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1.
Cell ; 177(3): 697-710.e17, 2019 04 18.
Artículo en Inglés | MEDLINE | ID: mdl-30982600

RESUMEN

Yeast ataxin-2, also known as Pbp1 (polyA binding protein-binding protein 1), is an intrinsically disordered protein implicated in stress granule formation, RNA biology, and neurodegenerative disease. To understand the endogenous function of this protein, we identify Pbp1 as a dedicated regulator of TORC1 signaling and autophagy under conditions that require mitochondrial respiration. Pbp1 binds to TORC1 specifically during respiratory growth, but utilizes an additional methionine-rich, low complexity (LC) region to inhibit TORC1. This LC region causes phase separation, forms reversible fibrils, and enables self-association into assemblies required for TORC1 inhibition. Mutants that weaken phase separation in vitro exhibit reduced capacity to inhibit TORC1 and induce autophagy. Loss of Pbp1 leads to mitochondrial dysfunction and reduced fitness during nutritional stress. Thus, Pbp1 forms a condensate in response to respiratory status to regulate TORC1 signaling.


Asunto(s)
Proteínas Portadoras/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Transducción de Señal , Secuencia de Aminoácidos , Autofagia/efectos de los fármacos , Proteínas Portadoras/química , Proteínas Portadoras/genética , Diana Mecanicista del Complejo 1 de la Rapamicina/antagonistas & inhibidores , Metionina/metabolismo , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Mutagénesis Sitio-Dirigida , Fosforilación , Unión Proteica , Dominios Proteicos , Saccharomyces cerevisiae/crecimiento & desarrollo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Transducción de Señal/efectos de los fármacos , Sirolimus/farmacología
2.
Cell ; 154(2): 403-15, 2013 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-23870128

RESUMEN

Autophagy is a process of cellular self-digestion induced by various forms of starvation. Although nitrogen deficit is a common trigger, some yeast cells induce autophagy upon switch from a rich to minimal media without nitrogen starvation. We show that the amino acid methionine is sufficient to inhibit such non-nitrogen-starvation (NNS)-induced autophagy. Methionine boosts synthesis of the methyl donor, S-adenosylmethionine (SAM). SAM inhibits autophagy and promotes growth through the action of the methyltransferase Ppm1p, which modifies the catalytic subunit of PP2A in tune with SAM levels. Methylated PP2A promotes dephosphorylation of Npr2p, a component of a conserved complex that regulates NNS autophagy and other growth-related processes. Thus, methionine and SAM levels represent a critical gauge of amino acid availability that is sensed via the methylation of PP2A to reciprocally regulate cell growth and autophagy.


Asunto(s)
Autofagia , Metionina/metabolismo , Proteína Fosfatasa 2/metabolismo , S-Adenosilmetionina/metabolismo , Saccharomyces cerevisiae/citología , Saccharomyces cerevisiae/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Metilación , Proteína Metiltransferasas/metabolismo , Saccharomyces cerevisiae/crecimiento & desarrollo , Proteínas de Saccharomyces cerevisiae/metabolismo
3.
Cell ; 154(2): 416-29, 2013 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-23870129

RESUMEN

Protein translation is an energetically demanding process that must be regulated in response to changes in nutrient availability. Herein, we report that intracellular methionine and cysteine availability directly controls the thiolation status of wobble-uridine (U34) nucleotides present on lysine, glutamine, or glutamate tRNAs to regulate cellular translational capacity and metabolic homeostasis. tRNA thiolation is important for growth under nutritionally challenging environments and required for efficient translation of genes enriched in lysine, glutamine, and glutamate codons, which are enriched in proteins important for translation and growth-specific processes. tRNA thiolation is downregulated during sulfur starvation in order to decrease sulfur consumption and growth, and its absence leads to a compensatory increase in enzymes involved in methionine, cysteine, and lysine biosynthesis. Thus, tRNA thiolation enables cells to modulate translational capacity according to the availability of sulfur amino acids, establishing a functional significance for this conserved tRNA nucleotide modification in cell growth control.


Asunto(s)
Aminoácidos Sulfúricos/metabolismo , Biosíntesis de Proteínas , ARN de Transferencia/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Uridina/metabolismo , Regulación hacia Abajo , ARN de Transferencia/química , Saccharomyces cerevisiae/crecimiento & desarrollo
4.
Trends Biochem Sci ; 48(8): 673-688, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37221124

RESUMEN

Spatiotemporal regulation of cell type-specific gene expression is essential to convert a zygote into a complex organism that contains hundreds of distinct cell types. A class of cis-regulatory elements called enhancers, which have the potential to enhance target gene transcription, are crucial for precise gene expression programs during development. Following decades of research, many enhancers have been discovered and how enhancers become activated has been extensively studied. However, the mechanisms underlying enhancer silencing are less well understood. We review current understanding of enhancer decommissioning and dememorization, both of which enable enhancer silencing. We highlight recent progress from genome-wide perspectives that have revealed the life cycle of enhancers and how its dynamic regulation underlies cell fate transition, development, cell regeneration, and epigenetic reprogramming.


Asunto(s)
Elementos de Facilitación Genéticos , Estadios del Ciclo de Vida , Animales , Diferenciación Celular
5.
Proc Natl Acad Sci U S A ; 121(1): e2307395120, 2024 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-38157451

RESUMEN

Oxidative stress, which can be activated by a variety of environmental risk factors, has been implicated as an important pathogenic factor for inflammatory bowel disease (IBD). However, how oxidative stress drives IBD onset remains elusive. Here, we found that oxidative stress was strongly activated in inflamed tissues from both ulcerative colitis patients and Crohn's disease patients, and it caused nuclear-to-cytosolic TDP-43 transport and a reduction in the TDP-43 protein level. To investigate the function of TDP-43 in IBD, we inducibly deleted exons 2 to 3 of Tardbp (encoding Tdp-43) in mouse intestinal epithelium, which disrupted its nuclear localization and RNA-processing function. The deletion gave rise to spontaneous intestinal inflammation by inducing epithelial cell necroptosis. Suppression of the necroptotic pathway with deletion of Mlkl or the RIP1 inhibitor Nec-1 rescued colitis phenotypes. Mechanistically, disruption of nuclear TDP-43 caused excessive R-loop accumulation, which triggered DNA damage and genome instability and thereby induced PARP1 hyperactivation, leading to subsequent NAD+ depletion and ATP loss, consequently activating mitochondrion-dependent necroptosis in intestinal epithelial cells. Importantly, restoration of cellular NAD+ levels with NAD+ or NMN supplementation, as well as suppression of ALKBH7, an α-ketoglutarate dioxygenase in mitochondria, rescued TDP-43 deficiency-induced cell death and intestinal inflammation. Furthermore, TDP-43 protein levels were significantly inversely correlated with γ-H2A.X and p-MLKL levels in clinical IBD samples, suggesting the clinical relevance of TDP-43 deficiency-induced mitochondrion-dependent necroptosis. Taken together, these findings identify a unique pathogenic mechanism that links oxidative stress to intestinal inflammation and provide a potent and valid strategy for IBD intervention.


Asunto(s)
Enfermedades Inflamatorias del Intestino , Necroptosis , Humanos , Animales , Ratones , NAD/metabolismo , Estructuras R-Loop , Enfermedades Inflamatorias del Intestino/metabolismo , Células Epiteliales/metabolismo , Mucosa Intestinal/metabolismo , Inflamación/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Mitocondrias/metabolismo
6.
FASEB J ; 38(5): e23532, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38451470

RESUMEN

Although elevated glycolysis has been widely recognized as a hallmark for highly proliferating cells like stem cells and cancer, its regulatory mechanisms are still being updated. Here, we found a previously unappreciated mechanism of mammalian target of rapamycin complex 2 (mTORC2) in regulating glycolysis in intestinal stem cell maintenance and cancer progression. mTORC2 key subunits expression levels and its kinase activity were specifically upregulated in intestinal stem cells, mouse intestinal tumors, and human colorectal cancer (CRC) tissues. Genetic ablation of its key scaffolding protein Rictor in both mouse models and cell lines revealed that mTORC2 played an important role in promoting intestinal stem cell proliferation and self-renewal. Moreover, utilizing mouse models and organoid culture, mTORC2 loss of function was shown to impair growth of gut adenoma and tumor organoids. Based on these findings, we performed RNA-seq and noticed significant metabolic reprogramming in Rictor conditional knockout mice. Among all the pathways, carbohydrate metabolism was most profoundly altered, and further studies demonstrated that mTORC2 promoted glycolysis in intestinal epithelial cells. Most importantly, we showed that a rate-limiting enzyme in regulating glycolysis, 6-phosphofructo-2-kinase (PFKFB2), was a direct target for the mTORC2-AKT signaling. PFKFB2 was phosphorylated upon mTORC2 activation, but not mTORC1, and this process was AKT-dependent. Together, this study has identified a novel mechanism underlying mTORC2 activated glycolysis, offering potential therapeutic targets for treating CRC.


Asunto(s)
Neoplasias , Proteínas Proto-Oncogénicas c-akt , Animales , Humanos , Ratones , Modelos Animales de Enfermedad , Células Epiteliales , Glucólisis , Mamíferos , Diana Mecanicista del Complejo 2 de la Rapamicina , Ratones Noqueados , Fosfofructoquinasa-2 , Sirolimus
7.
Nucleic Acids Res ; 51(3): 1443-1457, 2023 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-36651297

RESUMEN

Testicular nuclear receptor 4 (TR4) modulates the transcriptional activation of genes and plays important roles in many diseases. The regulation of TR4 on target genes involves direct interactions with DNA molecules via the DNA-binding domain (DBD) and recruitment of coregulators by the ligand-binding domain (LBD). However, their regulatory mechanisms are unclear. Here, we report high-resolution crystal structures of TR4DBD, TR4DBD-DNA complexes and the TR4LBD-JAZF1 complex. For DNA recognition, multiple factors come into play, and a specific mutual selectivity between TR4 and target genes is found. The coactivators SRC-1 and CREBBP can bind at the interface of TR4 originally occupied by the TR4 activation function region 2 (AF-2); however, JAZF1 suppresses the binding through a novel mechanism. JAZF1 binds to an unidentified surface of TR4 and stabilizes an α13 helix never reported in the nuclear receptor family. Moreover, the cancer-associated mutations affect the interactions and the transcriptional activation of TR4 in vitro and in vivo, respectively. Overall, our results highlight the crucial role of DNA recognition and a novel mechanism of how JAZF1 reinforces the autorepressed conformation and influences the transcriptional activation of TR4, laying out important structural bases for drug design for a variety of diseases, including diabetes and cancers.


Asunto(s)
Proteínas Co-Represoras , Regulación de la Expresión Génica , Receptores de Esteroides , Humanos , Proteínas Portadoras/genética , Proteínas Co-Represoras/metabolismo , ADN , Proteínas de Unión al ADN/genética , Receptores de Esteroides/química , Receptores de Esteroides/metabolismo , Activación Transcripcional
8.
PLoS Genet ; 18(1): e1009968, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34986146

RESUMEN

Taxane-induced peripheral neuropathy (TIPN) is a devastating survivorship issue for many cancer patients. In addition to its impact on quality of life, this toxicity may lead to dose reductions or treatment discontinuation, adversely impacting survival outcomes and leading to health disparities in African Americans (AA). Our lab has previously identified deleterious mutations in SET-Binding Factor 2 (SBF2) that significantly associated with severe TIPN in AA patients. Here, we demonstrate the impact of SBF2 on taxane-induced neuronal damage using an ex vivo model of SBF2 knockdown of induced pluripotent stem cell-derived sensory neurons. Knockdown of SBF2 exacerbated paclitaxel changes to cell viability and neurite outgrowth while attenuating paclitaxel-induced sodium current inhibition. Our studies identified paclitaxel-induced expression changes specific to mature sensory neurons and revealed candidate genes involved in the exacerbation of paclitaxel-induced phenotypes accompanying SBF2 knockdown. Overall, these findings provide ex vivo support for the impact of SBF2 on the development of TIPN and shed light on the potential pathways involved.


Asunto(s)
Paclitaxel/efectos adversos , Enfermedades del Sistema Nervioso Periférico/genética , Polimorfismo de Nucleótido Simple , Proteínas Tirosina Fosfatasas no Receptoras/genética , Células Receptoras Sensoriales/citología , Negro o Afroamericano/genética , Supervivencia Celular/efectos de los fármacos , Progresión de la Enfermedad , Femenino , Técnicas de Silenciamiento del Gen , Humanos , Células Madre Pluripotentes Inducidas/química , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/efectos de los fármacos , Paclitaxel/farmacología , Enfermedades del Sistema Nervioso Periférico/inducido químicamente , Enfermedades del Sistema Nervioso Periférico/etnología , Calidad de Vida , Células Receptoras Sensoriales/química , Células Receptoras Sensoriales/efectos de los fármacos , Análisis de Secuencia de ARN , Análisis de la Célula Individual , Población Blanca/genética
9.
J Cell Mol Med ; 28(9): e18328, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38683130

RESUMEN

Gallbladder cancer is a rare but fatal malignancy. However, the mechanisms underlying gallbladder carcinogenesis and its progression are poorly understood. The function of m6A modification and its regulators was still unclear for gallbladder cancer. The current study seeks to investigate the function of YTH m6A RNA-binding protein 1 (YTHDF1) in gallbladder cancer. Transcriptomic analysis and immunochemical staining of YTHDF1 in gallbladder cancer tissues revealed its upregulation compared to paracancerous tissues. Moreover, YTHDF1 promotes the proliferation assays, Transwell migration assays, and Transwell invasion assays of gallbladder cancer cells in vitro. And it also increased tumour growth in xenograft mouse model and metastases in tail vein injection model in vivo. In vitro, UHRF1 knockdown partly reversed the effects of YTHDF1 overexpression. Mechanistically, dual-luciferase assays proved that YTHDF1 promotes UHRF1 expression via direct binding to the mRNA 3'-UTR in a m6A-dependent manner. Overexpression of YTHDF1 enhanced UHRF1 mRNA stability, as demonstrated by mRNA stability assays, and Co-IP studies confirmed a direct interaction between YTHDF1 and PABPC1. Collectively, these findings provide new insights into the progression of gallbladder cancer as well as a novel post-transcriptional mechanism of YTHDF1 via stabilizing target mRNA.


Asunto(s)
Adenosina , Neoplasias de la Vesícula Biliar , Regulación Neoplásica de la Expresión Génica , Proteínas de Unión al ARN , Ubiquitina-Proteína Ligasas , Animales , Femenino , Humanos , Masculino , Ratones , Adenosina/análogos & derivados , Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Proteínas Potenciadoras de Unión a CCAAT/genética , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Progresión de la Enfermedad , Neoplasias de la Vesícula Biliar/genética , Neoplasias de la Vesícula Biliar/patología , Neoplasias de la Vesícula Biliar/metabolismo , Ratones Desnudos , Estabilidad del ARN/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genética , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitina-Proteína Ligasas/genética
10.
Plant J ; 114(1): 193-208, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36721966

RESUMEN

Iron (Fe) is an indispensable trace mineral element for the normal growth of plants, and it is involved in different biological processes; Fe shortage in plants can induce chlorosis and yield loss. The objective of this research is to identify novel genes that participated in the regulation of Fe-deficiency stress in Arabidopsis thaliana. A basic helix-loop-helix (bHLH) transcription factor (MYC1) was identified to be interacting with the FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (FIT) using a yeast-two-hybrid assay. Transcript-level analysis showed that there was a decrease in MYC1 expression in Arabidopsis to cope with Fe-deficiency stress. Functional deficiency of MYC1 in Arabidopsis leads to an increase in Fe-deficiency tolerance and Fe-accumulation, whereas MYC1-overexpressing plants have an enhanced sensitivity to Fe-deficiency stress. Additionally, MYC1 inhibited the formation of FIT and bHLH38/39 heterodimers, which suppressed the expressed level for Fe acquisition genes FRO2 and IRT1 during Fe-deficiency stress. These results showed that MYC1 functions as a negative modulator of the Fe-deficiency stress response by inhibiting the formation of FIT and bHLH38/39 heterodimers, thereby suppressing the binding of FIT and bHLH38/39 heterodimers to the promoters of FRO2 and IRT1 to modulate Fe intake during Fe-deficiency stress. Overall, the findings of this study elucidated the role of MYC1 in coping with Fe-deficiency stress, and provided potential targets for the developing of crop varieties resistant to Fe-deficiency stress.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulación de la Expresión Génica de las Plantas , Homeostasis/fisiología , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Raíces de Plantas/metabolismo
11.
J Neuroinflammation ; 21(1): 123, 2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38725082

RESUMEN

BACKGROUND: Hepatic encephalopathy (HE) is closely associated with inflammatory responses. However, as a crucial regulator of the immune and inflammatory responses, the role of leucine-rich repeat kinase 2 (LRRK2) in the pathogenesis of HE remains unraveled. Herein, we investigated this issue in thioacetamide (TAA)-induced HE following acute liver failure (ALF). METHODS: TAA-induced HE mouse models of LRRK2 wild type (WT), LRRK2 G2019S mutation (Lrrk2G2019S) and LRRK2 knockout (Lrrk2-/-) were established. A battery of neurobehavioral experiments was conducted. The biochemical indexes and pro-inflammatory cytokines were detected. The prefrontal cortex (PFC), striatum (STR), hippocampus (HIP), and liver were examined by pathology and electron microscopy. The changes of autophagy-lysosomal pathway and activity of critical Rab GTPases were analyzed. RESULTS: The Lrrk2-/--HE model reported a significantly lower survival rate than the other two models (24% vs. 48%, respectively, p < 0.05), with no difference found between the WT-HE and Lrrk2G2019S-HE groups. Compared with the other groups, after the TAA injection, the Lrrk2-/- group displayed a significant increase in ammonium and pro-inflammatory cytokines, aggravated hepatic inflammation/necrosis, decreased autophagy, and abnormal phosphorylation of lysosomal Rab10. All three models reported microglial activation, neuronal loss, disordered vesicle transmission, and damaged myelin structure. The Lrrk2-/--HE mice presented no severer neuronal injury than the other genotypes. CONCLUSIONS: LRRK2 deficiency may exacerbate TAA-induced ALF and HE in mice, in which inflammatory response is evident in the brain and aggravated in the liver. These novel findings indicate a need of sufficient clinical awareness of the adverse effects of LRRK2 inhibitors on the liver.


Asunto(s)
Encefalopatía Hepática , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina , Fallo Hepático Agudo , Ratones Noqueados , Tioacetamida , Animales , Ratones , Encefalopatía Hepática/patología , Encefalopatía Hepática/genética , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina/genética , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina/metabolismo , Fallo Hepático Agudo/inducido químicamente , Fallo Hepático Agudo/patología , Fallo Hepático Agudo/genética , Ratones Endogámicos C57BL , Tioacetamida/toxicidad
12.
Nat Mater ; 22(4): 489-494, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36959503

RESUMEN

Pressure-induced magnetic phase transitions are attracting interest as a means to detect superconducting behaviour at high pressures in diamond anvil cells, but determining the local magnetic properties of samples is a challenge due to the small volumes of sample chambers. Optically detected magnetic resonance of nitrogen vacancy centres in diamond has recently been used for the in situ detection of pressure-induced phase transitions. However, owing to their four orientation axes and temperature-dependent zero-field splitting, interpreting these optically detected magnetic resonance spectra remains challenging. Here we study the optical and spin properties of implanted silicon vacancy defects in 4H-silicon carbide that exhibit single-axis and temperature-independent zero-field splitting. Using this technique, we observe the magnetic phase transition of Nd2Fe14B at about 7 GPa and map the critical temperature-pressure phase diagram of the superconductor YBa2Cu3O6.6. These results highlight the potential of silicon vacancy-based quantum sensors for in situ magnetic detection at high pressures.

13.
New Phytol ; 242(6): 2586-2603, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38523234

RESUMEN

Nicotianamine (NA) plays a crucial role in transporting metal ions, including iron (Fe), in plants; therefore, NICOTIANAMINE SYNTHASE (NAS) genes, which control NA synthesis, are tightly regulated at the transcriptional level. However, the transcriptional regulatory mechanisms of NAS genes require further investigations. In this study, we determined the role of bZIP44 in mediating plant response to Fe deficiency stress by conducting transformation experiments and assays. bZIP44 positively regulated the response of Arabidopsis to Fe deficiency stress by interacting with MYB10 and MYB72 to enhance their abilities to bind at NAS2 and NAS4 promoters, thereby increasing NAS2 and NAS4 transcriptional levels and promote NA synthesis. In summary, the transcription activities of bZIP44, MYB10, and MYB72 were induced in response to Fe deficiency stress, which enhanced the interaction between bZIP44 and MYB10 or MYB72 proteins, synergistically activated the transcriptional activity of NAS2 and NAS4, promoted NA synthesis, and improved Fe transport, thereby enhancing plant tolerance to Fe deficiency stress.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico , Regulación de la Expresión Génica de las Plantas , Deficiencias de Hierro , Estrés Fisiológico , Factores de Transcripción , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Estrés Fisiológico/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Hierro/metabolismo , Regiones Promotoras Genéticas/genética , Unión Proteica , Transferasas Alquil y Aril/metabolismo , Transferasas Alquil y Aril/genética , Ácido Azetidinocarboxílico/análogos & derivados , Ácido Azetidinocarboxílico/metabolismo , Plantas Modificadas Genéticamente
14.
J Med Virol ; 96(1): e29314, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-38163276

RESUMEN

SARS-CoV-2 breakthrough infections in vaccinated individuals underscore the threat posed by continuous mutating variants, such as Omicron, to vaccine-induced immunity. This necessitates the search for broad-spectrum immunogens capable of countering infections from such variants. This study evaluates the immunogenicity relationship among SARS-CoV-2 variants, from D614G to XBB, through Guinea pig vaccination, covering D614G, Alpha, Beta, Gamma, Delta, BA.1, BA.2, BA.2.75, BA.2.75.2, BA.5, BF.7, BQ.1.1, and XBB, employing three immunization strategies: three-dose monovalent immunogens, three-dose bivalent immunogens, and a two-dose vaccination with D614G followed by a booster immunization with a variant strain immunogen. Three distinct immunogenicity clusters were identified: D614G, Alpha, Beta, Gamma, and Delta as cluster 1, BA.1, BA.2, and BA.2.75 as cluster 2, BA.2.75.2, BA.5, BF.7, BQ.1.1, and XBB as cluster 3. Broad-spectrum protection could be achieved through a combined immunization strategy using bivalent immunogens or D614G and XBB, or two initial D614G vaccinations followed by two XBB boosters. A comparison of neutralizing antibody levels induced by XBB boosting and equivalent dosing of D614G and XBB revealed that the XBB booster produced higher antibody levels. The study suggests that vaccine antigen selection should focus on the antigenic alterations among variants, eliminating the need for updating vaccine components for each variant.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , Animales , Cobayas , SARS-CoV-2/genética , COVID-19/prevención & control , Anticuerpos Neutralizantes , Análisis por Conglomerados , Vacunas Combinadas , Anticuerpos Antivirales
15.
Opt Express ; 32(8): 14555-14564, 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38859397

RESUMEN

In this paper, we demonstrate a novel hybrid 3C-silicon carbide-lithium niobate (3C-SiC-LN) platform for passive and active integrated nanophotonic devices enabled through wafer bonding. These devices are fabricated by etching the SiC layer, with the hybrid optical mode power distributed between SiC and LN layers through a taper design. We present a racetrack resonator-based electro-optic (EO) phase shifter where the resonator is fabricated in SiC while using LN for EO-effect (r33≈ 27 pm/V). The proposed phase shifter demonstrates efficient resonance wavelength tuning with low voltage-length product (Vπ.Lπ ≈ 2.18 V cm) using the EO effect of LN. This hybrid SiC-LN platform would enable high-speed, low-power, and miniaturized photonic devices (e.g., modulators, switches, filters) operable over a broad range of wavelengths (visible to infrared) with applications in both classical and quantum nanophotonics.

16.
Langmuir ; 40(21): 11263-11276, 2024 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-38743290

RESUMEN

Synergistic engineering of energy band alignment and interfacial electric field distribution is essential for photocatalyst design but is still challenging because of the limitation on refined regulation in the nanoscale. This study addresses the issue by employing surface modification and thermal-induced phase transformation in Bi2MoO6/BixOyIz hetero-nanofiber frameworks. The energy band alignment switches from a type-II interface to a Z-scheme contact with stronger redox potentials and inhibited electron traps, and the optimized built-in electric field distribution could be reached based on experimental and theoretical investigations. The engineered hetero-nanofibers exhibit outstanding visible-light-driven photocatalytic nitrogen reduction activity (605 µmol/g/h) and tetracycline hydrochloride removal rate (81.5% within 30 min), ranking them among the top-performing bismuth series materials. Furthermore, the photocatalysts show promise in activating advanced oxidants for efficient organic pollutant degradation. Moreover, the Bi2MoO6/Bi5O7I hetero-nanofibers possess good recycling stability owing to their three-dimensional network structure. This research offers valuable insights into heterojunction design for environmental remediation and industrial applications.

17.
EMBO Rep ; 23(11): e54507, 2022 11 07.
Artículo en Inglés | MEDLINE | ID: mdl-36148511

RESUMEN

A central principle of synaptic transmission is that action potential-induced presynaptic neurotransmitter release occurs exclusively via Ca2+ -dependent secretion (CDS). The discovery and mechanistic investigations of Ca2+ -independent but voltage-dependent secretion (CiVDS) have demonstrated that the action potential per se is sufficient to trigger neurotransmission in the somata of primary sensory and sympathetic neurons in mammals. One key question remains, however, whether CiVDS contributes to central synaptic transmission. Here, we report, in the central transmission from presynaptic (dorsal root ganglion) to postsynaptic (spinal dorsal horn) neurons in vitro, (i) excitatory postsynaptic currents (EPSCs) are mediated by glutamate transmission through both CiVDS (up to 87%) and CDS; (ii) CiVDS-mediated EPSCs are independent of extracellular and intracellular Ca2+ ; (iii) CiVDS is faster than CDS in vesicle recycling with much less short-term depression; (iv) the fusion machinery of CiVDS includes Cav2.2 (voltage sensor) and SNARE (fusion pore). Together, an essential component of activity-induced EPSCs is mediated by CiVDS in a central synapse.


Asunto(s)
Ganglios Espinales , Células del Asta Posterior , Animales , Células del Asta Posterior/fisiología , Transmisión Sináptica/fisiología , Potenciales Postsinápticos Excitadores/fisiología , Sinapsis , Mamíferos
18.
Dig Dis ; 42(1): 1-11, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37839406

RESUMEN

INTRODUCTION: Early gastric cancer with current Helicobacter pylori infection (HpC-EGC) is common, but it is still unclear whether H. pylori eradication therapy (Hp-ET) or endoscopic submucosal dissection (ESD) should be performed first. We evaluated Hp-ETs short-term effects on horizontal boundary delineations of HpC-EGC in ESD. METHODS: Prospectively enrolled HpC-EGC patients were randomly assigned to eradication or control groups. Operation scopes of HpC-EGC lesions were delineated with marking dots at 5 mm out of the endoscopic demarcation line by an independent endoscopist, unaware of eradication status, before formal circumferential incision. As representatives, precise delineation rate, the shortest distance of all marking dots to the pathological demarcation line in all slices of one intact resected specimen (Dmin), and negative marking dot specimen rate were examined. RESULTS: Twenty-three HpC-EGC patients (25 lesions) were allocated to eradication group and 26 patients (27 lesions) were allocated to the control group with similar eradication success rates and all were differentiated type. With improving background mucosa inflammation after Hp-ET and similar gastritis-like epithelium rates, 10 lesions (40.0%) in the eradication group were of precise delineation compared to control group with 2 lesions (7.4%) (relative risk = 5.40, 95% CI 1.31-22.28). Dmin of eradication and control groups were 4.17 ± 2.52 mm and 2.67 ± 2.30 mm (p = 0.029), accompanied by 4 (14.8%) and none (0.0%) specimens that exhibited positive marking dots (p = 0.11), respectively. CONCLUSION: For HpC-EGC patients, administrating eradication medication before ESD is beneficial for the precise delineation of lesions and reducing the risk of positive horizontal resection margins.


Asunto(s)
Resección Endoscópica de la Mucosa , Infecciones por Helicobacter , Helicobacter pylori , Neoplasias Gástricas , Humanos , Infecciones por Helicobacter/complicaciones , Infecciones por Helicobacter/tratamiento farmacológico , Neoplasias Gástricas/cirugía , Neoplasias Gástricas/patología , Mucosa Gástrica/cirugía , Mucosa Gástrica/patología
19.
Bioorg Chem ; 143: 107103, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38211549

RESUMEN

Three undescribed (1-3) and nine known (4-12) platanosides were isolated and characterized from a bioactive extract of the May leaves of Platanus × acerifolia that initially showed inhibition against Staphylococcus aureus. Targeted compound mining was guided by an LC-MS/MS-based molecular ion networking (MoIN) strategy combined with conventional isolation procedures from a unique geographic location. The novel structures were mainly determined by 2D NMR and computational (NMR/ECD calculations) methods. Compound 1 is a rare acylated kaempferol rhamnoside possessing a truxinate unit. 6 (Z,E-platanoside) and 7 (E,E-platanoside) were confirmed to have remarkable inhibitory effects against both methicillin-resistant S. aureus (MIC: ≤ 16 µg/mL) and glycopeptide-resistant Enterococcus faecium (MIC: ≤ 1 µg/mL). These platanosides were subjected to docking analyses against FabI (enoyl-ACP reductase) and PBP1/2 (penicillin binding protein), both of which are pivotal enzymes governing bacterial growth but not found in the human host. The results showed that 6 and 7 displayed superior binding affinities towards FabI and PBP2. Moreover, surface plasmon resonance studies on the interaction of 1/7 and FabI revealed that 7 has a higher affinity (KD = 1.72 µM), which further supports the above in vitro data and is thus expected to be a novel anti-antibacterial drug lead.


Asunto(s)
Glicósidos , Staphylococcus aureus Resistente a Meticilina , Fenoles , Sepsis , Infecciones Estafilocócicas , Humanos , Antibacterianos/química , Cromatografía Liquida , Enoil-ACP Reductasa (NADH) , Pruebas de Sensibilidad Microbiana , Espectrometría de Masas en Tándem , Relación Estructura-Actividad
20.
Acta Pharmacol Sin ; 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38632319

RESUMEN

Liver receptor homolog-1 (LRH-1), a member of the nuclear receptor superfamily, is a ligand-regulated transcription factor that plays crucial roles in metabolism, development, and immunity. Despite being classified as an 'orphan' receptor due to the ongoing debate surrounding its endogenous ligands, recent researches have demonstrated that LRH-1 can be modulated by various synthetic ligands. This highlights the potential of LRH-1 as an attractive drug target for the treatment of inflammation, metabolic disorders, and cancer. In this review, we provide an overview of the structural basis, functional activities, associated diseases, and advancements in therapeutic ligand research targeting LRH-1.

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