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1.
Nature ; 580(7801): 71-75, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32238943

RESUMEN

Chemical transformations determine the structure of a product, and therefore its properties, which in turn affect complex macroscopic functions such as the metabolic stability of pharmaceuticals or the volatility of perfumes. Therefore, reaction selection can influence the success or failure of a candidate molecule to meet a functional objective. The coupling of an amine with a carboxylic acid to form an amide bond is the most popular chemical reaction used for drug discovery1. However, there are many other ways to connect these two common functional groups together. Here we show computationally that amines and acids can couple via hundreds of hypothetical yet plausible transformations, and we demonstrate experimentally the application of a dozen such reactions. To investigate the contribution of chemical transformations to properties, we developed a string-based notation and used an enumerative combinatorics approach to produce a map of conceivable amine-acid coupling transformations, which can be charted using chemoinformatic techniques. We find that critical physicochemical parameters of the products, such as partition coefficient and polar surface area, vary considerably depending on the transformation chosen. Data mining the amine-acid coupling system produced here should enable reaction discovery, which we demonstrate by developing an esterification reaction found within the mapped space. Complex molecules with distinct property profiles can also be discovered within the amine-acid coupling system, as we show here via the late-stage diversification of drugs and natural products.

2.
J Virol ; : e0104224, 2024 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-39373477

RESUMEN

SARS-CoV-2 nonstructural protein 13 (nsp13) has been shown to selectively suppress the transcription of episomal DNA while sparing chromosomal DNA. Hepatitis B Virus (HBV) harbors covalently closed circular DNA (cccDNA), a form of viral episomal DNA found within infected hepatocyte nuclei. The persistence of cccDNA is the major cause of chronic HBV infection. In this study, we investigated the impact of SARS-CoV-2 nsp13 on HBV replication, particularly in the context of cccDNA. Our findings demonstrate that nsp13 effectively hinders HBV replication by suppressing the transcription of HBV cccDNA, both in vitro and in vivo. Additionally, we observed that SARS-CoV-2 nsp13 binds to HBV cccDNA and its NTPase and helicase activities contribute significantly to inhibiting HBV replication. Furthermore, our screening identified the interaction between nsp13 and structural maintenance of chromosomes 4, opening new avenues for future mechanistic inquiries. This study presents the evidence suggesting the potential utilization of SARS-CoV-2 nsp13 as a strategy to impede HBV replication by specifically targeting cccDNA. These findings provide a proof of concept for exploring nsp13 as a prospective approach in combating HBV infection. IMPORTANCE: To effectively combat hepatitis B virus (HBV), it is imperative to develop potent antiviral medications targeting covalently closed circular DNA (cccDNA). Our investigation aimed to assess the impact of SARS-CoV-2 nsp13 on HBV replication across diverse HBV models, confirming its ability to significantly reduce several HBV replication markers. Additionally, our identification of the interaction between nsp13 and SMC4 opens the door for further mechanistic exploration. This marks a paradigm shift in our approach to HBV antiviral therapy, introducing an entirely novel perspective. Our findings propose a novel strategy for developing anti-HBV drugs that specifically target HBV cccDNA.

3.
J Am Chem Soc ; 146(21): 14445-14452, 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38739877

RESUMEN

Transition-metal-catalyzed C-Si/Ge cross-coupling offers promising avenues for the synthesis of organosilanes/organogermanes, yet it is fraught with long-standing challenges. A Ni/Ti-catalyzed strategy is reported here, allowing the use of disubstituted malononitriles as tertiary C(sp3) coupling partners to couple with chlorosilanes and chlorogermanes, respectively. This method enables the catalytic cleavage of the C(sp3)-CN bond of the quaternary carbon followed by the formation of C(sp3)-Si/C(sp3)-Ge bonds from ubiquitously available starting materials. The efficiency and generality are showcased by a broad scope for both of the coupling partners, therefore holding the potential to synthesize structurally diverse quaternary organosilanes and organogermanes that were difficult to access previously.

4.
Small ; 20(7): e2306576, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37803924

RESUMEN

The widespread acceptance of nonaqueous rechargeable metal-gas batteries, known for their remarkably high theoretical energy density, faces obstacles such as poor reversibility and low energy efficiency under high charge-discharge current densities. To tackle these challenges, a novel catalytic cathode architecture for Mg-CO2 batteries, fabricated using a one-pot electrospinning method followed by heat treatment, is presented. The resulting structure features well-dispersed molybdenum carbide nanodots embedded within interconnected carbon nanofibers, forming a 3D macroporous conducting network. This cathode design enhances the volumetric efficiency, enabling effective discharge product deposition, while also improving electrical properties and boosting catalytic activity. This enhancement results in high discharge capacities and excellent rate capabilities, while simultaneously minimizing voltage hysteresis and maximizing energy efficiency. The battery exhibits a stable cycle life of over 250 h at a current density of 200 mA g-1 with a low initial charge-discharge voltage gap of 0.72 V. Even at incredibly high current densities, reaching 1600 mA g-1 , the battery maintains exceptional performance. These findings highlight the crucial role of cathode architecture design in enhancing the performance of Mg-CO2 batteries and hold promise for improving other metal-gas batteries that involve deposition-decomposition reactions.

5.
Chembiochem ; : e202400770, 2024 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-39419758

RESUMEN

Isocyanates are versatile electrophiles that can react with a wide range of nucleophiles to afford important organic structures. Although the reactions between isocyanates and alcohols, amines and organometallic reagents have been well established, the synthesis of amides through the decarboxylative condensation of carboxylic acids and isocyanates is less appreciated. In this review, the synthesis of isocyanates and its application on amide synthesis through the condensation with carboxylic acids are summarized and discussed. It is our hope that this review will attract more attention to this less mentioned transformation and inspire new developments in the fields of organic synthesis, polymer synthesis and chemical biology.

6.
Opt Lett ; 49(6): 1552-1555, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38489448

RESUMEN

We propose an asymmetry transmissive (AT) Helmholtz resonator metamaterial to interact with dual incidences of different polarizations from opposite directions to achieve coherent perfect absorption at a terahertz regime. More specifically, the proposed design will solely allow the x-polarized incidence tunnel into the Helmholtz resonator cavity array with roughly half the energy reflected. Meanwhile, the transmitted fields will be converted into the y-polarized counterparts so as to go out through the metamaterial and finally coherent canceled with the partially reflected fields of the other incidence. Our design, introducing the Helmholtz resonator array in the electromagnetics with an extension of the principle of polarization conversion under the coherent perfect absorption, should pave the way for the quest of building up more advanced wave trapping meta-devices for various applications in different disciplines.

7.
Stem Cells ; 41(10): 928-943, 2023 10 08.
Artículo en Inglés | MEDLINE | ID: mdl-37419489

RESUMEN

This study was performed to determine the effect of human umbilical cord mesenchymal stem cells (hucMSCs) treatment on pulmonary fibrosis and investigate the circFOXP1-mediated autophagic mechanism of hucMSCs treatment. Pulmonary fibrosis models were established by spraying bleomycin in mice and TGF-ß1 treatment of MRC-5 cells. Results showed that hucMSCs were retained in lung and hucMSCs treatment alleviated pulmonary fibrosis. Morphological staining indicated that hucMSCs-treated mice had thinner alveolar walls, effectively improved alveolar structure, significantly reduced alveolar inflammation, and decreased collagen deposition than control mice. Fibrotic proteins, including vimentin, α-SMA, collagens I and III, and the differentiation-related protein S100 calcium-binding protein A4 was reduced considerably in the hucMSCs-treated group. The mechanistic study revealed that the inhibition of hucMSCs treatment on pulmonary fibrogenesis depended on downregulating circFOXP1, in which hucMSCs treatment promoted circFOXP1-mediated autophagy process via blocking the nuclear human antigen R (HuR) translocation and promoting the HuR degradation, leading to a marked decrease in autophagy negative regulators EZH2, STAT1, and FOXK1. In conclusion, hucMSCs treatment significantly improved pulmonary fibrosis by downregulating the circFOXP1-HuR-EZH2/STAT1/FOXK1 autophagic axis. hucMSCs can act as an effective treatment for pulmonary fibrosis.


Asunto(s)
Células Madre Mesenquimatosas , Fibrosis Pulmonar , Ratones , Humanos , Animales , Fibrosis Pulmonar/terapia , Fibrosis , Pulmón/metabolismo , Células Madre Mesenquimatosas/metabolismo , Autofagia , Cordón Umbilical , Proteína Potenciadora del Homólogo Zeste 2/genética , Proteína Potenciadora del Homólogo Zeste 2/metabolismo , Factor de Transcripción STAT1 , Factores de Transcripción Forkhead/metabolismo
8.
Chemistry ; 30(41): e202401619, 2024 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-38773843

RESUMEN

Organic molecules with light-modifiable reactivity are important in many fields because they can serve as the "switch" for light to trigger chemical processes. Herein, we disclose a new type of stable non-twisted amides, the reactivity of which can be turned on by light as acyl transfer reagents. Upon photo-activation, these amides react with various nucleophiles including amines, phenols, hydroxide, thiols, boronic acids, and alkynes either under metal-free or metal-catalysis conditions. This reactivity hinges on the design and synthesis of a photo-activatable reagent (7-nitro-5,6-dihydrophenanthridine), which undergoes self-aromatization enabled by an internal oxidant under light. This masked acyl donor group is anticipated to be useful in scenarios where light is preferred to trigger a chemical process.

9.
Analyst ; 149(10): 2905-2914, 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38572989

RESUMEN

High cost, inherent destabilization, and intricate fixing of enzyme molecules are the main drawbacks of enzyme-based creatinine sensors. The design of a low-cost, stabilizable, and enzyme-free creatinine sensing probe is essential to address these limitations. In this work, an integrated three-dimensional (3D) free-standing electrode was designed to serve as a non-enzymatic creatinine sensing platform and was fabricated by rapid electrodeposition of a dense copper nanoparticle film on nickel foam (Cu NP film/NF). This low-cost, stable, easy-to-fabricate, and binder-free Cu NP film/NF electrode has abundant active sites and excellent electrochemical performance. Cyclic voltammetry measurements show a wide linear range (0.25-24 mM), low detection limit (0.17 mM), and high sensitivity (306 µA mM-1 cm-2). The developed sensor shows high recovery of creatinine concentration in real urine. Besides, it has better specificity, reproducibility, and robustness in detecting creatinine. These excellent results suggest that a non-enzymatic creatinine sensor based on an integrated 3D free-standing Cu NP film/NF electrode has good potential for non-invasive detection of urinary creatinine.


Asunto(s)
Cobre , Creatinina , Electrodos , Galvanoplastia , Límite de Detección , Nanopartículas del Metal , Níquel , Cobre/química , Níquel/química , Creatinina/orina , Creatinina/química , Nanopartículas del Metal/química , Humanos , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Reproducibilidad de los Resultados
10.
Arch Virol ; 169(2): 25, 2024 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-38214826

RESUMEN

Senecavirus A (SVA) is an emerging virus that causes vesicular disease in pigs. Construction of a full-length SVA cDNA clone is crucial for understanding its replication and pathogenesis. Here, we successfully constructed a CMV-promoter-driven infectious cDNA clone of the SVA isolate SVA/GX/CH/2018, which we named rSVA GX01. Sequence comparison between the pSVA GX01 and the parental isolate (SVA/GX/CH/2018) revealed three single-nucleotide differences. Four-week-old piglets were experimentally infected with either the parental virus or the cloned virus. The results showed that the cloned rSVA GX01 displayed weak pathogenicity in 4-week-old pigs compared to the parental virus SVA CH-GX-01-2018. The infectious clone of SVA will serve as a valuable tool for studying the viral replication cycle and for functional analysis of the viral genome.


Asunto(s)
Infecciones por Picornaviridae , Picornaviridae , Enfermedades de los Porcinos , Animales , Porcinos , ADN Complementario/genética , Células Clonales/patología
11.
Phys Chem Chem Phys ; 26(34): 22388-22394, 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39139147

RESUMEN

The external electric field has emerged as a powerful tool for building molecular switches with excellent properties. In this work, we investigate the impact of an external electric field on the transition between lithium salt and electride-like molecule conformations in Li@corannulene. Remarkably, the distance between the Li atom and the corannulene bottom displays a sharp increase under the influence of an external electric field strength of F-z = 110 × 10-4 a.u. As the external electric field strength increases, the Li atom brings about different directions of charge transfer (CT). The natural population analysis (NPA) charge and the molecular electrostatic potential (ESP) results show that the intermolecular CT occurs from the Li atom to the corannulene with the F-z ranging from 0 to 100 × 10-4 a.u. Interestingly, when the external electric field reaches F-z = 110 × 10-4 a.u., the CT is oriented from the corannulene to the Li atom. Moreover, electron localization function (ELF) basins are presented under an F-z of 110 × 10-4 a.u., which indicates that Li@corannulene exhibits electride-like (e-⋯[Li@corannulene]+) molecules and lithiation salt (Li+[corannulene]-) under an F-z of 0 to 100 × 10-4 a.u. Significantly, the differences in charge transfer also contribute to a significant improvement in hyperpolarizabilities (ßtot) during the conformation transition from lithiation salt (Li+[corannulene]-) to electride-like (e-⋯[Li@corannulene]+) molecules. This study explores the potential of Li@corannulene as a promising second-order NLO material, and the external electric field provides an efficient strategy for designing and developing NLO switching devices.

12.
J Nanobiotechnology ; 22(1): 563, 2024 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-39272146

RESUMEN

BACKGROUND: While small extracellular vesicles (sEVs)-derived circular RNAs (circRNAs) have been emerged as significant players in cancer, the function and underlying mechanism of sEVs-derived circRNAs in anti-cancer immunity remain unclear. METHODS: Gastric cancer (GC)-derived circRNAs were identified using RNA-seq data from GEO datasets and quantitative reverse transcription polymerase chain reaction (qRT-PCR), RNA immunoprecipitation, dual-luciferase assay, and bioinformatics analysis were performed to investigate the regulatory axis. Transwell assay, wound healing assay, cell counting kit-8 (CCK-8) assay, and xenograft models were used to evaluate its role in GC progression in vivo and in vitro. The delivery of specific circRNAs into sEVs were verified through electron microscopy, nanoparticle tracking analysis (NTA) and fuorescence in situ hybridization (FISH). Flow cytometric analysis and immunohistochemical staining were conducted to find out how specific circRNAs mediated CD8+ T cell exhaustion and resistant to anti-programmed cell death 1 (PD-1) therapy. RESULTS: We identified that circ_0001947, packaged by GC-derived sEVs, was obviously elevated in GC and was associated with poor clinical outcome. High circ0001947 level augmented the proliferation, migration, and invasion of GC cells. Mechanistically, circ0001947 sponged miR-661 and miR-671-5p to promote the expression of CD39, which further facilitated CD8+ T cell exhaustion and immune resistance. Conversely, blocking circ_0001947 attenuated CD8+ T cell exhaustion and increased the response to anti-PD-1 therapy. CONCLUSIONS: Our study manifested the therapeutic potential of targeting sEVs-transmitted circ_0001947 to prohibit CD8+ T cell exhaustion and immune resistance in GC.


Asunto(s)
Linfocitos T CD8-positivos , Vesículas Extracelulares , ARN Circular , Neoplasias Gástricas , Neoplasias Gástricas/patología , Neoplasias Gástricas/inmunología , ARN Circular/genética , Humanos , Vesículas Extracelulares/metabolismo , Animales , Linfocitos T CD8-positivos/inmunología , Ratones , Línea Celular Tumoral , Receptor de Muerte Celular Programada 1/metabolismo , Receptor de Muerte Celular Programada 1/genética , Progresión de la Enfermedad , Ratones Desnudos , Resistencia a Antineoplásicos , Proliferación Celular/efectos de los fármacos , Femenino , Ratones Endogámicos BALB C , Masculino , Inhibidores de Puntos de Control Inmunológico/farmacología , Agotamiento de Células T
13.
Graefes Arch Clin Exp Ophthalmol ; 262(5): 1409-1419, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-37815595

RESUMEN

PURPOSE: To compare the efficacy of different anti-vascular endothelial growth factor (VEGF) agents for the treatment of retinopathy of prematurity (ROP) in preterm infants. METHODS: Seven databases were searched for eligible literature up to February 22, 2023. Studies were included if they were randomised controlled trials (RCTs) investigating the efficacy of anti-VEGF agents for ROP in infants. A network meta-analysis (NMA) was performed. We also conducted subgroup analyses to determine the efficacy ranking of regimens used in different regions. The odds ratio (OR), standardised mean difference (SMD), and surface under the cumulative ranking curve (SUCRA) were calculated for each outcome. RESULTS: Thirteen RCTs of 10 different regimens, involving 1196 infants (2388 eyes), were identified. Bevacizumab (0.625 mg; OR = 0.16, 95% confidence interval [CI] 0.06-0.40, SUCRA = 80.6%) and conbercept (0.15 mg; OR = 0.08, 95% CI 0.02-0.30, SUCRA = 96.0%) were the most effective regimens in reducing the risk of ROP recurrence requiring retreatment in Western countries and China, respectively. Compared with laser therapy, bevacizumab (0.625 mg; SMD = 1.54, 95% CI 0.06-3.02) achieved significantly longer intervals between treatment and recurrence. No significant difference in the risk of retinal detachment was detected between any anti-VEGF agent and laser (p > 0.05). CONCLUSIONS: Bevacizumab (0.625 mg) and conbercept (0.15 mg) appeared to be the most effective therapies for ROP in Western countries and China, respectively. More high-quality RCTs are warranted to evaluate the efficacy and long-term safety of anti-VEGF drugs for the management of ROP.

14.
BMC Biol ; 21(1): 231, 2023 10 23.
Artículo en Inglés | MEDLINE | ID: mdl-37867192

RESUMEN

BACKGROUND: RNA splicing plays significant roles in fundamental biological activities. However, our knowledge about the roles of alternative splicing and underlying mechanisms during spermatogenesis is limited. RESULTS: Here, we report that Serine/arginine-rich splicing factor 2 (SRSF2), also known as SC35, plays critical roles in alternative splicing and male reproduction. Male germ cell-specific deletion of Srsf2 by Stra8-Cre caused complete infertility and defective spermatogenesis. Further analyses revealed that deletion of Srsf2 disrupted differentiation and meiosis initiation of spermatogonia. Mechanistically, by combining RNA-seq data with LACE-seq data, we showed that SRSF2 regulatory networks play critical roles in several major events including reproductive development, spermatogenesis, meiotic cell cycle, synapse organization, DNA recombination, chromosome segregation, and male sex differentiation. Furthermore, SRSF2 affected expression and alternative splicing of Stra8, Stag3 and Atr encoding critical factors for spermatogenesis in a direct manner. CONCLUSIONS: Taken together, our results demonstrate that SRSF2 has important functions in spermatogenesis and male fertility by regulating alternative splicing.


Asunto(s)
Empalme del ARN , Espermatogénesis , Masculino , Humanos , Espermatogénesis/genética , Proteínas de Unión al ARN/genética , Empalme Alternativo , Meiosis/genética , ARN Mensajero
15.
Sensors (Basel) ; 24(20)2024 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-39460152

RESUMEN

This paper reports the successful application of a self-developed, miniaturized, low-power nano-star tracker for precise attitude measurement of a 5-m-long satellite extension boom. Such extension booms are widely used in space science missions to extend and support payloads like magnetometers. The nano-star tracker, based on a CMOS image sensor, weighs 150 g (including the baffle), has a total power consumption of approximately 0.85 W, and achieves a pointing accuracy of about 5 arcseconds. It is paired with a low-cost, commercial lens and utilizes automated calibration techniques for measurement correction of the collected data. This system has been successfully applied to the precise attitude measurement of the 5-m magnetometer boom on the Chinese Advanced Space Technology Demonstration Satellite (SATech-01). Analysis of the in-orbit measurement data shows that within shadowed regions, the extension boom remains stable relative to the satellite, with a standard deviation of 30'' (1σ). The average Euler angles for the "X-Y-Z" rotation sequence from the extension boom to the satellite are [-89.49°, 0.08°, 90.11°]. In the transition zone from shadow to sunlight, influenced by vibrations and thermal factors during satellite attitude adjustments, the maximum angular fluctuation of the extension boom relative to the satellite is approximately ±2°. These data and the accuracy of the measurements can effectively correct magnetic field vector measurements.

16.
Int J Mol Sci ; 25(6)2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38542068

RESUMEN

The genus Neopestalotiopsis consists of obligate parasites that cause ring spot, scab, and leaf blight diseases in higher plant species. We assembled the three complete mitogenomes for the guava fruit ring spot pathogen, Neopestalotiopsis cubana. The mitogenomes are circular, with sizes of 38,666 bp, 33,846 bp, and 32,593 bp. The comparative analyses with Pestalotiopsis fici showed that N. cubana differs greatly from it in the length of the mitogenomes and the number of introns. Moreover, they showed significant differences in the gene content and tRNAs. The two genera showed little difference in gene skewness and codon preference for core protein-coding genes (PCGs). We compared gene sequencing in the mitogenomes of the order Xylariales and found large-scale gene rearrangement events, such as gene translocations and the duplication of tRNAs. N. cubana shows a unique evolutionary position in the phylum Ascomycota constructed in phylogenetic analyses. We also found a more concentrated distribution of evolutionary pressures on the PCGs of Neopestalotiopsis in the phylum Ascomycota and that they are under little selective pressure compared to other species and are subjected to purifying selection. This study explores the evolutionary dynamics of the mitogenomes of Neopestalotiopsis and provides important support for genetic and taxonomic studies.


Asunto(s)
Genoma Mitocondrial , Xylariales , Filogenia , Xylariales/genética , ARN de Transferencia/genética , Intrones
17.
J Environ Manage ; 358: 120834, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38631170

RESUMEN

The organic matter (OM) and nitrogen in Fresh leachate (FL) from waste compression sites pose environmental and health risks. Even though the constructed wetland (CW) can efficiently remove these pollutants, the molecular-level transformations of dissolved OM (DOM) in FL remain uncertain. This study reports the molecular dynamics of DOM and nitrogen removal during FL treatment in CWs. Two lab-scale vertical-flow CW systems were employed: one using only sand as substrates (act as a control, CW-C) and the other employing an equal mixture of manganese ore powder and sand (experimental, CW-M). Over 488 days of operation, CW-M exhibited significantly higher removal rates for chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), and dissolved organic matter (represented by dissolved organic carbon, DOC) at 98.2 ± 2.5%, 99.2 ± 1.4%, and 97.9 ± 1.9%, respectively, in contrast to CW-C (92.8 ± 6.8%, 77.1 ± 28.1%, and 74.7 ± 9.5%). The three-dimensional fluorescence excitation-emission matrix (3D-EEM) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analyses unveiled that the influent DOM was predominantly composed of readily biodegradable protein-like substances with high carbon content and low unsaturation. Throughout treatment, it led to the degradation of low O/C and high H/C compounds, resulting in the formation of DOM with higher unsaturation and aromaticity, resembling humic-like substances. CW-M showcased a distinct DOM composition, characterized by lower carbon content yet higher unsaturation and aromaticity than CW-C. The study also identified the presence of Gammaproteobacteria, reported as Mn-oxidizing bacteria with significantly higher abundance in the upper and middle layers of CW-M, facilitating manganese cycling and improving DOM removal. Key pathways contributing to DOM removal encompassed adsorption, catalytic oxidation by manganese oxides, and microbial degradation. This study offers novel insights into DOM transformation and removal from FL during CW treatment, which will facilitate better design and enhanced performance.


Asunto(s)
Manganeso , Contaminantes Químicos del Agua , Humedales , Manganeso/química , Contaminantes Químicos del Agua/química , Nitrógeno/química , Análisis de la Demanda Biológica de Oxígeno
18.
Pharm Dev Technol ; : 1-10, 2024 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-39329286

RESUMEN

Herein, we designed and synthesized novel reactive oxygen species (ROS)-responsive glycol chitosan-doxorubicin (DOX) prodrug via a ROS-cleavable thioketal (TK) linker. The obtained GC-TK-DOX formed self-assembled nanoparticles of 312 nm in aqueous media. Photosensitizers zinc phthalocyanine (ZnPc)-loaded GC-TK-DOX (GC-TK-DOX/ZnPc) nanoparticles were fabricated by using a dialysis approach. The GC-TK-DOX and GC-TK-DOX/ZnPc nanoparticles were nearly spherical by transmission electron microscopy (TEM) observation. Under 660-nm laser irradiation, GC-TK-DOX/ZnPc could generate singlet oxygen. Further, GC-TK-DOX/ZnPc nanoparticles exhibited ROS-sensitive release of DOX and ZnPc in vitro. GC-TK-DOX/ZnPc with laser irradiation showed more drug uptake and higher cytotoxic effects than GC-TK-DOX/ZnPc without irradiation, free DOX and GC-TK-DOX in HeLa tumor cells. Overall, these findings suggested that GC-TK-DOX/ZnPc could be a promising nanoarchitecture for synergetic chemo-photodynamic therapy against tumors.

19.
Korean J Physiol Pharmacol ; 28(3): 183-196, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38682167

RESUMEN

Ferroptosis is a novel mechanism of programmed cell death, characterized by intracellular iron overload, intensified lipid peroxidation, and abnormal accumulation of reactive oxygen species, which ultimately resulting in cell membrane impairment and demise. Research has revealed that cancer cells exhibit a greater demand for iron compared to normal cells, indicating a potential susceptibility of cancer cells to ferroptosis. Stomach and colorectal cancers are common gastrointestinal malignancies, and their elevated occurrence and mortality rates render them a global health concern. Despite significant advancements in medical treatments, certain unfavorable consequences and drug resistance persist. Consequently, directing attention towards the phenomenon of ferroptosis in gastric and colorectal cancers holds promise for enhancing therapeutic efficacy. This review aims to elucidate the intricate cellular metabolism associated with ferroptosis, encompassing lipid and amino acid metabolism, as well as iron metabolic processes. Furthermore, the significance of ferroptosis in the context of gastric and colorectal cancer is thoroughly examined and discussed.

20.
Angew Chem Int Ed Engl ; : e202415164, 2024 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-39394042

RESUMEN

Enantioselective synthesis of (spiro)cyclobutane derivatives poses significant challenges yet holds promising applications for both synthetic and medicinal chemistry. We report here a nickel-catalyzed asymmetric syn-hydrometalative 4-exo-trig cyclization of alkynones to synthesize alkenyl cyclobutanols with a tetrasubstituted stereocenter. This strategy features a broad substrate scope, delivering a variety of trifluoromethyl-containing rigid (spiro)carbocycle skeletons in good yields and high enantioselectivities (up to 84% yield and 98.5:1.5 er). The synthetic utility is demonstrated through stereospecific transformations into fused spirocycles. Experimental and computational mechanistic studies indicate that the reaction is initiated by an active Ni-H species, with carbonyl-directed hydrometalation as the key for regioselective control. This catalytic method provides a general solution for regioselective hydrofunctionalization of alkynes and represents an efficient reaction pattern for assembling highly strained enantioenriched bioisosteres.

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