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1.
J Biol Chem ; 299(10): 105216, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37660918

RESUMO

The Vps10p-domain (Vps10p-D) receptor family consists of Sortilin, SorLA, SorCS1, SorCS2, and SorCS3. They mediate internalization and intracellular sorting of specific cargo in various cell types, but underlying molecular determinants are incompletely understood. Deciphering the dynamic intracellular itineraries of Vps10p-D receptors is crucial for understanding their role in physiological and cytopathological processes. However, studying their spatial and temporal dynamics by live imaging has been challenging so far, as terminal tagging with fluorophores presumably impedes several of their protein interactions and thus functions. Here, we addressed the lack of appropriate tools and developed functional versions of all family members internally tagged in their ectodomains. We predict folding of the newly designed receptors by bioinformatics and show their exit from the endoplasmic reticulum. We examined their subcellular localization in immortalized cells and primary cultured neurons by immunocytochemistry and live imaging. This was, as far as known, identical to that of wt counterparts. We observed homodimerization of fluorophore-tagged SorCS2 by coimmunoprecipitation and fluorescence lifetime imaging, suggesting functional leucine-rich domains. Through ligand uptake experiments, live imaging and fluorescence lifetime imaging, we show for the first time that all Vps10p-D receptors interact with the neurotrophin brain-derived neurotrophic factor and mediate its uptake, indicating functionality of the Vps10p-Ds. In summary, we developed versions of all Vps10p-D receptors, with internal fluorophore tags that preserve several functions of the cytoplasmic and extracellular domains. These newly developed fluorophore-tagged receptors are likely to serve as powerful functional tools for accurate live studies of the individual cellular functions of Vps10p-D receptors.

2.
J Microsc ; 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38618985

RESUMO

The structure of the cell nucleus of higher organisms has become a major topic of advanced light microscopy. So far, a variety of methods have been applied, including confocal laser scanning fluorescence microscopy, 4Pi, STED and localisation microscopy approaches, as well as different types of patterned illumination microscopy, modulated either laterally (in the object plane) or axially (along the optical axis). Based on our experience, we discuss here some application perspectives of Modulated Illumination Microscopy (MIM) and its combination with single-molecule localisation microscopy (SMLM). For example, spatially modulated illumination microscopy/SMI (illumination modulation along the optical axis) has been used to determine the axial extension (size) of small, optically isolated fluorescent objects between ≤ 200 nm and ≥ 40 nm diameter with a precision down to the few nm range; it also allows the axial positioning of such structures down to the 1 nm scale; combined with laterally structured illumination/SIM, a 3D localisation precision of ≤1 nm is expected using fluorescence yields typical for SMLM applications. Together with the nanosizing capability of SMI, this can be used to analyse macromolecular nuclear complexes with a resolution approaching that of cryoelectron microscopy.

3.
J Microsc ; 2024 Apr 25.
Artigo em Italiano | MEDLINE | ID: mdl-38661499

RESUMO

Since its introduction in 2017, MINFLUX nanoscopy has shown that it can visualise fluorescent molecules with an exceptional localisation precision of a few nanometres. In this overview, we provide a brief insight into technical implementations, fluorescent marker developments and biological studies that have been conducted in connection with MINFLUX imaging and tracking. We also formulate ideas on how MINFLUX nanoscopy and derived technologies could influence bioimaging in the future. This insight is intended as a general starting point for an audience looking for a brief overview of MINFLUX nanoscopy from theory to application.

4.
PLoS Pathog ; 17(2): e1009304, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33544760

RESUMO

S. epidermidis is a substantial component of the human skin microbiota, but also one of the major causes of nosocomial infection in the context of implanted medical devices. We here aimed to advance the understanding of S. epidermidis genotypes and phenotypes conducive to infection establishment. Furthermore, we investigate the adaptation of individual clonal lines to the infection lifestyle based on the detailed analysis of individual S. epidermidis populations of 23 patients suffering from prosthetic joint infection. Analysis of invasive and colonizing S. epidermidis provided evidence that invasive S. epidermidis are characterized by infection-supporting phenotypes (e.g. increased biofilm formation, growth in nutrient poor media and antibiotic resistance), as well as specific genetic traits. The discriminating gene loci were almost exclusively assigned to the mobilome. Here, in addition to IS256 and SCCmec, chromosomally integrated phages was identified for the first time. These phenotypic and genotypic features were more likely present in isolates belonging to sequence type (ST) 2. By comparing seven patient-matched nasal and invasive S. epidermidis isolates belonging to identical genetic lineages, infection-associated phenotypic and genotypic changes were documented. Besides increased biofilm production, the invasive isolates were characterized by better growth in nutrient-poor media and reduced hemolysis. By examining several colonies grown in parallel from each infection, evidence for genetic within-host population heterogeneity was obtained. Importantly, subpopulations carrying IS insertions in agrC, mutations in the acetate kinase (AckA) and deletions in the SCCmec element emerged in several infections. In summary, these results shed light on the multifactorial processes of infection adaptation and demonstrate how S. epidermidis is able to flexibly repurpose and edit factors important for colonization to facilitate survival in hostile infection environments.


Assuntos
Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Infecção Hospitalar/microbiologia , Mutação , Mucosa Nasal/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus epidermidis/genética , Idoso , Idoso de 80 Anos ou mais , Proteínas de Bactérias/metabolismo , Infecção Hospitalar/genética , Infecção Hospitalar/metabolismo , Feminino , Genótipo , Hemólise , Humanos , Sequências Repetitivas Dispersas , Masculino , Pessoa de Meia-Idade , Mucosa Nasal/metabolismo , Fenótipo , Infecções Estafilocócicas/genética , Infecções Estafilocócicas/metabolismo , Staphylococcus epidermidis/classificação , Staphylococcus epidermidis/crescimento & desenvolvimento , Staphylococcus epidermidis/isolamento & purificação
5.
Mol Psychiatry ; 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-36450866

RESUMO

Postsynaptic scaffold proteins such as Shank, PSD-95, Homer and SAPAP/GKAP family members establish the postsynaptic density of glutamatergic synapses through a dense network of molecular interactions. Mutations in SHANK genes are associated with neurodevelopmental disorders including autism and intellectual disability. However, no SHANK missense mutations have been described which interfere with the key functions of Shank proteins believed to be central for synapse formation, such as GKAP binding via the PDZ domain, or Zn2+-dependent multimerization of the SAM domain. We identify two individuals with a neurodevelopmental disorder carrying de novo missense mutations in SHANK2. The p.G643R variant distorts the binding pocket for GKAP in the Shank2 PDZ domain and prevents interaction with Thr(-2) in the canonical PDZ ligand motif of GKAP. The p.L1800W variant severely delays the kinetics of Zn2+-dependent polymerization of the Shank2-SAM domain. Structural analysis shows that Trp1800 dislodges one histidine crucial for Zn2+ binding. The resulting conformational changes block the stacking of helical polymers of SAM domains into sheets through side-by-side contacts, which is a hallmark of Shank proteins, thereby disrupting the highly cooperative assembly process induced by Zn2+. Both variants reduce the postsynaptic targeting of Shank2 in primary cultured neurons and alter glutamatergic synaptic transmission. Super-resolution microscopy shows that both mutants interfere with the formation of postsynaptic nanoclusters. Our data indicate that both the PDZ- and the SAM-mediated interactions of Shank2 contribute to the compaction of postsynaptic protein complexes into nanoclusters, and that deficiencies in this process interfere with normal brain development in humans.

6.
RNA Biol ; 19(1): 877-884, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35796440

RESUMO

Stress granules (SGs) are membrane-less condensates composed of RNA and protein that assemble in response to stress stimuli and disassemble when stress is lifted. Both assembly and disassembly are tightly controlled processes, yet, it remains elusive whether mRNAs in SGs completely recover for translation following stress relief. Using RNA-seq of translating fractions in human cell line, we found that higher fraction of the m6A-modified mRNAs recovered for translation compared to unmodified mRNAs, i.e. 95% vs 84%, respectively. Considering structural mRNA analysis, we found that the m6A modification enhances structuring at nucleotides in its close vicinity. Our results suggest that SG-sequestered mRNAs disassemble nearly completely from SGs and the m6A modification may display some advantage to the mRNAs in their recovery for translation likely by m6A-driven structural stabilization.


Assuntos
Grânulos Citoplasmáticos , Grânulos de Estresse , Linhagem Celular , Grânulos Citoplasmáticos/metabolismo , Humanos , RNA/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
7.
BMC Surg ; 22(1): 68, 2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35216567

RESUMO

BACKGROUND: Periprosthetic hip infections with severe proximal femoral bone loss may require the use of limb salvage techniques, but no agreement exists in literature regarding the most effective treatment. Aim of this study is to analyze the infection eradication rate and implant survival at medium-term follow-up in patients treated with megaprostheses for periprosthetic hip infections with severe bone loss. METHODS: Twenty-one consecutive patients were retrospectively reviewed at a mean 64-month follow-up (24-120). Functional and pain scores, microbiological, radiological and intraoperative findings were registered. Kaplan Meier survival analysis and log rank test were used for infection free survival and implant survival analyses. RESULTS: The infection eradication rate was 90.5%, with an infection free survival of 95.2% at 2 years (95%CI 70.7-99.3) and 89.6%(95%CI 64.3-97.3) at 5 years. Only two patients required major implant revisions for aseptic implant loosening. The most frequent complication was dislocation (38.1%). The major revision-free survival of implants was 95.2% (95%CI 70.7-99.3) at 2 years and 89.6% (95%CI 64.3-97.3) at 5 years. The overall implant survival was 83.35% (CI95% 50.7-93.94) at 2 and 5 years. Subgroup analyses (cemented versus cementless MPs, coated versus uncoated MPs) revealed no significant differences at log rank test, but its reliability was limited by the small number of patients included. CONCLUSIONS: Proximal femoral arthroplasty is useful to treat periprosthetic hip infections with severe bone loss, providing good functional results with high infection eradication rates and rare major revisions at medium-term follow-up. No conclusions can be drawn on the role of cement and coatings.


Assuntos
Artroplastia de Quadril , Prótese de Quadril , Artroplastia de Quadril/efeitos adversos , Artroplastia de Quadril/métodos , Seguimentos , Prótese de Quadril/efeitos adversos , Humanos , Desenho de Prótese , Falha de Prótese , Reoperação/efeitos adversos , Reprodutibilidade dos Testes , Estudos Retrospectivos , Resultado do Tratamento
8.
PLoS Pathog ; 14(12): e1007527, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30586431

RESUMO

Type III secretion systems (T3SSs) are essential virulence factors of numerous bacterial pathogens. Upon host cell contact the T3SS machinery-also named injectisome-assembles a pore complex/translocon within host cell membranes that serves as an entry gate for the bacterial effectors. Whether and how translocons are physically connected to injectisome needles, whether their phenotype is related to the level of effector translocation and which target cell factors trigger their formation have remained unclear. We employed the superresolution fluorescence microscopy techniques Stimulated Emission Depletion (STED) and Structured Illumination Microscopy (SIM) as well as immunogold electron microscopy to visualize Y. enterocolitica translocons during infection of different target cell types. Thereby we were able to resolve translocon and needle complex proteins within the same injectisomes and demonstrate that these fully assembled injectisomes are generated in a prevacuole, a PI(4,5)P2 enriched host cell compartment inaccessible to large extracellular proteins like antibodies. Furthermore, the operable translocons were produced by the yersiniae to a much larger degree in macrophages (up to 25% of bacteria) than in HeLa cells (2% of bacteria). However, when the Rho GTPase Rac1 was activated in the HeLa cells, uptake of the yersiniae into the prevacuole, translocon formation and effector translocation were strongly enhanced reaching the same levels as in macrophages. Our findings indicate that operable T3SS translocons can be visualized as part of fully assembled injectisomes with superresolution fluorescence microscopy techniques. By using this technology, we provide novel information about the spatiotemporal organization of T3SS translocons and their regulation by host cell factors.


Assuntos
Sistemas de Secreção Tipo III , Yersiniose/transmissão , Yersinia enterocolitica/patogenicidade , Humanos , Microscopia de Fluorescência
9.
RNA Biol ; 17(4): 425-440, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31986967

RESUMO

The use of disease-specific signatures of microRNAs (miRNAs) in exosomes has become promising for clinical applications, either as biomarkers or direct therapeutic targets. However, a new approach for exosome enrichment and quantification of miRNAs is urgently needed for its clinical application, since the commercial techniques have shortcomings in quantity and quality. To overcome these deficiencies, we developed a new method for purification of exosomes with subsequent miRNA extraction, followed by quantitative reverse transcription polymerase chain reaction (RT-qPCR), and compared our assays with commercial techniques. For the establishment of these methods, numerous reagents, parameters, and combinations thereof were examined. Our new technique for exosome extraction is based on a mannuronate-guluronate polymer (MGP) which avoids co-precipitating plasma proteins. Quality, concentration and biological activity of the isolated exosomes were examined by Western blot, Nanoparticle Tracking Analysis (NTA), and confocal microscopy. A combination of chaotropic and non-chaotropic salts was used to extract miRNAs from plasma, serum, and exosomes, allowing the exclusion of hazardous components, such as phenol/chloroform. The performance of the miRNAs extraction was verified by RT-qPCR. The chemistry and TaqMan probe were also optimized for RT-qPCR. Sensitivity, efficiency, and linearity of RT-qPCR were tested on serial dilutions of synthetic miR-16 and miR-142. Our established procedure covers all steps of miRNA analyses, and measures the levels of either cell-free and exosomal miRNAs in plasma, serum and other body fluids with high performance.


Assuntos
MicroRNA Circulante/isolamento & purificação , Exossomos/genética , Polímeros/química , Precipitação Química , Perfilação da Expressão Gênica , Ácidos Hexurônicos/química , Humanos , Microscopia Confocal , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Imagem Individual de Molécula
10.
J Am Soc Nephrol ; 30(5): 824-839, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30971456

RESUMO

BACKGROUND: About 3%-5% of adults with membranous nephropathy have autoantibodies directed against thrombospondin type 1 domain-containing 7A (THSD7A), a podocyte-expressed transmembrane protein. However, the temporal and spatial expression of THSD7A and its biologic function for podocytes are unknown, information that is needed to understand the effects of THSD7A autoantibodies in this disease. METHODS: Using a variety of microscopic techniques, we analyzed THSD7A localization in postnatal, adult, and autoantibody-injected mice as well as in human podocytes. We also analyzed THSD7A function in human podocytes using confocal microscopy; Western blotting; and adhesion and migration assays. RESULTS: We found that THSD7A expression begins on glomerular vascularization with slit diaphragm formation in development. THSD7A localizes to the basal aspect of foot processes, closely following the meanders of the slit diaphragm in human and mice. Autoantibodies binding to THSD7A localize to the slit diaphragm. In human podocytes, THSD7A expression is accentuated at filopodia and thin arborized protrusions, an expression pattern associated with decreased membrane activity of cytoskeletal regulators. We also found that, phenotypically, THSD7A expression in human podocytes is associated not only with increases in cell size, enhanced adhesion, and reduced detachment from collagen type IV-coated plates but also, with decreased ability to migrate. CONCLUSIONS: Our findings suggest that THSD7A functions as a foot process protein involved in the stabilization of the slit diaphragm of mature podocytes and that autoantibodies to THSD7A, on the basis of their localization, might structurally and functionally alter the slit diaphragm's permeability to protein.


Assuntos
Antígenos de Superfície/genética , Glomerulonefrite Membranosa/genética , Glomérulos Renais/metabolismo , Proteínas de Membrana/metabolismo , Trombospondinas/imunologia , Animais , Antígenos de Superfície/imunologia , Autoanticorpos/imunologia , Western Blotting , Células Cultivadas , Regulação da Expressão Gênica , Taxa de Filtração Glomerular , Glomerulonefrite Membranosa/fisiopatologia , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Camundongos , Podócitos/imunologia , Proteinúria/metabolismo , Sensibilidade e Especificidade , Trombospondinas/metabolismo
11.
J Neurosci ; 38(1): 137-148, 2018 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-29138282

RESUMO

Reelin controls neuronal migration and layer formation. Previous studies in reeler mice deficient in Reelin focused on the result of the developmental process in fixed tissue sections. It has remained unclear whether Reelin affects the migratory process, migration directionality, or migrating neurons guided by the radial glial scaffold. Moreover, Reelin has been regarded as an attractive signal because newly generated neurons migrate toward the Reelin-containing marginal zone. Conversely, Reelin might be a stop signal because migrating neurons in reeler, but not in wild-type mice, invade the marginal zone. Here, we monitored the migration of newly generated proopiomelanocortin-EGFP-expressing dentate granule cells in slice cultures from reeler, reeler-like mutants and wild-type mice of either sex using real-time microscopy. We discovered that not the actual migratory process and migratory speed, but migration directionality of the granule cells is controlled by Reelin. While wild-type granule cells migrated toward the marginal zone of the dentate gyrus, neurons in cultures from reeler and reeler-like mutants migrated randomly in all directions as revealed by vector analyses of migratory trajectories. Moreover, live imaging of granule cells in reeler slices cocultured to wild-type dentate gyrus showed that the reeler neurons changed their directions and migrated toward the Reelin-containing marginal zone of the wild-type culture, thus forming a compact granule cell layer. In contrast, directed migration was not observed when Reelin was ubiquitously present in the medium of reeler slices. These results indicate that topographically administered Reelin controls the formation of a granule cell layer.SIGNIFICANCE STATEMENT Neuronal migration and the various factors controlling its onset, speed, directionality, and arrest are poorly understood. Slice cultures offer a unique model to study the migration of individual neurons in an almost natural environment. In the present study, we took advantage of the expression of proopiomelanocortin-EGFP by newly generated, migrating granule cells to analyze their migratory trajectories in hippocampal slice cultures from wild-type mice and mutants deficient in Reelin signaling. We show that the compartmentalized presence of Reelin is essential for the directionality, but not the actual migratory process or speed, of migrating granule cells leading to their characteristic lamination in the dentate gyrus.


Assuntos
Moléculas de Adesão Celular Neuronais/fisiologia , Movimento Celular/fisiologia , Giro Denteado/citologia , Proteínas da Matriz Extracelular/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Serina Endopeptidases/fisiologia , Animais , Movimento Celular/genética , Células Cultivadas , Córtex Cerebral/citologia , Grânulos Citoplasmáticos/fisiologia , Células Ependimogliais , Feminino , Cinética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes Neurológicos , Mutação , Neurônios/fisiologia , Pró-Opiomelanocortina/genética , Pró-Opiomelanocortina/metabolismo , Proteína Reelina
12.
Development ; 143(6): 1029-40, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26893343

RESUMO

In reeler mutant mice, which are deficient in reelin (Reln), the lamination of the cerebral cortex is disrupted. Reelin signaling induces phosphorylation of LIM kinase 1, which phosphorylates the actin-depolymerizing protein cofilin in migrating neurons. Conditional cofilin mutants show neuronal migration defects. Thus, both reelin and cofilin are indispensable during cortical development. To analyze the effects of cofilin phosphorylation on neuronal migration we used in utero electroporation to transfect E14.5 wild-type cortical neurons with pCAG-EGFP plasmids encoding either a nonphosphorylatable form of cofilin 1 (cofilin(S3A)), a pseudophosphorylated form (cofilin(S3E)) or wild-type cofilin 1 (cofilin(WT)). Wild-type controls and reeler neurons were transfected with pCAG-EGFP. Real-time microscopy and histological analyses revealed that overexpression of cofilin(WT) and both phosphomutants induced migration defects and morphological abnormalities of cortical neurons. Of note, reeler neurons and cofilin(S3A)- and cofilin(S3E)-transfected neurons showed aberrant backward migration towards the ventricular zone. Overexpression of cofilin(S3E), the pseudophosphorylated form, partially rescued the migration defect of reeler neurons, as did overexpression of Limk1. Collectively, the results indicate that reelin and cofilin cooperate in controlling cytoskeletal dynamics during neuronal migration.


Assuntos
Moléculas de Adesão Celular Neuronais/metabolismo , Movimento Celular , Forma Celular , Córtex Cerebral/citologia , Cofilina 1/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/citologia , Serina Endopeptidases/metabolismo , Animais , Contagem de Células , Eletroporação , Embrião de Mamíferos/citologia , Feminino , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Proteína Reelina , Transfecção
13.
J Microsc ; 269(3): 282-290, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-28960301

RESUMO

Understanding the cellular processes that occur between the cytosol and the plasma membrane is an important task for biological research. Till now, however, it was not possible to combine fast and high-resolution imaging of both the isolated plasma membrane and the surrounding intracellular volume. Here, we demonstrate the combination of fast high-resolution spinning disk (SD) and total internal reflection fluorescence (TIRF) microscopy for specific imaging of the plasma membrane. A customised SD-TIRF microscope was used with specific design of the light paths that allowed, for the first time, live SD-TIRF experiments at high acquisition rates. A series of experiments is shown to demonstrate the feasibility and performance of our setup.


Assuntos
Membrana Celular/ultraestrutura , Citoplasma/ultraestrutura , Microscopia Intravital/métodos , Microscopia de Fluorescência/métodos , Células Cultivadas , Humanos , Microscopia Intravital/instrumentação , Microscopia de Fluorescência/instrumentação
14.
Anal Bioanal Chem ; 407(14): 4029-34, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25855152

RESUMO

In this paper, we explain in detail the wavelength dependence of the elastic scattering pattern of individual, optically isolated gold nanorods by using confocal microscopy in combination with higher order laser modes, i.e., radially/azimuthally polarized laser modes. We demonstrate that the spectral dependence of the scattering pattern is mostly caused by the relative strength of the gold nanorods' plasmonic modes at different wavelengths. Since the gold nanorods' plasmonic modes are determined by the particles' geometrical parameter, e.g., size and aspect ratio, as well as the refractive index of the surrounding medium, we show that the spectral dependence of the scattering pattern is a simple, not invasive way to determine, e.g., the gold nanorod aspect ratio or physical variation of the local environment. Thus, a further development of spectral imaging of gold nanorods can lead to the employment of this technique in biomedical assays involving also living samples.


Assuntos
Técnicas Biossensoriais/métodos , Ouro/química , Nanopartículas Metálicas/química , Análise Espectral/métodos , Microscopia Confocal/métodos , Coloração e Rotulagem
15.
PLoS Genet ; 8(8): e1002856, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22912589

RESUMO

Cohesin is a protein complex that forms a ring around sister chromatids thus holding them together. The ring is composed of three proteins: Smc1, Smc3 and Scc1. The roles of three additional proteins that associate with the ring, Scc3, Pds5 and Wpl1, are not well understood. It has been proposed that these three factors form a complex that stabilizes the ring and prevents it from opening. This activity promotes sister chromatid cohesion but at the same time poses an obstacle for the initial entrapment of sister DNAs. This hindrance to cohesion establishment is overcome during DNA replication via acetylation of the Smc3 subunit by the Eco1 acetyltransferase. However, the full mechanistic consequences of Smc3 acetylation remain unknown. In the current work, we test the requirement of Scc3 and Pds5 for the stable association of cohesin with DNA. We investigated the consequences of Scc3 and Pds5 depletion in vivo using degron tagging in budding yeast. The previously described DHFR-based N-terminal degron as well as a novel Eco1-derived C-terminal degron were employed in our study. Scc3 and Pds5 associate with cohesin complexes independently of each other and require the Scc1 "core" subunit for their association with chromosomes. Contrary to previous data for Scc1 downregulation, depletion of either Scc3 or Pds5 had a strong effect on sister chromatid cohesion but not on cohesin binding to DNA. Quantity, stability and genome-wide distribution of cohesin complexes remained mostly unchanged after the depletion of Scc3 and Pds5. Our findings are inconsistent with a previously proposed model that Scc3 and Pds5 are cohesin maintenance factors required for cohesin ring stability or for maintaining its association with DNA. We propose that Scc3 and Pds5 specifically function during cohesion establishment in S phase.


Assuntos
Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Cromossomos Fúngicos , DNA Fúngico/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Acetiltransferases/genética , Acetiltransferases/metabolismo , Proteínas de Ciclo Celular/deficiência , Proteínas de Ciclo Celular/metabolismo , Cromátides/genética , Cromátides/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Segregação de Cromossomos/genética , DNA Fúngico/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fase S/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Coesinas
16.
Chem Soc Rev ; 43(4): 1263-86, 2014 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-24365864

RESUMO

While single-molecule fluorescence from emitters with high quantum efficiencies such as organic dye molecules can easily be detected by modern apparatus, many less efficient emission processes such as Raman scattering and metal luminescence require dramatic enhancement to exceed the single-particle detection limit. This enhancement can be achieved using resonant optical systems such as plasmonic particles or nanoantennas, the study of which has led to substantial progress in understanding the interaction of quantum emitters with their electromagnetic environment. This review is focused on the advances in measurement techniques and potential applications enabled by a deeper understanding of fundamental optical interaction processes occurring between single quantum systems on the nanoscale. While the affected phenomena are numerous, including molecular fluorescence and also exciton luminescence and Raman scattering, the interaction itself can often be described from a unified point of view. Starting from a single underlying model, this work elucidates the dramatic enhancement potential of plasmonic tips and nanoparticles and also the more deterministic influence of a Fabry-Pérot microresonator. With the extensive knowledge of the radiative behavior of a quantum system, insight can be gained into nonradiative factors as well, such as energy transfer phenomena or spatial and chemical configurations in single molecules.

17.
Histochem Cell Biol ; 141(4): 407-21, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24292845

RESUMO

Merkel cells, the neurosecretory cells of skin, are essential for light-touch responses and may probably fulfill additional functions. Whether these cells derive from an epidermal or a neural lineage has been a matter of dispute for a long time. In mice, recent studies have clearly demonstrated an epidermal origin of Merkel cells. Given the differences in Merkel cell distribution between human and murine skin, it is, however, unclear whether the same holds true for human Merkel cells. We therefore attempted to gain insight into the human Merkel cell lineage by co-immunodetection of the Merkel cell marker protein cytokeratin 20 (CK20) with various proteins known to be expressed either in epidermal or in neural stem cells of the skin. Neither Sox10 nor Pax3, both established markers of the neural crest lineage, exhibited any cell co-labeling with CK20. By contrast, ß1 integrin, known to be enriched in epidermal stem cells, was found in nearly 70 % of interfollicular epidermal and 25 % of follicular Merkel cells. Moreover, LRIG1, also enriched in epidermal stem cells, displayed significant co-immunolabeling with CK20 as well (approximately 20 % in the interfollicular epidermis and 7 % in the hair follicle, respectively). Further epidermal markers were detected in sporadic Merkel cells. Cells co-expressing CK20 with epidermal markers may represent a transitory state between stem cells and differentiated cells. ß1 integrin is probably also synthesized by a large subset of mature Merkel cells. Summarizing, our data suggest that human Merkel cells may originate from epidermal rather than neural progenitors.


Assuntos
Linhagem da Célula , Células Epidérmicas , Células de Merkel/citologia , Epiderme/química , Epiderme/metabolismo , Humanos , Imuno-Histoquímica , Integrina beta1/análise , Integrina beta1/metabolismo , Queratina-20/análise , Queratina-20/metabolismo , Glicoproteínas de Membrana/análise , Glicoproteínas de Membrana/metabolismo , Células de Merkel/química , Células de Merkel/metabolismo , Microscopia Confocal , Fator de Transcrição PAX3 , Fatores de Transcrição Box Pareados/análise , Fatores de Transcrição Box Pareados/metabolismo , Fatores de Transcrição SOXE/análise , Fatores de Transcrição SOXE/metabolismo
18.
Antibiotics (Basel) ; 13(5)2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38786128

RESUMO

The most frequent cause of periprosthetic infections (PJIs) is intraoperative contamination; hence, antibiotic prophylaxis plays a crucial role in prevention. Modifications to standard prophylaxis can be considered if there is a high incidence of microorganisms resistant to current protocols. To date, very few studies regarding microbial etiology have been published in Italy. In this single-center, retrospective study conducted at IRCCS Ospedale Galeazzi-Sant'Ambrogio in Milan, we analyzed hip, knee, and shoulder PJIs in patients undergoing first implantation between 1 January 17 and 31 December 2021. The primary aim was to derive a local microbiological case history. The secondary aim was to evaluate the adequacy of preoperative antibiotic prophylaxis in relation to the identified bacteria. A total of 57 PJIs and 65 pathogens were identified: 16 S. aureus, 15 S. epidermidis, and 10 other coagulase-negative staphylococci (CoNS), which accounted for 63% of the isolations. A total of 86.7% of S. epidermidis were methicillin-resistant (MRSE). In line with other case reports, we found a predominance of staphylococcal infections, with a lower percentage of MRSA than the Italian average, while we found a high percentage of MRSE. We estimated that 44.6% of the bacteria isolated were resistant to cefazolin, our standard prophylaxis. These PJIs could be prevented by using glycopeptide alone or in combination with cefazolin, but the literature reports conflicting results regarding the adequacy of such prophylaxis. In conclusion, our study showed that in our local hospital, our standard antibiotic prophylaxis is ineffective for almost half of the cases, highlighting the importance of defining specific antibiotic guidelines based on the local bacterial prevalence of each institution.

19.
One Health Outlook ; 6(1): 20, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39350275

RESUMO

INTRODUCTION: Around 75% of (re)emerging infections are of zoonotic origins. The risk of zoonotic transmission in Mozambique is high because approximately 81% of the country's labor force is involved with agriculture, which represents a vulnerability for more frequent human-animal interaction and risk of spillover events. A One Health Zoonotic Disease Prioritization (OHZDP) workshop was conducted in Mozambique to facilitate coordination and collaboration within and across sectors to prevent, detect, and respond to zoonotic disease threats. Based on the success of this integrated workshop, the stakeholders developed actions whose results have a great impact on animal welfare, environment and improving public health. METHODS: In 2018, representatives from Mozambique's human, animal, and environmental sectors from government, universities, research institutions and partners used US CDC's OHZDP Process to prioritize endemic and emerging zoonotic diseases of greatest national concern and develop recommendations and key interventions needed to advance One Health in Mozambique. After the OHZDP workshop, the Mozambique One Health Secretariat used a theory of change methodology to identify activities for implementation from the recommendations of the OHZDP workshop. Since the OHZDP workshop, the Secretariat has monitored progress of activities annually. RESULTS: Mozambique's priority zoonotic diseases are rabies, zoonotic tuberculosis, salmonellosis, zoonotic avian influenza, trypanosomiasis, brucellosis, and Crimean-Congo hemorrhagic fever. One Health recommendations and interventions to address the priority zoonotic diseases focused on One Health collaboration, communication, and coordination; laboratory; surveillance; preparedness and response; prevention; workforce development; and research. After the OHZDP workshop, Mozambique established One Health coordination mechanisms, developed training courses for surveillance, laboratory diagnosis, outbreak investigation, and preparedness and response for the priority zoonotic diseases, conducted joint research, and developed plans. CONCLUSION: Prioritization of zoonotic diseases is critical as it facilitated the key One Health players in Mozambique to optimize resources, gain a greater understanding of zoonotic diseases, and implement policies and activities that promote multisectoral, interdisciplinary, and transdisciplinary collaboration across human, animal, and environmental sectors to prevent, detect, and respond to public health threats. The success of these activities implemented by the local Government and One Health partners were built from the implementation and momentum from the Mozambique's OHZDP workshop.

20.
J Clin Invest ; 134(17)2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39225099

RESUMO

Adeno-associated virus (AAV) is a promising in vivo gene delivery platform showing advantages in delivering therapeutic molecules to difficult or undruggable cells. However, natural AAV serotypes have insufficient transduction specificity and efficiency in kidney cells. Here, we developed an evolution-directed selection protocol for renal glomeruli and identified what we believe to be a new vector termed AAV2-GEC that specifically and efficiently targets the glomerular endothelial cells (GEC) after systemic administration and maintains robust GEC tropism in healthy and diseased rodents. AAV2-GEC-mediated delivery of IdeS, a bacterial antibody-cleaving proteinase, provided sustained clearance of kidney-bound antibodies and successfully treated antiglomerular basement membrane glomerulonephritis in mice. Taken together, this study showcases the potential of AAV as a gene delivery platform for challenging cell types. The development of AAV2-GEC and its successful application in the treatment of antibody-mediated kidney disease represents a significant step forward and opens up promising avenues for kidney medicine.


Assuntos
Dependovirus , Terapia Genética , Vetores Genéticos , Animais , Dependovirus/genética , Camundongos , Terapia Genética/métodos , Vetores Genéticos/genética , Humanos , Células Endoteliais/metabolismo , Glomérulos Renais/patologia , Glomerulonefrite/terapia , Glomerulonefrite/genética , Glomerulonefrite/imunologia , Doença Antimembrana Basal Glomerular/terapia , Doença Antimembrana Basal Glomerular/genética , Doença Antimembrana Basal Glomerular/imunologia
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