior inferior cerebellar artery (PICA) territory. The initial MRI showed no findings suggestive of arterial dissection, and post-discharge MRI showed no temporal changes. Digital subtraction angiography (DSA) revealed vasodilation of the proximal portion of the PICA but it was uncertain whether dissection was present. Discrepancy between the outer contour seen on constructive interference in steady state (CISS) MRI and the inner contour seen on DSA suggested the presence of intramural hematoma. The patient was diagnosed with brain infarction caused by isolated PICA dissection (iPICAD). Imaging evaluation of combined CISS and DSA may be particularly useful for identification of small iPICAD lesions.


Asunto(s)
Cuidados Posteriores , Alta del Paciente , Masculino , Humanos , Persona de Mediana Edad , Angiografía de Substracción Digital , Arteria Vertebral/patología , Infarto Encefálico/patología , Cerebelo/irrigación sanguínea
20.
Neuroradiology ; 64(2): 279-288, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34247261

RESUMEN

PURPOSE: To discover common biomarkers correlating with the Mini-Mental State Examination (MMSE) scores from multi-country MRI datasets. METHODS: The first dataset comprised 112 subjects (49 men, 63 women; range, 46-94 years) at the National Hospital Organization Kyushu Medical Center. A second dataset comprised 300 subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database (177 men, 123 women; range, 57-91 years). Three-dimensional T1-weighted MR images were collected from both datasets. In total, 14 deep gray matter volumes and 70 cortical thicknesses were obtained from MR images using FreeSurfer software. Total hippocampal volume and the ratio of hippocampus to cerebral volume were also calculated. Correlations between each variable and MMSE scores were assessed using Pearson's correlation coefficient. Parameters with moderate correlation coefficients (r > 0.3) from each dataset were determined as independent variables and evaluated using general linear model (GLM) analyses. RESULTS: In Pearson's correlation coefficient, total and bilateral hippocampal volumes, right amygdala volume, and right entorhinal cortex (ERC) thickness showed moderate correlation coefficients (r > 0.3) with MMSE scores from the first dataset. The ADNI dataset showed moderate correlations with MMSE scores in more variables, including bilateral ERC thickness and hippocampal volume. GLM analysis revealed that right ERC thickness correlated significantly with MMSE score in both datasets. Cortical thicknesses of the left parahippocampal gyrus, left inferior parietal lobe, and right fusiform gyrus also significantly correlated with MMSE score in the ADNI dataset (p < 0.05). CONCLUSION: A positive correlation between right ERC thickness and MMSE score was identified from multi-country datasets.


Asunto(s)
Enfermedad de Alzheimer , Corteza Entorrinal , Enfermedad de Alzheimer/diagnóstico por imagen , Corteza Entorrinal/diagnóstico por imagen , Femenino , Hipocampo , Humanos , Imagen por Resonancia Magnética , Masculino , Lóbulo Temporal
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