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1.
Nat Immunol ; 21(11): 1444-1455, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32958928

RESUMO

Acquisition of a lipid-laden phenotype by immune cells has been defined in infectious diseases and atherosclerosis but remains largely uncharacterized in cancer. Here, in breast cancer models, we found that neutrophils are induced to accumulate neutral lipids upon interaction with resident mesenchymal cells in the premetastatic lung. Lung mesenchymal cells elicit this process through repressing the adipose triglyceride lipase (ATGL) activity in neutrophils in prostaglandin E2-dependent and -independent manners. In vivo, neutrophil-specific deletion of genes encoding ATGL or ATGL inhibitory factors altered neutrophil lipid profiles and breast tumor lung metastasis in mice. Mechanistically, lipids stored in lung neutrophils are transported to metastatic tumor cells through a macropinocytosis-lysosome pathway, endowing tumor cells with augmented survival and proliferative capacities. Pharmacological inhibition of macropinocytosis significantly reduced metastatic colonization by breast tumor cells in vivo. Collectively, our work reveals that neutrophils serve as an energy reservoir to fuel breast cancer lung metastasis.


Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Metabolismo dos Lipídeos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Células-Tronco Mesenquimais/metabolismo , Neutrófilos/metabolismo , Animais , Biomarcadores , Proliferação de Células , Progressão da Doença , Endocitose , Feminino , Imunofluorescência , Humanos , Camundongos , Metástase Neoplásica , Neutrófilos/ultraestrutura
2.
Nature ; 634(8033): 466-473, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38866050

RESUMO

Computational pathology1,2 has witnessed considerable progress in the development of both task-specific predictive models and task-agnostic self-supervised vision encoders3,4. However, despite the explosive growth of generative artificial intelligence (AI), there have been few studies on building general-purpose multimodal AI assistants and copilots5 tailored to pathology. Here we present PathChat, a vision-language generalist AI assistant for human pathology. We built PathChat by adapting a foundational vision encoder for pathology, combining it with a pretrained large language model and fine-tuning the whole system on over 456,000 diverse visual-language instructions consisting of 999,202 question and answer turns. We compare PathChat with several multimodal vision-language AI assistants and GPT-4V, which powers the commercially available multimodal general-purpose AI assistant ChatGPT-4 (ref. 6). PathChat achieved state-of-the-art performance on multiple-choice diagnostic questions from cases with diverse tissue origins and disease models. Furthermore, using open-ended questions and human expert evaluation, we found that overall PathChat produced more accurate and pathologist-preferable responses to diverse queries related to pathology. As an interactive vision-language AI copilot that can flexibly handle both visual and natural language inputs, PathChat may potentially find impactful applications in pathology education, research and human-in-the-loop clinical decision-making.


Assuntos
Inteligência Artificial , Tomada de Decisão Clínica , Diagnóstico por Imagem , Patologia , Humanos , Tomada de Decisão Clínica/métodos , Diagnóstico por Imagem/métodos , Diagnóstico por Imagem/tendências , Processamento de Linguagem Natural , Patologia/educação , Patologia/métodos , Patologia/tendências , Masculino , Feminino
3.
Nature ; 618(7966): 687-697, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37344649

RESUMO

Light and sound are the most ubiquitous forms of waves, associated with a variety of phenomena and physical effects such as rainbows and echoes. Light and sound, both categorized as classical waves, have lately been brought into unexpected connections with exotic topological phases of matter. We are currently witnessing the onset of a second wave of active research into this topic. The past decade has been marked by fundamental advances comprising two-dimensional quantum Hall insulators and quantum spin and valley Hall insulators, whose topological properties are characterized using linear band topology. Here, going beyond these conventional topological systems, we focus on the latest frontiers, including non-Hermitian, nonlinear and non-Abelian topology as well as topological defects, for which the characterization of the topological features goes beyond the standard band-topology language. In addition to an overview of the current state of the art, we also survey future research directions for valuable applications.

4.
Mol Cell ; 78(6): 1192-1206.e10, 2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32470318

RESUMO

Tumor-derived extracellular vesicles are important mediators of cell-to-cell communication during tumorigenesis. Here, we demonstrated that hepatocellular carcinoma (HCC)-derived ectosomes remodel the tumor microenvironment to facilitate HCC progression in an ectosomal PKM2-dependent manner. HCC-derived ectosomal PKM2 induced not only metabolic reprogramming in monocytes but also STAT3 phosphorylation in the nucleus to upregulate differentiation-associated transcription factors, leading to monocyte-to-macrophage differentiation and tumor microenvironment remodeling. In HCC cells, sumoylation of PKM2 induced its plasma membrane targeting and subsequent ectosomal excretion via interactions with ARRDC1. The PKM2-ARRDC1 association in HCC was reinforced by macrophage-secreted cytokines/chemokines in a CCL1-CCR8 axis-dependent manner, further facilitating PKM2 excretion from HCC cells to form a feedforward regulatory loop for tumorigenesis. In the clinic, ectosomal PKM2 was clearly detected in the plasma of HCC patients. This study highlights a mechanism by which ectosomal PKM2 remodels the tumor microenvironment and reveals ectosomal PKM2 as a potential diagnostic marker for HCC.


Assuntos
Proteínas de Transporte/metabolismo , Micropartículas Derivadas de Células/metabolismo , Proteínas de Membrana/metabolismo , Hormônios Tireóideos/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Proteínas de Transporte/genética , Diferenciação Celular/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Micropartículas Derivadas de Células/genética , Micropartículas Derivadas de Células/patologia , Quimiocina CCL1/metabolismo , Progressão da Doença , Células Hep G2 , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Macrófagos/metabolismo , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Monócitos/metabolismo , Prognóstico , Fator de Transcrição STAT3/metabolismo , Hormônios Tireóideos/genética , Microambiente Tumoral , Proteínas de Ligação a Hormônio da Tireoide
5.
Nature ; 594(7861): 106-110, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33953404

RESUMO

Cancer of unknown primary (CUP) origin is an enigmatic group of diagnoses in which the primary anatomical site of tumour origin cannot be determined1,2. This poses a considerable challenge, as modern therapeutics are predominantly specific to the primary tumour3. Recent research has focused on using genomics and transcriptomics to identify the origin of a tumour4-9. However, genomic testing is not always performed and lacks clinical penetration in low-resource settings. Here, to overcome these challenges, we present a deep-learning-based algorithm-Tumour Origin Assessment via Deep Learning (TOAD)-that can provide a differential diagnosis for the origin of the primary tumour using routinely acquired histology slides. We used whole-slide images of tumours with known primary origins to train a model that simultaneously identifies the tumour as primary or metastatic and predicts its site of origin. On our held-out test set of tumours with known primary origins, the model achieved a top-1 accuracy of 0.83 and a top-3 accuracy of 0.96, whereas on our external test set it achieved top-1 and top-3 accuracies of 0.80 and 0.93, respectively. We further curated a dataset of 317 cases of CUP for which a differential diagnosis was assigned. Our model predictions resulted in concordance for 61% of cases and a top-3 agreement of 82%. TOAD can be used as an assistive tool to assign a differential diagnosis to complicated cases of metastatic tumours and CUPs and could be used in conjunction with or in lieu of ancillary tests and extensive diagnostic work-ups to reduce the occurrence of CUP.


Assuntos
Inteligência Artificial , Simulação por Computador , Neoplasias Primárias Desconhecidas/patologia , Estudos de Coortes , Simulação por Computador/normas , Feminino , Humanos , Masculino , Metástase Neoplásica/patologia , Neoplasias Primárias Desconhecidas/diagnóstico , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fluxo de Trabalho
6.
J Biol Chem ; 300(3): 105765, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38367667

RESUMO

CLEC12A, a member of the C-type lectin receptor family involved in immune homeostasis, recognizes MSU crystals released from dying cells. However, the molecular mechanism underlying the CLEC12A-mediated recognition of MSU crystals remains unclear. Herein, we reported the crystal structure of the human CLEC12A-C-type lectin-like domain (CTLD) and identified a unique "basic patch" site on CLEC12A-CTLD that is necessary for the binding of MSU crystals. Meanwhile, we determined the interaction strength between CLEC12A-CTLD and MSU crystals using single-molecule force spectroscopy. Furthermore, we found that CLEC12A clusters at the cell membrane and seems to serve as an internalizing receptor of MSU crystals. Altogether, these findings provide mechanistic insights for understanding the molecular mechanisms underlying the interplay between CLEC12A and MSU crystals.


Assuntos
Lectinas Tipo C , Receptores Mitogênicos , Ácido Úrico , Humanos , Gota/metabolismo , Lectinas Tipo C/química , Lectinas Tipo C/imunologia , Receptores Mitogênicos/química , Receptores Mitogênicos/imunologia , Ácido Úrico/química , Ácido Úrico/imunologia , Domínios Proteicos , Cristalografia por Raios X , Imagem Individual de Molécula , Linhagem Celular
7.
Plant Physiol ; 195(3): 2129-2142, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38431291

RESUMO

DNA methylation affects agronomic traits and the environmental adaptability of crops, but the natural polymorphisms in DNA methylation-related genes and their contributions to phenotypic variation in maize (Zea mays) remain elusive. Here, we show that a polymorphic 10-bp insertion/deletion variant in the 3'UTR of Zea methyltransferase2 (ZMET2) alters its transcript level and accounts for variation in the number of maize husk layers. ZMET2 encodes a chromomethylase and is required for maintaining genome-wide DNA methylation in the CHG sequence context. Disruption of ZMET2 increased the number of husk layers and resulted in thousands of differentially methylated regions, a proportion of which were also distinguishable in natural ZMET2 alleles. Population genetic analyses indicated that ZMET2 was a target of selection and might play a role in the spread of maize from tropical to temperate regions. Our results provide important insights into the natural variation of ZMET2 that confers both global and locus-specific effects on DNA methylation, which contribute to phenotypic diversity in maize.


Assuntos
Metilação de DNA , Proteínas de Plantas , Polimorfismo Genético , Zea mays , Zea mays/genética , Metilação de DNA/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas , Alelos , DNA (Citosina-5-)-Metiltransferases
8.
Acc Chem Res ; 57(1): 70-92, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38112292

RESUMO

ConspectusThe pursuit of novel and eco-friendly methods in organic synthesis is gaining prominence, with a strong emphasis on green transformations using renewable and sustainable resources. Among these environmentally conscious approaches, water-compatible reactions stand out for their many advantages. Water, as a solvent, offers unmatched abundance, cost-efficiency, and environmental compatibility compared to organic solvents. Its use eliminates the need for complex protection and deprotection steps for reactive functional groups in multistep synthesis and enables the use of water-soluble substrates like proteins and carbohydrates. Water-compatible reactions also provide opportunities to combine with enzymes, resulting in chemoenzymatic transformations that can increase efficiency. Additionally, these reactions facilitate site-specific modification and the bioconjugation of biomolecules, leading to bioconjugate therapeutics.Over nearly three decades, our research group has been dedicated to developing innovative water-compatible methodologies and concepts. This Account provides a comprehensive overview of our contributions since 1994. Our central strategy revolves around integrating green chemistry principles into our methods, focusing on (i) developing reactions that can operate under mild conditions, including room temperature, atmospheric pressure, and physiological pH; (ii) designing atom-economical reactions that minimize waste production; (iii) replacing toxic and flammable organic solvents with eco-friendly alternatives like water and ethanol; and (iv) reducing reliance on metals or halogenated compounds in specific reactions.In this Account, we detail our achievements in developing efficient methodologies in aqueous media, highlighting their scope, limitations, asymmetric control, and applications for synthesizing complex molecules and functionalizing peptides and proteins. Mechanistic investigations underlying these developments are also discussed when applicable. Furthermore, we offer insights into the reasoning behind our work and address future opportunities and challenges in this area of research. We hope that this Account will inspire continued interest and foster new breakthroughs. By exploring innovative and broadly applicable strategies that expand the water-compatible synthetic toolbox, we aim to pave the way for the truly green and sustainable synthesis of complex molecules and pharmaceuticals.

9.
EMBO Rep ; 24(10): e57101, 2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37621232

RESUMO

The NLR family pyrin domain containing 3 (NLRP3) inflammasome plays an important role in the pathogenesis of a wide variety of human diseases. So far, drugs directly and specifically targeting the NLRP3 inflammasome are not available for clinical use since the safety and efficacy of new compounds are often unclear. A promising approach is thus to identify NLRP3 inhibitors from existing drugs that are already in clinical use. Here, we show that mefloquine, a well-known antimalarial drug, is a highly selective and potent NLRP3 inhibitor by screening a FDA-approved drug library. Mechanistically, mefloquine directly binds to the NLRP3 NACHT and LRR domains to prevent NLRP3 inflammasome activation. More importantly, mefloquine treatment attenuates the symptoms of lipopolysaccharide-induced systemic inflammation and Parkinson's disease-like neural damage in mice. Our findings identify mefloquine as a potential therapeutic agent for NLRP3-driven diseases and migth expand its clinical use considerably.

10.
Drug Resist Updat ; 73: 101038, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38181587

RESUMO

AIMS: Although cefiderocol (FDC) is not prescribed in China, FDC-resistant pandrug-resistant hypervirulent Klebsiella pneumoniae (PDR-hvKp) is emerging. In this study, we performed FDC susceptibility testing of clinical Kp isolates to explore the prevalence of FDC-resistant isolates and the mechanism of FDC-resistance. METHODS: We retrospectively selected 151 carbapenem-resistant Kp isolates to assess FDC susceptibility. Seven isolates harboring blaSHV-12 from two patients were enrolled for whole-genome sequencing. The antimicrobial resistance, virulence, blaSHV-12 expression, and fitness costs in different media were examined. The amplification of blaSHV-12 was further investigated by qPCR and long-read sequencing. RESULTS: The 151 isolates showed a low MIC50/MIC90 (1/4 mg/L) of FDC. The seven isolates were ST11 PDR-hvKp, and two represented FDC-resistance (MIC=32 mg/L). The IncR/IncFII plasmids of two FDC-resistant isolates harbored 6 and 15 copies of blaSHV-12, whereas four FDC-susceptible isolates carried one copy and one harbored three copies. These blaSHV-12 genes concatenated together and were located within the same 7.3 kb fragment flanked by IS26, which contributed to the increased expression and FDC resistance without fitness costs. The amplification of blaSHV-12 and FDC resistance could be induced by FDC in vitro and reversed during continuous passage. CONCLUSIONS: The amplification of blaSHV-12 and the consequent dynamic within-host heteroresistance are important concerns for the rational application of antibiotics. Long-read sequencing might be a superior way to detect resistance gene amplification rapidly and accurately.


Assuntos
Infecções por Klebsiella , Klebsiella pneumoniae , Humanos , Klebsiella pneumoniae/genética , Cefiderocol , Estudos Retrospectivos , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/epidemiologia , Testes de Sensibilidade Microbiana , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico
11.
Nano Lett ; 24(35): 10915-10920, 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39167685

RESUMO

Upconversion nanoparticles are popular as imaging probes due to their advantages in photostability and controllable emission dimensions. However, upconversion polarization remains largely uncharted with previous reports limited to microstructures. In this work, we report the observation of polarized upconversion emissions from ß-NaYF4 single nanostructures below 100 nm. At the sub-100 nm scale, nanorods, nanodiscs, and nanoplates exhibit distinctive polarization degrees despite the same doping concentrations of lanthanides. We find this varied polarization degree results from the crystallographic orientation of nanostructure in relation to the light field and can be linked to the distinctive emission spectrum profile with varied Stark splitting transition ratios from Er3+. Our findings provide a comprehensive understanding of the polarization properties of upconversion nanoparticles, revealing a previously unexplored aspect of light emission. This discovery expands our knowledge of upconversion nanoparticles and also opens new possibilities for their use in future imaging and sensing applications, where polarization sensitivity is crucial.

12.
Nano Lett ; 24(29): 8818-8825, 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-38985501

RESUMO

Stationary energy storage infrastructure based on zinc-ion transport and storage chemistry is attracting more attention due to favorable metrics, including cost, safety, and recycling feasibility. However, splitting water and liquid electrolyte fluidity lead to cathode dissolution and Zn corrosion, resulting in rapid attenuation of the capacity and service life. Herein, a new architecture of solid-state electrolytes with high zinc ionic conductivity at room temperature was prepared via solidification of deep eutectic solvents utilizing MXene as nucleation additives. The ionic conductivity of MXene/ZCEs reached 6.69 × 10-4 S cm-1 at room temperature. Dendrite-free Zn plating/stripping with high reversibility can remain for over 2500 h. Subsequently, the fabricated solid-state zinc-ion battery with eliminated HER and suppressed Zn dendrites exhibited excellent cycling performance and could work normally in a range from -10 to 60 °C. This design inspired by eutectic solidification affords new insights into the multivalent solid electrochemistry suffering from slow ion migration.

13.
J Lipid Res ; : 100680, 2024 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-39481851

RESUMO

Maintaining cholesterol homeostasis is critical for preserving adipocyte function during the progression of obesity. Despite this, the regulatory role of cholesterol esterification in governing adipocyte expandability has been understudied. Acyl-coenzyme A (CoA):cholesterol acyltransferase / Sterol O-acyltransferase 1 (ACAT1/SOAT1) is the dominant enzyme to synthesize cholesteryl ester in most tissues. Our previous study demonstrated that knockdown of either ACAT1 or ACAT2 impaired adipogenesis. However, the underlying mechanism of how ACAT1 mediates adipogenesis remains unclear. Here, we reported that ACAT1 is the dominant isoform in white adipose tissue of both humans and mice and knocking out ACAT1 reduced fat mass in mice. Furthermore, ACAT1-deficiency inhibited the early stage of adipogenesis via attenuating PPARγ pathway. Mechanistically, ACAT1 deficiency inhibited SREBP2-mediated cholesterol uptake and thus reduced intracellular and plasma membrane cholesterol level during adipogenesis. While replenishing cholesterol could rescue adipogenic master gene - Pparγ's transcription in ACAT1 deficient cells during adipogenesis. Finally, overexpression of catalytically functional ACAT1, not the catalytic-dead ACAT1, rescued cholesterol level and efficiently rescued the transcription of PPARγ, as well as the adipogenesis in ACAT1-deficient preadipocytes. In summary, our study revealed the indispensable role of ACAT1 in adipogenesis via regulating intracellular cholesterol homeostasis.

14.
Diabetologia ; 67(8): 1698-1713, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38819467

RESUMO

AIMS/HYPOTHESIS: Mutations in Isl1, encoding the insulin enhancer-binding protein islet-1 (ISL1), may contribute to attenuated insulin secretion in type 2 diabetes mellitus. We made an Isl1E283D mouse model to investigate the disease-causing mechanism of diabetes mellitus. METHODS: The ISL1E283D mutation (c. 849A>T) was identified by whole exome sequencing on an early-onset type 2 diabetes family and then the Isl1E283D knockin (KI) mouse model was created and an IPGTT and IPITT were conducted. Glucose-stimulated insulin secretion (GSIS), expression of Ins2 and other ISL1 target genes and interacting proteins were evaluated in isolated pancreas islets. Transcriptional activity of Isl1E283D was evaluated by cell-based luciferase reporter assay and electrophoretic mobility shift assay, and the expression levels of Ins2 driven by Isl1 wild-type (Isl1WT) and Isl1E283D mutation in rat INS-1 cells were determined by RT-PCR and western blotting. RESULTS: Impaired GSIS and elevated glucose level were observed in Isl1E283D KI mice while expression of Ins2 and other ISL1 target genes Mafa, Pdx1, Slc2a2 and the interacting protein NeuroD1 were downregulated in isolated islets. Transcriptional activity of the Isl1E283D mutation for Ins2 was reduced by 59.3%, and resulted in a marked downregulation of Ins2 expression when it was overexpressed in INS-1 cells, while overexpression of Isl1WT led to an upregulation of Ins2 expression. CONCLUSIONS/INTERPRETATION: Isl1E283D mutation reduces insulin expression and secretion by regulating insulin and other target genes, as well as its interacting proteins such as NeuroD1, leading to the development of glucose intolerance in the KI mice, which recapitulated the human diabetic phenotype. This study identified and highlighted the Isl1E283D mutation as a novel causative factor for type 2 diabetes, and suggested that targeting transcription factor ISL1 could offer an innovative avenue for the precise treatment of human type 2 diabetes.


Assuntos
Diabetes Mellitus Tipo 2 , Proteínas com Homeodomínio LIM , Mutação de Sentido Incorreto , Fatores de Transcrição , Animais , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Proteínas com Homeodomínio LIM/genética , Proteínas com Homeodomínio LIM/metabolismo , Camundongos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Humanos , Masculino , Insulina/metabolismo , Feminino , Ratos , Secreção de Insulina/genética , Ilhotas Pancreáticas/metabolismo
15.
J Cell Mol Med ; 28(7): e18205, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38506089

RESUMO

Retinoic acid (RA), a vitamin A derivative, is an effective cell differentiating factor which plays critical roles in neuronal differentiation induction and the production of neurotransmitters in neurons. However, the specific changes in phosphorylation levels and downstream signalling pathways associated with RA remain unclear. This study employed qualitative and quantitative phosphoproteomics approaches based on mass spectrometry to investigate the phosphorylation changes induced by RA in C17.2 neural stem cells (NSCs). Dimethyl labelling, in conjunction with TiO2 phosphopeptide enrichment, was utilized to profile the phosphoproteome of self-renewing and RA-induced differentiated cells in C17.2 NSCs. The results of our study revealed that, qualitatively, 230 and 14 phosphoproteins were exclusively identified in the self-renewal and RA-induced groups respectively. Quantitatively, we successfully identified and quantified 177 unique phosphoproteins, among which 70 exhibited differential phosphorylation levels. Analysis of conserved phosphorylation motifs demonstrated enrichment of motifs corresponding to cyclin-dependent kinase and MAPK in the RA-induced group. Additionally, through a comprehensive literature and database survey, we found that the differentially expressed proteins were associated with the Wnt/ß-catenin and Hippo signalling pathways. This work sheds light on the changes in phosphorylation levels induced by RA in C17.2 NSCs, thereby expanding our understanding of the molecular mechanisms underlying RA-induced neuronal differentiation.


Assuntos
Células-Tronco Neurais , Tretinoína , Tretinoína/farmacologia , Tretinoína/metabolismo , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , Diferenciação Celular , Fosfoproteínas/genética , Fosfoproteínas/metabolismo
16.
J Am Chem Soc ; 146(8): 5678-5692, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38359327

RESUMO

The rapid and controlled synthesis of high-molecular-weight (HMW) polysarcosine (pSar), a potential polyethylene glycol (PEG) alternative, via the ring-opening polymerization (ROP) of N-carboxyanhydride (NCA) is rare and challenging. Here, we report the well-controlled ROP of sarcosine NCA (Sar-NCA) that is catalyzed by various carboxylic acids, which accelerate the polymerization rate up to 50 times, and enables the robust synthesis of pSar with an unprecedented ultrahigh molecular weight (UHMW) up to 586 kDa (DP ∼ 8200) and exceptionally narrow dispersity (D̵) below 1.05. Mechanistic experiments and density functional theory calculations together elucidate the role of carboxylic acid as a bifunctional catalyst that significantly facilitates proton transfer processes and avoids charge separation and suggest the ring opening of NCA, rather than decarboxylation, as the rate-determining step. UHMW pSar demonstrates improved thermal and mechanical properties over the low-molecular-weight counterparts. This work provides a simple yet highly efficient approach to UHMW pSar and generates a new fundamental understanding useful not only for the ROP of Sar-NCA but also for other NCAs.

17.
J Am Chem Soc ; 146(36): 25101-25107, 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39196903

RESUMO

Tailoring the surface ligands of metal nanoclusters is important for engineering unique configurations of metal nanoclusters. Thiacalix[4]arene has found extensive applications in the construction of metal nanoclusters. In this investigation, we present the synthesis and characterization of the first all-calixarene-protected silver nanoclusters, [Ag(CH3CN)4]2[Ag44(BTCA)6] (Ag44, H4BTCA = p-tert-butylthiacalix[4]arene). Single-crystal X-ray structural analysis reveals that all silver atoms are in a face-centered cubic (fcc) arrangement. The formation of such an fcc structure is attributed to the selectively passivation on {100} facets by BTCA4-. Thiacalixarene substantially facilitates the stability of Ag44 due to its multiple coordination sites and bulkiness. Mass spectrometry and theoretical calculations reveal that Ag44 is a superatomic silver nanocluster with 22 free electrons in the following configuration: 1S21P61D61F22S21D4. This work not only elucidates the impact of macrocyclic ligands on the stabilization of silver clusters but also furnishes an approach for assembling atomically precise fcc nanoclusters.

18.
Am J Physiol Endocrinol Metab ; 327(4): E544-E551, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39230395

RESUMO

Ucp1 promoter-driven Cre transgenic mice are useful in the manipulation of gene expression specifically in thermogenic adipose tissues. However, the wildly used Ucp1-Cre line was generated by random insertion into the genome and showed ectopic activity in some tissues beyond adipose tissues. Here, we characterized a knockin mouse line Ucp1-iCre generated by targeting IRES-Cre cassette immediately downstream the stop codon of the Ucp1 gene. The Cre insertion had little to no effect on uncoupling protein 1 (UCP1) levels in brown adipose tissue. Ucp1-iCre mice of both genders exhibited normal thermogenesis and cold tolerance. When crossed with Rosa-tdTomato reporter mice, Ucp1-iCre mice showed robust Cre activity in thermogenic adipose tissues. In addition, limited Cre activity was sparsely present in the ventromedial hypothalamus (VMH), choroid plexus, kidney, adrenal glands, ovary, and testis in Ucp1-iCre mice, albeit to a much lesser extent and with reduced intensity compared with the conventional Ucp1-Cre line. Single-cell transcriptome analysis revealed Ucp1 mRNA expression in male spermatocytes. Moreover, male Ucp1-iCre mice displayed a high frequency of Cre-mediated recombination in the germline, whereas no such effect was observed in female Ucp1-iCre mice. These findings suggest that Ucp1-iCre mice offer promising utility in the context of conditional gene manipulation in thermogenic adipose tissues, while also highlighting the need for caution in mouse mating and genotyping procedures.NEW & NOTEWORTHY Ucp1 promoter-driven Cre transgenic mice are useful in the manipulation of gene expression specifically in thermogenic adipose tissues. The widely used Ucp1-Cre mouse line (Ucp1-CreEvdr), which was generated using the bacterial artificial chromosome (BAC) strategy, exhibits major brown and white fat transcriptomic dysregulation and ectopic activity beyond adipose tissues. Here, we comprehensively validate Ucp1-iCre knockin mice, which serve as another optional model besides Ucp1-CreEvdr mice for specific genetic manipulation in thermogenic tissue.


Assuntos
Tecido Adiposo Marrom , Integrases , Termogênese , Proteína Desacopladora 1 , Animais , Feminino , Masculino , Camundongos , Tecido Adiposo Marrom/metabolismo , Técnicas de Introdução de Genes , Células Germinativas/metabolismo , Integrases/genética , Integrases/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Recombinação Genética , Espermatócitos/metabolismo , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo
19.
Biochem Biophys Res Commun ; 717: 150021, 2024 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-38718565

RESUMO

Mesenchymal stem cells (MSCs) are ubiquitous multipotent cells exhibiting significant therapeutic potential for various diseases. It is generally accepted that clinical application requires massive expansion of MSCs, which is often accompanied by the occurrence of replicative senescence. Additionally, senescent MSCs exhibit significantly reduced proliferation, differentiation, and therapeutic potential. The scale-up of MSCs production and cellular senescence are major challenges for translational applications. This study first collected extracellular vesicles (EVs) from gingival MSCs (GMSCs) under hypoxia preconditioning combined with 3D dynamic culture (obtained EVs designed as H-3D-EVs). Subsequently, we further explored the effects and mechanisms of H-3D-EVs on aging-GMSCs. The results showed that H-3D-EVs improved the proliferation ability and cell activity of aging-GMSCs, and ameliorated their senescence. mRNA sequencing reveals transcriptomic changes in aging-GMSCs. It was found that H-3D-EVs up-regulated genes related to mitochondrial dynamics, cell cycle, and DNA repair, while down-regulated aging-related genes. Furthermore, we verified that H-3D-EVs corrected the mitochondrial dysfunction of aging-GMSCs by improving mitochondrial dynamics. In summary, this study provides a promising strategy for improving the culture methods of GMSCs and avoiding its senescence in large-scale production.


Assuntos
Senescência Celular , Vesículas Extracelulares , Células-Tronco Mesenquimais , Mitocôndrias , Vesículas Extracelulares/metabolismo , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/citologia , Mitocôndrias/metabolismo , Humanos , Hipóxia Celular , Células Cultivadas , Proliferação de Células , Envelhecimento/metabolismo , Envelhecimento/genética , Dinâmica Mitocondrial
20.
Cancer Immunol Immunother ; 73(7): 119, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38713205

RESUMO

BACKGROUND: The programmed death 1 inhibitor toripalimab plus the angio-immuno kinase inhibitor surufatinib showed a tolerable safety profile and preliminary efficacy in patients with advanced solid tumors in a phase I study. METHODS: This open-label, multi-cohort study in China enrolled patients with advanced solid tumors who had failed or were intolerable to standard treatment into tumor-specific cohorts. Patients received surufatinib (250 mg orally, once daily) plus toripalimab (240 mg intravenously, once every three weeks). Results for three cohorts (gastric/gastroesophageal junction [GC/GEJ] adenocarcinoma, esophageal squamous cell carcinoma [ESCC], and biliary tract carcinoma [BTC]) are reported here. The primary endpoint was investigator-assessed objective response rate (ORR) per Response Evaluation criteria in Solid Tumors version 1.1. RESULTS: Between December 17, 2019, and January 29, 2021, 60 patients were enrolled (GC/GEJ, n = 20; ESCC, n = 20; BTC, n = 20). At data cutoff (February 28, 2023), ORRs were 31.6%, 30.0%, and 11.1%, respectively. Median progression-free survival was 4.1, 2.7, and 2.9 months, respectively. Median overall survival was 13.7, 10.4, and 7.0 months, respectively. Overall, grade ≥ 3 treatment-related adverse events occurred in 28 (46.7%) patients. CONCLUSIONS: Surufatinib plus toripalimab showed promising antitumor activity and a tolerable safety profile in immunotherapy-naïve patients with GC/GEJ adenocarcinoma, ESCC, or BTC. These findings warrant further study in larger randomized trials comparing surufatinib plus toripalimab with standard therapies in these tumors. CLINICALTRIALS: gov NCT04169672.


Assuntos
Adenocarcinoma , Anticorpos Monoclonais Humanizados , Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias do Sistema Biliar , Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/patologia , Neoplasias do Sistema Biliar/tratamento farmacológico , Neoplasias do Sistema Biliar/patologia , Neoplasias do Sistema Biliar/mortalidade , Adulto , Carcinoma de Células Escamosas do Esôfago/tratamento farmacológico , Carcinoma de Células Escamosas do Esôfago/patologia , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/patologia , Adenocarcinoma/mortalidade , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologia , Junção Esofagogástrica/patologia , Imidazóis/administração & dosagem , Imidazóis/uso terapêutico , Imidazóis/efeitos adversos , Idoso de 80 Anos ou mais , Estudos de Coortes
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