Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 235
Filtrar
1.
Curr Opin Cell Biol ; 89: 102394, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38963953

RESUMO

This review examines the dynamic mechanisms underlying cellular signaling, communication, and adhesion via transient, nano-scale, liquid-like molecular assemblies on the plasma membrane (PM). Traditional views posit that stable, solid-like molecular complexes perform these functions. However, advanced imaging reveals that many signaling and scaffolding proteins only briefly reside in these molecular complexes and that micron-scale protein assemblies on the PM, including cell adhesion structures and synapses, are likely made of archipelagoes of nanoliquid protein islands. Borrowing the concept of liquid-liquid phase separation to form micron-scale biocondensates, we propose that these nano-scale oligomers and assemblies are enabled by multiple weak but specific molecular interactions often involving intrinsically disordered regions. The signals from individual nanoliquid signaling complexes would occur as pulses. Single-molecule imaging emerges as a crucial technique for characterizing these transient nanoliquid assemblies on the PM, suggesting a shift toward a model where the fluidity of interactions underpins signal regulation and integration.

2.
J Am Chem Soc ; 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38963258

RESUMO

Glycans cover the cell surface to form the glycocalyx, which governs a myriad of biological phenomena. However, understanding and regulating glycan functions is extremely challenging due to the large number of heterogeneous glycans that engage in intricate interaction networks with diverse biomolecules. Glycocalyx-editing techniques offer potent tools to probe their functions. In this study, we devised a HaloTag-based technique for glycan manipulation, which enables the introduction of chemically synthesized glycans onto a specific protein (protein of interest, POI) and concurrently incorporates fluorescent units to attach homogeneous, well-defined glycans to the fluorescence-labeled POIs. Leveraging this HaloTag-based glycan-display system, we investigated the influence of the interactions between Gal-3 and various N-glycans on protein dynamics. Our analyses revealed that glycosylation modulates the lateral diffusion of the membrane proteins in a structure-dependent manner through interaction with Gal-3, particularly in the context of the Gal-3-induced formation of the glycan network (galectin lattice). Furthermore, N-glycan attachment was also revealed to have a significant impact on the extracellular vesicle-loading of membrane proteins. Notably, our POI-specific glycan introduction does not disrupt intact glycan structures, thereby enabling a functional analysis of glycans in the presence of native glycan networks. This approach complements conventional glycan-editing methods and provides a means for uncovering the molecular underpinnings of glycan functions on the cell surface.

3.
Sci Rep ; 14(1): 16872, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39043900

RESUMO

Sphingomyelin (SM) is a major sphingolipid in mammalian cells. SM is enriched in the extracellular leaflet of the plasma membrane (PM). Besides this localization, recent electron microscopic and biochemical studies suggest the presence of SM in the cytosolic leaflet of the PM. In the present study, we generated a non-toxic SM-binding variant (NT-EqtII) based on equinatoxin-II (EqtII) from the sea anemone Actinia equina, and examined the dynamics of SM in the cytosolic leaflet of living cell PMs. NT-EqtII with two point mutations (Leu26Ala and Pro81Ala) had essentially the same specificity and affinity to SM as wild-type EqtII. NT-EqtII expressed in the cytosol was recruited to the PM in various cell lines. Super-resolution microscopic observation revealed that NT-EqtII formed tiny domains that were significantly colocalized with cholesterol and N-terminal Lyn. Meanwhile, single molecule observation at high resolutions down to 1 ms revealed that all the examined lipid probes including NT-EqtII underwent apparent fast simple Brownian diffusion, exhibiting that SM and other lipids in the cytosolic leaflet rapidly moved in and out of domains. Thus, the novel SM-binding probe demonstrated the presence of the raft-like domain in the cytosolic leaflet of living cell PMs.


Assuntos
Membrana Celular , Venenos de Cnidários , Citosol , Esfingomielinas , Esfingomielinas/metabolismo , Membrana Celular/metabolismo , Citosol/metabolismo , Animais , Venenos de Cnidários/metabolismo , Venenos de Cnidários/genética , Humanos , Anêmonas-do-Mar/metabolismo , Anêmonas-do-Mar/genética , Colesterol/metabolismo
4.
Nat Commun ; 15(1): 4514, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38802491

RESUMO

Knowledge on the distribution and dynamics of glycosylation enzymes in the Golgi is essential for better understanding this modification. Here, using a combination of CRISPR/Cas9 knockin technology and super-resolution microscopy, we show that the Golgi complex is assembled by a number of small 'Golgi units' that have 1-3 µm in diameter. Each Golgi unit contains small domains of glycosylation enzymes which we call 'zones'. The zones of N- and O-glycosylation enzymes are colocalised. However, they are less colocalised with the zones of a glycosaminoglycan synthesizing enzyme. Golgi units change shapes dynamically and the zones of glycosylation enzymes rapidly move near the rim of the unit. Photobleaching analysis indicates that a glycosaminoglycan synthesizing enzyme moves between units. Depletion of giantin dissociates units and prevents the movement of glycosaminoglycan synthesizing enzymes, which leads to insufficient glycosaminoglycan synthesis. Thus, we show the structure-function relationship of the Golgi and its implications in human pathogenesis.


Assuntos
Glicosaminoglicanos , Complexo de Golgi , Complexo de Golgi/metabolismo , Glicosilação , Humanos , Glicosaminoglicanos/metabolismo , Células HeLa , Sistemas CRISPR-Cas , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Proteínas da Matriz do Complexo de Golgi
5.
Cancer ; 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38682652

RESUMO

BACKGROUND: Genetic polymorphisms of molecules are known to cause individual differences in the therapeutic efficacy of anticancer drugs. However, to date, germline mutations (but not somatic mutations) for anticancer drugs have not been adequately studied. The objective of this study was to investigate the association between germline polymorphisms of gemcitabine metabolic and transporter genes with carbohydrate antigen 19-9 (CA 19-9) response (decrease ≥50% from the pretreatment level at 8 weeks) and overall survival (OS) in patients with metastatic pancreatic cancer who receive gemcitabine-based chemotherapy. METHODS: This multicenter, prospective, observational study enrolled patients with metastatic pancreatic cancer patients who were receiving gemcitabine monotherapy or gemcitabine plus nanoparticle albumin-bound paclitaxel combination chemotherapy. Thirteen polymorphisms that may be involved in gemcitabine responsiveness were genotyped, and univariate and multivariate logistic regression analyses were used to determine the association of these genotypes with CA 19-9 response and OS. The significance level was set at 5%. RESULTS: In total, 180 patients from 11 hospitals in Japan were registered, and 159 patients whose CA 19-9 response could be assessed were included in the final analysis. Patients who had a CA 19-9 response had significantly longer OS (372 vs. 241 days; p = .007). RRM1 2464A>G and RRM2 175T>G polymorphisms suggested a weak association with CA 19-9 response and OS, but it was not statistically significant. COX-2 -765G>C polymorphism did not significantly correlate with CA 19-9 response but was significantly associated with OS (hazard ratio, 2.031; p = .019). CONCLUSIONS: Genetic polymorphisms from the pharmacokinetics of gemcitabine did not indicate a significant association with efficacy, but COX-2 polymorphisms involved in tumor cell proliferation might affect OS.

6.
Nat Commun ; 15(1): 3340, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38649703

RESUMO

During organ regeneration, after the initial responses to injury, gene expression patterns similar to those in normal development are reestablished during subsequent morphogenesis phases. This supports the idea that regeneration recapitulates development and predicts the existence of genes that reboot the developmental program after the initial responses. However, such rebooting mechanisms are largely unknown. Here, we explore core rebooting factors that operate during Xenopus limb regeneration. Transcriptomic analysis of larval limb blastema reveals that hoxc12/c13 show the highest regeneration specificity in expression. Knocking out each of them through genome editing inhibits cell proliferation and expression of a group of genes that are essential for development, resulting in autopod regeneration failure, while limb development and initial blastema formation are not affected. Furthermore, the induction of hoxc12/c13 expression partially restores froglet regenerative capacity which is normally very limited compared to larval regeneration. Thus, we demonstrate the existence of genes that have a profound impact alone on rebooting of the developmental program in a regeneration-specific manner.


Assuntos
Extremidades , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio , Regeneração , Proteínas de Xenopus , Xenopus laevis , Animais , Proliferação de Células/genética , Extremidades/fisiologia , Edição de Genes , Perfilação da Expressão Gênica , Proteínas de Homeodomínio/metabolismo , Proteínas de Homeodomínio/genética , Larva/crescimento & desenvolvimento , Larva/genética , Regeneração/genética , Regeneração/fisiologia , Proteínas de Xenopus/metabolismo , Proteínas de Xenopus/genética , Masculino , Feminino
7.
Proc Natl Acad Sci U S A ; 121(11): e2314911121, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38442169

RESUMO

In amniote limbs, Fibroblast Growth Factor 10 (FGF10) is essential for limb development, but whether this function is broadly conserved in tetrapods and/or involved in adult limb regeneration remains unknown. To tackle this question, we established Fgf10 mutant lines in the newt Pleurodeles waltl which has amazing regenerative ability. While Fgf10 mutant forelimbs develop normally, the hindlimbs fail to develop and downregulate FGF target genes. Despite these developmental defects, Fgf10 mutants were able to regenerate normal hindlimbs rather than recapitulating the embryonic phenotype. Together, our results demonstrate an important role for FGF10 in hindlimb formation, but little or no function in regeneration, suggesting that different mechanisms operate during limb regeneration versus development.


Assuntos
Fator 10 de Crescimento de Fibroblastos , Animais , Fator 10 de Crescimento de Fibroblastos/genética , Fator 10 de Crescimento de Fibroblastos/metabolismo , Membro Posterior/crescimento & desenvolvimento , Regeneração , Pleurodeles/genética , Pleurodeles/crescimento & desenvolvimento , Pleurodeles/metabolismo
8.
Respirol Case Rep ; 12(2): e01287, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38314101

RESUMO

Achromobacter xylosoxidans is a common bacterium that rarely causes pneumonia. Determining whether A. xylosoxidans is the cause of lung infection in patients suspected of having chronic infectious lung disease is challenging because it can present with colonization. We report a case of a 56-year-old immunocompetent woman suspected of having non-tuberculous mycobacteria (NTM) infection on imaging examination and monitored for 3 years. Sputum examinations revealed A. xylosoxidans several times, and it was determined to be a colonization. A. xylosoxidans was isolated from bronchial lavage fluid and aspirated sputum, but no evidence of NTM was observed. She was diagnosed with A. xylosoxidans infection and given ceftazidime for 2 weeks. Her symptoms and imaging findings improved rapidly after treatment, without recurrences. A. xylosoxidans rarely causes chronic lower respiratory tract infections similar to NTM in immunocompetent patients. A. xylosoxidans may be a target for treatment when detected in lower respiratory tract specimens.

9.
Nat Commun ; 15(1): 220, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38212328

RESUMO

Stimulator of interferon genes (STING) is critical for the type I interferon response to pathogen- or self-derived DNA in the cytosol. STING may function as a scaffold to activate TANK-binding kinase 1 (TBK1), but direct cellular evidence remains lacking. Here we show, using single-molecule imaging of STING with enhanced time resolutions down to 5 ms, that STING becomes clustered at the trans-Golgi network (about 20 STING molecules per cluster). The clustering requires STING palmitoylation and the Golgi lipid order defined by cholesterol. Single-molecule imaging of TBK1 reveals that STING clustering enhances the association with TBK1. We thus provide quantitative proof-of-principle for the signaling STING scaffold, reveal the mechanistic role of STING palmitoylation in the STING activation, and resolve the long-standing question of the requirement of STING translocation for triggering the innate immune signaling.


Assuntos
Lipoilação , Rede trans-Golgi , Rede trans-Golgi/metabolismo , Microscopia , Imagem Individual de Molécula , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Colesterol , Análise por Conglomerados , Imunidade Inata
10.
Dev Biol ; 506: 42-51, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38052295

RESUMO

Xenopus laevis is a widely used model organism in developmental and regeneration studies. Despite several reports regarding targeted integration techniques in Xenopus, there is still room for improvement of them, especially in creating reporter lines that rely on endogenous regulatory enhancers/promoters. We developed a CRISPR-Cas9-based simple method to efficiently introduce a fluorescent protein gene into 5' untranslated regions (5'UTRs) of target genes in Xenopus laevis. A donor plasmid DNA encoding an enhanced green fluorescent protein (eGFP) flanked by a genomic fragment ranging from 66 bp to 878 bp including target 5'UTR was co-injected into fertilized eggs with a single guide RNA and Cas9 protein. Injections for krt12.2.L, myod1.S, sox2.L or brevican.S resulted in embryos expressing eGFP fluorescence in a tissue-specific manner, recapitulating endogenous expression of target genes. Integrations of the donor DNA into the target regions were examined by genotyping PCR for the eGFP-expressing embryos. The rate of embryos expressing the specific eGFP varied from 2.1% to 13.2% depending on the target locus and length of the genomic fragment in the donor plasmids. Germline transmission of an integrated DNA was observed. This simple method provides a powerful tool for exploring gene expression and function in developmental and regeneration research in X. laevis.


Assuntos
Sistemas CRISPR-Cas , RNA Guia de Sistemas CRISPR-Cas , Animais , Xenopus laevis/genética , Sistemas CRISPR-Cas/genética , Expressão Gênica , DNA
11.
Invest New Drugs ; 42(1): 44-52, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38055127

RESUMO

Dexamethasone is one of the key antiemetic agents and is widely used even now. However, dexamethasone has been associated with several adverse reactions even after short-term administration. Therefore, developing a steroid-free antiemetic regimen is an important issue to consider. Thus, the purpose of this study was to investigate the efficacy and safety of palonosetron, aprepitant, and olanzapine in a multi-institutional phase II study. Chemotherapy-naive patients scheduled to receive cisplatin were enrolled and evaluated for the occurrence of chemotherapy-induced nausea and vomiting during 120 h after chemotherapy. The primary endpoint of the study was total control (TC) in the overall phase. The key secondary endpoint was complete response (CR), which was assessed in the acute, delayed, and overall phase, respectively. Adverse events were evaluated according to the Common Terminology Criteria for Adverse Events. Eighty-five patients were enrolled from 8 centers in Japan, of which 83 were evaluable for analyses. The percentage of patients who achieved TC during the overall phase was 31.3%. CR was achieved in 61.4%, 84.3%, and 65.1% of patients during the overall, acute, and delayed phases, respectively. The most frequently reported adverse event was anorexia. The primary endpoint was below the threshold and we could not find benefit in the dexamethasone-free regimen, but CR during the overall phase was similar to that of the conventional three-drug regimen. This antiemetic regimen without dexamethasone might be an option for patients for whom corticosteroids should not be an active application.


Assuntos
Antieméticos , Humanos , Antieméticos/efeitos adversos , Aprepitanto/efeitos adversos , Cisplatino/efeitos adversos , Dexametasona/efeitos adversos , Olanzapina/efeitos adversos , Palonossetrom/efeitos adversos , Resposta Patológica Completa
12.
Yakugaku Zasshi ; 143(12): 1075-1081, 2023.
Artigo em Japonês | MEDLINE | ID: mdl-38044112

RESUMO

Since it is important that patients take their oral anticancer therapy as prescribed, pharmacists need to assess adherence. In addition, oral anticancer drugs are expensive, and reuse of leftover drugs at outpatient pharmacy clinics is useful in reducing drug costs. The present study aimed to clarify when and why patients have leftover capecitabine tablets, and the cost of leftover capecitabine tablets reused at an outpatient pharmacy clinic, focusing on adjuvant capecitabine plus oxaliplatin (CAPOX) chemotherapy for gastric cancer. We retrospectively studied patients who received adjuvant CAPOX chemotherapy for gastric cancer between November 1, 2015, and April 30, 2021, at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research. The cost of leftover capecitabine reused by pharmacists was calculated based on the National Health Insurance drug price standard for the study period. This study included 64 patients who received adjuvant CAPOX chemotherapy. Thirty-seven patients had 152 leftover capecitabine tablets. The most common reasons for leftover capecitabine tablets were nausea and vomiting (21.7%), missed doses (18.4%), and diarrhea (13.2%). The leftover capecitabine tablets for 25 patients were reused at the outpatient pharmacy clinic at a cost of JPY 604142.8 (JPY 24165.7 per patient). The study results suggest that evaluating capecitabine adherence and the reasons for leftover capecitabine tablets at outpatient pharmacy clinics as well as reusing leftover medication can contribute to reducing drug costs.


Assuntos
Neoplasias Gástricas , Humanos , Capecitabina/efeitos adversos , Oxaliplatina , Neoplasias Gástricas/tratamento farmacológico , Estudos Retrospectivos , Quimioterapia Adjuvante/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Comprimidos , Fluoruracila/efeitos adversos
13.
J Med Invest ; 70(3.4): 411-414, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37940525

RESUMO

INTRODUCTION: Branch atheromatous disease (BAD) is a type of cerebral infarction caused by stenosis or occlusion at the entrance of the penetrating branch due to the presence of plaque. Despite its clinical significance, it is not clear how these plaques are formed. Focal geometrical characteristics are expected to be as important as vascular risk factors in the development of atherosclerosis. This study aimed to analyze the association between middle cerebral artery (MCA) geometric features and the onset of BAD. Shear stress results from the blood flow exerting force on the inner wall of the vessels and places with low wall shear stress may be prone to atherosclerosis. At the curvature of blood vessels, the shear stress is weak on the inside of the curve and plaque is likely to form. When this is applied to the MCA M1 segment, downward type M1 is likely to form plaques on the superior side. Because the lenticulostriate artery usually branches off from the superior side of the MCA M1 segment, in downward type M1, a plaque is likely to be formed at the entrance of the penetrating branch, and for that reason, BAD is likely to onset. METHODS: We retrospectively reviewed hospitalized stroke patients with BAD and investigated the morphology of their MCA using magnetic resonance imaging. The M1 segment was classified as straight or curved. Additionally, we compared the difference between the symptomatic and the asymptomatic side. Data regarding patients' medical history were also collected. RESULTS: A total of 56 patients with lenticulostriate artery infarctions and BAD were analyzed. On the symptomatic side, downward type M1 accounted for the largest proportion at 44%, whereas on the asymptomatic side, it was the lowest, at 16%. CONCLUSION: A downward type MCA may be associated with the onset of BAD and the morphological characteristics might affect the site of plaque formation. J. Med. Invest. 70 : 411-414, August, 2023.


Assuntos
Aterosclerose , Arteriosclerose Intracraniana , Placa Aterosclerótica , Humanos , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/patologia , Estudos Retrospectivos , Arteriosclerose Intracraniana/diagnóstico por imagem , Arteriosclerose Intracraniana/complicações , Arteriosclerose Intracraniana/patologia , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/complicações , Placa Aterosclerótica/patologia , Imageamento por Ressonância Magnética
14.
Cancer Med ; 12(18): 18745-18754, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37676079

RESUMO

BACKGROUND: Female sex and younger age are reported risk factors for chemotherapy-induced nausea and vomiting (CINV) in highly emetogenic chemotherapy, but the underlying mechanism has not been elucidated. The purpose of this study was to clarify the impact of menopause on CINV. METHODS: This retrospective observational study analyzed data from consecutive patients who received their first cycle of perioperative anthracycline-based chemotherapy for breast cancer between January 2018 and June 2020. The endpoints were association between CINV (vomiting, ≥Grade 2 nausea, complete response [CR] failure) and menopause as well as the association between CINV and follicle-stimulating hormone [FSH]/estradiol [E2]. RESULTS: Data for 639 patients were analyzed. Among these patients, 109 (17.1%) received olanzapine (four antiemetic combinations) and 530 (82.9%) did not (three antiemetic combinations). Premenopausal state (amenorrhea lasting ≥12 months) was significantly associated with ≥Grade 2 nausea and CR failure in univariate analysis but not in multivariate analysis. The premenopausal FSH/E2 group (defined by serum levels; FSH <40 mIU/mL and E2 ≥20 pg/mL) had a significantly higher rate of ≥Grade 2 nausea than the postmenopausal FSH/E2 group (FSH ≥40 mIU/mL and E2 <20 pg/mL) (48.8% vs. 18.8%, p = 0.023). CONCLUSIONS: Our results suggest that changes in FSH and E2 due to menopause may affect the severity of nausea and that FSH and E2 (especially FSH) levels might be useful indicators for CINV risk assessment.

15.
STAR Protoc ; 4(3): 102382, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37389994

RESUMO

We have established a new transgenesis protocol based on CRISPR-Cas9, "New and Easy XenopusTransgenesis (NEXTrans)," and identified a novel safe harbor site in African clawed frogs, Xenopus laevis. We describe steps in detail for the construction of NEXTrans plasmid and guide RNA, CRISPR-Cas9-mediated NEXTrans plasmid integration into the locus, and its validation by genomic PCR. This improved strategy allows us to simply generate transgenic animals that stably express the transgene. For complete details on the use and execution of this protocol, please refer to Shibata et al. (2022).1.


Assuntos
Sistemas CRISPR-Cas , RNA Guia de Sistemas CRISPR-Cas , Animais , Sistemas CRISPR-Cas/genética , Xenopus laevis/genética , Técnicas de Transferência de Genes , Transgenes
16.
J Cell Biol ; 222(8)2023 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-37278763

RESUMO

The spatial resolution of fluorescence microscopy has recently been greatly enhanced. However, improvements in temporal resolution have been limited, despite their importance for examining living cells. Here, we developed an ultrafast camera system that enables the highest time resolutions in single fluorescent-molecule imaging to date, which were photon-limited by fluorophore photophysics: 33 and 100 µs with single-molecule localization precisions of 34 and 20 nm, respectively, for Cy3, the optimal fluorophore we identified. Using theoretical frameworks developed for the analysis of single-molecule trajectories in the plasma membrane (PM), this camera successfully detected fast hop diffusion of membrane molecules in the PM, previously detectable only in the apical PM using less preferable 40-nm gold probes, thus helping to elucidate the principles governing the PM organization and molecular dynamics. Furthermore, as described in the companion paper, this camera allows simultaneous data acquisitions for PALM/dSTORM at as fast as 1 kHz, with 29/19 nm localization precisions in the 640 × 640 pixel view-field.


Assuntos
Corantes Fluorescentes , Nanotecnologia , Membrana Celular , Difusão , Microscopia de Fluorescência/métodos , Imagem Individual de Molécula , Biologia Celular
17.
J Cell Biol ; 222(8)2023 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-37278764

RESUMO

Using our newly developed ultrafast camera described in the companion paper, we reduced the data acquisition periods required for photoactivation/photoconversion localization microscopy (PALM, using mEos3.2) and direct stochastic reconstruction microscopy (dSTORM, using HMSiR) by a factor of ≈30 compared with standard methods, for much greater view-fields, with localization precisions of 29 and 19 nm, respectively, thus opening up previously inaccessible spatiotemporal scales to cell biology research. Simultaneous two-color PALM-dSTORM and PALM-ultrafast (10 kHz) single fluorescent-molecule imaging-tracking has been realized. They revealed the dynamic nanoorganization of the focal adhesion (FA), leading to the compartmentalized archipelago FA model, consisting of FA-protein islands with broad diversities in size (13-100 nm; mean island diameter ≈30 nm), protein copy numbers, compositions, and stoichiometries, which dot the partitioned fluid membrane (74-nm compartments in the FA vs. 109-nm compartments outside the FA). Integrins are recruited to these islands by hop diffusion. The FA-protein islands form loose ≈320 nm clusters and function as units for recruiting FA proteins.


Assuntos
Adesões Focais , Simulação de Dinâmica Molecular , Difusão , Adesões Focais/metabolismo , Integrinas/metabolismo , Imagem Individual de Molécula , Biologia Celular
18.
Glycoconj J ; 40(3): 305-314, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37133616

RESUMO

Glycosphingolipids, including gangliosides, are representative lipid raft markers that perform a variety of physiological roles in cell membranes. However, studies aimed at revealing their dynamic behavior in living cells are rare, mostly due to a lack of suitable fluorescent probes. Recently, the ganglio-series, lacto-series, and globo-series glycosphingolipid probes, which mimic the behavior of the parental molecules in terms of partitioning to the raft fraction, were developed by conjugating hydrophilic dyes to the terminal glycans of glycosphingolipids using state-of-art entirely chemical-based synthetic techniques. High-speed, single-molecule observation of these fluorescent probes revealed that gangliosides were scarcely trapped in small domains (100 nm in diameter) for more than 5 ms in steady-state cells, suggesting that rafts including gangliosides were always moving and very small. Furthermore, dual-color, single-molecule observations clearly showed that homodimers and clusters of GPI-anchored proteins were stabilized by transiently recruiting sphingolipids, including gangliosides, to form homodimer rafts and the cluster rafts, respectively. In this review, we briefly summarize recent studies, the development of a variety of glycosphingolipid probes as well as the identification of the raft structures including gangliosides in living cells by single-molecule imaging.


Assuntos
Corantes Fluorescentes , Glicoesfingolipídeos , Glicoesfingolipídeos/metabolismo , Corantes Fluorescentes/química , Imagem Individual de Molécula , Gangliosídeos/metabolismo , Membrana Celular/metabolismo , Microdomínios da Membrana/metabolismo
19.
JAMA Netw Open ; 6(5): e2310894, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-37129897

RESUMO

Importance: It is unknown whether olanzapine combined with triplet antemetic therapy is effective for all patients undergoing highly emetogenic chemotherapy. A secondary analysis of randomized clinical trials using olanzapine may provide insight into the effectiveness of olanzapine for chemotherapy-induced nausea and vomiting (CINV), including cisplatin. Objective: To examine the add-on effect of olanzapine according to risk factors for CINV. Design, Setting, and Participants: This preplanned secondary analysis evaluated results of the J-FORCE trial, a large double-blind, placebo-controlled phase 3 randomized clinical trial conducted in Japan from February 9, 2017, to July 18, 2018. Participants were enrolled from 26 participating hospitals across Japan and included patients aged 20 to 75 years who had a malignant tumor and were cisplatin-naive. The efficacy analysis population of the J-FORCE trial was analyzed according to allocation adjustment factors (sex [male or female], age [≥55 years or <55 years], and cisplatin dose [≥70 mg/m2 or <70 mg/m2]) and patient-related risk factors (history of motion sickness, drinking habit [defined as alcoholic drinks consumption in excess of occasional drinking], and history of morning sickness during pregnancy). Statistical analysis was performed from February 18 to April 18, 2020. Interventions: Patients were randomized 1:1 to receive 5 mg of olanzapine or placebo combined with standard triplet antiemetic therapy. Main Outcomes and Measures: The primary end point was complete response (CR, defined as no vomiting and no use of rescue medication) in the delayed phase (24-120 hours after cisplatin-based chemotherapy administration). Secondary end points were CR, complete control, and total control in the acute, delayed, and overall phases for 6 CINV risk factors as well as time to treatment failure. The CR point estimates and 95% CIs of the differences between groups were calculated, and a Mantel-Haenszel test was performed. Results: Of the 705 patients (mean [SD] age, 63.0 [9.2] years; 471 males [66.8%]) included in the efficacy analysis population; 581 patients (82.4%) were 55 years or older, and 526 (74.6%) were treated with a cisplatin dose of 70 mg/m2 or more. Risk difference (RD) for a CR in the delayed phase was significantly greater in the olanzapine group than the placebo group in males (RD, 12.6% [95% CI, 5.0%-20.1%]; P = .001); in females (RD, 14.5% [95% CI, 2.2%-26.3%]; P = .02); in those 55 years or older (RD, 11.1% [95% CI, 3.9%-18.2%]; P = .003) or younger than 55 years (RD, 23.6% [95% CI, 7.3%-38.3%]; P = .005); for a cisplatin dose of 70 mg/m2 or more (RD, 13.5% [95% CI, 5.9%-21.0%]; P < .001); for those without a history of motion sickness (RD, 13.9% [95% CI, 6.9%-20.6%]; P < .001); for those with a drinking habit (RD, 14.9% [95% CI, 6.1%-23.4%]; P = .001) or without a drinking habit (RD, 12.0% [95% CI, 2.5%-21.3%]; P = .01); and for those with a history of morning sickness during pregnancy (RD, 27.2% [9.7%-42.6%]; P = .002). In other subgroups, a delayed CR was higher in the olanzapine group than the placebo group, although not significantly higher. Conclusions and Relevance: Results of this study suggest a benefit of using 5 mg of olanzapine plus triplet antiemetic therapy to counter CINV regardless of the presence or absence of risk factors. Trial Registration: University Hospital Medical Information Network Clinical Trials Registry Identifier: UMIN000024676.


Assuntos
Antieméticos , Êmese Gravídica , Enjoo devido ao Movimento , Humanos , Masculino , Feminino , Gravidez , Pessoa de Meia-Idade , Olanzapina/efeitos adversos , Cisplatino/uso terapêutico , Vômito/induzido quimicamente , Vômito/tratamento farmacológico , Vômito/prevenção & controle , Náusea/induzido quimicamente , Náusea/prevenção & controle , Náusea/tratamento farmacológico , Enjoo devido ao Movimento/induzido quimicamente , Enjoo devido ao Movimento/tratamento farmacológico , Êmese Gravídica/tratamento farmacológico
20.
Mol Biol Cell ; 34(5)2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-37039596

RESUMO

Two very polarized views exist for understanding the cellular plasma membrane (PM). For some, it is the simple fluid described by the original Singer-Nicolson fluid mosaic model. For others, due to the presence of thousands of molecular species that extensively interact with each other, the PM forms various clusters and domains that are constantly changing and therefore, no simple rules exist that can explain the structure and molecular dynamics of the PM. In this article, we propose that viewing the PM from its two predominant components, cholesterol and actin filaments, provides an excellent and transparent perspective of PM organization, dynamics, and mechanisms for its functions. We focus on the actin-induced membrane compartmentalization and lipid raft domains coexisting in the PM and how they interact with each other to perform PM functions. This view provides an important update of the fluid mosaic model.


Assuntos
Actinas , Canto , Actinas/metabolismo , Aniversários e Eventos Especiais , Membrana Celular/metabolismo , Colesterol/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA