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1.
Nat Immunol ; 21(4): 477-478, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32099101

RESUMEN

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

2.
Nat Immunol ; 20(12): 1621-1630, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31740800

RESUMEN

Interferon-γ (IFN-γ) is essential for the innate immune response to intracellular bacteria. Noncoding RNAs and RNA-binding proteins (RBPs) need to be further considered in studies of regulation of the IFN-γ-activated signaling pathway in macrophages. In the present study, we found that the microRNA miR-1 promoted IFN-γ-mediated clearance of Listeria monocytogenes in macrophages by indirectly stabilizing the Stat1 messenger RNA through the degradation of the cytoplasmic long noncoding RNA Sros1. Inducible degradation or genetic loss of Sros1 led to enhanced IFN-γ-dependent activation of the innate immune response. Mechanistically, Sros1 blocked the binding of Stat1 mRNA to the RBP CAPRIN1, which stabilized the Stat1 mRNA and, consequently, promoted IFN-γ-STAT1-mediated innate immunity. These observations shed light on the complex RNA-RNA regulatory networks involved in cytokine-initiated innate responses in host-pathogen interactions.


Asunto(s)
Citoplasma/metabolismo , Listeria monocytogenes/fisiología , Listeriosis/inmunología , Macrófagos/inmunología , ARN Largo no Codificante/genética , ARN Mensajero/genética , Factor de Transcripción STAT1/metabolismo , Animales , Proteínas de Ciclo Celular/metabolismo , Inmunidad Innata , Interferón gamma/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , MicroARNs/genética , Unión Proteica , Células RAW 264.7 , Estabilidad del ARN , ARN Largo no Codificante/metabolismo , Factor de Transcripción STAT1/genética
3.
EMBO J ; 43(1): 61-86, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38177310

RESUMEN

Accumulation of DNA damage in the lung induces cellular senescence and promotes age-related diseases such as idiopathic pulmonary fibrosis (IPF). Hence, understanding the mechanistic regulation of DNA damage repair is important for anti-aging therapies and disease control. Here, we identified an m6A-independent role of the RNA-binding protein YTHDC1 in counteracting stress-induced pulmonary senescence and fibrosis. YTHDC1 is primarily expressed in pulmonary alveolar epithelial type 2 (AECII) cells and its AECII expression is significantly decreased in AECIIs during fibrosis. Exogenous overexpression of YTHDC1 alleviates pulmonary senescence and fibrosis independent of its m6A-binding ability, while YTHDC1 deletion enhances disease progression in mice. Mechanistically, YTHDC1 promotes the interaction between TopBP1 and MRE11, thereby activating ATR and facilitating DNA damage repair. These findings reveal a noncanonical function of YTHDC1 in delaying cellular senescence, and suggest that enhancing YTHDC1 expression in the lung could be an effective treatment strategy for pulmonary fibrosis.


Asunto(s)
Senescencia Celular , Fibrosis Pulmonar Idiopática , Proteínas del Tejido Nervioso , Factores de Empalme de ARN , Animales , Ratones , Envejecimiento/genética , Fibrosis Pulmonar Idiopática/genética , Fibrosis Pulmonar Idiopática/inducido químicamente , Fibrosis Pulmonar Idiopática/metabolismo , Pulmón/metabolismo , Factores de Empalme de ARN/metabolismo , Proteínas del Tejido Nervioso/metabolismo
4.
Mol Cell ; 79(3): 425-442.e7, 2020 08 06.
Artículo en Inglés | MEDLINE | ID: mdl-32615088

RESUMEN

Double-strand breaks (DSBs) are the most deleterious DNA lesions, which, if left unrepaired, may lead to genome instability or cell death. Here, we report that, in response to DSBs, the RNA methyltransferase METTL3 is activated by ATM-mediated phosphorylation at S43. Phosphorylated METTL3 is then localized to DNA damage sites, where it methylates the N6 position of adenosine (m6A) in DNA damage-associated RNAs, which recruits the m6A reader protein YTHDC1 for protection. In this way, the METTL3-m6A-YTHDC1 axis modulates accumulation of DNA-RNA hybrids at DSBs sites, which then recruit RAD51 and BRCA1 for homologous recombination (HR)-mediated repair. METTL3-deficient cells display defective HR, accumulation of unrepaired DSBs, and genome instability. Accordingly, depletion of METTL3 significantly enhances the sensitivity of cancer cells and murine xenografts to DNA damage-based therapy. These findings uncover the function of METTL3 and YTHDC1 in HR-mediated DSB repair, which may have implications for cancer therapy.


Asunto(s)
Adenosina/análogos & derivados , Neoplasias de Cabeza y Cuello/genética , Metiltransferasas/genética , Proteínas del Tejido Nervioso/genética , Factores de Empalme de ARN/genética , Reparación del ADN por Recombinación/efectos de los fármacos , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Adenosina/metabolismo , Animales , Antibióticos Antineoplásicos/farmacología , Proteínas de la Ataxia Telangiectasia Mutada/genética , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Bleomicina/farmacología , Línea Celular Tumoral , ADN/genética , ADN/metabolismo , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Células Epiteliales/patología , Femenino , Células HEK293 , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/mortalidad , Neoplasias de Cabeza y Cuello/patología , Humanos , Metiltransferasas/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Proteínas del Tejido Nervioso/metabolismo , Hibridación de Ácido Nucleico , Osteoblastos/efectos de los fármacos , Osteoblastos/metabolismo , Osteoblastos/patología , Fosforilación , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Factores de Empalme de ARN/metabolismo , Recombinasa Rad51/genética , Recombinasa Rad51/metabolismo , Ribonucleasa H/genética , Ribonucleasa H/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/tratamiento farmacológico , Carcinoma de Células Escamosas de Cabeza y Cuello/mortalidad , Carcinoma de Células Escamosas de Cabeza y Cuello/patología , Análisis de Supervivencia , Ensayos Antitumor por Modelo de Xenoinjerto
5.
Mol Cell ; 75(6): 1188-1202.e11, 2019 09 19.
Artículo en Inglés | MEDLINE | ID: mdl-31399345

RESUMEN

The maternal-to-zygotic transition (MZT) is a conserved and fundamental process during which the maternal environment is converted to an environment of embryonic-driven development through dramatic reprogramming. However, how maternally supplied transcripts are dynamically regulated during MZT remains largely unknown. Herein, through genome-wide profiling of RNA 5-methylcytosine (m5C) modification in zebrafish early embryos, we found that m5C-modified maternal mRNAs display higher stability than non-m5C-modified mRNAs during MZT. We discovered that Y-box binding protein 1 (Ybx1) preferentially recognizes m5C-modified mRNAs through π-π interactions with a key residue, Trp45, in Ybx1's cold shock domain (CSD), which plays essential roles in maternal mRNA stability and early embryogenesis of zebrafish. Together with the mRNA stabilizer Pabpc1a, Ybx1 promotes the stability of its target mRNAs in an m5C-dependent manner. Our study demonstrates an unexpected mechanism of RNA m5C-regulated maternal mRNA stabilization during zebrafish MZT, highlighting the critical role of m5C mRNA modification in early development.


Asunto(s)
5-Metilcitosina/metabolismo , Embrión no Mamífero/embriología , Desarrollo Embrionario/fisiología , Estabilidad del ARN/fisiología , ARN Mensajero Almacenado/metabolismo , Pez Cebra/embriología , Animales , Células HeLa , Humanos , Ratones , ARN Mensajero Almacenado/genética , Pez Cebra/genética
6.
Proc Natl Acad Sci U S A ; 121(30): e2405160121, 2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-38976765

RESUMEN

Due to the scarcity of rock samples, the Hadean Era predating 4 billion years ago (Ga) poses challenges in understanding geological processes like subaerial weathering and plate tectonics that are critical for the evolution of life. The Jack Hills zircon from Western Australia, the primary Hadean samples available, offer valuable insights into magma sources and tectonic genesis through trace element signatures. However, a consensus on these signatures has not been reached. To address this, we developed a machine learning classifier capable of deciphering the geochemical fingerprints of zircon. This allowed us to identify the oldest detrital zircon originating from sedimentary-derived "S-type" granites. Our results indicate the presence of S-type granites as early as 4.24 Ga, persisting throughout the Hadean into the Archean. Examining global detrital zircon across Earth's history reveals consistent supercontinent-like cycles from the present back to the Hadean. These findings suggest that a significant amount of Hadean continental crust was exposed, weathered into sediments, and incorporated into the magma sources of Jack Hills zircon. Only the early operation of both subaerial weathering and plate subduction can account for the prevalence of S-type granites we observe. Additionally, the periodic evolution of S-type granite proportions implies that subduction-driven tectonic cycles were active during the Hadean, at least around 4.2 Ga. The evidence thus points toward an early Earth resembling the modern Earth in terms of active tectonics and habitable surface conditions. This suggests the potential for life to originate in environments like warm ponds rather than extreme hydrothermal settings.

7.
PLoS Genet ; 19(9): e1010937, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37756323

RESUMEN

Telomeric repeat-containing RNA (TERRA) is a class of long noncoding RNAs (lncRNAs) that are transcribed from subtelomeric to telomeric region of chromosome ends. TERRA is prone to form R-loop structures at telomeres by invading into telomeric DNA. Excessive telomere R-loops result in telomere instability, so the TERRA level needs to be delicately modulated. However, the molecular mechanisms and factors controlling TERRA level are still largely unknown. In this study, we report that the RNA binding protein RBMX is a novel regulator of TERRA level and telomere integrity. The expression level of TERRA is significantly elevated in RBMX depleted cells, leading to enhanced telomere R-loop formation, replication stress, and telomere instability. We also found that RBMX binds to TERRA and the nuclear exosome targeting protein ZCCHC8 simultaneously, and that TERRA degradation slows down upon RBMX depletion, implying that RBMX promotes TERRA degradation by regulating its transportation to the nuclear exosome, which decays nuclear RNAs. Altogether, these findings uncover a new role of RBMX in TERRA expression regulation and telomere integrity maintenance, and raising RBMX as a potential target of cancer therapy.


Asunto(s)
Exosomas , ARN Largo no Codificante , Exosomas/genética , Heterocromatina , Proteínas Nucleares , ARN Largo no Codificante/genética , Telómero/genética , Humanos
8.
PLoS Genet ; 19(7): e1010856, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37463174

RESUMEN

Premature telomere shortening is a known factor correlated to idiopathic pulmonary fibrosis (IPF) occurrence, which is a chronic, progressive, age-related disease with high mortality. The etiology of IPF is still unknown. Here, we found that UBQLN1 plays a key role in telomere length maintenance and is potentially relevant to IPF. UBQLN1 involves in DNA replication by interacting with RPA1 and shuttling it off from the replication fork. The deficiency of UBQLN1 retains RPA1 at replication fork, hinders replication and thus causes cell cycle arrest and genome instability. Especially at telomere regions of the genome, where more endogenous replication stress exists because of G rich sequences, UBQLN1 depletion leads to rapid telomere shortening in HeLa cells. It revealed that UBQLN1 depletion also shortens telomere length at mouse lung and accelerates mouse lung fibrosis. In addition, the UBQLN1 expression level in IPF patients is downregulated and correlated to poor prognosis. Altogether, these results uncover a new role of UBQLN1 in ensuring DNA replication and maintaining telomere stability, which may shed light on IPF pathogenesis and prevention.


Asunto(s)
Fibrosis Pulmonar Idiopática , Acortamiento del Telómero , Humanos , Animales , Ratones , Acortamiento del Telómero/genética , Células HeLa , Fibrosis Pulmonar Idiopática/genética , Fibrosis Pulmonar Idiopática/epidemiología , Fibrosis Pulmonar Idiopática/patología , Homeostasis del Telómero , Telómero/genética , Proteína de Replicación A/genética , Proteínas Relacionadas con la Autofagia/genética , Proteínas Adaptadoras Transductoras de Señales/genética
9.
Eur J Immunol ; 54(3): e2350836, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38234007

RESUMEN

T lymphocytes are pivotal in adaptive immunity. The role of the trafficking protein particle complex (TRAPPC) in regulating T-cell development and homeostasis is unknown. Using CD4cre -Trappc1flox/flox (Trappc1 cKO) mice, we found that Trappc1 deficiency in T cells significantly decreased cell number of naive T cells in the periphery, whereas thymic T-cell development in Trappc1 cKO mice was identical as WT mice. In the culture assays and mouse models with adoptive transfer of the sorted WT (CD45.1+ CD45.2+ ) and Trappc1 cKO naive T cells (CD45.2+ ) to CD45.1+ syngeneic mice, Trappc1-deficient naive T cells showed significantly reduced survival ability compared with WT cells. RNA-seq and molecular studies showed that Trappc1 deficiency in naive T cells reduced protein transport from the endoplasmic reticulum to the Golgi apparatus, enhanced unfolded protein responses, increased P53 transcription, intracellular Ca2+ , Atf4-CHOP, oxidative phosphorylation, and lipid peroxide accumulation, and subsequently led to ferroptosis. Trappc1 deficiency in naive T cells increased ferroptosis-related damage-associated molecular pattern molecules like high mobility group box 1 or lipid oxidation products like prostaglandin E2, leukotriene B4, leukotriene C4, and leukotriene D4. Functionally, the culture supernatant of Trappc1 cKO naive T cells significantly promoted neutrophils to express inflammatory cytokines like TNFα and IL-6, which was rescued by lipid peroxidation inhibitor Acetylcysteine. Importantly, Trappc1 cKO mice spontaneously developed severe autoinflammatory disease 4 weeks after birth. Thus, intrinsic expression of Trappc1 in naive T cells plays an integral role in maintaining T-cell homeostasis to avoid proinflammatory naive T-cell death-caused autoinflammatory syndrome in mice. This study highlights the importance of the TRAPPC in T-cell biology.


Asunto(s)
Ferroptosis , Enfermedades Autoinflamatorias Hereditarias , Ratones , Animales , Linfocitos T , Ratones Noqueados , Diferenciación Celular
10.
Nat Chem Biol ; 19(12): 1532-1539, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37828399

RESUMEN

Terpenoids are the most diverse group of specialized metabolites with numerous applications. Their biosynthesis is based on the five-carbon isoprene building block and, as a result, almost all terpenoids isolated to date are based on backbones that contain multiples of five carbon atoms. Intrigued by the discovery of an unusual bacterial terpenoid with a 16-carbon skeleton, here we investigate whether the biosynthesis of 16-carbon terpenoids is more widespread than this single example. We mine bacterial genomic information and identify potential C16 biosynthetic clusters in more than 700 sequenced genomes. We study selected clusters using a yeast synthetic biology platform and reveal that the encoded synthases produce at least 47 different noncanonical terpenoids. By thorough chemical analysis, we explain the structures of 13 C16 metabolites, most of which possess intricate highly strained bi- and tricyclic backbones. Our results unveil the existence of an extensive class of terpenoids in bacteria.


Asunto(s)
Bacterias , Terpenos , Terpenos/metabolismo , Bacterias/genética , Bacterias/metabolismo , Saccharomyces cerevisiae/genética , Biología Sintética/métodos
11.
EMBO Rep ; 24(2): e55503, 2023 02 06.
Artículo en Inglés | MEDLINE | ID: mdl-36440617

RESUMEN

Myeloid cell development in bone marrow is essential for the maintenance of peripheral immune homeostasis. However, the role of intracellular protein trafficking pathways during myeloid cell differentiation is currently unknown. By mining bioinformatics data, we identify trafficking protein particle complex subunit 1 (TRAPPC1) as continuously upregulated during myeloid cell development. Using inducible ER-TRAPPC1 knockout mice and bone marrow chimeric mouse models, we demonstrate that TRAPPC1 deficiency causes severe monocyte and neutrophil defects, accompanied by a selective decrease in common myeloid progenitors (CMPs) and subsequent cell subsets in bone marrow. TRAPPC1-deleted CMPs differentiate poorly into monocytes and neutrophils in vivo and in vitro, in addition to exhibiting enhanced endoplasmic reticulum stress and apoptosis via a Ca2+ -mitochondria-dependent pathway. Cell cycle arrest and senescence of TRAPPC1-deleted CMPs are mediated by the activation of pancreatic endoplasmic reticulum kinase and the upregulation of cyclin-dependent kinase inhibitor p21. This study reveals the essential role of TRAPPC1 in the maintenance and differentiation of CMPs and highlights the significance of protein processing and trafficking processes in myeloid cell development.


Asunto(s)
Médula Ósea , Células Progenitoras Mieloides , Proteínas de Transporte Vesicular , Animales , Ratones , Médula Ósea/metabolismo , Diferenciación Celular , Ratones Noqueados , Monocitos , Células Progenitoras Mieloides/metabolismo , Neutrófilos , Proteínas de Transporte Vesicular/metabolismo
12.
Chromosome Res ; 32(2): 5, 2024 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-38502277

RESUMEN

Artemisia is a large genus encompassing about 400 diverse species, many of which have considerable medicinal and ecological value. However, complex morphological information and variation in ploidy level and nuclear DNA content have presented challenges for evolution studies of this genus. Consequently, taxonomic inconsistencies within the genus persist, hindering the utilization of such large plant resources. Researchers have utilized satellite DNAs to aid in chromosome identification, species classification, and evolutionary studies due to their significant sequence and copy number variation between species and close relatives. In the present study, the RepeatExplorer2 pipeline was utilized to identify 10 satellite DNAs from three species (Artemisia annua, Artemisia vulgaris, Artemisia viridisquama), and fluorescence in situ hybridization confirmed their distribution on chromosomes in 24 species, including 19 Artemisia species with 5 outgroup species from Ajania and Chrysanthemum. Signals of satellite DNAs exhibited substantial differences between species. We obtained one genus-specific satellite from the sequences. Additionally, molecular cytogenetic maps were constructed for Artemisia vulgaris, Artemisia leucophylla, and Artemisia viridisquama. One species (Artemisia verbenacea) showed a FISH distribution pattern suggestive of an allotriploid origin. Heteromorphic FISH signals between homologous chromosomes in Artemisia plants were observed at a high level. Additionally, the relative relationships between species were discussed by comparing ideograms. The results of the present study provide new insights into the accurate identification and taxonomy of the Artemisia genus using molecular cytological methods.


Asunto(s)
Artemisia , Artemisia/genética , Hibridación Fluorescente in Situ , Filogenia , ADN Satélite/genética , Variaciones en el Número de Copia de ADN
13.
Proc Natl Acad Sci U S A ; 119(6)2022 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-35110413

RESUMEN

Changes in population density lead to phenotypic differentiation of solitary and gregarious locusts, which display different resistance to fungal pathogens; however, how to regulate their cellular immune strategies remains unknown. Here, our stochastic simulation of pathogen proliferation suggested that humoral defense always enhanced resistance to fungal pathogens, while phagocytosis sometimes reduced defense against pathogens. Further experimental data proved that gregarious locusts had significantly decreased phagocytosis of hemocytes compared to solitary locusts. Additionally, transcriptional analysis showed that gregarious locusts promoted immune effector expression (gnbp1 and dfp) and reduced phagocytic gene expression (eater) and the cytokine tumor necrosis factor (TNF). Interestingly, higher expression of the cytokine TNF in solitary locusts simultaneously promoted eater expression and inhibited gnbp1 and dfp expression. Moreover, inhibition of TNF increased the survival of solitary locusts, and injection of TNF decreased the survival of gregarious locusts after fungal infection. Therefore, our results indicate that the alerted expression of TNF regulated the immune strategy of locusts to adapt to environmental changes.


Asunto(s)
Saltamontes/inmunología , Saltamontes/microbiología , Inmunidad Celular/inmunología , Metarhizium/inmunología , Factor de Necrosis Tumoral alfa/inmunología , Animales , Expresión Génica/inmunología , Fagocitosis/inmunología , Densidad de Población , Transcripción Genética/inmunología
14.
Nano Lett ; 24(7): 2352-2359, 2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38345565

RESUMEN

Ion-selective membrane has broad application in various fields, while the present solution-processed techniques can only prepare uniform membrane with microscale thickness. Herein, a high-quality polymer membrane with nanoscale thickness and uniformity is precisely prepared by controlling solution spreading and solvent evaporation stability/rate. With the arrayed capillaries, the stable spreading of polymer solution with volume of microliter induces the formation of solution film with micrometers thickness. Moreover, the fast increase of solution dynamic viscosity during solvent evaporation inhibits nonuniform Marangoni flow and capillary flow in solution film. Consequently, the uniform Nafion-Li membranes with ∼200 nm thickness are prepared, while their Li+ conductivity is 2 orders of magnitude higher than that of commercially Nafion-117 membrane. Taking lithium-sulfur battery as a model device, the cells (capacities of 8-10 mAh cm-2) can stably operate for 150 cycles at a S loading of 12 mg cm-2 and an electrolyte/sulfur ratio of ∼7.

15.
Pflugers Arch ; 476(2): 197-210, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37994929

RESUMEN

Intermittent hypoxia training (IHT) is a promising approach that has been used to induce acclimatization to hypoxia and subsequently lower the risk of developing acute mountain sickness (AMS). However, the effects of IHT on cognitive and cerebrovascular function after acute hypoxia exposure have not been characterized. In the present study, we first confirmed that the simplified IHT paradigm was effective at relieving AMS at 4300 m. Second, we found that IHT improved participants' cognitive and neural alterations when they were exposed to hypoxia. Specifically, impaired working memory performance, decreased conflict control function, impaired cognitive control, and aggravated mental fatigue induced by acute hypoxia exposure were significantly alleviated in the IHT group. Furthermore, a reversal of brain swelling induced by acute hypoxia exposure was visualized in the IHT group using magnetic resonance imaging. An increase in cerebral blood flow (CBF) was observed in multiple brain regions of the IHT group after hypoxia exposure as compared with the control group. Based on these findings, the simplified IHT paradigm might facilitate hypoxia acclimatization, alleviate AMS symptoms, and increase CBF in multiple brain regions, thus ameliorating brain swelling and cognitive dysfunction.


Asunto(s)
Mal de Altura , Edema Encefálico , Disfunción Cognitiva , Humanos , Hipoxia/complicaciones , Mal de Altura/prevención & control , Aclimatación/fisiología , Enfermedad Aguda , Disfunción Cognitiva/etiología , Disfunción Cognitiva/prevención & control
16.
J Am Chem Soc ; 146(1): 801-810, 2024 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-38129385

RESUMEN

Taxol is a potent drug used in various cancer treatments. Its complex structure has prompted extensive research into its biosynthesis. However, certain critical steps, such as the formation of the oxetane ring, which is essential for its activity, have remained unclear. Previous proposals suggested that oxetane formation follows the acetylation of taxadien-5α-ol. Here, we proposed that the oxetane ring is formed by cytochrome P450-mediated oxidation events that occur prior to C5 acetylation. To test this hypothesis, we analyzed the genomic and transcriptomic information for Taxus species to identify cytochrome P450 candidates and employed two independent systems, yeast (Saccharomyces cerevisiae) and plant (Nicotiana benthamiana), for their characterization. We revealed that a single enzyme, CYP725A4, catalyzes two successive epoxidation events, leading to the formation of the oxetane ring. We further showed that both taxa-4(5)-11(12)-diene (endotaxadiene) and taxa-4(20)-11(12)-diene (exotaxadiene) are precursors to the key intermediate, taxologenic oxetane, indicating the potential existence of multiple routes in the Taxol pathway. Thus, we unveiled a long-elusive step in Taxol biosynthesis.


Asunto(s)
Sistema Enzimático del Citocromo P-450 , Taxus , Sistema Enzimático del Citocromo P-450/metabolismo , Paclitaxel/metabolismo , Éteres Cíclicos , Catálisis , Taxus/genética , Taxus/metabolismo
17.
J Am Chem Soc ; 146(12): 8260-8268, 2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-38497725

RESUMEN

We report the synthesis, crystal structure, and physical properties of a novel ternary compound, Th2Cu4As5. The material crystallizes in a tetragonal structure with lattice parameters a = 4.0639(3) Å and c = 24.8221(17) Å. Its structure can be described as an alternating stacking of fluorite-type Th2As2 layers with antifluorite-type double-layered Cu4As3 slabs. The measurement of electrical resistivity, magnetic susceptibility, and specific heat reveals that Th2Cu4As5 undergoes bulk superconducting transition at 4.2 K. Additionally, all these physical quantities exhibit anomalies at 48 K, accompanied by a sign change in the Hall coefficient, suggesting a charge-density-wave-like (CDW) phase transition. Drawing from both experimental data and band calculations, we propose that the superconducting and CDW-like phase transitions are, respectively, associated with the Cu4As3 slabs and the As plane in the Th2As2 layers.

18.
Gastroenterology ; 165(6): 1488-1504.e20, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37634735

RESUMEN

BACKGROUND & AIMS: Studies have demonstrated that activated pancreatic stellate cells (PSCs) play a crucial role in pancreatic fibrogenesis in chronic pancreatitis (CP); however, the precise mechanism for PSCs activation has not been fully elucidated. We analyzed the role of injured pancreatic acinar cells (iPACs) in the activation of PSCs of CP. METHODS: Sphingosine kinase 1 (SPHK1)/sphingosine-1-phosphate (S1P) signaling was evaluated in experimental CP induced by cerulein injection or pancreatic duct ligation, as well as in PACs injured by cholecystokinin. The activation of PSCs and pancreatic fibrosis in CP samples was evaluated by immunohistochemical and immunofluorescence analyses. In vitro coculture assay of iPACs and PSCs was created to evaluate the effect of the SPHK1/S1P pathway and S1P receptor 2 (SIPR2) on autophagy and activation of PSCs. The pathogenesis of CP was assessed in SPHK1-/- mice or PACs-specific SPHK1-knockdown mice with recombinant adeno-associated virus serotypes 9-SPHK1-knockdown, as well as in mice treated with inhibitor of SPHK1 and S1P receptor 2 (S1PR2). RESULTS: SPHK1/S1P was remarkably increased in iPACs and acinar cells in pancreatic tissues of CP mice. Meanwhile, the pathogenesis, fibrosis, and PSCs activation of CP was significantly prevented in SPHK1-/- mice and recombinant adeno-associated virus serotypes 9-SPHK1-knockdown mice. Meanwhile, iPACs obviously activated PSCs, which was prevented by SPHK1 knockdown in iPACs. Moreover, iPACs-derived S1P specifically combined to S1PR2 of PSCs, by which modulated 5' adenosine monophosphate-activated protein kinase/mechanistic target of rapamycin pathway and consequently induced autophagy and activation of PSCs. Furthermore, hypoxia-inducible factor 1-α and -2α promoted SPHK1 transcription of PACs under hypoxia conditions, which is a distinct characteristic of the CP microenvironment. Coincidently, inhibition of SPHK1 and S1PR2 activity with inhibitor PF-543 and JTE-013 obviously impeded pancreatic fibrogenesis of CP mice. CONCLUSIONS: The activated SPHK1/S1P pathway in iPACs induces autophagy and activation of PSCs by regulating the S1PR2/5' adenosine monophosphate-activated protein kinase/mammalian target of rapamycin pathway, which promotes fibrogenesis of CP. The hypoxia microenvironment might contribute to the cross talk between PACs and PSCs in pathogenesis of CP.


Asunto(s)
Células Acinares , Pancreatitis Crónica , Animales , Ratones , Receptores de Esfingosina-1-Fosfato , Células Estrelladas Pancreáticas , Pancreatitis Crónica/inducido químicamente , Autofagia , Proteínas Quinasas Activadas por AMP , Fibrosis , Adenosina Monofosfato , Hipoxia , Mamíferos
19.
Anal Chem ; 96(18): 6906-6913, 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38656893

RESUMEN

Glycerol tributyrate as a low-density lipoprotein plays a crucial role in drug development and food safety. In this work, a novel high-stability fiber optic sensor for glyceryl tributyrate based on the poly(acrylic acid) (PAA) and chitosan (CS) composite hydrogel embedding method is first proposed. Compared with traditional functionalization, the lipase in a polymer network structure used in this article can not only avoid chemical reactions that cause damage to the enzyme structure but also avoid the instability of ionic bonds and physical adsorption. Therefore, the PAA/CS hydrogel method proposed in this article can effectively retain enzyme structure. First, the impact of different layers (one to five layers) of PAA/CS on pH sensing performance was explored, and it was determined that layers 1-3 could be used for subsequent sensing experiments. Within the linear detection range of 0.5-10 mM, the detection sensitivities of the one to three layers of the biosensor are divided into 0.65, 0.95, and 1.51 nm/mM, respectively, with the three layers having the best effect. When the number of coating layers is three, the detection limit of the sensor is 0.47 mM, meeting the millimole level detection standard for anticancer requirement. Furthermore, the stability and selectivity of the sensor (in the presence of hemoglobin, urea, cholesterol, acetylcholine, and glucose) were analyzed. The three-layer sensor is used for sample detection. At concentrations of 1-10 mM, the absolute value of the recovery percentage (%) is 82-99%, which can accurately detect samples. The sensor proposed in this paper has the advantages of low sample consumption, high sensitivity, simple structure, and label-free measurement. The enzyme-embedding method provides a new route for rapid and reliable glyceryl tributyrate detection, which has potential applications in food safety as well as the development of anticancer drugs.


Asunto(s)
Resinas Acrílicas , Quitosano , Fibras Ópticas , Resonancia por Plasmón de Superficie , Resinas Acrílicas/química , Quitosano/química , Hidrogeles/química , Límite de Detección , Lipasa/química , Lipasa/metabolismo , Técnicas Biosensibles/métodos
20.
Anal Chem ; 96(22): 9069-9077, 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38749062

RESUMEN

Solid contact (SC) calcium ion-selective electrodes (Ca2+-ISEs) have been widely applied in the analysis of water quality and body fluids by virtue of the unique advantages of easy operation and rapid response. However, the potential drift during the long-term stability test hinders their further practical applications. Designing novel redox SC layers with large capacitance and high hydrophobicity is a promising approach to stabilize the potential stability, meanwhile, exploring the transduction mechanism is also of great guiding significance for the precise design of SC layer materials. Herein, flower-like copper sulfide (CunS-50) composed of nanosheets is meticulously designed as the redox SC layer by modification with the surfactant (CTAB). The CunS-50-based Ca2+-ISE (CunS-50/Ca2+-ISE) demonstrates a near-Nernstian slope of 28.23 mV/dec for Ca2+ in a wide activity linear range of 10-7 to 10-1 M, with a low detection limit of 3.16 × 10-8 M. CunS-50/Ca2+-ISE possesses an extremely low potential drift of only 1.23 ± 0.13 µV/h in the long-term potential stability test. Notably, X-ray absorption fine-structure (XAFS) spectra and electrochemical experiments are adopted to elucidate the transduction mechanism that the lipophilic anion (TFPB-) participates in the redox reaction of CunS-50 at the solid-solid interface of ion-selective membrane (ISM) and redox inorganic SC layer (CunS-50), thereby promoting the generation of free electrons to accelerate ion-electron transduction. This work provides an in-depth comprehension of the transduction mechanism of the potentiometric response and an effective strategy for designing redox materials of ion-electron transduction triggered by lipophilic anions.

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