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1.
Cell ; 160(3): 393-406, 2015 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-25601461

RESUMEN

Colorectal cancer primarily metastasizes to the liver and globally kills over 600,000 people annually. By functionally screening 661 microRNAs (miRNAs) in parallel during liver colonization, we have identified miR-551a and miR-483 as robust endogenous suppressors of liver colonization and metastasis. These miRNAs convergently target creatine kinase, brain-type (CKB), which phosphorylates the metabolite creatine, to generate phosphocreatine. CKB is released into the extracellular space by metastatic cells encountering hepatic hypoxia and catalyzes production of phosphocreatine, which is imported through the SLC6A8 transporter and used to generate ATP­fueling metastatic survival. Combinatorial therapeutic viral delivery of miR-551a and miR-483-5p through single-dose adeno-associated viral (AAV) delivery significantly suppressed colon cancer metastasis, as did CKB inhibition with a small-molecule inhibitor. Importantly, human liver metastases express higher CKB and SLC6A8 levels and reduced miR-551a/miR-483 levels relative to primary tumors. We identify the extracellular space as an important compartment for malignant energetic catalysis and therapeutic targeting.


Asunto(s)
Neoplasias Colorrectales/metabolismo , Neoplasias Hepáticas/secundario , MicroARNs/metabolismo , Metástasis de la Neoplasia/genética , Animales , Línea Celular Tumoral , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Forma BB de la Creatina-Quinasa/metabolismo , Metabolismo Energético , Matriz Extracelular , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Hepáticas/metabolismo , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Metástasis de la Neoplasia/patología , Proteínas del Tejido Nervioso/metabolismo , Proteínas de Transporte de Neurotransmisores en la Membrana Plasmática/metabolismo
2.
Mol Cell ; 82(21): 3985-4000.e4, 2022 11 03.
Artículo en Inglés | MEDLINE | ID: mdl-36265486

RESUMEN

Alternative lengthening of telomeres (ALT), a telomerase-independent process maintaining telomeres, is mediated by break-induced replication (BIR). RAD52 promotes ALT by facilitating D-loop formation, but ALT also occurs through a RAD52-independent BIR pathway. Here, we show that the telomere non-coding RNA TERRA forms dynamic telomeric R-loops and contributes to ALT activity in RAD52 knockout cells. TERRA forms R-loops in vitro and at telomeres in a RAD51AP1-dependent manner. The formation of R-loops by TERRA increases G-quadruplexes (G4s) at telomeres. G4 stabilization enhances ALT even when TERRA is depleted, suggesting that G4s act downstream of R-loops to promote BIR. In vitro, the telomeric R-loops assembled by TERRA and RAD51AP1 generate G4s, which persist after R-loop resolution and allow formation of telomeric D-loops without RAD52. Thus, the dynamic telomeric R-loops formed by TERRA and RAD51AP1 enable the RAD52-independent ALT pathway, and G4s orchestrate an R- to D-loop switch at telomeres to stimulate BIR.


Asunto(s)
ARN Largo no Codificante , Telomerasa , Homeostasis del Telómero , Telómero/genética , Telómero/metabolismo , Telomerasa/genética , Telomerasa/metabolismo , Estructuras R-Loop/genética , Reparación del ADN
3.
Nature ; 623(7986): 397-405, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37914940

RESUMEN

Microglia are specialized brain-resident macrophages that arise from primitive macrophages colonizing the embryonic brain1. Microglia contribute to multiple aspects of brain development, but their precise roles in the early human brain remain poorly understood owing to limited access to relevant tissues2-6. The generation of brain organoids from human induced pluripotent stem cells recapitulates some key features of human embryonic brain development7-10. However, current approaches do not incorporate microglia or address their role in organoid maturation11-21. Here we generated microglia-sufficient brain organoids by coculturing brain organoids with primitive-like macrophages generated from the same human induced pluripotent stem cells (iMac)22. In organoid cocultures, iMac differentiated into cells with microglia-like phenotypes and functions (iMicro) and modulated neuronal progenitor cell (NPC) differentiation, limiting NPC proliferation and promoting axonogenesis. Mechanistically, iMicro contained high levels of PLIN2+ lipid droplets that exported cholesterol and its esters, which were taken up by NPCs in the organoids. We also detected PLIN2+ lipid droplet-loaded microglia in mouse and human embryonic brains. Overall, our approach substantially advances current human brain organoid approaches by incorporating microglial cells, as illustrated by the discovery of a key pathway of lipid-mediated crosstalk between microglia and NPCs that leads to improved neurogenesis.


Asunto(s)
Encéfalo , Colesterol , Células Madre Pluripotentes Inducidas , Microglía , Células-Madre Neurales , Neurogénesis , Organoides , Animales , Humanos , Ratones , Encéfalo/citología , Encéfalo/metabolismo , Diferenciación Celular , Células Madre Pluripotentes Inducidas/citología , Microglía/citología , Microglía/metabolismo , Organoides/citología , Organoides/metabolismo , Colesterol/metabolismo , Células-Madre Neurales/citología , Células-Madre Neurales/metabolismo , Axones , Proliferación Celular , Ésteres/metabolismo , Gotas Lipídicas/metabolismo
4.
Mol Cell ; 81(5): 1027-1042.e4, 2021 03 04.
Artículo en Inglés | MEDLINE | ID: mdl-33453166

RESUMEN

Alternative lengthening of telomeres (ALT) is mediated by break-induced replication (BIR), but how BIR is regulated at telomeres is poorly understood. Here, we show that telomeric BIR is a self-perpetuating process. By tethering PML-IV to telomeres, we induced telomere clustering in ALT-associated PML bodies (APBs) and a POLD3-dependent ATR response at telomeres, showing that BIR generates replication stress. Ablation of BLM helicase activity in APBs abolishes telomere synthesis but causes multiple chromosome bridges between telomeres, revealing a function of BLM in processing inter-telomere BIR intermediates. Interestingly, the accumulation of BLM in APBs requires its own helicase activity and POLD3, suggesting that BIR triggers a feedforward loop to further recruit BLM. Enhancing BIR induces PIAS4-mediated TRF2 SUMOylation, and PIAS4 loss deprives APBs of repair proteins and compromises ALT telomere synthesis. Thus, a BLM-driven and PIAS4-mediated feedforward loop operates in APBs to perpetuate BIR, providing a critical mechanism to extend ALT telomeres.


Asunto(s)
Proteínas del Grupo de Complementación de la Anemia de Fanconi/genética , Retroalimentación Fisiológica , Proteínas de Unión a Poli-ADP-Ribosa/genética , Proteínas Inhibidoras de STAT Activados/genética , ARN Helicasas/genética , Homeostasis del Telómero , Telómero/química , Proteína 2 de Unión a Repeticiones Teloméricas/metabolismo , Línea Celular , Línea Celular Tumoral , ADN Polimerasa III/genética , ADN Polimerasa III/metabolismo , Células Epiteliales/citología , Células Epiteliales/metabolismo , Proteínas del Grupo de Complementación de la Anemia de Fanconi/antagonistas & inhibidores , Proteínas del Grupo de Complementación de la Anemia de Fanconi/metabolismo , Fibroblastos/citología , Fibroblastos/metabolismo , Regulación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Humanos , Cuerpos de Inclusión Intranucleares/genética , Cuerpos de Inclusión Intranucleares/metabolismo , Proteínas de Unión a Poli-ADP-Ribosa/antagonistas & inhibidores , Proteínas de Unión a Poli-ADP-Ribosa/metabolismo , Proteínas Inhibidoras de STAT Activados/antagonistas & inhibidores , Proteínas Inhibidoras de STAT Activados/metabolismo , ARN Helicasas/antagonistas & inhibidores , ARN Helicasas/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Proteína Recombinante y Reparadora de ADN Rad52/genética , Proteína Recombinante y Reparadora de ADN Rad52/metabolismo , RecQ Helicasas/genética , RecQ Helicasas/metabolismo , Transducción de Señal , Sumoilación , Telómero/metabolismo , Proteína 2 de Unión a Repeticiones Teloméricas/genética
5.
Mol Cell ; 81(19): 4041-4058.e15, 2021 10 07.
Artículo en Inglés | MEDLINE | ID: mdl-34624217

RESUMEN

Deregulation of oncogenic signals in cancer triggers replication stress. Immediate early genes (IEGs) are rapidly and transiently expressed following stressful signals, contributing to an integrated response. Here, we find that the orphan nuclear receptor NR4A1 localizes across the gene body and 3' UTR of IEGs, where it inhibits transcriptional elongation by RNA Pol II, generating R-loops and accessible chromatin domains. Acute replication stress causes immediate dissociation of NR4A1 and a burst of transcriptionally poised IEG expression. Ectopic expression of NR4A1 enhances tumorigenesis by breast cancer cells, while its deletion leads to massive chromosomal instability and proliferative failure, driven by deregulated expression of its IEG target, FOS. Approximately half of breast and other primary cancers exhibit accessible chromatin domains at IEG gene bodies, consistent with this stress-regulatory pathway. Cancers that have retained this mechanism in adapting to oncogenic replication stress may be dependent on NR4A1 for their proliferation.


Asunto(s)
Neoplasias de la Mama/metabolismo , Proliferación Celular , Proteínas Inmediatas-Precoces/metabolismo , Mitosis , Células Neoplásicas Circulantes/metabolismo , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Regiones no Traducidas 3' , Animales , Antineoplásicos/farmacología , Sitios de Unión , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Proliferación Celular/efectos de los fármacos , Ensamble y Desensamble de Cromatina , Femenino , Regulación Neoplásica de la Expresión Génica , Inestabilidad Genómica , Células HEK293 , Humanos , Proteínas Inmediatas-Precoces/genética , Indoles/farmacología , Células MCF-7 , Ratones Endogámicos NOD , Ratones SCID , Mitosis/efectos de los fármacos , Células Neoplásicas Circulantes/efectos de los fármacos , Células Neoplásicas Circulantes/patología , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/antagonistas & inhibidores , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/genética , Fenilacetatos/farmacología , Proteínas Proto-Oncogénicas c-fos/genética , Proteínas Proto-Oncogénicas c-fos/metabolismo , Estructuras R-Loop , ARN Polimerasa II/genética , ARN Polimerasa II/metabolismo , Transducción de Señal , Elongación de la Transcripción Genética , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto
6.
Mol Cell ; 77(3): 514-527.e4, 2020 02 06.
Artículo en Inglés | MEDLINE | ID: mdl-31708417

RESUMEN

R loops arising during transcription induce genomic instability, but how cells respond to the R loop-associated genomic stress is still poorly understood. Here, we show that cells harboring high levels of R loops rely on the ATR kinase for survival. In response to aberrant R loop accumulation, the ataxia telangiectasia and Rad3-related (ATR)-Chk1 pathway is activated by R loop-induced reversed replication forks. In contrast to the activation of ATR by replication inhibitors, R loop-induced ATR activation requires the MUS81 endonuclease. ATR protects the genome from R loops by suppressing transcription-replication collisions, promoting replication fork recovery, and enforcing a G2/M cell-cycle arrest. Furthermore, ATR prevents excessive cleavage of reversed forks by MUS81, revealing a MUS81-triggered and ATR-mediated feedback loop that fine-tunes MUS81 activity at replication forks. These results suggest that ATR is a key sensor and suppressor of R loop-induced genomic instability, uncovering a signaling circuitry that safeguards the genome against R loops.


Asunto(s)
Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Proteínas de Unión al ADN/metabolismo , Endonucleasas/metabolismo , Estructuras R-Loop/genética , Proteínas de la Ataxia Telangiectasia Mutada/fisiología , Proteínas de Ciclo Celular/metabolismo , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/genética , Daño del ADN , Reparación del ADN , Replicación del ADN/genética , Replicación del ADN/fisiología , Proteínas de Unión al ADN/genética , Endonucleasas/genética , Inestabilidad Genómica/fisiología , Células HeLa , Humanos , Fosforilación , Proteínas Quinasas/metabolismo , Transducción de Señal
7.
Nature ; 594(7862): 283-288, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33981036

RESUMEN

Homologous recombination (HR) repairs DNA double-strand breaks (DSBs) in the S and G2 phases of the cell cycle1-3. Several HR proteins are preferentially recruited to DSBs at transcriptionally active loci4-10, but how transcription promotes HR is poorly understood. Here we develop an assay to assess the effect of local transcription on HR. Using this assay, we find that transcription stimulates HR to a substantial extent. Tethering RNA transcripts to the vicinity of DSBs recapitulates the effects of local transcription, which suggests that transcription enhances HR through RNA transcripts. Tethered RNA transcripts stimulate HR in a sequence- and orientation-dependent manner, indicating that they function by forming DNA-RNA hybrids. In contrast to most HR proteins, RAD51-associated protein 1 (RAD51AP1) only promotes HR when local transcription is active. RAD51AP1 drives the formation of R-loops in vitro and is required for tethered RNAs to stimulate HR in cells. Notably, RAD51AP1 is necessary for the DSB-induced formation of DNA-RNA hybrids in donor DNA, linking R-loops to D-loops. In vitro, RAD51AP1-generated R-loops enhance the RAD51-mediated formation of D-loops locally and give rise to intermediates that we term 'DR-loops', which contain both DNA-DNA and DNA-RNA hybrids and favour RAD51 function. Thus, at DSBs in transcribed regions, RAD51AP1 promotes the invasion of RNA transcripts into donor DNA, and stimulates HR through the formation of DR-loops.


Asunto(s)
ADN/genética , ADN/metabolismo , Recombinación Homóloga/genética , Estructuras R-Loop/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transcripción Genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Línea Celular , ADN/química , Roturas del ADN de Doble Cadena , Reparación del ADN , Proteínas de Unión al ADN/metabolismo , Genes/genética , Genes Reporteros/genética , Proteínas Fluorescentes Verdes/genética , Humanos , Técnicas In Vitro , ARN Mensajero/química , Proteínas de Unión al ARN/metabolismo , Recombinasa Rad51/metabolismo
8.
Genes Dev ; 33(1-2): 75-89, 2019 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-30567999

RESUMEN

Numerous DNA repair and signaling proteins function at DNA damage sites to protect the genome. Here, we show that fusion of the promiscuous biotin ligase BirAR118G with RAD18 leads to localized protein biotinylation at DNA damage sites, allowing identification of ZPET (zinc finger protein proximal to RAD eighteen)/ZNF280C as a potential DNA damage response (DDR) protein. ZPET binds ssDNA and localizes to DNA double-strand breaks (DSBs) and stalled replication forks. In vitro, ZPET inhibits MRE11 binding to ssDNA. In cells, ZPET delays MRE11 binding to chromatin after DSB formation and slows DNA end resection through binding ssDNA. ZPET hinders resection independently of 53BP1 and HELB. Cells lacking ZPET displayed enhanced homologous recombination (HR), accelerated replication forks under stress, and increased resistance to DSBs and PARP inhibition. These results not only reveal ZPET as an HR repressor but also suggest that localized protein biotinylation at DNA damage sites is a useful strategy to identify DDR proteins.


Asunto(s)
Biotinilación/métodos , Daño del ADN , Reparación del ADN/genética , Proteínas de Unión al ADN/metabolismo , Recombinación Homóloga/genética , Factores de Transcripción/metabolismo , Ligasas de Carbono-Nitrógeno/genética , Línea Celular , Roturas del ADN de Doble Cadena , ADN de Cadena Simple/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Escherichia coli/genética , Técnicas de Silenciamiento del Gen , Humanos , Proteína Homóloga de MRE11/metabolismo , Unión Proteica , Transporte de Proteínas/genética , Proteínas Represoras/genética , Factores de Transcripción/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo
9.
EMBO J ; 41(19): e110988, 2022 10 04.
Artículo en Inglés | MEDLINE | ID: mdl-35942625

RESUMEN

One of the hallmarks of plant senescence is the global transcriptional reprogramming coordinated by a plethora of transcription factors (TFs). However, mechanisms underlying the interactions between different TFs in modulating senescence remain obscure. Previously, we discovered that plant ABS3 subfamily MATE transporter genes regulate senescence and senescence-associated transcriptional changes. In a genetic screen for mutants suppressing the accelerated senescence phenotype of the gain-of-function mutant abs3-1D, AUXIN RESPONSE FACTOR 2 (ARF2) and PHYTOCHROME-INTERACTING FACTOR 5 (PIF5) were identified as key TFs responsible for transcriptional regulation in the ABS3-mediated senescence pathway. ARF2 and PIF5 (as well as PIF4) interact directly and function interdependently to promote senescence, and they share common target genes such as key senescence promoting genes ORESARA 1 (ORE1) and STAY-GREEN 1 (SGR1) in the ABS3-mediated senescence pathway. In addition, we discovered reciprocal regulation between ABS3-subfamily MATEs and the ARF2 and PIF5/4 TFs. Taken together, our findings reveal a regulatory paradigm in which the ARF2-PIF5/4 functional module facilitates the transcriptional reprogramming in the ABS3-mediated senescence pathway.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Fitocromo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factor V/genética , Factor V/metabolismo , Regulación de la Expresión Génica de las Plantas , Ácidos Indolacéticos/metabolismo , Fitocromo/genética , Senescencia de la Planta , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
10.
Plant Physiol ; 2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38781292

RESUMEN

Plant senescence is a highly regulated developmental program crucial for nutrient reallocation and stress adaptation in response to developmental and environmental cues. Stress-induced and age-dependent natural senescence share both overlapping and distinct molecular responses and regulatory schemes. Previously, we have utilized a carbon-deprivation (C-deprivation) senescence assay using Arabidopsis (Arabidopsis thaliana) seedlings to investigate senescence regulation. Here we conducted a comprehensive time-resolved transcriptomic analysis of Arabidopsis wild type seedlings subjected to C-deprivation treatment at multiple time points, unveiling substantial temporal changes and distinct gene expression patterns. Moreover, we identified ALTERED MERISTEM PROGRAM 1 (AMP1), encoding an endoplasmic reticulum protein, as a potential regulator of senescence based on its expression profile. By characterizing loss-of-function alleles and overexpression lines of AMP1, we confirmed its role as a negative regulator of plant senescence. Genetic analyses further revealed a synergistic interaction between AMP1 and the autophagy pathway in regulating senescence. Additionally, we discovered a functional association between AMP1 and the endosome-localized ABNORMAL SHOOT3 (ABS3)-mediated senescence pathway and positioned key senescence-promoting transcription factors downstream of AMP1. Overall, our findings shed light on the molecular intricacies of transcriptome reprogramming during C-deprivation-induced senescence and the functional interplay among endomembrane compartments in controlling plant senescence.

11.
Proc Natl Acad Sci U S A ; 119(22): e2120633119, 2022 05 31.
Artículo en Inglés | MEDLINE | ID: mdl-35605119

RESUMEN

Dysregulated epigenetic and transcriptional programming due to abnormalities of transcription factors (TFs) contributes to and sustains the oncogenicity of cancer cells. Here, we unveiled the role of zinc finger protein 280C (ZNF280C), a known DNA damage response protein, as a tumorigenic TF in colorectal cancer (CRC), required for colitis-associated carcinogenesis and Apc deficiency­driven intestinal tumorigenesis in mice. Consistently, ZNF280C silencing in human CRC cells inhibited proliferation, clonogenicity, migration, xenograft growth, and liver metastasis. As a C2H2 (Cys2-His2) zinc finger-containing TF, ZNF280C occupied genomic intervals with both transcriptionally active and repressive states and coincided with CCCTC-binding factor (CTCF) and cohesin binding. Notably, ZNF280C was crucial for the repression program of trimethylation of histone H3 at lysine 27 (H3K27me3)-marked genes and the maintenance of both focal and broad H3K27me3 levels. Mechanistically, ZNF280C counteracted CTCF/cohesin activities and condensed the chromatin environment at the cis elements of certain tumor suppressor genes marked by H3K27me3, at least partially through recruiting the epigenetic repressor structural maintenance of chromosomes flexible hinge domain-containing 1 (SMCHD1). In clinical relevance, ZNF280C was highly expressed in primary CRCs and distant metastases, and a higher ZNF280C level independently predicted worse prognosis of CRC patients. Thus, our study uncovered a contributor with good prognostic value to CRC pathogenesis and also elucidated the essence of DNA-binding TFs in orchestrating the epigenetic programming of gene regulation.


Asunto(s)
Cromatina , Neoplasias Colorrectales , Represión Epigenética , Factor de Unión a CCCTC/metabolismo , Carcinogénesis/genética , Cromatina/genética , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Proteínas de Unión al ADN , Histonas/genética , Histonas/metabolismo , Humanos , Pronóstico , Factores de Transcripción , Dedos de Zinc
12.
Proc Natl Acad Sci U S A ; 119(30): e2203556119, 2022 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-35867832

RESUMEN

Skin microbiome sampling is currently performed with tools such as swabs and tape strips to collect microbes from the skin surface. However, these conventional approaches may be unable to detect microbes deeper in the epidermis or in epidermal invaginations. We describe a sampling tool with a depth component, a transepidermal microprojection array (MPA), which captures microbial biomass from both the epidermal surface and deeper skin layers. We leveraged the rapid customizability of 3D printing to enable systematic optimization of MPA for human skin sampling. Evaluation of sampling efficacy on human scalp revealed the optimized MPA was comparable in sensitivity to swab and superior to tape strip, especially for nonstandard skin surfaces. We observed differences in species diversity, with the MPA detecting clinically relevant fungi more often than other approaches. This work delivers a tool in the complex field of skin microbiome sampling to potentially address gaps in our understanding of its role in health and disease.


Asunto(s)
Epidermis , Microbiota , Impresión Tridimensional , Manejo de Especímenes , Análisis de Matrices Tisulares , Epidermis/microbiología , Humanos , Manejo de Especímenes/métodos
13.
J Am Chem Soc ; 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39008121

RESUMEN

Hemoproteins have recently emerged as powerful biocatalysts for new-to-nature carbene transfer reactions. Despite this progress, these strategies have remained largely limited to diazo-based carbene precursor reagents. Here, we report the development of a biocatalytic strategy for the stereoselective construction of pyridine-functionalized cyclopropanes via the hemoprotein-mediated activation of pyridotriazoles (PyTz) as stable and readily accessible carbene sources. This method enables the asymmetric cyclopropanation of a variety of olefins, including electron-rich and electrodeficient ones, with high activity, high stereoselectivity, and enantiodivergent selectivity, providing access to mono- and diarylcyclopropanes that incorporate a pyridine moiety and thus two structural motifs of high value in medicinal chemistry. Mechanistic studies reveal a multifaceted role of 7-halogen substitution in the pyridotriazole reagent toward favoring multiple catalytic steps in the transformation. This work provides the first example of asymmetric olefin cyclopropanation with pyridotriazoles, paving the way to the exploitation of these attractive and versatile reagents for enzyme-catalyzed carbene-mediated reactions.

14.
Breast Cancer Res ; 26(1): 115, 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38978071

RESUMEN

Various histopathological, clinical and imaging parameters have been evaluated to identify a subset of women diagnosed with lesions with uncertain malignant potential (B3 or BIRADS 3/4A lesions) who could safely be observed rather than being treated with surgical excision, with little impact on clinical practice. The primary reason for surgery is to rule out an upgrade to either ductal carcinoma in situ or invasive breast cancer, which occurs in up to 30% of patients. We hypothesised that the stromal immune microenvironment could indicate the presence of carcinoma associated with a ductal B3 lesion and that this could be detected in biopsies by counting lymphocytes as a predictive biomarker for upgrade. A higher number of lymphocytes in the surrounding specialised stroma was observed in upgraded ductal and papillary B3 lesions than non-upgraded (p < 0.01, negative binomial model, n = 307). We developed a model using lymphocytes combined with age and the type of lesion, which was predictive of upgrade with an area under the curve of 0.82 [95% confidence interval 0.77-0.87]. The model can identify some patients at risk of upgrade with high sensitivity, but with limited specificity. Assessing the tumour microenvironment including stromal lymphocytes may contribute to reducing unnecessary surgeries in the clinic, but additional predictive features are needed.


Asunto(s)
Neoplasias de la Mama , Linfocitos , Células del Estroma , Microambiente Tumoral , Humanos , Femenino , Neoplasias de la Mama/patología , Neoplasias de la Mama/inmunología , Microambiente Tumoral/inmunología , Persona de Mediana Edad , Anciano , Linfocitos/inmunología , Linfocitos/patología , Células del Estroma/patología , Adulto , Clasificación del Tumor , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/metabolismo , Carcinoma Intraductal no Infiltrante/patología , Carcinoma Intraductal no Infiltrante/inmunología , Carcinoma Ductal de Mama/patología , Carcinoma Ductal de Mama/inmunología , Biomarcadores de Tumor
15.
Anal Chem ; 96(17): 6784-6793, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38632870

RESUMEN

Hepatitis B virus (HBV) is a major cause of liver cirrhosis and hepatocellular carcinoma, with HBV surface antigen (HBsAg) being a crucial marker in the clinical detection of HBV. Due to the significant harm and ease of transmission associated with HBV, HBsAg testing has become an essential part of preoperative assessments, particularly for emergency surgeries where healthcare professionals face exposure risks. Therefore, a timely and accurate detection method for HBsAg is urgently needed. In this study, a surface-enhanced Raman scattering (SERS) sensor with a sandwich structure was developed for HBsAg detection. Leveraging the ultrasensitive and rapid detection capabilities of SERS, this sensor enables quick detection results, significantly reducing waiting times. By systematically optimizing critical factors in the detection process, such as the composition and concentration of the incubation solution as well as the modification conditions and amount of probe particles, the sensitivity of the SERS immune assay system was improved. Ultimately, the sensor achieved a sensitivity of 0.00576 IU/mL within 12 min, surpassing the clinical requirement of 0.05 IU/mL by an order of magnitude. In clinical serum assay validation, the issue of false positives was effectively addressed by adding a blocker. The final sensor demonstrated 100% specificity and sensitivity at the threshold of 0.05 IU/mL. Therefore, this study not only designed an ultrasensitive SERS sensor for detecting HBsAg in actual clinical serum samples but also provided theoretical support for similar systems, filling the knowledge gap in existing literature.


Asunto(s)
Antígenos de Superficie de la Hepatitis B , Espectrometría Raman , Antígenos de Superficie de la Hepatitis B/sangre , Espectrometría Raman/métodos , Humanos , Virus de la Hepatitis B/aislamiento & purificación , Nanopartículas del Metal/química , Hepatitis B/sangre , Hepatitis B/diagnóstico , Propiedades de Superficie , Límite de Detección
16.
BMC Plant Biol ; 24(1): 64, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38262910

RESUMEN

BACKGROUND: Corynespora leaf spot is a common leaf disease occurring in sesame, and the disease causes leaf yellowing and even shedding, which affects the growth quality of sesame. At present, the mechanism of sesame resistance to this disease is still unclear. Understanding the resistance mechanism of sesame to Corynespora leaf spot is highly important for the control of infection. In this study, the leaves of the sesame resistant variety (R) and the sesame susceptible variety (S) were collected at 0-48 hpi for transcriptome sequencing, and used a combined third-generation long-read and next-generation short-read technology approach to identify some key genes and main pathways related to resistance. RESULTS: The gene expression levels of the two sesame varieties were significantly different at 0, 6, 12, 24, 36 and 48 hpi, indicating that the up-regulation of differentially expressed genes in the R might enhanced the resistance. Moreover, combined with the phenotypic observations of sesame leaves inoculated at different time points, we found that 12 hpi was the key time point leading to the resistance difference between the two sesame varieties at the molecular level. The WGCNA identified two modules significantly associated with disease resistance, and screened out 10 key genes that were highly expressed in R but low expressed in S, which belonged to transcription factors (WRKY, AP2/ERF-ERF, and NAC types) and protein kinases (RLK-Pelle_DLSV, RLK-Pelle_SD-2b, and RLK-Pelle_WAK types). These genes could be the key response factors in the response of sesame to infection by Corynespora cassiicola. GO and KEGG enrichment analysis showed that specific modules could be enriched, which manifested as enrichment in biologically important pathways, such as plant signalling hormone transduction, plant-pathogen interaction, carbon metabolism, phenylpropanoid biosynthesis, glutathione metabolism, MAPK and other stress-related pathways. CONCLUSIONS: This study provides an important resource of genes contributing to disease resistance and will deepen our understanding of the regulation of disease resistance, paving the way for further molecular breeding of sesame.


Asunto(s)
Ascomicetos , Sesamum , Resistencia a la Enfermedad , RNA-Seq , Transcriptoma , Reguladores del Crecimiento de las Plantas
17.
Small ; 20(4): e2305877, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37718437

RESUMEN

The precise design of low-cost, efficient, and definite electrocatalysts is the key to sustainable renewable energy. The urea oxidation reaction (UOR) offers a promising alternative to the oxygen evolution reaction for energy-saving hydrogen generation. In this study, by tuning the lattice expansion, a series of M-FeNi layered double hydroxides (M-FeNi LDHs, M: Mo, Mn, V) with excellent UOR performance are synthesized. The hydrolytic transformation of Fe-MIL-88A is assisted by urea, Ni2+ and high-valence metals, to form a hollow M-FeNi LDH. Owing to the large atomic radius of the high-valence metal, lattice expansion is induced, and the electronic structure of the FeNi-LDH is regulated. Doping with high-valence metal is more favorable for the formation of the high-valence active species, NiOOH, for the UOR. Moreover, the hollow spindle structure promoted mass transport. Thus, the optimal Mo-FeNi LDH showed outstanding UOR electrocatalytic activity, with 1.32 V at 10 mA cm-2 . Remarkably, the Pt/C||Mo-FeNi LDH catalyst required a cell voltage of 1.38 V at 10 mA·cm-2 in urea-assisted water electrolysis. This study suggests a new direction for constructing nanostructures and modulating electronic structures, which is expected to ultimately lead to the development of a class of auxiliary electrocatalysts.

18.
Chembiochem ; : e202400128, 2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38842537

RESUMEN

Amid the bourgeoning demand for in-silico designed, environmentally sustainable, and highly effective hair care formulations, a growing interest is evident in the exploration of realistic computational model for the hair surface. In this work, we present an atomistic model for the outermost layer of the hair surface derived through molecular dynamics simulations, which comprises 18-Methyleicosanoic acid (18-MEA) fatty acid chains covalently bound onto the keratin-associated protein 10-4 (KAP10-4) at a spacing distance of ~1 nm. Remarkably, this hair surface model facilitates the inclusion of free fatty acids (free 18-MEA) into the gaps between chemically bound 18-MEA chains, up to a maximum number that results in a packing density of 0.22 nm2 per fatty acid molecule, consistent with the optimal spacing identified through free energy analysis. Atomistic insights are provided for the organization of fatty acid chains, structural features, and interaction energies on protein-inclusive hair surface models with varying amounts of free 18-MEA (FMEA) depletion, as well as varying degrees of anionic cysteic acid from damaged bound 18-MEA (BMEA), under both dry and wet conditions. In the presence of FMEA and water, the fatty acid chains in a pristine hair surface prefers to adopt a thermodynamically favored extended chain conformation, forming a thicker protective layer (~3 nm) on the protein surface. Our simulation results reveal that, while the depletion of FMEA can induce a pronounced impact on the thickness, tilt angle, and order parameters of fatty acid chains, the removal of BMEA has a marked effect on water penetration. There is a "sweet spot" spacing between the 18-MEA whereby damaged hair surface properties can be reinstated by replenishing FMEA. Through the incorporation of the protein layer and free fatty acids, the hair surface models presented in this study enables a realistic representation of the intricate details within the hair epicuticle, facilitating a molecular scale assessment of surface properties during the formulation design process.

19.
J Med Virol ; 96(5): e29635, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38682660

RESUMEN

Guangzhou has been the city most affected by the dengue virus (DENV) in China, with a predominance of DENV serotype 1 (DENV-1). Viral factors such as dengue serotype and genotype are associated with severe dengue (SD). However, none of the studies have investigated the relationship between DENV-1 genotypes and SD. To understand the association between DENV-1 genotypes and SD, the clinical manifestations of patients infected with different genotypes were investigated. A total of 122 patients with confirmed DENV-1 genotype infection were recruited for this study. The clinical manifestations, laboratory tests, and levels of inflammatory mediator factors were statistically analyzed to investigate the characteristics of clinical manifestations and immune response on the DENV-1 genotype. In the case of DENV-1 infection, the incidence of SD with genotype V infection was significantly higher than that with genotype I infection. Meanwhile, patients infected with genotype V were more common in ostealgia and bleeding significantly. In addition, levels of inflammatory mediator factors including IFN-γ, TNF-α, IL-10, and soluble vascular cell adhesion molecule 1 were higher in patients with SD infected with genotype V. Meanwhile, the concentrations of regulated upon activation normal T-cell expressed and secreted and growth-related gene alpha were lower in patients with SD infected with genotype V. The higher incidence of SD in patients infected with DENV-1 genotype V may be attributed to elevated cytokines and adhesion molecules, along with decreased chemokines.


Asunto(s)
Virus del Dengue , Genotipo , Serogrupo , Dengue Grave , Humanos , Virus del Dengue/genética , Virus del Dengue/clasificación , China/epidemiología , Masculino , Femenino , Adulto , Persona de Mediana Edad , Dengue Grave/virología , Dengue Grave/epidemiología , Adulto Joven , Citocinas/sangre , Adolescente , Anciano , Incidencia , Niño , Dengue/virología , Dengue/epidemiología
20.
Histopathology ; 84(4): 577-586, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37991396

RESUMEN

In recent years anatomical pathology has been revolutionised by the incorporation of molecular findings into routine diagnostic practice, and in some diseases the presence of specific molecular alterations are now essential for diagnosis. Spatial transcriptomics describes a group of technologies that provide up to transcriptome-wide expression profiling while preserving the spatial origin of the data, with many of these technologies able to provide these data using a single tissue section. Spatial transcriptomics allows expression profiling of highly specific areas within a tissue section potentially to subcellular resolution, and allows correlation of expression data with morphology, tissue type and location relative to other structures. While largely still research laboratory-based, several spatial transcriptomics methods have now achieved compatibility with formalin-fixed paraffin-embedded tissue (FFPE), allowing their use in diagnostic tissue samples, and with further development potentially leading to their incorporation in routine anatomical pathology practice. This mini review provides an overview of spatial transcriptomics methods, with an emphasis on platforms compatible with FFPE tissue, approaches to assess the data and potential applications in anatomical pathology practice.


Asunto(s)
Perfilación de la Expresión Génica , Patólogos , Humanos , Adhesión en Parafina/métodos , Perfilación de la Expresión Génica/métodos , Transcriptoma , Formaldehído/metabolismo
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