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1.
Cell ; 184(16): 4268-4283.e20, 2021 08 05.
Artículo en Inglés | MEDLINE | ID: mdl-34233163

RESUMEN

Ultraviolet (UV) light and incompletely understood genetic and epigenetic variations determine skin color. Here we describe an UV- and microphthalmia-associated transcription factor (MITF)-independent mechanism of skin pigmentation. Targeting the mitochondrial redox-regulating enzyme nicotinamide nucleotide transhydrogenase (NNT) resulted in cellular redox changes that affect tyrosinase degradation. These changes regulate melanosome maturation and, consequently, eumelanin levels and pigmentation. Topical application of small-molecule inhibitors yielded skin darkening in human skin, and mice with decreased NNT function displayed increased pigmentation. Additionally, genetic modification of NNT in zebrafish alters melanocytic pigmentation. Analysis of four diverse human cohorts revealed significant associations of skin color, tanning, and sun protection use with various single-nucleotide polymorphisms within NNT. NNT levels were independent of UVB irradiation and redox modulation. Individuals with postinflammatory hyperpigmentation or lentigines displayed decreased skin NNT levels, suggesting an NNT-driven, redox-dependent pigmentation mechanism that can be targeted with NNT-modifying topical drugs for medical and cosmetic purposes.


Asunto(s)
Factor de Transcripción Asociado a Microftalmía/metabolismo , NADP Transhidrogenasas/metabolismo , Pigmentación de la Piel/efectos de la radiación , Rayos Ultravioleta , Animales , Línea Celular , Estudios de Cohortes , AMP Cíclico/metabolismo , Daño del ADN , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Predisposición Genética a la Enfermedad , Humanos , Melanocitos/efectos de los fármacos , Melanocitos/metabolismo , Melanosomas/efectos de los fármacos , Melanosomas/metabolismo , Melanosomas/efectos de la radiación , Ratones , Ratones Endogámicos C57BL , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Monofenol Monooxigenasa/genética , Monofenol Monooxigenasa/metabolismo , NADP Transhidrogenasas/antagonistas & inhibidores , Oxidación-Reducción/efectos de los fármacos , Oxidación-Reducción/efectos de la radiación , Polimorfismo de Nucleótido Simple/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteolisis/efectos de los fármacos , Proteolisis/efectos de la radiación , ARN Mensajero/genética , ARN Mensajero/metabolismo , Pigmentación de la Piel/efectos de los fármacos , Pigmentación de la Piel/genética , Ubiquitina/metabolismo , Pez Cebra
2.
Mol Cell Proteomics ; 23(1): 100700, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38104799

RESUMEN

Protein lysine acetylation is a critical post-translational modification involved in a wide range of biological processes. To date, about 20,000 acetylation sites of Homo sapiens were identified through mass spectrometry-based proteomic technology, but more than 95% of them have unclear functional annotations because of the lack of existing prioritization strategy to assess the functional importance of the acetylation sites on large scale. Hence, we established a lysine acetylation functional evaluating model (LAFEM) by considering eight critical features surrounding lysine acetylation site to high-throughput estimate the functional importance of given acetylation sites. This was achieved by selecting one of the random forest models with the best performance in 10-fold cross-validation on undersampled training dataset. The global analysis demonstrated that the molecular environment of acetylation sites with high acetylation functional scores (AFSs) mainly had the features of larger solvent-accessible surface area, stronger hydrogen bonding-donating abilities, near motif and domain, higher homology, and disordered degree. Importantly, LAFEM performed well in validation dataset and acetylome, showing good accuracy to screen out fitness directly relevant acetylation sites and assisting to explain the core reason for the difference between biological models from the perspective of acetylome. We further used cellular experiments to confirm that, in nuclear casein kinase and cyclin-dependent kinase substrate 1, acetyl-K35 with higher AFS was more important than acetyl-K9 with lower AFS in the proliferation of A549 cells. LAFEM provides a prioritization strategy to large scale discover the fitness directly relevant acetylation sites, which constitutes an unprecedented resource for better understanding of functional acetylome.


Asunto(s)
Lisina , Proteómica , Humanos , Lisina/metabolismo , Acetilación , Espectrometría de Masas , Procesamiento Proteico-Postraduccional , Proteoma/metabolismo
3.
EMBO Rep ; 24(6): e56282, 2023 06 05.
Artículo en Inglés | MEDLINE | ID: mdl-37009826

RESUMEN

Human microproteins encoded by long non-coding RNAs (lncRNA) have been increasingly discovered, however, complete functional characterization of these emerging proteins is scattered. Here, we show that LINC00493-encoded SMIM26, an understudied microprotein localized in mitochondria, is tendentiously downregulated in clear cell renal cell carcinoma (ccRCC) and correlated with poor overall survival. LINC00493 is recognized by RNA-binding protein PABPC4 and transferred to ribosomes for translation of a 95-amino-acid protein SMIM26. SMIM26, but not LINC00493, suppresses ccRCC growth and metastatic lung colonization by interacting with acylglycerol kinase (AGK) and glutathione transport regulator SLC25A11 via its N-terminus. This interaction increases the mitochondrial localization of AGK and subsequently inhibits AGK-mediated AKT phosphorylation. Moreover, the formation of the SMIM26-AGK-SCL25A11 complex maintains mitochondrial glutathione import and respiratory efficiency, which is abrogated by AGK overexpression or SLC25A11 knockdown. This study functionally characterizes the LINC00493-encoded microprotein SMIM26 and establishes its anti-metastatic role in ccRCC, and therefore illuminates the importance of hidden proteins in human cancers.


Asunto(s)
Carcinoma de Células Renales , Neoplasias Renales , ARN Largo no Codificante , Humanos , Carcinoma de Células Renales/genética , Carcinoma de Células Renales/patología , Línea Celular Tumoral , Mitocondrias/metabolismo , Proliferación Celular/genética , Neoplasias Renales/genética , Neoplasias Renales/patología , Regulación Neoplásica de la Expresión Génica , ARN Largo no Codificante/metabolismo , Micropéptidos
4.
Nano Lett ; 24(1): 331-338, 2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38108571

RESUMEN

Solar-driven photothermal catalytic H2 production from lignocellulosic biomass was achieved by using 1T-2H MoS2 with tunable Lewis acidic sites as catalysts in an alkaline aqueous solution, in which the number of Lewis acidic sites derived from the exposed Mo edges of MoS2 was successfully regulated by both the formation of an edge-terminated 1T-2H phase structure and tunable layer number. Owing to the abundant Lewis acidic sites for the oxygenolysis of lignocellulosic biomass, the 1T-2H MoS2 catalyst shows high photothermal catalytic lignocellulosic biomass-to-H2 transformation performance in polar wood chips, bamboo, rice straw corncobs, and rice hull aqueous solutions, and the highest H2 generation rate and solar-to-H2 (STH) efficiency respectively achieves 3661 µmol·h-1·g-1 and 0.18% in the polar wood chip system under 300 W Xe lamp illumination. This study provides a sustainable and cost-effective method for the direct transformation of renewable lignocellulosic biomass to H2 fuel driven by solar energy.

5.
J Proteome Res ; 23(7): 2323-2331, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38865581

RESUMEN

The Chromosome-Centric Human Proteome Project (C-HPP) aims to identify all proteins encoded by the human genome. Currently, the human proteome still contains approximately 2000 PE2-PE5 proteins, referring to annotated coding genes that lack sufficient protein-level evidence. During the past 10 years, it has been increasingly difficult to identify PE2-PE5 proteins in C-HPP approaches due to the limited occurrence. Therefore, we proposed that reanalyzing massive MS data sets in repository with newly developed algorithms may increase the occurrence of the peptides of these proteins. In this study, we downloaded 1000 MS data sets via the ProteomeXchange database. Using pFind software, we identified peptides referring to 1788 PE2-PE5 proteins. Among them, 11 PE2 and 16 PE5 proteins were identified with at least 2 peptides, and 12 of them were identified using 2 peptides in a single data set, following the criteria of the HPP guidelines. We found translation evidence for 16 of the 11 PE2 and 16 PE5 proteins in our RNC-seq data, supporting their existence. The properties of the PE2 and PE5 proteins were similar to those of the PE1 proteins. Our approach demonstrated that mining PE2 and PE5 proteins in massive data repository is still worthy, and multidata set peptide identifications may support the presence of PE2 and PE5 proteins or at least prompt additional studies for validation. Extremely high throughput could be a solution to finding more PE2 and PE5 proteins.


Asunto(s)
Bases de Datos de Proteínas , Proteoma , Programas Informáticos , Humanos , Proteoma/análisis , Proteoma/genética , Algoritmos , Espectrometría de Masas/métodos , Proteómica/métodos , Péptidos/genética , Péptidos/análisis , Péptidos/química , Genoma Humano
6.
J Proteome Res ; 23(6): 2195-2205, 2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38661673

RESUMEN

The programmed death-ligand 1 (PD-L1) is a key mediator of immunosuppression in the tumor microenvironment. The expression of PD-L1 in cancer cells is useful for the clinical determination of an immune checkpoint blockade (ICB). However, the regulatory mechanism of the PD-L1 abundance remains incompletely understood. Here, we integrated the proteomics of 52 patients with solid tumors and examined immune cell infiltration to reveal PD-L1-related regulatory modules. Wiskott-Aldrich syndrome protein (WASP) was identified as a potential regulator of PD-L1 transcription. In two independent cohorts containing 164 cancer patients, WASP expression was significantly associated with PD-L1. High WASP expression contributed to immunosuppressive cell composition, including cells positive for immune checkpoints (PD1, CTLA4, TIGIT, and TIM3), FoxP3+ Treg cells, and CD163+ tumor-associated macrophages. Overexpression of WASP increased, whereas knockdown of WASP decreased the protein level of PD-L1 in cancer cells without alteration of PD-L1 protein stability. The WASP-mediated cell migration and invasion were markedly attenuated by the silence of PD-L1. Collectively, our data suggest that WASP is a potential regulator of PD-L1 and the WASP/PD-L1 axis is responsible for cell migration and an immunosuppressive microenvironment.


Asunto(s)
Antígeno B7-H1 , Neoplasias , Proteómica , Microambiente Tumoral , Proteína del Síndrome de Wiskott-Aldrich , Humanos , Antígeno B7-H1/metabolismo , Antígeno B7-H1/genética , Proteómica/métodos , Proteína del Síndrome de Wiskott-Aldrich/metabolismo , Proteína del Síndrome de Wiskott-Aldrich/genética , Neoplasias/metabolismo , Neoplasias/genética , Movimiento Celular/genética , Regulación Neoplásica de la Expresión Génica , Línea Celular Tumoral
7.
J Am Chem Soc ; 146(18): 12485-12495, 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38651836

RESUMEN

Understanding the mechanisms of C-H activation of alkanes is a very important research topic. The reactions of metal clusters with alkanes have been extensively studied to reveal the electronic features governing C-H activation, while the experimental cluster reactivity was qualitatively interpreted case by case in the literature. Herein, we prepared and mass-selected over 100 rhodium-based clusters (RhxVyOz- and RhxCoyOz-) to react with light alkanes, enabling the determination of reaction rate constants spanning six orders of magnitude. A satisfactory model being able to quantitatively describe the rate data in terms of multiple cluster electronic features (average electron occupancy of valence s orbitals, the minimum natural charge on the metal atom, cluster polarizability, and energy gap involved in the agostic interaction) has been constructed through a machine learning approach. This study demonstrates that the general mechanisms governing the very important process of C-H activation by diverse metal centers can be discovered by interpreting experimental data with artificial intelligence.

8.
Small ; 20(28): e2308483, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38329171

RESUMEN

Phosphates featuring a 3D framework offer a promising alternative to aqueous sodium-ion batteries, known for their safety, cost-effectiveness, scalability, high power density, and tolerance to mishandling. Nevertheless, they often suffer from poor reversible capacity stemming from limited redox couples. Herein, N-containing Na2VTi(PO4)3 is synthesized for aqueous sodium-ion storage through multi-electron redox reactions. It demonstrates a capacity of 155.2 mAh g-1 at 1 A g-1 (≈ 5.3 C) and delivers an ultrahigh specific energy of 55.9 Wh kg-1 in a symmetric aqueous sodium-ion battery. The results from in situ X-ray diffraction analysis, ex situ X-ray photoelectron spectroscopy analysis, and first-principle calculations provide insights into the local chemical environment of sodium ions, the mechanisms underlying capacity decay during cycling, and the dynamics of ion and electron transfer at various states of charge. This understanding will contribute to the advancement of electrode materials for aqueous sodium-ion batteries.

9.
J Antimicrob Chemother ; 79(4): 903-917, 2024 04 02.
Artículo en Inglés | MEDLINE | ID: mdl-38412335

RESUMEN

BACKGROUND: MDR Staphylococcus aureus infections, along with the severity of biofilm-associated infections, continue to threaten human health to a great extent. It necessitates the urgent development of novel antimicrobial and antibiofilm agents. OBJECTIVES: To reveal the mechanism and target of cinacalcet as an antibacterial and antimicrobial agent for S. aureus. METHODS: Screening of non-antibiotic drugs for antibacterial and antibiofilm properties was conducted using a small-molecule drug library. In vivo efficacy was assessed through animal models, and the antibacterial mechanism was studied using quantitative proteomics, biochemical assays, LiP-SMap, BLI detection and gene knockout techniques. RESULTS: Cinacalcet, an FDA-approved drug, demonstrated antibacterial and antibiofilm activity against S. aureus, with less observed development of bacterial resistance. Importantly, cinacalcet significantly improved survival in a pneumonia model and bacterial clearance in a biofilm infection model. Moreover, the antibacterial mechanism of cinacalcet mainly involves the destruction of membrane-targeted structures, alteration of energy metabolism, and production of reactive oxygen species (ROS). Cinacalcet was found to target IcaR, inhibiting biofilm formation through the negative regulation of IcaADBC. CONCLUSIONS: The findings suggest that cinacalcet has potential for repurposing as a therapeutic agent for MDR S. aureus infections and associated biofilms, warranting further investigation.


Asunto(s)
Antiinfecciosos , Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Animales , Humanos , Staphylococcus aureus , Cinacalcet/farmacología , Cinacalcet/uso terapéutico , Complejo Hierro-Dextran/uso terapéutico , Reposicionamiento de Medicamentos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Antiinfecciosos/uso terapéutico , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiología , Membrana Celular , Biopelículas , Pruebas de Sensibilidad Microbiana
10.
Drug Metab Dispos ; 52(7): 681-689, 2024 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-38719743

RESUMEN

This study aimed to characterize the effects of arsenic exposure on the expression of microsomal epoxide hydrolase (mEH or EPHX1) and soluble epoxide hydrolase (sEH or EPHX2) in the liver and small intestine. C57BL/6 mice were exposed to sodium arsenite in drinking water at various doses for up to 28 days. Intestinal, but not hepatic, mEH mRNA and protein expression was induced by arsenic at 25 ppm, in both males and females, whereas hepatic mEH expression was induced by arsenic at 50 or 100 ppm. The induction of mEH was gene specific, as the arsenic exposure did not induce sEH expression in either tissue. Within the small intestine, mEH expression was induced only in the proximal, but not the distal segments. The induction of intestinal mEH was accompanied by increases in microsomal enzymatic activities toward a model mEH substrate, cis-stilbene oxide, and an epoxide-containing drug, oprozomib, in vitro, and by increases in the levels of PR-176, the main hydrolysis metabolite of oprozomib, in the proximal small intestine of oprozomib-treated mice. These findings suggest that intestinal mEH, playing a major role in converting xenobiotic epoxides to less reactive diols, but not sEH, preferring endogenous epoxides as substrates, is relevant to the adverse effects of arsenic exposure, and that further studies of the interactions between drinking water arsenic exposure and the disposition or possible adverse effects of epoxide-containing drugs and other xenobiotic compounds in the intestine are warranted. SIGNIFICANCE STATEMENT: Consumption of arsenic-contaminated water has been associated with increased risks of various adverse health effects, such as diabetes, in humans. The small intestinal epithelial cells are the main site of absorption of ingested arsenic, but they are not well characterized for arsenic exposure-related changes. This study identified gene expression changes in the small intestine that may be mechanistically linked to the adverse effects of arsenic exposure and possible interactions between arsenic ingestion and the pharmacokinetics of epoxide-containing drugs in vivo.


Asunto(s)
Agua Potable , Epóxido Hidrolasas , Intestino Delgado , Ratones Endogámicos C57BL , Animales , Epóxido Hidrolasas/metabolismo , Epóxido Hidrolasas/genética , Ratones , Masculino , Femenino , Intestino Delgado/efectos de los fármacos , Intestino Delgado/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/enzimología , Arsénico/toxicidad , Arsénico/metabolismo , Arsenitos/toxicidad , Arsenitos/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/efectos de los fármacos , Microsomas/efectos de los fármacos , Microsomas/metabolismo , Microsomas/enzimología , Compuestos de Sodio/toxicidad
11.
Glycoconj J ; 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38954268

RESUMEN

A glucosyl-rich pectin, JMMP-3 (Mw, 2.572 × 104 g/mol, O-methyl % = 3.62%), was isolated and purified from the pericarp of the immature fruit of Juglans mandshurica Maxim. (QingLongYi). The structure of JMMP-3 was studied systematically by infrared spectroscopy, monosaccharide compositions, methylation analysis, partial acid hydrolysis, and 1/2D-NMR. The backbone of JMMP-3 possessed a smooth region (→ 4GalA1 →) and a hairy region (→ 4GalA1 → 2Rha1 →) with a molar ratio of 2: 5. The substitution of four characteristic side chains (R1-R4) occurs at C-4 of → 2,4)-α-Rhap-(1→, where R1 is composed of → 5)-α-Araf-(1→, R2 is composed of → 4)-ß-Galp-(1 → and ß-Galp-(1→, R3 is composed of α-Glcp-(1→, →4)-α-Glcp-(1 → and → 4,6)-α-Glcp-(1→, and R4 is composed of → 5)-α-Araf-(1→, ß-Galp-(1→, → 4)-ß-Galp-(1→, → 3,4)-ß-Galp-(1→, → 4,6)-ß-Galp-(1 → and → 2,4)-ß-Galp-(1 → . In addition, the antitumor activity of JMMP-3 on HepG2 cells was preliminarily investigated.

12.
Chemphyschem ; 25(9): e202400116, 2024 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-38380870

RESUMEN

Activation and transformation of methane is one of the "holy grails" in catalysis. Understanding the nature of active sites and mechanistic details via spectroscopic characterization of the reactive sites and key intermediates is of great challenge but crucial for the development of novel strategies for methane transformation. Herein, by employing photoelectron velocity-map imaging (PEVMI) spectroscopy in conjunction with quantum chemistry calculations, the Lewis acid-base pair (LABP) of [Taδ+-Nδ-] unit in Ta2N3 - acting as an active center to accomplish the heterolytic cleavage of C-H bond in CH4 has been confirmed by direct characterization of the reactant ion Ta2N3 - and the CH4-adduct intermediate Ta2N3CH4 -. Two active vibrational modes for the reactant (Ta2N3 -) and four active vibrational modes for the intermediate (Ta2N3CH4 -) were observed from the vibrationally resolved PEVMI spectra, which unequivocally determined the structure of Ta2N3 - and Ta2N3CH4 -. Upon heating, the LABP intermediate (Ta2N3CH4 -) containing the NH and Ta-CH3 unit can undergo the processes of C-N coupling and dehydrogenation to form the product with an adsorbed HCN molecule.

13.
Pharmacol Res ; 199: 106990, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37984506

RESUMEN

Resistance to temozolomide (TMZ), the frontline chemotherapeutic agent for glioblastoma (GBM), has emerged as a formidable obstacle, underscoring the imperative to identify alternative therapeutic strategies to improve patient outcomes. In this study, we comprehensively evaluated a novel agent, O6-methyl-2'-deoxyguanosine-5'-triphosphate (O6-methyl-dGTP) for its anti-GBM activity both in vitro and in vivo. Notably, O6-methyl-dGTP exhibited pronounced cytotoxicity against GBM cells, including those resistant to TMZ and overexpressing O6-methylguanine-DNA methyltransferase (MGMT). Mechanistic investigations revealed that O6-methyl-dGTP could be incorporated into genomic DNA, disrupting nucleotide pools balance, and inducing replication stress, resulting in S-phase arrest and DNA damage. The compound exerted its anti-tumor properties through the activation of AIF-mediated apoptosis and the parthanatos pathway. In vivo studies using U251 and Ln229 cell xenografts supported the robust tumor-inhibitory capacity of O6-methyl-dGTP. In an orthotopic transplantation model with U87MG cells, O6-methyl-dGTP showcased marginally superior tumor-suppressive activity compared to TMZ. In summary, our research, for the first time, underscores the potential of O6-methyl-dGTP as an effective candidate against GBM, laying a robust scientific groundwork for its potential clinical adoption in GBM treatment regimens.


Asunto(s)
Glioblastoma , Polifosfatos , Humanos , Glioblastoma/tratamiento farmacológico , Glioblastoma/metabolismo , Antineoplásicos Alquilantes/farmacología , Antineoplásicos Alquilantes/uso terapéutico , Nucleósidos/farmacología , Nucleósidos/uso terapéutico , Caspasas , Línea Celular Tumoral , Temozolomida/farmacología , Temozolomida/uso terapéutico , Nucleótidos , O(6)-Metilguanina-ADN Metiltransferasa/metabolismo , O(6)-Metilguanina-ADN Metiltransferasa/farmacología , O(6)-Metilguanina-ADN Metiltransferasa/uso terapéutico , Desoxiguanosina/farmacología , Desoxiguanosina/uso terapéutico , ADN , Resistencia a Antineoplásicos
14.
J Org Chem ; 89(4): 2741-2747, 2024 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-38299344

RESUMEN

Acyl radicals have been generated from the decarboxylation of α-oxocarboxylic acids by using a readily accessible organic pyrimidopteridine photoredox catalyst under ultraviolet-A (UV-A) light irradiation. These reactive acyl radicals were smoothly added to olefins such as styrenes and diverse Michael acceptors, with the assistance of H2O/D2O as hydrogen donors, enabling easy access to a diverse range of ketones/ß-deuterio ketones. A wide range of α-oxocarboxylic acids are compatible with this reaction, which shows a reliable, atom-economical, and eco-friendly protocol. Furthermore, postsynthetic diversifications and applications are presented.

15.
Org Biomol Chem ; 22(3): 482-485, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38108209

RESUMEN

An iodine-mediated cyclization has been developed to 4-aryl-NH-1,2,3-triazoles, with p-toluenesulfonyl hydrazide and sulfamic acid used as nitrogen sources. Sulfamic acid plays a crucial role in this reaction by both acting as a substrate and providing an acidic environment. This reaction offers a metal- and azide-free strategy to access NH-1,2,3-triazoles.

16.
Phys Chem Chem Phys ; 26(19): 14186-14193, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38713092

RESUMEN

Cost-effective and readily accessible 3d transition metals (TMs) have been considered as promising candidates for alkane activation while 3d TMs especially the early TMs are usually not very reactive with light alkanes. In this study, the reactivity of Vn+ and VnO+ (n = 1-9) cluster cations towards ethane under thermal collision conditions has been investigated using mass spectrometry and density functional theory calculations. Among Vn+ (n = 1-9) clusters, only V3-5+ can react with C2H6 to generate dehydrogenation products and the reaction rate constants are below 10-13 cm3 molecule-1 s-1. In contrast, the reaction rate constants for all VnO+ (n = 1-9) with C2H6 significantly increase by about 2-4 orders of magnitude. Theoretical analysis evidences that the addition of ligand O affects the charge distribution of the metal centers, resulting in a significant increase in the cluster reactivity. The analysis of frontier orbitals indicates that the agostic interaction determines the size-dependent reactivity of VnO+ cluster cations. This study provides a novel approach for improving the reactivity of early 3d TMs.

17.
J Phys Chem A ; 128(27): 5253-5259, 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38937133

RESUMEN

Metal oxide clusters with atomic oxygen radical anions are important model systems to study the mechanisms of activating and transforming very stable alkane molecules under ambient conditions. It is extremely challenging to characterize the activation and conversion of methane, the most stable alkane molecule, by metal oxide cluster anions due to the low reactivity of the anionic species. In this study, using a ship-lock type reactor that could be run at relatively high pressure conditions to provide a high number of collisions in ion-molecule reactions, the rate constants of the reactions between (MoO3)NO- (N = 1-21) cluster anions and the light alkanes (C1-C4) were measured under thermal collision conditions. The relationships among the reaction rates of different alkanes were obtained to establish a model to predict the low rate constants with methane from the high rate constants with C2-C4 alkanes. The model was tested by using available experimental results in literature. This study provides a new method to estimate the relatively low reactivity of atomic oxygen radical anions with methane on metal oxide clusters.

18.
Mol Ther ; 31(7): 2169-2187, 2023 07 05.
Artículo en Inglés | MEDLINE | ID: mdl-37211762

RESUMEN

Hypertrophic lysosomes are critical for tumor progression and drug resistance; however, effective and specific lysosome-targeting compounds for cancer therapy are lacking. Here we conducted a lysosomotropic pharmacophore-based in silico screen in a natural product library (2,212 compounds), and identified polyphyllin D (PD) as a novel lysosome-targeted compound. PD treatment was found to cause lysosomal damage, as evidenced by the blockade of autophagic flux, loss of lysophagy, and the release of lysosomal contents, thus exhibiting anticancer effects on hepatocellular carcinoma (HCC) cell both in vitro and in vivo. Closer mechanistic examination revealed that PD suppressed the activity of acid sphingomyelinase (SMPD1), a lysosomal phosphodieserase that catalyzes the hydrolysis of sphingomyelin to produce ceramide and phosphocholine, by directly occupying its surface groove, with Trp148 in SMPD1 acting as a major binding residue; this suppression of SMPD1 activity irreversibly triggers lysosomal injury and initiates lysosome-dependent cell death. Furthermore, PD-enhanced lysosomal membrane permeabilization to release sorafenib, augmenting the anticancer effect of sorafenib both in vivo and in vitro. Overall, our study suggests that PD can potentially be further developed as a novel autophagy inhibitor, and a combination of PD with classical chemotherapeutic anticancer drugs could represent a novel therapeutic strategy for HCC intervention.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/patología , Sorafenib/farmacología , Esfingomielina Fosfodiesterasa/farmacología , Neoplasias Hepáticas/metabolismo , Lisosomas/metabolismo , Autofagia , Resistencia a Medicamentos , Punciones
19.
Appl Opt ; 63(8): 1947-1951, 2024 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-38568633

RESUMEN

Three samples whose growth temperatures were 450°C, 500°C, and 560°C for S E S A M 1, S E S A M 2, and S E S A M 3, respectively, were tested by femto-second time-resolved transient absorption spectroscopy. The results indicate that the carrier dynamics of excited state absorption were dominant, and the lifetimes of carriers trapped by defect levels were about tens of pico-seconds. To further study the influence of carrier dynamics and recovery time of samples by ion-implantation, B + ions of 80 and 130 KeV were implanted into the samples with dose of 1014/c m 2. The modified samples showed a dominance of ultra-fast carrier dynamics of ground-state bleaching and direct recombination, which lasted for hundreds of femto-seconds, over excited state absorption. Additionally, carrier fast trapping was observed to be competitive with the excited state absorption process. After ion-implantation, the carrier dynamics of carrier trapping were enhanced, which contributed to forming an ultra-short laser, while the carrier dynamics of absorption of the excited state were suppressed. The conclusion that defect levels were partially eliminated by B + ion-implantation can be drawn.

20.
BMC Musculoskelet Disord ; 25(1): 522, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38970051

RESUMEN

BACKGROUND: For the treatment of coronoid process fractures, medial, lateral, anterior, anteromedial, and posterior approaches have been increasingly reported; however, there is no general consensus on the method of fixation of coronal fractures. Here, we present a highly-extensile minimally invasive approach to treat coronoid process fractures using a mini-plate that can achieve anatomic reduction, stable fixation, and anterior capsular repair. Further, the study aimed to determine the complication rate of the anterior minimally invasive approach and to evaluate functional and clinical patient-reported outcomes during follow-up. METHODS: Thirty-one patients diagnosed with coronoid fractures accompanied with a "terrible triad" or posteromedial rotational instability between April 2012 and October 2018 were included in the analysis. Anatomical reduction and mini-plate fixation of coronoid fractures were performed using an anterior minimally invasive approach. Patient-reported outcomes were evaluated using the Mayo Elbow Performance Index (MEPI) score, range of motion (ROM), and the visual analog score (VAS). The time of fracture healing and complications were recorded. RESULTS: The mean follow-up time was 26.7 months (range, 14-60 months). The average time to radiological union was 3.6 ± 1.3 months. During the follow-up period, the average elbow extension was 6.8 ± 2.9° while the average flexion was 129.6 ± 4.6°. According to Morrey's criteria, 26 (81%) elbows achieved a normal desired ROM. At the last follow-up, the mean MEPI score was 98 ± 3.3 points. There were no instances of elbow instability, elbow joint stiffness, subluxation or dislocation, infection, blood vessel complications, or nerve palsy. Overall, 10 elbows (31%) experienced heterotopic ossification. CONCLUSION: An anterior minimally invasive approach allows satisfactory fixation of coronoid fractures while reducing incision complications due to over-dissection of soft tissue injuries. In addition, this incision does not compromise the soft tissue stability of the elbow joint and allows the patient a more rapid return to rehabilitation exercises.


Asunto(s)
Placas Óseas , Articulación del Codo , Fijación Interna de Fracturas , Fracturas Conminutas , Rango del Movimiento Articular , Fracturas del Cúbito , Humanos , Masculino , Femenino , Fracturas del Cúbito/cirugía , Fracturas del Cúbito/diagnóstico por imagen , Fijación Interna de Fracturas/métodos , Fijación Interna de Fracturas/instrumentación , Persona de Mediana Edad , Adulto , Fracturas Conminutas/cirugía , Fracturas Conminutas/diagnóstico por imagen , Articulación del Codo/cirugía , Articulación del Codo/diagnóstico por imagen , Articulación del Codo/fisiopatología , Resultado del Tratamiento , Estudios Retrospectivos , Estudios de Seguimiento , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Procedimientos Quirúrgicos Mínimamente Invasivos/instrumentación , Curación de Fractura , Anciano , Medición de Resultados Informados por el Paciente , Adulto Joven
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