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1.
Cell ; 186(11): 2361-2379.e25, 2023 05 25.
Artículo en Inglés | MEDLINE | ID: mdl-37192619

RESUMEN

Multiple anticancer drugs have been proposed to cause cell death, in part, by increasing the steady-state levels of cellular reactive oxygen species (ROS). However, for most of these drugs, exactly how the resultant ROS function and are sensed is poorly understood. It remains unclear which proteins the ROS modify and their roles in drug sensitivity/resistance. To answer these questions, we examined 11 anticancer drugs with an integrated proteogenomic approach identifying not only many unique targets but also shared ones-including ribosomal components, suggesting common mechanisms by which drugs regulate translation. We focus on CHK1 that we find is a nuclear H2O2 sensor that launches a cellular program to dampen ROS. CHK1 phosphorylates the mitochondrial DNA-binding protein SSBP1 to prevent its mitochondrial localization, which in turn decreases nuclear H2O2. Our results reveal a druggable nucleus-to-mitochondria ROS-sensing pathway-required to resolve nuclear H2O2 accumulation and mediate resistance to platinum-based agents in ovarian cancers.


Asunto(s)
Antineoplásicos , Especies Reactivas de Oxígeno , Antineoplásicos/farmacología , Antineoplásicos/metabolismo , Peróxido de Hidrógeno/metabolismo , Mitocondrias/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Núcleo Celular/metabolismo , Humanos
2.
Cell ; 175(6): 1546-1560.e17, 2018 11 29.
Artículo en Inglés | MEDLINE | ID: mdl-30500537

RESUMEN

Mammalian folate metabolism is comprised of cytosolic and mitochondrial pathways with nearly identical core reactions, yet the functional advantages of such an organization are not well understood. Using genome-editing and biochemical approaches, we find that ablating folate metabolism in the mitochondria of mammalian cell lines results in folate degradation in the cytosol. Mechanistically, we show that QDPR, an enzyme in tetrahydrobiopterin metabolism, moonlights to repair oxidative damage to tetrahydrofolate (THF). This repair capacity is overwhelmed when cytosolic THF hyperaccumulates in the absence of mitochondrially produced formate, leading to THF degradation. Unexpectedly, we also find that the classic antifolate methotrexate, by inhibiting its well-known target DHFR, causes even more extensive folate degradation in nearly all tested cancer cell lines. These findings shed light on design features of folate metabolism, provide a biochemical basis for clinically observed folate deficiency in QDPR-deficient patients, and reveal a hitherto unknown and unexplored cellular effect of methotrexate.


Asunto(s)
Carbono/metabolismo , Citosol/metabolismo , Formiatos/metabolismo , Mitocondrias/metabolismo , Neoplasias/metabolismo , Tetrahidrofolatos/metabolismo , Citosol/patología , Células HCT116 , Células HeLa , Humanos , Células MCF-7 , Metotrexato/farmacocinética , Metotrexato/farmacología , Mitocondrias/patología , Proteínas Mitocondriales/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Tetrahidrofolato Deshidrogenasa/metabolismo
3.
Nature ; 627(8005): 854-864, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38480880

RESUMEN

The heart, which is the first organ to develop, is highly dependent on its form to function1,2. However, how diverse cardiac cell types spatially coordinate to create the complex morphological structures that are crucial for heart function remains unclear. Here we integrated single-cell RNA-sequencing with high-resolution multiplexed error-robust fluorescence in situ hybridization to resolve the identity of the cardiac cell types that develop the human heart. This approach also provided a spatial mapping of individual cells that enables illumination of their organization into cellular communities that form distinct cardiac structures. We discovered that many of these cardiac cell types further specified into subpopulations exclusive to specific communities, which support their specialization according to the cellular ecosystem and anatomical region. In particular, ventricular cardiomyocyte subpopulations displayed an unexpected complex laminar organization across the ventricular wall and formed, with other cell subpopulations, several cellular communities. Interrogating cell-cell interactions within these communities using in vivo conditional genetic mouse models and in vitro human pluripotent stem cell systems revealed multicellular signalling pathways that orchestrate the spatial organization of cardiac cell subpopulations during ventricular wall morphogenesis. These detailed findings into the cellular social interactions and specialization of cardiac cell types constructing and remodelling the human heart offer new insights into structural heart diseases and the engineering of complex multicellular tissues for human heart repair.


Asunto(s)
Tipificación del Cuerpo , Corazón , Miocardio , Animales , Humanos , Ratones , Corazón/anatomía & histología , Corazón/embriología , Cardiopatías/metabolismo , Cardiopatías/patología , Ventrículos Cardíacos/anatomía & histología , Ventrículos Cardíacos/citología , Ventrículos Cardíacos/embriología , Hibridación Fluorescente in Situ , Modelos Animales , Miocardio/citología , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Análisis de Expresión Génica de una Sola Célula
4.
Nature ; 629(8014): 1174-1181, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38720073

RESUMEN

Phosphorylation of proteins on tyrosine (Tyr) residues evolved in metazoan organisms as a mechanism of coordinating tissue growth1. Multicellular eukaryotes typically have more than 50 distinct protein Tyr kinases that catalyse the phosphorylation of thousands of Tyr residues throughout the proteome1-3. How a given Tyr kinase can phosphorylate a specific subset of proteins at unique Tyr sites is only partially understood4-7. Here we used combinatorial peptide arrays to profile the substrate sequence specificity of all human Tyr kinases. Globally, the Tyr kinases demonstrate considerable diversity in optimal patterns of residues surrounding the site of phosphorylation, revealing the functional organization of the human Tyr kinome by substrate motif preference. Using this information, Tyr kinases that are most compatible with phosphorylating any Tyr site can be identified. Analysis of mass spectrometry phosphoproteomic datasets using this compendium of kinase specificities accurately identifies specific Tyr kinases that are dysregulated in cells after stimulation with growth factors, treatment with anti-cancer drugs or expression of oncogenic variants. Furthermore, the topology of known Tyr signalling networks naturally emerged from a comparison of the sequence specificities of the Tyr kinases and the SH2 phosphotyrosine (pTyr)-binding domains. Finally we show that the intrinsic substrate specificity of Tyr kinases has remained fundamentally unchanged from worms to humans, suggesting that the fidelity between Tyr kinases and their protein substrate sequences has been maintained across hundreds of millions of years of evolution.


Asunto(s)
Fosfotirosina , Proteínas Tirosina Quinasas , Especificidad por Sustrato , Tirosina , Animales , Humanos , Secuencias de Aminoácidos , Evolución Molecular , Espectrometría de Masas , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Fosforilación , Fosfotirosina/metabolismo , Proteínas Tirosina Quinasas/efectos de los fármacos , Proteínas Tirosina Quinasas/metabolismo , Proteoma/química , Proteoma/metabolismo , Proteómica , Transducción de Señal , Dominios Homologos src , Tirosina/metabolismo , Tirosina/química
5.
Nature ; 613(7945): 759-766, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36631611

RESUMEN

Protein phosphorylation is one of the most widespread post-translational modifications in biology1,2. With advances in mass-spectrometry-based phosphoproteomics, 90,000 sites of serine and threonine phosphorylation have so far been identified, and several thousand have been associated with human diseases and biological processes3,4. For the vast majority of phosphorylation events, it is not yet known which of the more than 300 protein serine/threonine (Ser/Thr) kinases encoded in the human genome are responsible3. Here we used synthetic peptide libraries to profile the substrate sequence specificity of 303 Ser/Thr kinases, comprising more than 84% of those predicted to be active in humans. Viewed in its entirety, the substrate specificity of the kinome was substantially more diverse than expected and was driven extensively by negative selectivity. We used our kinome-wide dataset to computationally annotate and identify the kinases capable of phosphorylating every reported phosphorylation site in the human Ser/Thr phosphoproteome. For the small minority of phosphosites for which the putative protein kinases involved have been previously reported, our predictions were in excellent agreement. When this approach was applied to examine the signalling response of tissues and cell lines to hormones, growth factors, targeted inhibitors and environmental or genetic perturbations, it revealed unexpected insights into pathway complexity and compensation. Overall, these studies reveal the intrinsic substrate specificity of the human Ser/Thr kinome, illuminate cellular signalling responses and provide a resource to link phosphorylation events to biological pathways.


Asunto(s)
Fosfoproteínas , Proteínas Serina-Treonina Quinasas , Proteoma , Serina , Treonina , Humanos , Fosforilación , Proteínas Serina-Treonina Quinasas/metabolismo , Serina/metabolismo , Especificidad por Sustrato , Treonina/metabolismo , Proteoma/química , Proteoma/metabolismo , Conjuntos de Datos como Asunto , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Línea Celular , Fosfoserina/metabolismo , Fosfotreonina/metabolismo
6.
Genes Dev ; 35(21-22): 1445-1460, 2021 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-34711653

RESUMEN

Joubert syndrome (JS) is a recessive ciliopathy in which all affected individuals have congenital cerebellar vermis hypoplasia. Here, we report that CEP120, a JS-associated protein involved in centriole biogenesis and cilia assembly, regulates timely neuronal differentiation and the departure of granule neuron progenitors (GNPs) from their germinal zone during cerebellar development. Our results show that depletion of Cep120 perturbs GNP cell cycle progression, resulting in a delay of cell cycle exit in vivo. To dissect the potential mechanism, we investigated the association between CEP120 interactome and the JS database and identified KIAA0753 (a JS-associated protein) as a CEP120-interacting protein. Surprisingly, we found that CEP120 recruits KIAA0753 to centrioles, and that loss of this interaction induces accumulation of GNPs in the germinal zone and impairs neuronal differentiation. Importantly, the replenishment of wild-type CEP120 rescues the above defects, whereas expression of JS-associated CEP120 mutants, which hinder KIAA0753 recruitment, does not. Together, our data reveal a close interplay between CEP120 and KIAA0753 for the germinal zone exit and timely neuronal differentiation of GNPs during cerebellar development, and mutations in CEP120 and KIAA0753 may participate in the heterotopia and cerebellar hypoplasia observed in JS patients.


Asunto(s)
Centriolos , Enfermedades Renales Quísticas , Anomalías Múltiples , Ciclo Celular , Proteínas de Ciclo Celular/metabolismo , Centriolos/genética , Centriolos/metabolismo , Cerebelo/anomalías , Cerebelo/metabolismo , Anomalías del Ojo , Humanos , Enfermedades Renales Quísticas/genética , Enfermedades Renales Quísticas/metabolismo , Proteínas Asociadas a Microtúbulos , Retina/anomalías
7.
Proc Natl Acad Sci U S A ; 121(25): e2322588121, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38861598

RESUMEN

The nematode intestine is the primary site for nutrient uptake and storage as well as the synthesis of biomolecules; lysosome-related organelles known as gut granules are important for many of these functions. Aspects of intestine biology are not well understood, including the export of the nutrients it imports and the molecules it synthesizes, as well as the complete functions and protein content of the gut granules. Here, we report a mass spectrometry (MS)-based proteomic analysis of the intestine of the Caenorhabditis elegans and of its gut granules. Overall, we identified approximately 5,000 proteins each in the intestine and the gonad and showed that most of these proteins can be detected in samples extracted from a single worm, suggesting the feasibility of individual-level genetic analysis using proteomes. Comparing proteomes and published transcriptomes of the intestine and the gonad, we identified proteins that appear to be synthesized in the intestine and then transferred to the gonad. To identify gut granule proteins, we compared the proteome of individual intestines deficient in gut granules to the wild type. The identified gut granule proteome includes proteins known to be exclusively localized to the granules and additional putative gut granule proteins. We selected two of these putative gut granule proteins for validation via immunohistochemistry, and our successful confirmation of both suggests that our strategy was effective in identifying the gut granule proteome. Our results demonstrate the practicability of single-tissue MS-based proteomic analysis in small organisms and in its future utility.


Asunto(s)
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Lisosomas , Proteómica , Animales , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteómica/métodos , Lisosomas/metabolismo , Proteoma/metabolismo , Intestinos , Mucosa Intestinal/metabolismo , Gónadas/metabolismo , Espectrometría de Masas/métodos , Orgánulos/metabolismo
8.
Nat Chem Biol ; 20(1): 62-73, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37474759

RESUMEN

Cells interpret a variety of signals through G-protein-coupled receptors (GPCRs) and stimulate the generation of second messengers such as cyclic adenosine monophosphate (cAMP). A long-standing puzzle is deciphering how GPCRs elicit different physiological responses despite generating similar levels of cAMP. We previously showed that some GPCRs generate cAMP from both the plasma membrane and the Golgi apparatus. Here we demonstrate that cardiomyocytes distinguish between subcellular cAMP inputs to elicit different physiological outputs. We show that generating cAMP from the Golgi leads to the regulation of a specific protein kinase A (PKA) target that increases the rate of cardiomyocyte relaxation. In contrast, cAMP generation from the plasma membrane activates a different PKA target that increases contractile force. We further validated the physiological consequences of these observations in intact zebrafish and mice. Thus, we demonstrate that the same GPCR acting through the same second messenger regulates cardiac contraction and relaxation dependent on its subcellular location.


Asunto(s)
Transducción de Señal , Pez Cebra , Ratones , Animales , AMP Cíclico/metabolismo , Sistemas de Mensajero Secundario , Miocitos Cardíacos , Receptores Acoplados a Proteínas G/metabolismo
9.
PLoS Genet ; 19(5): e1010779, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37216398

RESUMEN

Integration of light and phytohormones is essential for plant growth and development. FAR-RED INSENSITIVE 219 (FIN219)/JASMONATE RESISTANT 1 (JAR1) participates in phytochrome A (phyA)-mediated far-red (FR) light signaling in Arabidopsis and is a jasmonate (JA)-conjugating enzyme for the generation of an active JA-isoleucine. Accumulating evidence indicates that FR and JA signaling integrate with each other. However, the molecular mechanisms underlying their interaction remain largely unknown. Here, the phyA mutant was hypersensitive to JA. The double mutant fin219-2phyA-211 showed a synergistic effect on seedling development under FR light. Further evidence revealed that FIN219 and phyA antagonized with each other in a mutually functional demand to modulate hypocotyl elongation and expression of light- and JA-responsive genes. Moreover, FIN219 interacted with phyA under prolonged FR light, and MeJA could enhance their interaction with CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) in the dark and FR light. FIN219 and phyA interaction occurred mainly in the cytoplasm, and they regulated their mutual subcellular localization under FR light. Surprisingly, the fin219-2 mutant abolished the formation of phyA nuclear bodies under FR light. Overall, these data identified a vital mechanism of phyA-FIN219-COP1 association in response to FR light, and MeJA may allow the photoactivated phyA to trigger photomorphogenic responses.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Fitocromo , Fitocromo A/genética , Fitocromo A/metabolismo , Hipocótilo/genética , Hipocótilo/metabolismo , Proteínas de Arabidopsis/metabolismo , Fitocromo/genética , Mutación , Regulación de la Expresión Génica de las Plantas
10.
PLoS Genet ; 19(12): e1011103, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38127821

RESUMEN

Some animals respond to injury by inducing new growth to regenerate the lost structures. This regenerative growth must be carefully controlled and constrained to prevent aberrant growth and to allow correct organization of the regenerating tissue. However, the factors that restrict regenerative growth have not been identified. Using a genetic ablation system in the Drosophila wing imaginal disc, we have identified one mechanism that constrains regenerative growth, impairment of which also leads to erroneous patterning of the final appendage. Regenerating discs with reduced levels of the RNA-regulator Brain tumor (Brat) exhibit enhanced regeneration, but produce adult wings with disrupted margins that are missing extensive tracts of sensory bristles. In these mutants, aberrantly high expression of the pro-growth factor Myc and its downstream targets likely contributes to this loss of cell-fate specification. Thus, Brat constrains the expression of pro-regeneration genes and ensures that the regenerating tissue forms the proper final structure.


Asunto(s)
Proteínas de Drosophila , Regeneración , Animales , Drosophila/genética , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Discos Imaginales/metabolismo , Regeneración/genética , Alas de Animales , Proteínas de Unión al ADN/genética
11.
Nucleic Acids Res ; 51(5): 2011-2032, 2023 03 21.
Artículo en Inglés | MEDLINE | ID: mdl-36617428

RESUMEN

Transfer RNA (tRNA) molecules are essential to decode messenger RNA codons during protein synthesis. All known tRNAs are heavily modified at multiple positions through post-transcriptional addition of chemical groups. Modifications in the tRNA anticodons are directly influencing ribosome decoding and dynamics during translation elongation and are crucial for maintaining proteome integrity. In eukaryotes, wobble uridines are modified by Elongator, a large and highly conserved macromolecular complex. Elongator consists of two subcomplexes, namely Elp123 containing the enzymatically active Elp3 subunit and the associated Elp456 hetero-hexamer. The structure of the fully assembled complex and the function of the Elp456 subcomplex have remained elusive. Here, we show the cryo-electron microscopy structure of yeast Elongator at an overall resolution of 4.3 Å. We validate the obtained structure by complementary mutational analyses in vitro and in vivo. In addition, we determined various structures of the murine Elongator complex, including the fully assembled mouse Elongator complex at 5.9 Å resolution. Our results confirm the structural conservation of Elongator and its intermediates among eukaryotes. Furthermore, we complement our analyses with the biochemical characterization of the assembled human Elongator. Our results provide the molecular basis for the assembly of Elongator and its tRNA modification activity in eukaryotes.


The multi-subunit Elongator complex mediates the addition of a carboxymethyl group to wobble uridines in eukaryotic tRNAs. This tRNA modification is crucial to preserve the integrity of cellular proteomes and to protects us against severe neurodegenerative diseases. Elongator is organized in two distinct modules (i) the larger Elp123 subcomplex that binds and modifies the suitable tRNA substrate and (ii) the smaller Elp456 subcomplex that assists the release of the modified tRNA. The presented cryo-EM structures of Elongator show that the assemblies are very dynamic and undergo conformational rearrangements at consecutive steps of the process. Last but not least, the study provides a detailed reaction scheme and shows that the architecture of Elongator is highly conserved from yeast to mammals.


Asunto(s)
Complejos Multiproteicos , Extensión de la Cadena Peptídica de Translación , Proteínas de Unión al ARN , Saccharomyces cerevisiae , Animales , Humanos , Ratones , Microscopía por Crioelectrón , Histona Acetiltransferasas/metabolismo , Unión Proteica , ARN de Transferencia/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Complejos Multiproteicos/química , Complejos Multiproteicos/ultraestructura
12.
Proc Natl Acad Sci U S A ; 119(26): e2122897119, 2022 06 28.
Artículo en Inglés | MEDLINE | ID: mdl-35700355

RESUMEN

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolves rapidly under the pressure of host immunity, as evidenced by waves of emerging variants despite effective vaccinations, highlighting the need for complementing antivirals. We report that targeting a pyrimidine synthesis enzyme restores inflammatory response and depletes the nucleotide pool to impede SARS-CoV-2 infection. SARS-CoV-2 deploys Nsp9 to activate carbamoyl-phosphate synthetase, aspartate transcarbamoylase, and dihydroorotase (CAD) that catalyzes the rate-limiting steps of the de novo pyrimidine synthesis. Activated CAD not only fuels de novo nucleotide synthesis but also deamidates RelA. While RelA deamidation shuts down NF-κB activation and subsequent inflammatory response, it up-regulates key glycolytic enzymes to promote aerobic glycolysis that provides metabolites for de novo nucleotide synthesis. A newly synthesized small-molecule inhibitor of CAD restores antiviral inflammatory response and depletes the pyrimidine pool, thus effectively impeding SARS-CoV-2 replication. Targeting an essential cellular metabolic enzyme thus offers an antiviral strategy that would be more refractory to SARS-CoV-2 genetic changes.


Asunto(s)
Antivirales , Aspartato Carbamoiltransferasa , Tratamiento Farmacológico de COVID-19 , Carbamoil-Fosfato Sintasa (Glutamina-Hidrolizante) , Dihidroorotasa , Inhibidores Enzimáticos , Pirimidinas , SARS-CoV-2 , Replicación Viral , Animales , Antivirales/farmacología , Antivirales/uso terapéutico , Aspartato Carbamoiltransferasa/antagonistas & inhibidores , Carbamoil-Fosfato Sintasa (Glutamina-Hidrolizante)/antagonistas & inhibidores , Dihidroorotasa/antagonistas & inhibidores , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/uso terapéutico , Humanos , Inflamación/tratamiento farmacológico , Ratones , Pirimidinas/antagonistas & inhibidores , Pirimidinas/biosíntesis , Proteínas de Unión al ARN/metabolismo , SARS-CoV-2/efectos de los fármacos , SARS-CoV-2/fisiología , Factor de Transcripción ReIA/metabolismo , Proteínas no Estructurales Virales/metabolismo , Replicación Viral/efectos de los fármacos
13.
J Proteome Res ; 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38832920

RESUMEN

The advancement of sophisticated instrumentation in mass spectrometry has catalyzed an in-depth exploration of complex proteomes. This exploration necessitates a nuanced balance in experimental design, particularly between quantitative precision and the enumeration of analytes detected. In bottom-up proteomics, a key challenge is that oversampling of abundant proteins can adversely affect the identification of a diverse array of unique proteins. This issue is especially pronounced in samples with limited analytes, such as small tissue biopsies or single-cell samples. Methods such as depletion and fractionation are suboptimal to reduce oversampling in single cell samples, and other improvements on LC and mass spectrometry technologies and methods have been developed to address the trade-off between precision and enumeration. We demonstrate that by using a monosubstrate protease for proteomic analysis of single-cell equivalent digest samples, an improvement in quantitative accuracy can be achieved, while maintaining high proteome coverage established by trypsin. This improvement is particularly vital for the field of single-cell proteomics, where single-cell samples with limited number of protein copies, especially in the context of low-abundance proteins, can benefit from considering analyte complexity. Considerations about analyte complexity, alongside chromatographic complexity, integration with data acquisition methods, and other factors such as those involving enzyme kinetics, will be crucial in the design of future single-cell workflows.

14.
J Biol Chem ; 299(8): 104966, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37380076

RESUMEN

tRNAs are short noncoding RNAs responsible for decoding mRNA codon triplets, delivering correct amino acids to the ribosome, and mediating polypeptide chain formation. Due to their key roles during translation, tRNAs have a highly conserved shape and large sets of tRNAs are present in all living organisms. Regardless of sequence variability, all tRNAs fold into a relatively rigid three-dimensional L-shaped structure. The conserved tertiary organization of canonical tRNA arises through the formation of two orthogonal helices, consisting of the acceptor and anticodon domains. Both elements fold independently to stabilize the overall structure of tRNAs through intramolecular interactions between the D- and T-arm. During tRNA maturation, different modifying enzymes posttranscriptionally attach chemical groups to specific nucleotides, which not only affect translation elongation rates but also restrict local folding processes and confer local flexibility when required. The characteristic structural features of tRNAs are also employed by various maturation factors and modification enzymes to assure the selection, recognition, and positioning of specific sites within the substrate tRNAs. The cellular functional repertoire of tRNAs continues to extend well beyond their role in translation, partly, due to the expanding pool of tRNA-derived fragments. Here, we aim to summarize the most recent developments in the field to understand how three-dimensional structure affects the canonical and noncanonical functions of tRNA.


Asunto(s)
Anticodón , ARN de Transferencia , Conformación de Ácido Nucleico , ARN de Transferencia/genética , ARN de Transferencia/metabolismo , Anticodón/metabolismo , Biosíntesis de Proteínas , Ribosomas/metabolismo
15.
J Neurophysiol ; 131(4): 709-722, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38478896

RESUMEN

Neurons in sensory and motor cortices tend to aggregate in clusters with similar functional properties. Within the primate dorsal ("where") pathway, an important interface between three-dimensional (3-D) visual processing and motor-related functions consists of two hierarchically organized areas: V3A and the caudal intraparietal (CIP) area. In these areas, 3-D visual information, choice-related activity, and saccade-related activity converge, often at the single-neuron level. Characterizing the clustering of functional properties in areas with mixed selectivity, such as these, may help reveal organizational principles that support sensorimotor transformations. Here we quantified the clustering of visual feature selectivity, choice-related activity, and saccade-related activity by performing correlational and parametric comparisons of the responses of well-isolated, simultaneously recorded neurons in macaque monkeys. Each functional domain showed statistically significant clustering in both areas. However, there were also domain-specific differences in the strength of clustering across the areas. Visual feature selectivity and saccade-related activity were more strongly clustered in V3A than in CIP. In contrast, choice-related activity was more strongly clustered in CIP than in V3A. These differences in clustering may reflect the areas' roles in sensorimotor processing. Stronger clustering of visual and saccade-related activity in V3A may reflect a greater role in within-domain processing, as opposed to cross-domain synthesis. In contrast, stronger clustering of choice-related activity in CIP may reflect a greater role in synthesizing information across functional domains to bridge perception and action.NEW & NOTEWORTHY The occipital and parietal cortices of macaque monkeys are bridged by hierarchically organized areas V3A and CIP. These areas support 3-D visual transformations, carry choice-related activity during 3-D perceptual tasks, and possess saccade-related activity. This study quantifies the functional clustering of neuronal response properties within V3A and CIP for each of these domains. The findings reveal domain-specific cross-area differences in clustering that may reflect the areas' roles in sensorimotor processing.


Asunto(s)
Movimientos Sacádicos , Percepción Visual , Animales , Macaca mulatta , Percepción Visual/fisiología , Neuronas/fisiología , Estimulación Luminosa/métodos
16.
Hum Mol Genet ; 31(18): 3161-3180, 2022 09 10.
Artículo en Inglés | MEDLINE | ID: mdl-35567414

RESUMEN

RTL1/PEG11, which has been associated with anxiety disorders, is a retrotransposon-derived imprinted gene in the placenta. However, imprinting patterns and functions of RTL1 in the brain have not been well-investigated. We found Rtl1 was paternally, but not maternally, expressed in brain stem, thalamus, and hypothalamus of mice, and imprinting status of RTL1 was maintained in human brain. Paternal Rtl1 knockout (Rtl1m+/p-) mice had higher neonatal death rates due to impaired suckling, and low body weights beginning on embryonic day 16.5. High paternal expression of Rtl1 was detected in the locus coeruleus (LC) and Rtl1m+/p- mice showed an increased delay in time of onset for action potentials and inward currents with decreased neuronal excitability of LC neurons. Importantly, Rtl1m+/p- mice exhibited behaviors associated with anxiety, depression, fear-related learning and memory, social dominance, and low locomotor activity. Taken together, our findings demonstrate RTL1 is imprinted in brain, mediates emotional and social behaviors, and regulates excitability in LC neurons.


Asunto(s)
Proteínas Gestacionales , Retroelementos , Animales , Ansiedad/genética , Trastornos de Ansiedad/genética , Femenino , Impresión Genómica , Humanos , Locus Coeruleus/metabolismo , Ratones , Neuronas/metabolismo , Embarazo , Proteínas Gestacionales/genética , Proteínas Gestacionales/metabolismo , Conducta Social
17.
Br J Cancer ; 130(7): 1096-1108, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38341509

RESUMEN

BACKGROUND: Pancreatic neuroendocrine tumors (PNETs) with low microvessel density and fibrosis often exhibit clinical aggressiveness. Given the contribution of cancer-associated fibroblasts (CAFs) to the hypovascular fibrotic stroma in pancreatic ductal adenocarcinoma, investigating whether CAFs play a similar role in PNETs becomes imperative. In this study, we investigated the involvement of CAFs in PNETs and their effects on clinical outcomes. METHODS: We examined 79 clinical PNET specimens to evaluate the number and spatial distribution of α-smooth muscle actin (SMA)-positive cells, which are indicative of CAFs. Then, the findings were correlated with clinical outcomes. In vitro and in vivo experiments were conducted to assess the effects of CAFs (isolated from clinical specimens) on PNET metastasis and growth. Additionally, the role of the stromal-cell-derived factor 1 (SDF1)-AGR2 axis in mediating communication between CAFs and PNET cells was investigated. RESULTS: αSMA-positive and platelet-derived growth factor-α-positive CAFs were detected in the hypovascular stroma of PNET specimens. A higher abundance of α-SMA-positive CAFs within the PNET stroma was significantly associated with a higher level of clinical aggressiveness. Notably, conditioned medium from PNET cells induced an inflammatory phenotype in isolated CAFs. These CAFs promoted PNET growth and metastasis. Mechanistically, PNET cells secreted interleukin-1, which induced the secretion of SDF1 from CAFs. This cascade subsequently elevated AGR2 expression in PNETs, thereby promoting tumor growth and metastasis. The downregulation of AGR2 in PNET cells effectively suppressed the CAF-mediated promotion of PNET growth and metastasis. CONCLUSION: CAFs drive the growth and metastasis of aggressive PNETs. The CXCR4-SDF1 axis may be a target for antistromal therapy in the treatment of PNET. This study clarifies mechanisms underlying PNET aggressiveness and may guide future therapeutic interventions targeting the tumor microenvironment.


Asunto(s)
Fibroblastos Asociados al Cáncer , Tumores Neuroectodérmicos Primitivos , Tumores Neuroendocrinos , Neoplasias Pancreáticas , Humanos , Fibroblastos Asociados al Cáncer/metabolismo , Tumores Neuroendocrinos/patología , Línea Celular Tumoral , Neoplasias Pancreáticas/patología , Tumores Neuroectodérmicos Primitivos/metabolismo , Tumores Neuroectodérmicos Primitivos/patología , Microambiente Tumoral , Fibroblastos/metabolismo , Mucoproteínas/metabolismo , Mucoproteínas/uso terapéutico , Proteínas Oncogénicas/metabolismo
18.
Biochem Biophys Res Commun ; 693: 149199, 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38118311

RESUMEN

With economic development and overnutrition, including high-fat diets (HFD) and high-glucose diets (HGD), the incidence of obesity in children is increasing, and thus, the incidence of precocious puberty is increasing. Therefore, it is of great importance to construct a suitable animal model of overnutrition-induced precocious puberty for further in-depth study. Here, we fed a HFD, HGD, or HFD combined with a HGD to pups after P-21 weaning, while weaned pups fed a normal diet served as the control group. The results showed that HFD combined with a HGD increased the body weight (BW) of weaned rat pups. In addition, a HFD, HGD, and HFD combined with a HGD lowered the age at which vaginal opening occurred and accelerated the vaginal cell cycle. Furthermore, a HFD combined with a HGD increased the weight of the uterus and ovaries of weaned rat pups. Additionally, a HFD combined with a HGD promoted the development of reproductive organs in weaned female rat pups. Ultimately, a HFD combined with a HGD was found to elevate the serum levels of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle stimulating hormone (FSH), leptin, adiponectin, and oestradiol (E2) and increase hypothalamic GnRH, Kiss-1, and GPR54 expression levels in weaned female rat pups. The current study found that overnutrition, such as that through a HFD combined with HGD, could induce precocious puberty in weaned female rat pups. In addition, a rat model of overnutrition-induced precocious puberty was established.


Asunto(s)
Obesidad Infantil , Pubertad Precoz , Humanos , Niño , Animales , Ratas , Femenino , Ratas Sprague-Dawley , Pubertad Precoz/inducido químicamente , Obesidad Infantil/complicaciones , Hormona Liberadora de Gonadotropina , Dieta Alta en Grasa/efectos adversos , Glucosa
19.
Am J Gastroenterol ; 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38084857

RESUMEN

INTRODUCTION: Despite the serious risks of diabetes with hepatitis C virus (HCV) infection, this preventable comorbidity is rarely a priority for HCV elimination. We aim to examine how a shared care model could eliminate HCV in patients with diabetes (PwD) in primary care. METHODS: There were 27 community-based Diabetes Health Promotion Institutes in each township/city of Changhua, Taiwan. PwD from these institutes from January 2018 to December 2020 were enrolled. HCV screening and treatment were integrated into diabetes structured care through collaboration between diabetes care and HCV care teams. Outcome measures included HCV care continuum indicators. Township/city variation in HCV infection prevalence and care cascades were also examined. RESULTS: Of the 10,684 eligible PwD, 9,984 (93.4%) underwent HCV screening, revealing a 6.18% (n = 617) anti-HCV seroprevalence. Among the 597 eligible seropositive individuals, 507 (84.9%) completed the RNA test, obtaining 71.8% positives. Treatment was initiated by 327 (89.8%) of 364 viremic patients, and 315 (86.5%) completed it, resulting in a final cure rate of 79.4% (n = 289). Overall, with the introduction of antivirals in this cohort, the prevalence of viremic HCV infection dropped from 4.44% to 1.34%, yielding a 69.70% (95% credible interval 63.64%-77.03%) absolute reduction. DISCUSSION: Although HCV prevalence varied, the care cascades achieved consistent results across townships/cities. We have further successfully implemented the model in county-wide hospital-based diabetes clinics, eventually treating 89.6% of the total PwD. A collaborative effort between diabetes care and HCV elimination enhanced the testing and treatment in PwD through an innovative shared care model.

20.
Small ; 20(7): e2307111, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37806755

RESUMEN

Nanodrug delivery systems have demonstrated a great potential for tumor therapy with the development of nanotechnology. Nonetheless, traditional drug delivery systems are faced with issues such as complex synthetic procedures, low reproducibility, nonspecific distribution, impenetrability of biological barrier, systemic toxicity, etc. In recent years, phage-based nanoplatforms have attracted increasing attention in tumor treatment for their regular structure, fantastic carrying property, high transduction efficiency and biosafety. Notably, therapeutic or targeting peptides can be expressed on the surface of the phages through phage display technology, enabling the phage vectors to possess multifunctions. As a result, the drug delivery efficiency on tumor will be vastly improved, thereby enhancing the therapeutic efficacy while reducing the side effects on normal tissues. Moreover, phages can overcome the hindrance of biofilm barrier to elicit antitumor effects, which exhibit great advantages compared with traditional synthetic drug delivery systems. Herein, this review not only summarizes the structure and biology of the phages, but also presents their potential as prominent nanoplatforms against tumor in different pathways to inspire the development of effective nanomedicine.


Asunto(s)
Bacteriófagos , Neoplasias , Humanos , Reproducibilidad de los Resultados , Sistemas de Liberación de Medicamentos/métodos , Neoplasias/tratamiento farmacológico , Péptidos/química
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