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1.
Nat Immunol ; 24(11): 1813-1824, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37813965

RESUMEN

Kupffer cells, the liver tissue resident macrophages, are critical in the detection and clearance of cancer cells. However, the molecular mechanisms underlying their detection and phagocytosis of cancer cells are still unclear. Using in vivo genome-wide CRISPR-Cas9 knockout screening, we found that the cell-surface transmembrane protein ERMAP expressed on various cancer cells signaled to activate phagocytosis in Kupffer cells and to control of liver metastasis. ERMAP interacted with ß-galactoside binding lectin galectin-9 expressed on the surface of Kupffer cells in a manner dependent on glycosylation. Galectin-9 formed a bridging complex with ERMAP and the transmembrane receptor dectin-2, expressed on Kupffer cells, to induce the detection and phagocytosis of cancer cells by Kupffer cells. Patients with low expression of ERMAP on tumors had more liver metastases. Thus, our study identified the ERMAP-galectin-9-dectin-2 axis as an 'eat me' signal for Kupffer cells.


Asunto(s)
Citofagocitosis , Macrófagos del Hígado , Humanos , Fagocitosis/genética , Galectinas/genética , Galectinas/metabolismo , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo
2.
Nature ; 626(7999): 523-528, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38356068

RESUMEN

Spatial, momentum and energy separation of electronic spins in condensed-matter systems guides the development of new devices in which spin-polarized current is generated and manipulated1-3. Recent attention on a set of previously overlooked symmetry operations in magnetic materials4 leads to the emergence of a new type of spin splitting, enabling giant and momentum-dependent spin polarization of energy bands on selected antiferromagnets5-10. Despite the ever-growing theoretical predictions, the direct spectroscopic proof of such spin splitting is still lacking. Here we provide solid spectroscopic and computational evidence for the existence of such materials. In the noncoplanar antiferromagnet manganese ditelluride (MnTe2), the in-plane components of spin are found to be antisymmetric about the high-symmetry planes of the Brillouin zone, comprising a plaid-like spin texture in the antiferromagnetic (AFM) ground state. Such an unconventional spin pattern, further found to diminish at the high-temperature paramagnetic state, originates from the intrinsic AFM order instead of spin-orbit coupling (SOC). Our finding demonstrates a new type of quadratic spin texture induced by time-reversal breaking, placing AFM spintronics on a firm basis and paving the way for studying exotic quantum phenomena in related materials.

3.
Nature ; 615(7950): 67-72, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36603811

RESUMEN

Pyridines and related N-heteroarenes are commonly found in pharmaceuticals, agrochemicals and other biologically active compounds1,2. Site-selective C-H functionalization would provide a direct way of making these medicinally active products3-5. For example, nicotinic acid derivatives could be made by C-H carboxylation, but this remains an elusive transformation6-8. Here we describe the development of an electrochemical strategy for the direct carboxylation of pyridines using CO2. The choice of the electrolysis setup gives rise to divergent site selectivity: a divided electrochemical cell leads to C5 carboxylation, whereas an undivided cell promotes C4 carboxylation. The undivided-cell reaction is proposed to operate through a paired-electrolysis mechanism9,10, in which both cathodic and anodic events play critical roles in altering the site selectivity. Specifically, anodically generated iodine preferentially reacts with a key radical anion intermediate in the C4-carboxylation pathway through hydrogen-atom transfer, thus diverting the reaction selectivity by means of the Curtin-Hammett principle11. The scope of the transformation was expanded to a wide range of N-heteroarenes, including bipyridines and terpyridines, pyrimidines, pyrazines and quinolines.


Asunto(s)
Dióxido de Carbono , Electroquímica , Pirazinas , Piridinas , Pirimidinas , Quinolinas , Hidrógeno/química , Pirazinas/química , Piridinas/química , Pirimidinas/química , Electroquímica/métodos , Dióxido de Carbono/química , Quinolinas/química , Preparaciones Farmacéuticas/síntesis química , Preparaciones Farmacéuticas/química
4.
Cell ; 152(5): 984-96, 2013 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-23452848

RESUMEN

Mutations in the X-linked MECP2 cause Rett syndrome, a devastating neurological disorder typified by a period of apparently normal development followed by loss of cognitive and psychomotor skills. Data from rare male patients suggest symptom onset and severity can be influenced by the location of the mutation, with amino acids 270 and 273 marking the difference between neonatal encephalopathy and death, on the one hand, and survival with deficits on the other. We therefore generated two mouse models expressing either MeCP2-R270X or MeCP2-G273X. The mice developed phenotypes at strikingly different rates and showed differential ATRX nuclear localization within the nervous system, over time, coinciding with phenotypic progression. We discovered that MeCP2 contains three AT-hook-like domains over a stretch of 250 amino acids, like HMGA DNA-bending proteins; one conserved AT-hook is disrupted in MeCP2-R270X, lending further support to the notion that one of MeCP2's key functions is to alter chromatin structure.


Asunto(s)
Proteína 2 de Unión a Metil-CpG/química , Proteína 2 de Unión a Metil-CpG/metabolismo , Síndrome de Rett/metabolismo , Secuencia de Aminoácidos , Animales , ADN Helicasas/metabolismo , Modelos Animales de Enfermedad , Femenino , Heterocromatina/metabolismo , Masculino , Proteína 2 de Unión a Metil-CpG/genética , Ratones , Ratones Noqueados , Ratones Transgénicos , Datos de Secuencia Molecular , Proteínas Nucleares/metabolismo , Estructura Terciaria de Proteína , Síndrome de Rett/genética , Síndrome de Rett/fisiopatología , Alineación de Secuencia , Transcripción Genética , Proteína Nuclear Ligada al Cromosoma X
5.
Nature ; 600(7887): 75-80, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34853455

RESUMEN

Nonlinear wave-matter interactions may give rise to solitons, phenomena that feature inherent stability in wave propagation and unusual spectral characteristics. Solitons have been created in a variety of physical systems and have had important roles in a broad range of applications, including communications, spectroscopy and metrology1-4. In recent years, the realization of dissipative Kerr optical solitons in microcavities has led to the generation of frequency combs in a chip-scale platform5-10. Within a cavity, photons can interact with mechanical modes. Cavity optomechanics has found applications for frequency conversion, such as microwave-to-optical or radio-frequency-to-optical11-13, of interest for communications and interfacing quantum systems operating at different frequencies. Here we report the observation of mechanical micro-solitons excited by optical fields in an optomechanical microresonator, expanding soliton generation in optical resonators to a different spectral window. The optical field circulating along the circumference of a whispering gallery mode resonator triggers a mechanical nonlinearity through optomechanical coupling, which in turn induces a time-varying periodic modulation on the propagating mechanical mode, leading to a tailored modal dispersion. Stable localized mechanical wave packets-mechanical solitons-can be realized when the mechanical loss is compensated by phonon gain and the optomechanical nonlinearity is balanced by the tailored modal dispersion. The realization of mechanical micro-solitons driven by light opens up new avenues for optomechanical technologies14 and may find applications in acoustic sensing, information processing, energy storage, communications and surface acoustic wave technology.

6.
Proc Natl Acad Sci U S A ; 121(25): e2400546121, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38857407

RESUMEN

Reduction of carbon dioxide (CO2) by renewable electricity to produce multicarbon chemicals, such as ethylene (C2H4), continues to be a challenge because of insufficient Faradaic efficiency, low production rates, and complex mechanistic pathways. Here, we report that the rate-determining steps (RDS) on common copper (Cu) surfaces diverge in CO2 electroreduction, leading to distinct catalytic performances. Through a combination of experimental and computational studies, we reveal that C─C bond-making is the RDS on Cu(100), whereas the protonation of *CO with adsorbed water becomes rate-limiting on Cu(111) with a higher energy barrier. On an oxide-derived Cu(100)-dominant Cu catalyst, we reach a high C2H4 Faradaic efficiency of 72%, partial current density of 359 mA cm-2, and long-term stability exceeding 100 h at 500 mA cm-2, greatly outperforming its Cu(111)-rich counterpart. We further demonstrate constant C2H4 selectivity of >60% over 70 h in a membrane electrode assembly electrolyzer with a full-cell energy efficiency of 23.4%.

7.
Proc Natl Acad Sci U S A ; 120(42): e2302482120, 2023 10 17.
Artículo en Inglés | MEDLINE | ID: mdl-37816050

RESUMEN

Myocardial infarction (MI) is a leading cause of heart failure (HF), associated with morbidity and mortality worldwide. As an essential part of gene expression regulation, the role of alternative polyadenylation (APA) in post-MI HF remains elusive. Here, we revealed a global, APA-mediated, 3' untranslated region (3' UTR)-lengthening pattern in both human and murine post-MI HF samples. Furthermore, the 3' UTR of apoptotic repressor gene, AVEN, is lengthened after MI, contributing to its downregulation. AVEN knockdown increased cardiomyocyte apoptosis, whereas restoration of AVEN expression substantially improved cardiac function. Mechanistically, AVEN 3' UTR lengthening provides additional binding sites for miR-30b-5p and miR-30c-5p, thus reducing AVEN expression. Additionally, PABPN1 (poly(A)-binding protein 1) was identified as a potential regulator of AVEN 3' UTR lengthening after MI. Altogether, our findings revealed APA as a unique mechanism regulating cardiac injury in response to MI and also indicated that the APA-regulated gene, AVEN, holds great potential as a critical therapeutic target for treating post-MI HF.


Asunto(s)
Lesiones Cardíacas , MicroARNs , Infarto del Miocardio , Animales , Humanos , Ratones , Regiones no Traducidas 3'/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Regulación hacia Abajo , Lesiones Cardíacas/genética , Proteínas de la Membrana/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Miocitos Cardíacos/metabolismo , Proteína I de Unión a Poli(A)
8.
Proc Natl Acad Sci U S A ; 120(51): e2312876120, 2023 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-38085783

RESUMEN

Electrochemical synthesis of valuable chemicals and feedstocks through carbon dioxide (CO2) reduction in acidic electrolytes can surmount the considerable CO2 loss in alkaline and neutral conditions. However, achieving high productivity, while operating steadily in acidic electrolytes, remains a big challenge owing to the severe competing hydrogen evolution reaction. Here, we show that vertically grown bismuth nanosheets on a gas-diffusion layer can create numerous cavities as electrolyte reservoirs, which confine in situ-generated hydroxide and potassium ions and limit inward proton diffusion, producing locally alkaline environments. Based on this design, we achieve formic acid Faradaic efficiency of 96.3% and partial current density of 471 mA cm-2 at pH 2. When operated in a slim continuous-flow electrolyzer, the system exhibits a full-cell formic acid energy efficiency of 40% and a single pass carbon efficiency of 79% and performs steadily over 50 h. We further demonstrate the production of pure formic acid aqueous solution with a concentration of 4.2 weight %.

9.
Circulation ; 149(14): 1121-1138, 2024 04 02.
Artículo en Inglés | MEDLINE | ID: mdl-38152931

RESUMEN

BACKGROUND: Progressive remodeling of cardiac gene expression underlies decline in cardiac function, eventually leading to heart failure. However, the major determinants of transcriptional network switching from normal to failed hearts remain to be determined. METHODS: In this study, we integrated human samples, genetic mouse models, and genomic approaches, including bulk RNA sequencing, single-cell RNA sequencing, chromatin immunoprecipitation followed by high-throughput sequencing, and assay for transposase-accessible chromatin with high-throughput sequencing, to identify the role of chromatin remodeling complex INO80 in heart homeostasis and dysfunction. RESULTS: The INO80 chromatin remodeling complex was abundantly expressed in mature cardiomyocytes, and its expression further increased in mouse and human heart failure. Cardiomyocyte-specific overexpression of Ino80, its core catalytic subunit, induced heart failure within 4 days. Combining RNA sequencing, chromatin immunoprecipitation followed by high-throughput sequencing, and assay for transposase-accessible chromatin with high-throughput sequencing, we revealed INO80 overexpression-dependent reshaping of the nucleosomal landscape that remodeled a core set of transcription factors, most notably the MEF2 (Myocyte Enhancer Factor 2) family, whose target genes were closely associated with cardiac function. Conditional cardiomyocyte-specific deletion of Ino80 in an established mouse model of heart failure demonstrated remarkable preservation of cardiac function. CONCLUSIONS: In summary, our findings shed light on the INO80-dependent remodeling of the chromatin landscape and transcriptional networks as a major mechanism underlying cardiac dysfunction in heart failure, and suggest INO80 as a potential preventative or interventional target.


Asunto(s)
Redes Reguladoras de Genes , Insuficiencia Cardíaca , Humanos , Animales , Ratones , Ensamble y Desensamble de Cromatina , Cromatina/metabolismo , Miocitos Cardíacos/metabolismo , Insuficiencia Cardíaca/genética , Insuficiencia Cardíaca/metabolismo , ARN/metabolismo , Transposasas/metabolismo , ATPasas Asociadas con Actividades Celulares Diversas/metabolismo , Proteínas de Unión al ADN/metabolismo
10.
Eur J Immunol ; : e2350655, 2024 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-38973083

RESUMEN

Sepsis arises from an uncontrolled inflammatory response triggered by infection or stress, accompanied by alteration in cellular energy metabolism, and a strong correlation exists between these factors. Alpha-ketoglutarate (α-KG), an intermediate product of the TCA cycle, has the potential to modulate the inflammatory response and is considered a crucial link between energy metabolism and inflammation. The scavenger receptor (SR-A5), a significant pattern recognition receptor, assumes a vital function in anti-inflammatory reactions. In the current investigation, we have successfully illustrated the ability of α-KG to mitigate inflammatory factors in the serum of septic mice and ameliorate tissue damage. Additionally, α-KG has been shown to modulate metabolic reprogramming and macrophage polarization. Moreover, our findings indicate that the regulatory influence of α-KG on sepsis is mediated through SR-A5. We also elucidated the mechanism by which α-KG regulates SR-A5 expression and found that α-KG reduced the N6-methyladenosine level of macrophages by up-regulating the m6A demethylase ALKBH5. α-KG plays a crucial role in inhibiting inflammation by regulating SR-A5 expression through m6A demethylation during sepsis. The outcomes of this research provide valuable insights into the relationship between energy metabolism and inflammation regulation, as well as the underlying molecular regulatory mechanism.

11.
Plant Physiol ; 2024 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-39190817

RESUMEN

Cold stress during early development limits maize (Zea mays L.) production in temperate zones. Low temperatures restrict root growth and reprogram gene expression. Here, we provide a systematic transcriptomic landscape of maize primary roots, their tissues, and cell types in response to cold stress. The epidermis exhibited a unique transcriptomic cold response, and genes involved in root hair formation were dynamically regulated in this cell type by cold. Consequently, activation of genes involved in root hair tip growth contributed to root hair recovery under moderate cold conditions. The maize root hair defective mutants roothair defective 5 (rth5) and roothair defective 6 (rth6) displayed enhanced cold tolerance with respect to primary root elongation. Furthermore, dehydration response element-binding protein 2.1 (dreb2.1) was the only member of the dreb subfamily of AP2/EREB transcription factor genes upregulated in primary root tissues and cell types but exclusively downregulated in root hairs upon cold stress. Plants overexpressing dreb2.1 significantly suppressed root hair elongation after moderate cold stress. Finally, the expression of rth3 was regulated by dreb2.1 under cold conditions, while rth6 transcription was regulated by dreb2.1 irrespective of the temperature regime. We demonstrated that dreb2.1 negatively regulates root hair plasticity at low temperatures by coordinating the expression of root hair defective genes in maize.

12.
Blood ; 142(10): 903-917, 2023 09 07.
Artículo en Inglés | MEDLINE | ID: mdl-37319434

RESUMEN

The bone marrow microenvironment (BMM) can regulate leukemia stem cells (LSCs) via secreted factors. Increasing evidence suggests that dissecting the mechanisms by which the BMM maintains LSCs may lead to the development of effective therapies for the eradication of leukemia. Inhibitor of DNA binding 1 (ID1), a key transcriptional regulator in LSCs, previously identified by us, controls cytokine production in the BMM, but the role of ID1 in acute myeloid leukemia (AML) BMM remains obscure. Here, we report that ID1 is highly expressed in the BMM of patients with AML, especially in BM mesenchymal stem cells, and that the high expression of ID1 in the AML BMM is induced by BMP6, secreted from AML cells. Knocking out ID1 in mesenchymal cells significantly suppresses the proliferation of cocultured AML cells. Loss of Id1 in the BMM results in impaired AML progression in AML mouse models. Mechanistically, we found that Id1 deficiency significantly reduces SP1 protein levels in mesenchymal cells cocultured with AML cells. Using ID1-interactome analysis, we found that ID1 interacts with RNF4, an E3 ubiquitin ligase, and causes a decrease in SP1 ubiquitination. Disrupting the ID1-RNF4 interaction via truncation in mesenchymal cells significantly reduces SP1 protein levels and delays AML cell proliferation. We identify that the target of Sp1, Angptl7, is the primary differentially expression protein factor in Id1-deficient BM supernatant fluid to regulate AML progression in mice. Our study highlights the critical role of ID1 in the AML BMM and aids the development of therapeutic strategies for AML.


Asunto(s)
Proteína 7 Similar a la Angiopoyetina , Proteína 1 Inhibidora de la Diferenciación , Leucemia Mieloide Aguda , Animales , Ratones , Proteína 7 Similar a la Angiopoyetina/genética , Proteína 7 Similar a la Angiopoyetina/metabolismo , Médula Ósea/metabolismo , Modelos Animales de Enfermedad , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Microambiente Tumoral , Humanos , Proteína 1 Inhibidora de la Diferenciación/metabolismo
13.
Plant Cell ; 34(11): 4313-4328, 2022 10 27.
Artículo en Inglés | MEDLINE | ID: mdl-35904763

RESUMEN

Leaf morphology is one of the most important features of the ideal plant architecture. However, the genetic and molecular mechanisms controlling this feature in crops remain largely unknown. Here, we characterized the rice (Oryza sativa) wide leaf 1 (wl1) mutant, which has wider leaves than the wild-type due to more vascular bundles and greater distance between small vascular bundles. WL1 encodes a Cys-2/His-2-type zinc finger protein that interacts with Tillering and Dwarf 1 (TAD1), a co-activator of the anaphase-promoting complex/cyclosome (APC/C) (a multi-subunit E3 ligase). The APC/CTAD1 complex degrades WL1 via the ubiquitin-26S proteasome degradation pathway. Loss-of-function of TAD1 resulted in plants with narrow leaves due to reduced vascular bundle numbers and distance between the small vascular bundles. Interestingly, we found that WL1 negatively regulated the expression of a narrow leaf gene, NARROW LEAF 1 (NAL1), by recruiting the co-repressor TOPLESS-RELATED PROTEIN and directly binding to the NAL1 regulatory region to inhibit its expression by reducing the chromatin histone acetylation. Furthermore, biochemical and genetic analyses revealed that TAD1, WL1, and NAL1 operated in a common pathway to control the leaf width. Our study establishes an important framework for understanding the APC/CTAD1-WL1-NAL1 pathway-mediated control of leaf width in rice, and provides insights for improving crop plant architecture.


Asunto(s)
Oryza , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas , Fenotipo , Mutación/genética , Hojas de la Planta/genética , Hojas de la Planta/metabolismo
14.
Nano Lett ; 24(5): 1816-1824, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38270101

RESUMEN

Accurate quantification of exosomal PD-L1 protein in tumors is closely linked to the response to immunotherapy, but robust methods to achieve high-precision quantitative detection of PD-L1 expression on the surface of circulating exosomes are still lacking. In this work, we developed a signal amplification approach based on aptamer recognition and DNA scaffold hybridization-triggered assembly of quantum dot nanospheres, which enables bicolor phenotyping of exosomes to accurately screen for cancers and predict PD-L1-guided immunotherapeutic effects through machine learning. Through DNA-mediated assembly, we utilized two aptamers for simultaneous ultrasensitive detection of exosomal antigens, which have synergistic roles in tumor diagnosis and treatment prediction, and thus, we achieved better sample classification and prediction through machine-learning algorithms. With a drop of blood, we can distinguish between different cancer patients and healthy individuals and predict the outcome of immunotherapy. This approach provides valuable insights into the development of personalized diagnostics and precision medicine.


Asunto(s)
Nanosferas , Neoplasias , Puntos Cuánticos , Humanos , Detección Precoz del Cáncer , Antígeno B7-H1 , Inmunoterapia , Aprendizaje Automático , Oligonucleótidos , ADN
15.
J Mol Cell Cardiol ; 195: 55-67, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39089571

RESUMEN

Acute lung injury (ALI) including acute respiratory distress syndrome (ARDS) is a major complication and increase the mortality of patients with cardiac surgery. We previously found that the protein cargoes enriched in circulating extracellular vesicles (EVs) are closely associated with cardiopulmonary disease. We aimed to evaluate the implication of EVs on cardiac surgery-associated ALI/ARDS. The correlations between "oncoprotein-induced transcript 3 protein (OIT3) positive" circulating EVs and postoperative ARDS were assessed. The effects of OIT3-overexpressed EVs on the cardiopulmonary bypass (CPB) -induced ALI in vivo and inflammation of human bronchial epithelial cells (BEAS-2B) were detected. OIT3 enriched in circulating EVs is reduced after cardiac surgery with CPB, especially with postoperative ARDS. The "OIT3 positive" EVs negatively correlate with lung edema, hypoxemia and CPB time. The OIT3-overexpressed EVs can be absorbed by pulmonary epithelial cells and OIT3 transferred by EVs triggered K48- and K63-linked polyubiquitination to inactivate NOD-like receptor protein 3 (NLRP3) inflammasome, and restrains pro-inflammatory cytokines releasing and immune cells infiltration in lung tissues, contributing to the alleviation of CPB-induced ALI. Overexpression of OIT3 in human bronchial epithelial cells have similar results. OIT3 promotes the E3 ligase Cbl proto-oncogene B associated with NLRP3 to induce the ubiquitination of NLRP3. Immunofluorescence tests reveal that OIT3 is reduced in the generation from the liver sinusoids endothelial cells (LSECs) and secretion in liver-derived EVs after CPB. In conclusion, OIT3 enriched in EVs is a promising biomarker of postoperative ARDS and a therapeutic target for ALI after cardiac surgery.


Asunto(s)
Lesión Pulmonar Aguda , Vesículas Extracelulares , Proteína con Dominio Pirina 3 de la Familia NLR , Ubiquitinación , Lesión Pulmonar Aguda/metabolismo , Lesión Pulmonar Aguda/etiología , Lesión Pulmonar Aguda/patología , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Vesículas Extracelulares/metabolismo , Humanos , Animales , Masculino , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Ratones , Inflamasomas/metabolismo , Proto-Oncogenes Mas , Puente Cardiopulmonar/efectos adversos , Células Epiteliales/metabolismo , Síndrome de Dificultad Respiratoria/metabolismo , Síndrome de Dificultad Respiratoria/etiología , Pulmón/metabolismo , Pulmón/patología , Péptidos y Proteínas de Señalización Intracelular
16.
J Am Chem Soc ; 146(5): 2928-2932, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38289153

RESUMEN

The asymmetric total synthesis of pedrolide (>200 mg) with an unprecedented [5-5-5-6-6-3] hexacyclic core (pedrolane) was achieved. Its unique bicyclo[2.2.1]heptane ring system was efficiently constructed via an enantioselective ene reaction of cyclopentadiene followed by a Wittig reaction, isomerization, and a diastereoselective intramolecular Diels-Alder reaction cascade. The highly oxygenated carane [6-3] ring system was synthesized via a ring-closing metathesis reaction followed by an unusual free carbene cyclopropanation. Furthermore, the 12 contiguous stereocenters of pedrolide were installed diastereoselectively.

17.
J Am Chem Soc ; 146(29): 20379-20390, 2024 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-39011931

RESUMEN

Scarce and expensive iridium oxide is still the cornerstone catalyst of polymer-electrolyte membrane electrolyzers for green hydrogen production because of its exceptional stability under industrially relevant oxygen evolution reaction (OER) conditions. Earth-abundant transition metal oxides used for this task, however, show poor long-term stability. We demonstrate here the use of nitrogen-doped cobalt oxide as an effective iridium substitute. The catalyst exhibits a low overpotential of 240 mV at 10 mA cm-2 and negligible activity decay after 1000 h of operation in an alkaline electrolyte. Incorporation of nitrogen dopants not only triggers the OER mechanism switched from the traditional adsorbate evolution route to the lattice oxygen oxidation route but also achieves oxygen nonbonding (ONB) states as electron donors, thereby preventing structural destabilization. In a practical anion-exchange membrane water electrolyzer, this catalyst at anode delivers a current density of 1000 mA cm-2 at 1.78 V and an electrical efficiency of 47.8 kW-hours per kilogram hydrogen.

18.
J Neurochem ; 168(9): 2577-2586, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38690718

RESUMEN

Positron emission tomography (PET) imaging studies in laboratory animals are almost always performed under isoflurane anesthesia to ensure that the subject stays still during the image acquisition. Isoflurane is effective, safe, and easy to use, and it is generally assumed to not have an impact on the imaging results. Motivated by marked differences observed in the brain uptake and metabolism of the PET tracer 3-[18F]fluoro-4-aminopyridine [(18F]3F4AP) between human and nonhuman primate studies, this study investigates the possible effect of isoflurane on this process. Mice received [18F]3F4AP injection while awake or under anesthesia and the tracer brain uptake and metabolism was compared between groups. A separate group of mice received the known cytochrome P450 2E1 inhibitor disulfiram prior to tracer administration. Isoflurane was found to largely abolish tracer metabolism in mice (74.8 ± 1.6 vs. 17.7 ± 1.7% plasma parent fraction, % PF) resulting in a 4.0-fold higher brain uptake in anesthetized mice at 35 min post-radiotracer administration. Similar to anesthetized mice, animals that received disulfiram showed reduced metabolism (50.0 ± 6.9% PF) and a 2.2-fold higher brain signal than control mice. The higher brain uptake and lower metabolism of [18F]3F4AP observed in anesthetized mice compared to awake mice are attributed to isoflurane's interference in the CYP2E1-mediated breakdown of the tracer, which was confirmed by reproducing the effect upon treatment with the known CYP2E1 inhibitor disulfiram. These findings underscore the critical need to examine the effect of isoflurane in PET imaging studies before translating tracers to humans that will be scanned without anesthesia.


Asunto(s)
Encéfalo , Isoflurano , Tomografía de Emisión de Positrones , Animales , Tomografía de Emisión de Positrones/métodos , Isoflurano/farmacología , Ratones , Encéfalo/metabolismo , Encéfalo/diagnóstico por imagen , Encéfalo/efectos de los fármacos , Masculino , Ratones Endogámicos C57BL , Radiofármacos , Radioisótopos de Flúor , Disulfiram/farmacología , Anestésicos por Inhalación/farmacología , Aminopiridinas/farmacología , Aminopiridinas/farmacocinética
19.
Neurobiol Dis ; 196: 106505, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38642715

RESUMEN

Alzheimer's and Parkinson's diseases are two of the most frequent neurological diseases. The clinical features of AD are memory decline and cognitive dysfunction, while PD mainly manifests as motor dysfunction such as limb tremors, muscle rigidity abnormalities, and slow gait. Abnormalities in cholesterol, sphingolipid, and glycerophospholipid metabolism have been demonstrated to directly exacerbate the progression of AD by stimulating Aß deposition and tau protein tangles. Indirectly, abnormal lipids can increase the burden on brain vasculature, induce insulin resistance, and affect the structure of neuronal cell membranes. Abnormal lipid metabolism leads to PD through inducing accumulation of α-syn, dysfunction of mitochondria and endoplasmic reticulum, and ferroptosis. Great progress has been made in targeting lipid metabolism abnormalities for the treatment of AD and PD in recent years, like metformin, insulin, peroxisome proliferator-activated receptors (PPARs) agonists, and monoclonal antibodies targeting apolipoprotein E (ApoE). This review comprehensively summarizes the involvement of dysregulated lipid metabolism in the pathogenesis of AD and PD, the application of Lipid Monitoring, and emerging lipid regulatory drug targets. A better understanding of the lipidological bases of AD and PD may pave the way for developing effective prevention and treatment methods for neurodegenerative disorders.


Asunto(s)
Enfermedad de Alzheimer , Metabolismo de los Lípidos , Enfermedad de Parkinson , Humanos , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/tratamiento farmacológico , Metabolismo de los Lípidos/efectos de los fármacos , Metabolismo de los Lípidos/fisiología , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/tratamiento farmacológico , Animales
20.
Cancer Sci ; 115(9): 2923-2930, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39014520

RESUMEN

The development of resistance in hepatocellular carcinoma (HCC) cells limits the effectiveness of sorafenib, but combination therapy with other drugs may have a positive effect. However, the effect of ropivacaine combined with sorafenib on the treatment of HCC cells and its potential regulatory mechanisms remain unclear. The proliferation and apoptosis of HCC cells treated with ropivacaine, sorafenib, and ropivacaine plus sorafenib were analyzed by cell-counting kit 8 and flow cytometry. The protein levels were measured by Western blot. The antitumor effect of ropivacaine, sorafenib, and their combination was verified by a tumor xenograft model. Ropivacaine and sorafenib markedly impeded the viability of HCC cells in a concentration-dependent manner. Compared with ropivacaine or sorafenib treatment alone, ropivacaine and sorafenib combination treatment impeded HCC cell proliferation, facilitated apoptosis, enhanced cleaved caspase-3, cleaved caspase-9, and cyclin D1 protein expression, while it reduced IL-6 and p-STAT3 expression and inhibited tumor growth in vivo. Importantly, the activation of the IL-6/STAT3 pathway could reverse the repressive or stimulative effects of ropivacaine and sorafenib on the proliferation and apoptosis in HCC cells. In summary, ropivacaine synergistically induces sorafenib-stimulated apoptosis of HCC cells via the IL-6/STAT3 pathway. Ropivacaine is a potential drug for the treatment of HCC when combined with sorafenib.


Asunto(s)
Apoptosis , Carcinoma Hepatocelular , Proliferación Celular , Sinergismo Farmacológico , Interleucina-6 , Neoplasias Hepáticas , Ropivacaína , Factor de Transcripción STAT3 , Transducción de Señal , Sorafenib , Ensayos Antitumor por Modelo de Xenoinjerto , Ropivacaína/farmacología , Sorafenib/farmacología , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Humanos , Factor de Transcripción STAT3/metabolismo , Apoptosis/efectos de los fármacos , Animales , Interleucina-6/metabolismo , Ratones , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Ratones Desnudos , Antineoplásicos/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Ratones Endogámicos BALB C , Masculino
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