Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 67.595
Filtrar
1.
Parasitol Res ; 121(1): 143-154, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34988668

RESUMO

The sampling of 22 specimens of Rhizoprionodon oligolinx Springer from the Persian Gulf made possible the description of three new species of Anthobothrium van Beneden, 1850. Anthobothrium parimae sp. nov. is different from its congeners, except for A. altavelae Neifar, Euzet and Ben Hassine, 2002, A. lyndoni Ruhnke and Caira, 2009, and A. lesteri Williams, Burt and Caira, 2004, in the total length. It differs from A. altavelae in the number of the proglottids; from A. lyndoni in the length of the mature proglottids; and from A. lesteri Williams, Burt and Caira, 2004 in possessing one hemicircular band, rather than two circular bands, of musculature in its bothridia. The other two new species, being the smallest in size within the genus, most closely resemble each other but differ in the position of the genital pore in the proglottid, the number of post-vaginal testes, the number of the ventral and dorsal columns of vitelline follicles in each lateral band, and the distribution of the gladiate spinitriches on the strobila. These three new species are the only "tetraphyllidean" species reported to date from the southern waters of Iran. In addition, for the first time, more than two congeners belonging to Anthobothrium are reported from the same host species sympatrically and simultaneously. The morphological variation within this genus is also discussed.


Assuntos
Cestoides , Infecções por Cestoides , Doenças dos Peixes , Tubarões , Animais , Citoplasma , Feminino , Oceano Índico , Masculino , Microscopia Eletrônica de Varredura , Testículo
2.
Biochim Biophys Acta Biomembr ; 1864(1): 183809, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34699768

RESUMO

Human aquaporin 10 (hAQP10) is an aquaglyceroporin that assists in maintaining glycerol flux in adipocytes during lipolysis at low pH. Hence, a molecular understanding of the pH-sensitive glycerol conductance may open up for drug development in obesity and metabolically related disorders. Control of hAQP10-mediated glycerol flux has been linked to the cytoplasmic end of the channel, where a unique loop is regulated by the protonation status of histidine 80 (H80). Here, we performed unbiased molecular dynamics simulations of three protonation states of H80 to unravel channel gating. Strikingly, at neutral pH, we identified a water coordination pattern with an inverted orientation of the water molecules in vicinity of the loop. Protonation of H80 results in a more hydrophobic loop conformation, causing loss of water coordination and leaving the pore often dehydrated. Our results indicate that the loss of such water interaction network may be integral for the destabilization of the loop in the closed configuration at low pH. Additionally, a residue unique to hAQP10 (F85) reveals structural importance by flipping into the channel in correlation with loop movements, indicating a loop-stabilizing role in the closed configuration. Taken together, our simulations suggest a unique gating mechanism combining complex interaction networks between water molecules and protein residues at the loop interface. Considering the role of hAQP10 in adipocytes, the detailed molecular insights of pH-regulation presented here will help to understand glycerol pathways in these cells and may assist in drug discovery for better management of human adiposity and obesity.


Assuntos
Adiposidade/genética , Aquaporinas/genética , Glicerol/metabolismo , Água/metabolismo , Aquaporinas/química , Citoplasma/química , Citoplasma/genética , Histidina/genética , Humanos , Concentração de Íons de Hidrogênio , Lipólise/genética , Simulação de Dinâmica Molecular , Obesidade/genética , Obesidade/metabolismo , Prótons
3.
Biochim Biophys Acta Biomembr ; 1864(1): 183814, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34774499

RESUMO

The toxicity of α-synuclein (α-syn), the amyloidogenic protein responsible for Parkinson's disease, is likely related to its interaction with the asymmetric neuronal membrane. α-Syn exists as cytoplasmatic and as extracellular protein as well. To shed light on the different interactions occurring at the different α-syn localizations, we have here modelled the external and internal membrane leaflets of the neuronal membrane with two complex lipid mixtures, characterized by phase coexistence and with negative charge confined to either the ordered or the disordered phase, respectively. To this purpose, we selected a five-component (DOPC/SM/DOPE/DOPS/chol) and a four-component (DOPC/SM/GM1/chol) lipid mixtures, which contained the main membrane lipid constituents and exhibited a phase separation with formation of ordered domains. We have compared the action of α-syn in monomeric form and at different concentrations (1 nM, 40 nM, and 200 nM) with respect to lipid systems with different composition and shape by AFM, QCM-D, and vesicle leakage experiments. The experiments coherently showed a higher stability of the membranes composed by the internal leaflet mixture to the interaction with α-syn. Damage to membranes made of the external leaflet mixture was detected in a concentration-dependent manner. Interestingly, the membrane damage was related to the fluidity of the lipid domains and not to the presence of negatively charged lipids.


Assuntos
Membrana Celular/genética , Lipídeos de Membrana/química , Neurônios/química , alfa-Sinucleína/genética , Biomimética , Citoplasma/química , Citoplasma/genética , Humanos , Lipídeos de Membrana/genética , Neurônios/metabolismo , Doença de Parkinson/genética , Doença de Parkinson/patologia , Fosfatidilcolinas/química , Fosfatidiletanolaminas/química , alfa-Sinucleína/química
4.
Methods Mol Biol ; 2382: 233-243, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34705243

RESUMO

Membrane trafficking is central to cell plate construction during plant cytokinesis. Studies on cell plate formation can provide answers to basic biology questions including molecular mechanisms of membrane trafficking, tissue patterning, and cytoskeletal dynamics. Consequently, a detailed understanding of cytokinesis depends on the characterization of molecules that function in the formation, transport, targeting, and fusion of membrane vesicles and delivery of proteins to the developing and maturing plate. This chapter describes a pipeline based on fluorescence recovery after photobleaching (FRAP) to measure and analyze turnover of peripheral or transmembrane proteins on the cell plate. The approach described here can also be applied in other biological contexts.


Assuntos
Citocinese , Citoplasma , Recuperação de Fluorescência Após Fotodegradação
5.
J Theor Biol ; 533: 110936, 2022 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-34695383

RESUMO

Scaling of nuclear size with cell size has been observed in many species and cell types. In this work we formulate a modeling framework based on the limiting component hypothesis. We derive a family of spatio-temporal mathematical models for nuclear size determination based on different transport and growth mechanisms. We analyse model properties and use in vitro experimental data to identify the most probable mechanism. This suggests that nuclear volume scales with cell volume and that a nucleus controls its import rate as it grows. We further test the model by comparing to data of early frog development, where rapid cell divisions set the relevant time scales.


Assuntos
Núcleo Celular , Modelos Teóricos , Tamanho Celular , Citoplasma , Citosol
6.
Micron ; 152: 103176, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34763214

RESUMO

The fine structure of the larval eyes of the hangingfly Terrobittacus implicatus (Huang & Hua) was investigated using scanning and transmission electron microscopy. The results show that the larval eyes of T. implicatus each consist of seven spaced ommatidia. Each ommatidium is composed of a corneal lens with about 45 lamellae, a tetrapartite eucone type of crystalline cone, eight retinula cells, two primary pigment cells, and an undetermined number of secondary pigment cells. The rhabdomeres of eight retinula cells effectively fuse into a centrally-fused, tiered funnel-shaped rhabdom extending from the base of the crystalline cone deeply into the ommatidium. In light of different positions in the ommatidium, the retinula cells can be divided into four distal and four proximal retinula cells. Pigment cells envelop the entire ommatidium. Electron-lucent vesicles are abundant throughout the cytoplasm of the eight retinula cells. The larval ommatidia of T. implicatus are similar to those of the Panorpidae, except for the distal retinula cells that also participate in the formation of the proximal rhabdom. In this case, the larval eyes of T. implicatus may lie in the transitional stage during the larval eye evolution of insects from ommatidia to stemmata.


Assuntos
Córnea , Insetos , Animais , Citoplasma , Olho , Larva , Microscopia Eletrônica de Transmissão
7.
Methods Mol Biol ; 2360: 209-216, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34495517

RESUMO

Currently, RNAi-based techniques have exhibited considerable potential for pest control, and considerable progress has been made in identifying a large number of potential target genes in the laboratory. However, applying potential target genes effectively in the field to control pests requires further research. At present, transgenic crops expressing dsRNA are widely recognized as the most practical and economical means of applying RNAi-based techniques using laboratory-identified target genes to control pests in the field. Among the three plant-mediated RNAi techniques, plant-mediated RNA interference expressing dsRNA in cytoplasm is most often considered to be an economical and practical RNAi method for pest control, both in the laboratory and in the field. In this chapter, I describe the procedure for expressing dsRNA in plant cytoplasm for RNAi-based pest control.


Assuntos
Controle de Pragas , Interferência de RNA , Citoplasma , RNA de Cadeia Dupla/genética , RNA de Plantas
8.
Viruses ; 13(12)2021 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-34960809

RESUMO

Infectious bronchitis virus (IBV), a gammacoronavirus, is an economically important virus to the poultry industry, as well as a significant welfare issue for chickens. As for all positive strand RNA viruses, IBV infection causes rearrangements of the host cell intracellular membranes to form replication organelles. Replication organelle formation is a highly conserved and vital step in the viral life cycle. Here, we investigate the localization of viral RNA synthesis and the link with replication organelles in host cells. We have shown that sites of viral RNA synthesis and virus-related dsRNA are associated with one another and, significantly, that they are located within a membrane-bound compartment within the cell. We have also shown that some viral RNA produced early in infection remains within these membranes throughout infection, while a proportion is trafficked to the cytoplasm. Importantly, we demonstrate conservation across all four coronavirus genera, including SARS-CoV-2. Understanding more about the replication of these viruses is imperative in order to effectively find ways to control them.


Assuntos
Coronavirus/metabolismo , Membranas Intracelulares/metabolismo , RNA Viral/biossíntese , Animais , Linhagem Celular , Coronavirus/classificação , Coronavirus/crescimento & desenvolvimento , Citoplasma/metabolismo , Humanos , Vírus da Bronquite Infecciosa/crescimento & desenvolvimento , Vírus da Bronquite Infecciosa/metabolismo , RNA de Cadeia Dupla/metabolismo , Compartimentos de Replicação Viral/metabolismo
9.
BMC Plant Biol ; 21(1): 589, 2021 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-34903178

RESUMO

BACKGROUND: Plasma membrane intrinsic proteins (PIPs) are plant channel proteins involved in water deficit and salinity tolerance. PIPs play a major role in plant cell water balance and responses to salt stress. Although sugarcane is prone to high salt stress, there is no report on PIPs in sugarcane. RESULTS: In the present study, eight PIP family genes, termed ScPIP1-1, ScPIP1-2, ScPIP1-3, ScPIP1-4, ScPIP2-1, ScPIP2-2, ScPIP2-4 and ScPIP2-5, were obtained based on the sugarcane transcriptome database. Then, ScPIP2-1 in sugarcane was cloned and characterized. Confocal microscopy observation indicated that ScPIP2-1 was located in the plasma membrane and cytoplasm. A yeast two-hybridization experiment revealed that ScPIP2-1 does not have transcriptional activity. Real time quantitative PCR (RT-qPCR) analysis showed that ScPIP2-1 was mainly expressed in the leaf, root and bud, and its expression levels in both below- and aboveground tissues of ROC22 were up-regulated by abscisic acid (ABA), polyethylene glycol (PEG) 6000 and sodium chloride (NaCl) stresses. The chlorophyll content and ion leakage measurement suggested that ScPIP2-1 played a significant role in salt stress resistance in Nicotiana benthamiana through the transient expression test. Overexpression of ScPIP2-1 in Arabidopsis thaliana proved that this gene enhanced the salt tolerance of transgenic plants at the phenotypic (healthier state, more stable relative water content and longer root length), physiologic (more stable ion leakage, lower malondialdehyde content, higher proline content and superoxide dismutase activity) and molecular levels (higher expression levels of AtKIN2, AtP5CS1, AtP5CS2, AtDREB2, AtRD29A, AtNHX1, AtSOS1 and AtHKT1 genes and a lower expression level of the AtTRX5 gene). CONCLUSIONS: This study revealed that the ScPIP2-1-mediated osmotic stress signaling cascade played a positive role in plant response to salt stress.


Assuntos
Aquaporinas/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Plantas/metabolismo , Saccharum/genética , Tolerância ao Sal/genética , Transdução de Sinais , Ácido Abscísico/metabolismo , Aquaporinas/genética , Arabidopsis/genética , Arabidopsis/fisiologia , Membrana Celular/metabolismo , Clorofila/metabolismo , Citoplasma/metabolismo , Expressão Gênica , Malondialdeído/metabolismo , Pressão Osmótica , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Prolina/metabolismo , Saccharum/fisiologia , Estresse Salino , Tabaco/genética , Tabaco/fisiologia
10.
FEMS Microbiol Lett ; 368(21-24)2021 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-34910142

RESUMO

Almost all major classes of bacteria are surrounded by a peptidoglycan cell wall, which is a crucial target for antibiotics. It is now understood that many bacteria can tolerate loss of the cell wall provided that they are in an isotonic environment. Furthermore, in some cases the cells can continue to proliferate in a state known as the L-form. L-form proliferation occurs by an unusual blebbing or tubulation mechanism that is completely independent of the normally essential division machine or cell wall synthetic enzymes, and is resistant to cell wall-active antibiotics. However, the growth is limited by reactive oxygen species generated by the respiratory chain pathway. In this work, we examined the walled to L-form transition in a pathogenic Gram-negative bacterium, Streptobacillus moniliformis, which naturally lacks the respiratory chain pathway, under aerobic conditions. L-form-like cells often emerged spontaneously, but proliferation was not observed unless the cells were treated with cell wall-active antibiotics. Time-lapse imaging revealed that cell division of S. moniliformis L-forms involves unusual membrane dynamics with an apparent imbalance between outer membrane and cytoplasmic volume growth. The results suggest that outer membrane expansion may be an important general factor for L-form proliferation of diderm bacteria.


Assuntos
Formas L , Antibacterianos/farmacologia , Membrana Externa Bacteriana/efeitos dos fármacos , Membrana Externa Bacteriana/metabolismo , Proliferação de Células/fisiologia , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Citoplasma/metabolismo , Formas L/fisiologia , Streptobacillus/efeitos dos fármacos , Streptobacillus/crescimento & desenvolvimento
11.
DNA Cell Biol ; 40(12): 1476-1494, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34931869

RESUMO

In mammals, a large part of the gene expression products come from the non-coding ribonucleotide sequences of the protein. These short and long sequences are within the range of tens to hundreds of nucleotides, encompassing more than 200 RNA molecules, and their function is known as the molecular structure of long non-coding RNA (lncRNA). LncRNA molecules are unique nucleotides that have a substantial role in epigenetic regulation, transcription, and post-transcriptional modifications in different ways. According to the results of recent studies, lncRNAs have been shown to assume various roles, including tumor suppression or oncogenic functions in common types of cancer such as lung and breast cancer. These non-coding RNAs (ncRNAs) play a pivotal role in activating transcription factors, managing the ribonucleoproteins, the framework for collecting co-proteins, intermittent processing regulations, chromatin status alterations, and maintaining the control within the cell. Cutting-edge technologies have been introduced to disclose several types of lncRNAs within the nucleus and the cytoplasm, which have accomplished important achievements that are applicable in medicine. Due to these efforts, various data centers have been created to facilitate and modify scientific information related to these molecules, including detection, classification, biological evolution, gene status, spatial structure, status, and location of these small molecules. In the present study, we attempt to present the impacts of these ncRNAs on lung cancer with an emphasis on their mechanisms and functions.


Assuntos
Neoplasias Pulmonares/genética , RNA Longo não Codificante/genética , Animais , Núcleo Celular/genética , Citoplasma/genética , Epigênese Genética/genética , Humanos , Ribonucleoproteínas/genética , Fatores de Transcrição/genética
12.
J Cardiothorac Surg ; 16(1): 324, 2021 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-34742341

RESUMO

BACKGROUND: SCIRT has been characterized as a key player in cancer biology, while its role in other human diseases is unclear. This study explored its role in atherosclerosis, with a specific focus on its interaction with SCIRT and miR-146a. METHODS: The expression of SCIRT and miR-146a in atherosclerosis-affected tissues and healthy tissues from 56 atherosclerosis patients were analyzed by RT-qPCR. The expression of SCIRT in nuclear and cytoplasm samples was detected by RNA fractionation assay. The direct interaction between SCIRT and miR-146a was detected by RNA pull-down assay. SCIRT and miR-146a were overexpressed in human aortic smooth muscle cells (HAOSMCs) to study the crosstalk between them. The role of SCIRT and miR-146a in the proliferation of HAOSMCs was analyzed with BrdU assay. RESULTS: SCIRT was downregulated by atherosclerosis, while miR-146a was upregulated by atherosclerosis. SCIRT was detected in both cytoplasm and nuclear samples, and it directly interacted with miR-146a. In HAOSMCs, overexpression of SCIRT and miR-146a did not affect the expression of each other. Interestingly, SCIRT suppressed the proliferation of HAOSMCs and reduced the enhancing effects of miR-146a on cell proliferation. CONCLUSION: Therefore, SCIRT is downregulated in atherosclerosis and it suppresses the proliferation of HAOSMCs by sponging miR-146a in cytoplasm.


Assuntos
Aterosclerose , MicroRNAs , RNA Longo não Codificante , Aterosclerose/genética , Proliferação de Células , Citoplasma , Humanos , MicroRNAs/genética , Miócitos de Músculo Liso , RNA Longo não Codificante/genética
13.
Signal Transduct Target Ther ; 6(1): 382, 2021 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-34732709

RESUMO

The global coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a positive-sense RNA virus. How the host immune system senses and responds to SARS-CoV-2 infection remain largely unresolved. Here, we report that SARS-CoV-2 infection activates the innate immune response through the cytosolic DNA sensing cGAS-STING pathway. SARS-CoV-2 infection induces the cellular level of 2'3'-cGAMP associated with STING activation. cGAS recognizes chromatin DNA shuttled from the nucleus as a result of cell-to-cell fusion upon SARS-CoV-2 infection. We further demonstrate that the expression of spike protein from SARS-CoV-2 and ACE2 from host cells is sufficient to trigger cytoplasmic chromatin upon cell fusion. Furthermore, cytoplasmic chromatin-cGAS-STING pathway, but not MAVS-mediated viral RNA sensing pathway, contributes to interferon and pro-inflammatory gene expression upon cell fusion. Finally, we show that cGAS is required for host antiviral responses against SARS-CoV-2, and a STING-activating compound potently inhibits viral replication. Together, our study reported a previously unappreciated mechanism by which the host innate immune system responds to SARS-CoV-2 infection, mediated by cytoplasmic chromatin from the infected cells. Targeting the cytoplasmic chromatin-cGAS-STING pathway may offer novel therapeutic opportunities in treating COVID-19. In addition, these findings extend our knowledge in host defense against viral infection by showing that host cells' self-nucleic acids can be employed as a "danger signal" to alarm the immune system.


Assuntos
COVID-19/imunologia , Cromatina/imunologia , Citoplasma/imunologia , Imunidade Inata , Nucleotidiltransferases/imunologia , SARS-CoV-2/imunologia , Animais , COVID-19/genética , Cromatina/genética , Citoplasma/genética , Modelos Animais de Doenças , Células HEK293 , Células HeLa , Humanos , Camundongos , Camundongos Transgênicos , Nucleotidiltransferases/genética , SARS-CoV-2/genética
14.
Biophys J ; 120(21): 4698-4709, 2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34624272

RESUMO

Nuclear morphology is an important indicator of cell function. It is regulated by a variety of factors such as the osmotic pressure difference between the nucleoplasm and cytoplasm, cytoskeletal forces, elasticity of the nuclear envelope and chromosomes. Nucleus shape and size are typically quantified using multiple geometrical quantities that are not necessarily independent of one another. This interdependence makes it difficult to decipher the implications of changes in nuclear morphology. We resolved this by analyzing nucleus shapes of populations for multiple cell lines using a mechanics-based model. We deduced two independent nondimensional parameters, namely, flatness index and isometric scale factor. We show that nuclei in a cell population have similar flatness but variable scale factor. Furthermore, nuclei of different cell lines segregate according to flatness. Cellular perturbations using biochemical and biomechanical techniques suggest that the flatness index correlates with actin tension and the scale factor anticorrelates with elastic modulus of nuclear envelope. We argue that nuclear morphology measures such as volume, projected area, height etc., are subsumed by flatness and scale factor, which can unambiguously characterize nuclear morphology.


Assuntos
Núcleo Celular , Citoesqueleto , Actinas , Forma do Núcleo Celular , Citoplasma , Membrana Nuclear
15.
Nat Commun ; 12(1): 6064, 2021 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-34663815

RESUMO

Calcineurin, the conserved protein phosphatase and target of immunosuppressants, is a critical mediator of Ca2+ signaling. Here, to discover calcineurin-regulated processes we examined an understudied isoform, CNAß1. We show that unlike canonical cytosolic calcineurin, CNAß1 localizes to the plasma membrane and Golgi due to palmitoylation of its divergent C-terminal tail, which is reversed by the ABHD17A depalmitoylase. Palmitoylation targets CNAß1 to a distinct set of membrane-associated interactors including the phosphatidylinositol 4-kinase (PI4KA) complex containing EFR3B, PI4KA, TTC7B and FAM126A. Hydrogen-deuterium exchange reveals multiple calcineurin-PI4KA complex contacts, including a calcineurin-binding peptide motif in the disordered tail of FAM126A, which we establish as a calcineurin substrate. Calcineurin inhibitors decrease PI4P production during Gq-coupled GPCR signaling, suggesting that calcineurin dephosphorylates and promotes PI4KA complex activity. In sum, this work discovers a calcineurin-regulated signaling pathway which highlights the PI4KA complex as a regulatory target and reveals that dynamic palmitoylation confers unique localization, substrate specificity and regulation to CNAß1.


Assuntos
1-Fosfatidilinositol 4-Quinase/metabolismo , Membrana Celular/metabolismo , Lipoilação/fisiologia , Monoéster Fosfórico Hidrolases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Calcineurina/metabolismo , Linhagem Celular , Citoplasma/metabolismo , Complexo de Golgi/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Ligação Proteica , Isoformas de Proteínas/metabolismo , Transdução de Sinais/fisiologia
16.
Nat Commun ; 12(1): 6067, 2021 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-34663821

RESUMO

Living cells are a complex soft material with fascinating mechanical properties. A striking feature is that, regardless of their types or states, cells exhibit a universal power-law rheological behavior which to this date still has not been captured by a single theoretical model. Here, we propose a cellular structural model that accounts for the essential mechanical responses of cell membrane, cytoplasm and cytoskeleton. We demonstrate that this model can naturally reproduce the universal power-law characteristics of cell rheology, as well as how its power-law exponent is related to cellular stiffness. More importantly, the power-law exponent can be quantitatively tuned in the range of 0.1 ~ 0.5, as found in most types of cells, by varying the stiffness or architecture of the cytoskeleton. Based on the structural characteristics, we further develop a self-similar hierarchical model that can spontaneously capture the power-law characteristics of creep compliance over time and complex modulus over frequency. The present model suggests that mechanical responses of cells may depend primarily on their generic architectural mechanism, rather than specific molecular properties.


Assuntos
Citoplasma/fisiologia , Citoesqueleto/fisiologia , Modelos Estruturais , Reologia , Membrana Celular , Modelos Teóricos
17.
Elife ; 102021 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-34633289

RESUMO

To assure complete tumor removal, frozen section analysis is the most common procedure for intraoperative pathological assessment of resected tumor margins. However, during one operation, multiple biopsies may be sent for examination, but only few of them are made into cryosections because of the complex preparation protocols and time-consuming pathological analysis, which potentially increases the risk of overlooking tumor involvement. Here, we propose a fluorescence-based pre-screening strategy that allows high-throughput, convenient, and fast gross assessment of resected tumor margins. A dual-activatable cationic fluorescent molecular rotor was developed to specifically illuminate live tumor cells' cytoplasm by emitting two different fluorescence signals in response to elevations in hypoxia-induced nitroreductase (a biochemical marker) and cytoplasmic viscosity (a biophysical marker), two characteristics of cancer cells. The ability of the fluorescent molecular rotor in detecting tumor cells was evaluated in mouse and human specimens of multiple tissues by comparing with hematoxylin and eosin staining. Importantly, the fluorescent molecular rotor achieved 100 % specificity in discriminating lung and liver cancers from normal tissue, allowing pre-screening of the tumor-free surgical margins and promoting clinical decision. Altogether, this type of fluorescent molecular rotor and the proposed strategy may serve as a new option to facilitate intraoperative assessment of resected tumor margins.


Assuntos
Carcinoma Hepatocelular/cirurgia , Carcinoma de Células Renais/cirurgia , Citoplasma/química , Neoplasias Renais/cirurgia , Neoplasias Hepáticas/cirurgia , Margens de Excisão , Neoplasias/cirurgia , Adulto , Idoso , Feminino , Fluorescência , Humanos , Masculino , Pessoa de Meia-Idade , Viscosidade
18.
PLoS Genet ; 17(10): e1009836, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34634043

RESUMO

A small number of peptide growth factor ligands are used repeatedly in development and homeostasis to drive programs of cell differentiation and function. Cells and tissues must integrate inputs from these diverse signals correctly, while failure to do so leads to pathology, reduced fitness, or death. Previous work using the nematode C. elegans identified an interaction between the bone morphogenetic protein (BMP) and insulin/IGF-1-like signaling (IIS) pathways in the regulation of lipid homeostasis. The molecular components required for this interaction, however, were not fully understood. Here we report that INS-4, one of 40 insulin-like peptides (ILPs), is regulated by BMP signaling to modulate fat accumulation. Furthermore, we find that the IIS transcription factor DAF-16/FoxO, but not SKN-1/Nrf, acts downstream of BMP signaling in lipid homeostasis. Interestingly, BMP activity alters sensitivity of these two transcription factors to IIS-promoted cytoplasmic retention in opposite ways. Finally, we probe the extent of BMP and IIS interactions by testing additional IIS functions including dauer formation, aging, and autophagy induction. Coupled with our previous work and that of other groups, we conclude that BMP and IIS pathways have at least three modes of interaction: independent, epistatic, and antagonistic. The molecular interactions we identify provide new insight into mechanisms of signaling crosstalk and potential therapeutic targets for IIS-related pathologies such as diabetes and metabolic syndrome.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Insulina/metabolismo , Lipídeos/fisiologia , Transdução de Sinais/fisiologia , Envelhecimento/metabolismo , Animais , Autofagia/fisiologia , Citoplasma/metabolismo , Diabetes Mellitus/metabolismo , Homeostase/fisiologia , Fator de Crescimento Insulin-Like I/metabolismo , Síndrome Metabólica/metabolismo , Fatores de Transcrição/metabolismo
19.
Anal Chem ; 93(42): 14113-14120, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34657412

RESUMO

Membrane proteins tend to interact with each other in the cell membranes to form protein clusters and perform the corresponding physiological functions. However, because channel proteins are involved in many biological functions, their distribution and nano-organization in these protein clusters are unclear. To study the distribution patterns and relationships between the different channel proteins, we identified the locations of glucose transporter 1 (Glut1) and Band3 (anion transporter 1) precisely in the topography of the cytoplasmic side of the human red blood cell (hRBC) membranes using combined atomic force microscopy (AFM) and single-molecule localization microscopy (SMLM). The AFM results revealed that membrane proteins interacted with each other and aggregated into protein islands. The SMLM results showed that Glut1 and Band3 tended to form protein clusters in the hRBC membranes, and there was a strong colocalization between the two proteins. The results of the combined AFM and SMLM method indicated that the protein clusters of Glut1 and Band3 were mainly located in the protein islands of topography, and the protein islands in topography also interacted with each other to assemble into larger protein clusters or functional microdomains.


Assuntos
Membrana Eritrocítica , Imagem Individual de Molécula , Citoplasma , Humanos , Proteínas de Membrana , Microscopia de Força Atômica
20.
Anal Chem ; 93(42): 14204-14213, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34648273

RESUMO

It is of significant importance in cancer biology to identify signaling pathways that play key roles in cell fate determination. Dissecting cellular signaling pathways requires the measurement of a large number of signaling proteins. However, tools for simultaneously monitoring multiple signaling pathway components in single living cells remain limited at present. Herein, we describe an approach, termed multiplexed single-cell plasmonic immunosandwich assay (mxscPISA), for simultaneous detection of multiple signaling proteins in individual living cells. This approach enabled simultaneous non-destructive monitoring of multiple (up to five, currently the highest multiplexing capacity in living cells) cytoplasmic and nucleus signaling proteins in individual cells with ultrahigh detection sensitivity. As a proof of principle, the epidermal growth factor receptor (EGFR) pathway, which plays a central role in cell fate determination, was investigated using this approach in this study. We found that there were differential attenuation rate of pro-survival and accumulation rate of pro-death signaling protein of the EGFR pathway in response to EGFR inactivation. These findings implicate that, after EGFR inactivation, a transient imbalance between survival and apoptotic signaling outputs contributed to the final cell fate of death. The mxscPISA approach can be a promising tool to reveal a signaling dynamic pattern at the single-cell level and to identify key components of signaling pathways that contribute to the final cell fate using only a limited number of cells.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular , Transdução de Sinais , Núcleo Celular , Citoplasma , Imunoensaio
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...