Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 827
Filtrar
Más filtros

Intervalo de año de publicación
1.
Cell ; 179(1): 132-146.e14, 2019 09 19.
Artículo en Inglés | MEDLINE | ID: mdl-31522887

RESUMEN

Oligodendrocytes extend elaborate microtubule arbors that contact up to 50 axon segments per cell, then spiral around myelin sheaths, penetrating from outer to inner layers. However, how they establish this complex cytoarchitecture is unclear. Here, we show that oligodendrocytes contain Golgi outposts, an organelle that can function as an acentrosomal microtubule-organizing center (MTOC). We identify a specific marker for Golgi outposts-TPPP (tubulin polymerization promoting protein)-that we use to purify this organelle and characterize its proteome. In in vitro cell-free assays, recombinant TPPP nucleates microtubules. Primary oligodendrocytes from Tppp knockout (KO) mice have aberrant microtubule branching, mixed microtubule polarity, and shorter myelin sheaths when cultured on 3-dimensional (3D) microfibers. Tppp KO mice exhibit hypomyelination with shorter, thinner myelin sheaths and motor coordination deficits. Together, our data demonstrate that microtubule nucleation outside the cell body at Golgi outposts by TPPP is critical for elongation of the myelin sheath.


Asunto(s)
Proteínas Portadoras/metabolismo , Aparato de Golgi/metabolismo , Microtúbulos/metabolismo , Vaina de Mielina/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Animales , Animales Recién Nacidos , Axones/metabolismo , Proteínas Portadoras/genética , Sistema Libre de Células/metabolismo , Células Cultivadas , Escherichia coli/metabolismo , Técnicas de Silenciamiento del Gen , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Centro Organizador de los Microtúbulos/metabolismo , Proteínas del Tejido Nervioso/genética , Células Precursoras de Oligodendrocitos/metabolismo , Ratas , Ratas Sprague-Dawley , Tubulina (Proteína)/metabolismo
2.
Mol Cell ; 84(14): 2618-2633.e10, 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-39025073

RESUMEN

The twenty-three Fanconi anemia (FA) proteins cooperate in the FA/BRCA pathway to repair DNA interstrand cross-links (ICLs). The cell division cycle and apoptosis regulator 1 (CCAR1) protein is also a regulator of ICL repair, though its possible function in the FA/BRCA pathway remains unknown. Here, we demonstrate that CCAR1 plays a unique upstream role in the FA/BRCA pathway and is required for FANCA protein expression in human cells. Interestingly, CCAR1 co-immunoprecipitates with FANCA pre-mRNA and is required for FANCA mRNA processing. Loss of CCAR1 results in retention of a poison exon in the FANCA transcript, thereby leading to reduced FANCA protein expression. A unique domain of CCAR1, the EF hand domain, is required for interaction with the U2AF heterodimer of the spliceosome and for excision of the poison exon. Taken together, CCAR1 is a splicing modulator required for normal splicing of the FANCA mRNA and other mRNAs involved in various cellular pathways.


Asunto(s)
Proteínas Reguladoras de la Apoptosis , Proteínas de Ciclo Celular , Proteína del Grupo de Complementación A de la Anemia de Fanconi , Anemia de Fanconi , Empalme del ARN , Factor de Empalme U2AF , Humanos , Proteína BRCA1/metabolismo , Proteína BRCA1/genética , Proteína BRCA2/metabolismo , Proteína BRCA2/genética , Reparación del ADN , Endodesoxirribonucleasas , Exones , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación A de la Anemia de Fanconi/metabolismo , Células HEK293 , Células HeLa , Unión Proteica , Precursores del ARN/metabolismo , Precursores del ARN/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transducción de Señal , Empalmosomas/metabolismo , Empalmosomas/genética , Factor de Empalme U2AF/metabolismo , Factor de Empalme U2AF/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo
3.
Nature ; 633(8031): 932-940, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39232161

RESUMEN

CDK1 has been known to be the sole cyclin-dependent kinase (CDK) partner of cyclin B1 to drive mitotic progression1. Here we demonstrate that CDK5 is active during mitosis and is necessary for maintaining mitotic fidelity. CDK5 is an atypical CDK owing to its high expression in post-mitotic neurons and activation by non-cyclin proteins p35 and p392. Here, using independent chemical genetic approaches, we specifically abrogated CDK5 activity during mitosis, and observed mitotic defects, nuclear atypia and substantial alterations in the mitotic phosphoproteome. Notably, cyclin B1 is a mitotic co-factor of CDK5. Computational modelling, comparison with experimentally derived structures of CDK-cyclin complexes and validation with mutational analysis indicate that CDK5-cyclin B1 can form a functional complex. Disruption of the CDK5-cyclin B1 complex phenocopies CDK5 abrogation in mitosis. Together, our results demonstrate that cyclin B1 partners with both CDK5 and CDK1, and CDK5-cyclin B1 functions as a canonical CDK-cyclin complex to ensure mitotic fidelity.


Asunto(s)
Ciclina B1 , Quinasa 5 Dependiente de la Ciclina , Mitosis , Complejos Multiproteicos , Humanos , Coenzimas/metabolismo , Ciclina B1/metabolismo , Quinasa 5 Dependiente de la Ciclina/antagonistas & inhibidores , Quinasa 5 Dependiente de la Ciclina/deficiencia , Quinasa 5 Dependiente de la Ciclina/genética , Quinasa 5 Dependiente de la Ciclina/metabolismo , Células HeLa , Modelos Moleculares , Complejos Multiproteicos/metabolismo , Mutación , Fosfoproteínas/metabolismo , Unión Proteica , Proteoma/metabolismo , Reproducibilidad de los Resultados
4.
Mol Cell ; 81(12): 2583-2595.e6, 2021 06 17.
Artículo en Inglés | MEDLINE | ID: mdl-33961797

RESUMEN

53BP1 influences genome stability via two independent mechanisms: (1) regulating DNA double-strand break (DSB) repair and (2) enhancing p53 activity. We discovered a protein, Tudor-interacting repair regulator (TIRR), that associates with the 53BP1 Tudor domain and prevents its recruitment to DSBs. Here, we elucidate how TIRR affects 53BP1 function beyond its recruitment to DSBs and biochemically links the two distinct roles of 53BP1. Loss of TIRR causes an aberrant increase in the gene transactivation function of p53, affecting several p53-mediated cell-fate programs. TIRR inhibits the complex formation between the Tudor domain of 53BP1 and a dimethylated form of p53 (K382me2) that is poised for transcriptional activation of its target genes. TIRR mRNA expression levels negatively correlate with the expression of key p53 target genes in breast and prostate cancers. Further, TIRR loss is selectively not tolerated in p53-proficient tumors. Therefore, we establish that TIRR is an important inhibitor of the 53BP1-p53 complex.


Asunto(s)
Linaje de la Célula/genética , Proteínas de Unión al ARN/metabolismo , Proteína 1 de Unión al Supresor Tumoral P53/metabolismo , Sitios de Unión , Proteínas Portadoras/metabolismo , Línea Celular Tumoral , Linaje de la Célula/fisiología , ADN/genética , Roturas del ADN de Doble Cadena , Reparación del ADN , Histonas/metabolismo , Humanos , Unión Proteica , Proteínas de Unión al ARN/fisiología , Dominio Tudor , Proteína p53 Supresora de Tumor/metabolismo , Proteína 1 de Unión al Supresor Tumoral P53/fisiología
5.
Mol Cell ; 80(3): 410-422.e6, 2020 11 05.
Artículo en Inglés | MEDLINE | ID: mdl-33108758

RESUMEN

While effective anti-cancer drugs targeting the CHK1 kinase are advancing in the clinic, drug resistance is rapidly emerging. Here, we demonstrate that CRISPR-mediated knockout of the little-known gene FAM122A/PABIR1 confers cellular resistance to CHK1 inhibitors (CHK1is) and cross-resistance to ATR inhibitors. Knockout of FAM122A results in activation of PP2A-B55α, a phosphatase that dephosphorylates the WEE1 protein and rescues WEE1 from ubiquitin-mediated degradation. The resulting increase in WEE1 protein expression reduces replication stress, activates the G2/M checkpoint, and confers cellular resistance to CHK1is. Interestingly, in tumor cells with oncogene-driven replication stress, CHK1 can directly phosphorylate FAM122A, leading to activation of the PP2A-B55α phosphatase and increased WEE1 expression. A combination of a CHK1i plus a WEE1 inhibitor can overcome CHK1i resistance of these tumor cells, thereby enhancing anti-cancer activity. The FAM122A expression level in a tumor cell can serve as a useful biomarker for predicting CHK1i sensitivity or resistance.


Asunto(s)
Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Fosfoproteínas/metabolismo , Pirazinas/farmacología , Pirazoles/farmacología , Animales , Apoptosis/efectos de los fármacos , Puntos de Control del Ciclo Celular , Proteínas de Ciclo Celular/metabolismo , Línea Celular , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/antagonistas & inhibidores , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/metabolismo , Daño del ADN/efectos de los fármacos , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Humanos , Péptidos y Proteínas de Señalización Intracelular/fisiología , Proteínas Nucleares/metabolismo , Fosfoproteínas/fisiología , Fosforilación , Inhibidores de Proteínas Quinasas/farmacología , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Proteínas Tirosina Quinasas/genética , Pirazinas/metabolismo , Pirazoles/metabolismo , Transducción de Señal/efectos de los fármacos
6.
Nat Methods ; 21(7): 1245-1256, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38844629

RESUMEN

Microscopy-based spatially resolved omic methods are transforming the life sciences. However, these methods rely on high numerical aperture objectives and cannot resolve crowded molecular targets, limiting the amount of extractable biological information. To overcome these limitations, here we develop Deconwolf, an open-source, user-friendly software for high-performance deconvolution of widefield fluorescence microscopy images, which efficiently runs on laptop computers. Deconwolf enables accurate quantification of crowded diffraction limited fluorescence dots in DNA and RNA fluorescence in situ hybridization images and allows robust detection of individual transcripts in tissue sections imaged with ×20 air objectives. Deconvolution of in situ spatial transcriptomics images with Deconwolf increased the number of transcripts identified more than threefold, while the application of Deconwolf to images obtained by fluorescence in situ sequencing of barcoded Oligopaint probes drastically improved chromosome tracing. Deconwolf greatly facilitates the use of deconvolution in many bioimaging applications.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Hibridación Fluorescente in Situ , Microscopía Fluorescente , Programas Informáticos , Microscopía Fluorescente/métodos , Hibridación Fluorescente in Situ/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Animales , Ratones , Humanos
7.
Proc Natl Acad Sci U S A ; 121(38): e2401241121, 2024 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-39250661

RESUMEN

Despite longstanding excitement and progress toward understanding liquid-liquid phase separation in natural and artificial membranes, fundamental questions have persisted about which molecules are required for this phenomenon. Except in extraordinary circumstances, the smallest number of components that has produced large-scale, liquid-liquid phase separation in bilayers has stubbornly remained at three: a sterol, a phospholipid with ordered chains, and a phospholipid with disordered chains. This requirement of three components is puzzling because only two components are required for liquid-liquid phase separation in lipid monolayers, which resemble half of a bilayer. Inspired by reports that sterols interact closely with lipids with ordered chains, we tested whether phase separation would occur in bilayers in which a sterol and lipid were replaced by a single, joined sterol-lipid. By evaluating a panel of sterol-lipids, some of which are present in bacteria, we found a minimal bilayer of only two components (PChemsPC and diPhyPC) that robustly demixes into micron-scale, liquid phases. It suggests an additional role for sterol-lipids in nature, and it reveals a membrane in which tie-lines (and, therefore, the lipid composition of each phase) are straightforward to determine and will be consistent across multiple laboratories.


Asunto(s)
Membrana Dobles de Lípidos , Esteroles , Membrana Dobles de Lípidos/química , Esteroles/química , Transición de Fase , Fosfatidilcolinas/química , Fosfolípidos/química , Separación de Fases
8.
Proc Natl Acad Sci U S A ; 119(49): e2214935119, 2022 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-36442094

RESUMEN

The 53BP1-RIF1 pathway restricts the resection of DNA double-strand breaks (DSBs) and promotes blunt end-ligation by non-homologous end joining (NHEJ) repair. The Shieldin complex is a downstream effector of the 53BP1-RIF1 pathway. Here, we identify a component of this pathway, CCAR2/DBC1, which is also required for restriction of DNA end-resection. CCAR2 co-immunoprecipitates with the Shieldin complex, and knockout of CCAR2 in a BRCA1-deficient cell line results in elevated DSB end-resection, RAD51 loading, and PARP inhibitor (PARPi) resistance. Knockout of CCAR2 is epistatic with knockout of other Shieldin proteins. The S1-like RNA-binding domain of CCAR2 is required for its interaction with the Shieldin complex and for suppression of DSB end-resection. CCAR2 functions downstream of the Shieldin complex, and CCAR2 knockout cells have delayed resolution of Shieldin complex foci. Forkhead-associated (FHA)-dependent targeting of CCAR2 to DSB sites re-sensitized BRCA1-/-SHLD2-/- cells to PARPi. Taken together, CCAR2 is a functional component of the 53BP1-RIF1 pathway, promotes the refill of resected DSBs, and suppresses homologous recombination.


Asunto(s)
Roturas del ADN de Doble Cadena , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Reparación del ADN por Unión de Extremidades , Recombinación Homóloga , ADN
9.
PLoS Genet ; 18(11): e1010459, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36441774

RESUMEN

Overexpression of the TGFß pathway impairs the proliferation of the hematopoietic stem and progenitor cells (HSPCs) pool in Fanconi anemia (FA). TGFß promotes the expression of NHEJ genes, known to function in a low-fidelity DNA repair pathway, and pharmacological inhibition of TGFß signaling rescues FA HSPCs. Here, we demonstrate that genetic disruption of Smad3, a transducer of the canonical TGFß pathway, modifies the phenotype of FA mouse models deficient for Fancd2. We observed that the TGFß and NHEJ pathway genes are overexpressed during the embryogenesis of Fancd2-/- mice and that the Fancd2-/-Smad3-/- double knockout (DKO) mice undergo high levels of embryonic lethality due to loss of the TGFß-NHEJ axis. Fancd2-deficient embryos acquire extensive genomic instability during gestation which is not reversed by Smad3 inactivation. Strikingly, the few DKO survivors have activated the non-canonical TGFß-ERK pathway, ensuring expression of NHEJ genes during embryogenesis and improved survival. Activation of the TGFß-NHEJ axis was critical for the survival of the few Fancd2-/-Smad3-/- DKO newborn mice but had detrimental consequences for these surviving mice, such as enhanced genomic instability and ineffective hematopoiesis.


Asunto(s)
Anemia de Fanconi , Ratones , Animales , Anemia de Fanconi/genética , Factor de Crecimiento Transformador beta/genética
10.
Nano Lett ; 24(33): 10090-10097, 2024 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-39106977

RESUMEN

Metasurfaces allow light to be manipulated at the nanoscale. Integrating metasurfaces with transition metal dichalcogenide monolayers provides additional functionality to ultrathin optics, including tunable optical properties with enhanced light-matter interactions. In this work, we demonstrate the realization of a polaritonic metasurface utilizing the sizable light-matter coupling of excitons in monolayer WSe2 and the collective lattice resonances of nanoplasmonic gold arrays. We developed a novel fabrication method to integrate gold nanodisk arrays in hexagonal boron nitride and thus simultaneously ensure spectrally narrow exciton transitions and their immediate proximity to the near-field of array surface lattice resonances. In the regime of strong light-matter coupling, the resulting van der Waals metasurface exhibits all key characteristics of lattice polaritons, with a directional and linearly polarized far-field emission profile dictated by the underlying nanoplasmonic lattice. Our work can be straightforwardly adapted to other lattice geometries, establishing structured van der Waals metasurfaces as means to engineer polaritonic lattices.

11.
J Infect Dis ; 230(3): 645-656, 2024 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-38718223

RESUMEN

BACKGROUND: COVID-19 remains a global public health challenge due to new immune-evasive SARS-CoV-2 variants and heterogeneous immunity. METHODS: In this cross-sectional study, we evaluated the adaptive immune responses in US active duty personnel who completed a COVID-19 primary vaccine series and had heterogenous SARS-CoV-2 vaccination and infection histories to 3 previously dominant variants (ancestral, Delta, BA.5) and 3 circulating variants (XBB.1.5, EG.5, and BA.2.86) in late 2023. Analyses were based on the most recent exposure in terms of timing (within or beyond 12 months) and type (vaccine or infection). RESULTS: Significant reduction was observed in binding antibodies, neutralization antibodies, memory B cells, and CD8+ T cells against circulating variants when compared with previous variants. The reduction in antibody response was more pronounced in those whose most recent exposure was >12 months from enrollment. In contrast, the CD4+ T-cell response was largely consistent across all tested variants. The type of most recent exposure was not a significant factor in determining the magnitude of current immune responses. CONCLUSIONS: Administration of the XBB.1.5-based booster is likely to enhance cross-reactive humoral responses against SARS-CoV-2 circulating lineages. Ongoing surveillance of immune responses to emerging variants is needed for informing vaccine composition and timing.


Asunto(s)
Anticuerpos Neutralizantes , Anticuerpos Antivirales , Linfocitos T CD8-positivos , Vacunas contra la COVID-19 , COVID-19 , Inmunización Secundaria , SARS-CoV-2 , Humanos , SARS-CoV-2/inmunología , COVID-19/inmunología , COVID-19/prevención & control , Estudios Transversales , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Vacunas contra la COVID-19/inmunología , Vacunas contra la COVID-19/administración & dosificación , Masculino , Adulto , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/inmunología , Femenino , Linfocitos T CD8-positivos/inmunología , Adulto Joven , Personal Militar , Células B de Memoria/inmunología , Inmunidad Adaptativa/inmunología
12.
J Neurosci ; 43(25): 4625-4641, 2023 06 21.
Artículo en Inglés | MEDLINE | ID: mdl-37188516

RESUMEN

Electrical stimulation of retinal ganglion cells (RGCs) with electronic implants provides rudimentary artificial vision to people blinded by retinal degeneration. However, current devices stimulate indiscriminately and therefore cannot reproduce the intricate neural code of the retina. Recent work has demonstrated more precise activation of RGCs using focal electrical stimulation with multielectrode arrays in the peripheral macaque retina, but it is unclear how effective this can be in the central retina, which is required for high-resolution vision. This work probes the neural code and effectiveness of focal epiretinal stimulation in the central macaque retina, using large-scale electrical recording and stimulation ex vivo The functional organization, light response properties, and electrical properties of the major RGC types in the central retina were mostly similar to the peripheral retina, with some notable differences in density, kinetics, linearity, spiking statistics, and correlations. The major RGC types could be distinguished by their intrinsic electrical properties. Electrical stimulation targeting parasol cells revealed similar activation thresholds and reduced axon bundle activation in the central retina, but lower stimulation selectivity. Quantitative evaluation of the potential for image reconstruction from electrically evoked parasol cell signals revealed higher overall expected image quality in the central retina. An exploration of inadvertent midget cell activation suggested that it could contribute high spatial frequency noise to the visual signal carried by parasol cells. These results support the possibility of reproducing high-acuity visual signals in the central retina with an epiretinal implant.SIGNIFICANCE STATEMENT Artificial restoration of vision with retinal implants is a major treatment for blindness. However, present-day implants do not provide high-resolution visual perception, in part because they do not reproduce the natural neural code of the retina. Here, we demonstrate the level of visual signal reproduction that is possible with a future implant by examining how accurately responses to electrical stimulation of parasol retinal ganglion cells can convey visual signals. Although the precision of electrical stimulation in the central retina was diminished relative to the peripheral retina, the quality of expected visual signal reconstruction in parasol cells was greater. These findings suggest that visual signals could be restored with high fidelity in the central retina using a future retinal implant.


Asunto(s)
Retina , Prótesis Visuales , Animales , Retina/fisiología , Células Ganglionares de la Retina/fisiología , Macaca , Prótesis e Implantes , Estimulación Eléctrica/métodos , Estimulación Luminosa/métodos
13.
J Neurosci ; 43(26): 4808-4820, 2023 06 28.
Artículo en Inglés | MEDLINE | ID: mdl-37268418

RESUMEN

High-fidelity electronic implants can in principle restore the function of neural circuits by precisely activating neurons via extracellular stimulation. However, direct characterization of the individual electrical sensitivity of a large population of target neurons, to precisely control their activity, can be difficult or impossible. A potential solution is to leverage biophysical principles to infer sensitivity to electrical stimulation from features of spontaneous electrical activity, which can be recorded relatively easily. Here, this approach is developed and its potential value for vision restoration is tested quantitatively using large-scale multielectrode stimulation and recording from retinal ganglion cells (RGCs) of male and female macaque monkeys ex vivo Electrodes recording larger spikes from a given cell exhibited lower stimulation thresholds across cell types, retinas, and eccentricities, with systematic and distinct trends for somas and axons. Thresholds for somatic stimulation increased with distance from the axon initial segment. The dependence of spike probability on injected current was inversely related to threshold, and was substantially steeper for axonal than somatic compartments, which could be identified by their recorded electrical signatures. Dendritic stimulation was largely ineffective for eliciting spikes. These trends were quantitatively reproduced with biophysical simulations. Results from human RGCs were broadly similar. The inference of stimulation sensitivity from recorded electrical features was tested in a data-driven simulation of visual reconstruction, revealing that the approach could significantly improve the function of future high-fidelity retinal implants.SIGNIFICANCE STATEMENT This study demonstrates that individual in situ primate retinal ganglion cells of different types respond to artificially generated, external electrical fields in a systematic manner, in accordance with theoretical predictions, that allows for prediction of electrical stimulus sensitivity from recorded spontaneous activity. It also provides evidence that such an approach could be immensely helpful in the calibration of clinical retinal implants.


Asunto(s)
Retina , Células Ganglionares de la Retina , Animales , Masculino , Femenino , Humanos , Células Ganglionares de la Retina/fisiología , Potenciales de Acción/fisiología , Retina/fisiología , Primates , Estimulación Eléctrica/métodos
14.
J Am Chem Soc ; 146(7): 4582-4591, 2024 02 21.
Artículo en Inglés | MEDLINE | ID: mdl-38330910

RESUMEN

The effort to modulate challenging protein targets has stimulated interest in ligands that are larger and more complex than typical small-molecule drugs. While combinatorial techniques such as mRNA display routinely produce high-affinity macrocyclic peptides against classically undruggable targets, poor membrane permeability has limited their use toward primarily extracellular targets. Understanding the passive membrane permeability of macrocyclic peptides would, in principle, improve our ability to design libraries whose leads can be more readily optimized against intracellular targets. Here, we investigate the permeabilities of over 200 macrocyclic 10-mers using the thioether cyclization motif commonly found in mRNA display macrocycle libraries. We identified the optimal lipophilicity range for achieving permeability in thioether-cyclized 10-mer cyclic peptide-peptoid hybrid scaffolds and showed that permeability could be maintained upon extensive permutation in the backbone. In one case, changing a single amino acid from d-Pro to d-NMe-Ala, representing the loss of a single methylene group in the side chain, resulted in a highly permeable scaffold in which the low-dielectric conformation shifted from the canonical cross-beta geometry of the parent compounds into a novel saddle-shaped fold in which all four backbone NH groups were sequestered from the solvent. This work provides an example by which pre-existing physicochemical knowledge of a scaffold can benefit the design of macrocyclic peptide mRNA display libraries, pointing toward an approach for biasing libraries toward permeability by design. Moreover, the compounds described herein are a further demonstration that geometrically diverse, highly permeable scaffolds exist well beyond conventional drug-like chemical space.


Asunto(s)
Péptidos Cíclicos , Péptidos , Péptidos/química , Péptidos Cíclicos/química , Biblioteca de Péptidos , Permeabilidad , ARN Mensajero , Sulfuros
15.
Am J Physiol Renal Physiol ; 327(4): F623-F636, 2024 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-39116350

RESUMEN

The chemotherapeutic agent cisplatin accumulates in the kidneys, leading to acute kidney injury (AKI). Preclinical and clinical studies have demonstrated sex-dependent outcomes of cisplatin-AKI. Deranged histone deacetylase (HDAC) activity is hypothesized to promote the pathogenesis of male murine cisplatin-AKI; however, it is unknown whether there are sex differences in the kidney HDACs. We hypothesized that there would be sex-specific Hdac expression, localization, or enzymatic activity, which may explain sexual dimorphic responses to cisplatin-AKI. In normal human kidney RNA samples, HDAC10 was significantly greater in the kidneys of women compared with men, whereas HDAC1, HDAC6, HDAC10, and HDAC11 were differentially expressed between the kidney cortex and medulla, regardless of sex. In a murine model of cisplatin-AKI (3 days after a 15 mg/kg injection), we found few sex- or cisplatin-related differences in Hdac kidney transcripts among the mice. Although Hdac9 was significantly greater in female mice compared with male mice, HDAC9 protein localization did not differ. Hdac7 transcripts were greater in the inner medulla of cisplatin-AKI mice, regardless of sex, and this agreed with a greater HDAC7 abundance. HDAC activity within the cortex, outer medulla, and inner medulla was significantly lower in cisplatin-AKI mice but did not differ between the sexes. In agreement with these findings, a class I HDAC inhibitor did not improve kidney injury or function. In conclusion, even though cisplatin-AKI was evident and there were transcript level differences among the different kidney regions in this model, there were few sex- or cisplatin-dependent effects on kidney HDAC localization or activity.NEW & NOTEWORTHY Kidney histone deacetylases (HDACs) are abundant in male and female mice, and the inner medulla has the greatest HDAC activity. A low dose of cisplatin caused acute kidney injury (AKI) in these mice, but there were few changes in kidney HDACs at the RNA/protein/activity level. A class I HDAC inhibitor failed to improve AKI outcomes. Defining the HDAC isoform, cellular source, and interventional timing is necessary to determine whether HDAC inhibition is a therapeutic strategy to prevent cisplatin-AKI in both sexes.


Asunto(s)
Lesión Renal Aguda , Cisplatino , Histona Desacetilasas , Ratones Endogámicos C57BL , Animales , Cisplatino/toxicidad , Lesión Renal Aguda/inducido químicamente , Lesión Renal Aguda/metabolismo , Lesión Renal Aguda/enzimología , Lesión Renal Aguda/patología , Femenino , Masculino , Histona Desacetilasas/metabolismo , Histona Desacetilasas/genética , Humanos , Factores Sexuales , Ratones , Inhibidores de Histona Desacetilasas/farmacología , Modelos Animales de Enfermedad , Riñón/efectos de los fármacos , Riñón/metabolismo , Riñón/enzimología , Riñón/patología , Antineoplásicos/toxicidad , Corteza Renal/metabolismo , Corteza Renal/efectos de los fármacos , Corteza Renal/enzimología , Caracteres Sexuales
16.
Emerg Infect Dis ; 30(11): 2385-2390, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39322418

RESUMEN

We studied a community cluster of 25 mpox cases in Vietnam caused by emerging monkeypox virus sublineage C.1 and imported into Vietnam through 2 independent events; 1 major cluster carried a novel APOBEC3-like mutation. Three patients died; all had advanced HIV co-infection. Viral evolution and its potential consequences should be closely monitored.


Asunto(s)
Monkeypox virus , Mpox , Filogenia , Vietnam/epidemiología , Humanos , Mpox/epidemiología , Mpox/virología , Mpox/transmisión , Monkeypox virus/genética , Monkeypox virus/clasificación , Masculino , Femenino , Adulto , Persona de Mediana Edad , Enfermedades Transmisibles Emergentes/virología , Enfermedades Transmisibles Emergentes/transmisión , Enfermedades Transmisibles Emergentes/epidemiología , Infecciones por VIH/transmisión , Infecciones por VIH/virología , Infecciones por VIH/epidemiología , Historia del Siglo XXI , Mutación , Coinfección/virología
17.
Lancet ; 402(10406): 965-974, 2023 09 16.
Artículo en Inglés | MEDLINE | ID: mdl-37640037

RESUMEN

BACKGROUND: Intravenous thrombolysis is recommended before endovascular treatment, but its value has been questioned in patients who are admitted directly to centres capable of endovascular treatment. Existing randomised controlled trials have indicated non-inferiority of endovascular treatment alone or have been statistically inconclusive. We formed the Improving Reperfusion Strategies in Acute Ischaemic Stroke collaboration to assess non-inferiority of endovascular treatment alone versus intravenous thrombolysis plus endovascular treatment. METHODS: We conducted a systematic review and individual participant data meta-analysis to establish non-inferiority of endovascular treatment alone versus intravenous thrombolysis plus endovascular treatment. We searched PubMed and MEDLINE with the terms "stroke", "endovascular treatment", "intravenous thrombolysis", and synonyms for articles published from database inception to March 9, 2023. We included randomised controlled trials on the topic of interest, without language restrictions. Authors of the identified trials agreed to take part, and individual participant data were provided by the principal investigators of the respective trials and collated centrally by the collaborators. Our primary outcome was the 90-day modified Rankin Scale (mRS) score. Non-inferiority of endovascular treatment alone was assessed using a lower boundary of 0·82 for the 95% CI around the adjusted common odds ratio (acOR) for shift towards improved outcome (analogous to 5% absolute difference in functional independence) with ordinal regression. We used mixed-effects models for all analyses. This study is registered with PROSPERO, CRD42023411986. FINDINGS: We identified 1081 studies, and six studies (n=2313; 1153 participants randomly assigned to receive endovascular treatment alone and 1160 randomly assigned to receive intravenous thrombolysis and endovascular treatment) were eligible for analysis. The risk of bias of the included studies was low to moderate. Variability between studies was small, and mainly related to the choice and dose of the thrombolytic drug and country of execution. The median mRS score at 90 days was 3 (IQR 1-5) for participants who received endovascular treatment alone and 2 (1-4) for participants who received intravenous thrombolysis plus endovascular treatment (acOR 0·89, 95% CI 0·76-1·04). Any intracranial haemorrhage (0·82, 0·68-0·99) occurred less frequently with endovascular treatment alone than with intravenous thrombolysis plus endovascular treatment. Symptomatic intracranial haemorrhage and mortality rates did not differ significantly. INTERPRETATION: We did not establish non-inferiority of endovascular treatment alone compared with intravenous thrombolysis plus endovascular treatment in patients presenting directly at endovascular treatment centres. Further research could focus on cost-effectiveness analysis and on individualised decisions when patient characteristics, medication shortages, or delays are expected to offset a potential benefit of administering intravenous thrombolysis before endovascular treatment. FUNDING: Stryker and Amsterdam University Medical Centers, University of Amsterdam.


Asunto(s)
Isquemia Encefálica , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Accidente Cerebrovascular/tratamiento farmacológico , Hemorragias Intracraneales , Accidente Cerebrovascular Isquémico/tratamiento farmacológico , Accidente Cerebrovascular Isquémico/cirugía , Terapia Trombolítica , Ensayos Clínicos Controlados Aleatorios como Asunto
18.
Lancet ; 402(10395): 27-40, 2023 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-37245517

RESUMEN

BACKGROUND: Early control of elevated blood pressure is the most promising treatment for acute intracerebral haemorrhage. We aimed to establish whether implementing a goal-directed care bundle incorporating protocols for early intensive blood pressure lowering and management algorithms for hyperglycaemia, pyrexia, and abnormal anticoagulation, implemented in a hospital setting, could improve outcomes for patients with acute spontaneous intracerebral haemorrhage. METHODS: We performed a pragmatic, international, multicentre, blinded endpoint, stepped wedge cluster randomised controlled trial at hospitals in nine low-income and middle-income countries (Brazil, China, India, Mexico, Nigeria, Pakistan, Peru, Sri Lanka, and Viet Nam) and one high-income country (Chile). Hospitals were eligible if they had no or inconsistent relevant, disease-specific protocols, and were willing to implement the care bundle to consecutive patients (aged ≥18 years) with imaging-confirmed spontaneous intracerebral haemorrhage presenting within 6 h of the onset of symptoms, had a local champion, and could provide the required study data. Hospitals were centrally randomly allocated using permuted blocks to three sequences of implementation, stratified by country and the projected number of patients to be recruited over the 12 months of the study period. These sequences had four periods that dictated the order in which the hospitals were to switch from the control usual care procedure to the intervention implementation of the care bundle procedure to different clusters of patients in a stepped manner. To avoid contamination, details of the intervention, sequence, and allocation periods were concealed from sites until they had completed the usual care control periods. The care bundle protocol included the early intensive lowering of systolic blood pressure (target <140 mm Hg), strict glucose control (target 6·1-7·8 mmol/L in those without diabetes and 7·8-10·0 mmol/L in those with diabetes), antipyrexia treatment (target body temperature ≤37·5°C), and rapid reversal of warfarin-related anticoagulation (target international normalised ratio <1·5) within 1 h of treatment, in patients where these variables were abnormal. Analyses were performed according to a modified intention-to-treat population with available outcome data (ie, excluding sites that withdrew during the study). The primary outcome was functional recovery, measured with the modified Rankin scale (mRS; range 0 [no symptoms] to 6 [death]) at 6 months by masked research staff, analysed using proportional ordinal logistic regression to assess the distribution in scores on the mRS, with adjustments for cluster (hospital site), group assignment of cluster per period, and time (6-month periods from Dec 12, 2017). This trial is registered at Clinicaltrials.gov (NCT03209258) and the Chinese Clinical Trial Registry (ChiCTR-IOC-17011787) and is completed. FINDINGS: Between May 27, 2017, and July 8, 2021, 206 hospitals were assessed for eligibility, of which 144 hospitals in ten countries agreed to join and were randomly assigned in the trial, but 22 hospitals withdrew before starting to enrol patients and another hospital was withdrawn and their data on enrolled patients was deleted because regulatory approval was not obtained. Between Dec 12, 2017, and Dec 31, 2021, 10 857 patients were screened but 3821 were excluded. Overall, the modified intention-to-treat population included 7036 patients enrolled at 121 hospitals, with 3221 assigned to the care bundle group and 3815 to the usual care group, with primary outcome data available in 2892 patients in the care bundle group and 3363 patients in the usual care group. The likelihood of a poor functional outcome was lower in the care bundle group (common odds ratio 0·86; 95% CI 0·76-0·97; p=0·015). The favourable shift in mRS scores in the care bundle group was generally consistent across a range of sensitivity analyses that included additional adjustments for country and patient variables (0·84; 0·73-0·97; p=0·017), and with different approaches to the use of multiple imputations for missing data. Patients in the care bundle group had fewer serious adverse events than those in the usual care group (16·0% vs 20·1%; p=0·0098). INTERPRETATION: Implementation of a care bundle protocol for intensive blood pressure lowering and other management algorithms for physiological control within several hours of the onset of symptoms resulted in improved functional outcome for patients with acute intracerebral haemorrhage. Hospitals should incorporate this approach into clinical practice as part of active management for this serious condition. FUNDING: Joint Global Health Trials scheme from the Department of Health and Social Care, the Foreign, Commonwealth & Development Office, and the Medical Research Council and Wellcome Trust; West China Hospital; the National Health and Medical Research Council of Australia; Sichuan Credit Pharmaceutic and Takeda China.


Asunto(s)
Hipotensión , Paquetes de Atención al Paciente , Humanos , Adolescente , Adulto , Presión Sanguínea , Resultado del Tratamiento , Hemorragia Cerebral/tratamiento farmacológico , Cuidados Críticos , Anticoagulantes/uso terapéutico
19.
Hum Brain Mapp ; 45(1): e26558, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38224546

RESUMEN

Age is an important variable to describe the expected brain's anatomy status across the normal aging trajectory. The deviation from that normative aging trajectory may provide some insights into neurological diseases. In neuroimaging, predicted brain age is widely used to analyze different diseases. However, using only the brain age gap information (i.e., the difference between the chronological age and the estimated age) can be not enough informative for disease classification problems. In this paper, we propose to extend the notion of global brain age by estimating brain structure ages using structural magnetic resonance imaging. To this end, an ensemble of deep learning models is first used to estimate a 3D aging map (i.e., voxel-wise age estimation). Then, a 3D segmentation mask is used to obtain the final brain structure ages. This biomarker can be used in several situations. First, it enables to accurately estimate the brain age for the purpose of anomaly detection at the population level. In this situation, our approach outperforms several state-of-the-art methods. Second, brain structure ages can be used to compute the deviation from the normal aging process of each brain structure. This feature can be used in a multi-disease classification task for an accurate differential diagnosis at the subject level. Finally, the brain structure age deviations of individuals can be visualized, providing some insights about brain abnormality and helping clinicians in real medical contexts.


Asunto(s)
Enfermedad de Alzheimer , Humanos , Enfermedad de Alzheimer/patología , Imagen por Resonancia Magnética/métodos , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Neuroimagen/métodos , Biomarcadores
20.
Opt Lett ; 49(17): 4787-4790, 2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-39207964

RESUMEN

We report an experimental measurement of giant group index in the 85Rb atomic medium at room temperature via a four-level V-type scheme on the D2 line. Our experiment uses co-propagation configuration of probe and coupling lasers through an atomic sample. In this configuration, three sharp EIT windows with significant transparency depths are observed on the probe absorption spectrum. By establishing a Mach-Zehnder interferometer, we measure the dispersive curve and hence obtain the group index curve with three enhanced positive peaks at the locations of the EIT windows, interspersed with negative peaks. The amplitude of the group index curve is increased as the temperature decreases and is decreased as the temperature increases. We estimate from our experimental results the good values of the group index to be ng = 5.8 × 104 (slow light regime) and ng = -4.0 × 104 (fast light regime). We also show that the experimental measurements are in good agreement with the theoretical results.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA