Spectral cytometry
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Assays based on Förster resonance energy transfer (FRET) can be used to study many processes in cell biology. Although this is most often done with microscopy for fluorescence detection, we report two ways to measure FRET in living cells by flow cytometry. Using a conventional flow cytometer and the "3-cube method" for intensity-based calculation of FRET efficiency, we measured the enzymatic activity of specific kinases in cells expressing a genetically-encoded reporter. For both AKT and protein kinase A, the method measured kinase activity in time-course, dose-response, and kinetic assays. Using the Cytek Aurora spectral flow cytometer, which applies linear unmixing to emission measured in multiple wavelength ranges, FRET from the same reporters was measured with greater single-cell precision, in real time and in the presence of other fluorophores. Results from gene-knockout studies suggested that spectral flow cytometry might enable the sorting of cells on the basis of FRET. The methods we present provide convenient and flexible options for using FRET with flow cytometry in studies of cell biology.
Herein, an advanced bioconjugation technique to synthesize hybrid polymer-antibody nanoprobes tailored for fluorescent cell barcoding in flow cytometry-based immunophenotyping of leukocytes is applied. A novel approach of attachment combining two fluorescent dyes on the copolymer precursor and its conjugation to antibody is employed to synthesize barcoded nanoprobes of antibody polymer dyes allowing up to six nanoprobes to be resolved in two-dimensional cytometry analysis. The major advantage of these nanoprobes is the construct design in which the selected antibody is labeled with an advanced copolymer bearing two types of fluorophores in different molar ratios. The cells after antibody recognition and binding to the target antigen have a characteristic double fluorescence signal for each nanoprobe providing a unique position on the dot plot, thus allowing antibody-based barcoding of cellular samples in flow cytometry assays. This technique is valuable for cellular assays that require low intersample variability and is demonstrated by the live cell barcoding of clinical samples with B cell abnormalities. In total, the samples from six various donors were successfully barcoded using only two detection channels. This barcoding of clinical samples enables sample preparation and measurement in a single tube.
There is a wide range of techniques utilizing fluorescence of doxorubicin (Dox) commonly used for analysis of intracellular accumulation and destiny of various drug delivery systems containing this anthracycline antibiotic. Unfortunately, results of these studies can be significantly influenced by doxorubicin degradation product, 7,8-dehydro-9,10-desacetyldoxorubicinone (D*) forming spontaneously in aqueous environment, whose fluorescence strongly interfere with that of doxorubicin. Here, we define two microscopy techniques enabling to distinguish and separate Dox and D* emission based either on its spectral properties or on fluorescence lifetime analysis. To analyze influx and nuclear accumulation of Dox (free or polymer-bound) by flow cytometry, we propose using an indirect method based on its DNA intercalation competition with Hoechst 33342 rather than a direct measurement of doxorubicin fluorescence inside the cells.
- MeSH
- buněčné jádro metabolismus MeSH
- buňky 3T3 MeSH
- DNA metabolismus MeSH
- doxorubicin analogy a deriváty metabolismus farmakologie MeSH
- fluorescenční spektrometrie MeSH
- hydrofobní a hydrofilní interakce MeSH
- lékové transportní systémy MeSH
- lidé MeSH
- lymfom T-buněčný farmakoterapie metabolismus MeSH
- myši MeSH
- nádorové buňky kultivované MeSH
- polymery metabolismus MeSH
- protinádorová antibiotika metabolismus farmakologie MeSH
- průtoková cytometrie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND INFORMATION: Macarpine (MA) is a quaternary benzophenanthridine plant alkaloid isolated from Macleaya microcarpa or Stylophorum lasiocarpum. Benzophenanthridine alkaloids are interesting natural products that display antiproliferative, antimicrobial, antifungal and anti-inflammatory activities, and also fluorescence properties. In a previous study, we demonstrated that thanks to its ability to interact with DNA and its spectral properties MA could be used as a supravital DNA probe for fluorescence microscopy and flow cytometry including analyses of the cell cycle. In this study, we evaluated the suitability of MA as a DNA dye for time-lapse microscopy and flow-cytometric cell sorting. RESULTS: Living A-375 and MEF cells stained with MA were monitored by time-lapse microscopy for 24 h. Mitoses were observed at MA concentrations up to 0.5 μg/ml during the first 2-3 h. After this period of time, cells treated with MA at concentrations of 0.75 and 0.5 μg/ml underwent apoptosis. Cells cultivated with MA at concentration of 0.25 μg/ml or lower survived throughout the 24 h period. Toxicity of MA was dependent on light wavelength and frequency of image capturing. The intensity of MA fluorescence decreased during the incubation. MA concentration of 0.1 μg/ml was identified as the most suitable for live cell imaging with respect to fluorescence intensity and toxicity. MA at the concentration 10 μg/ml was used for sorting of enhanced green fluorescent protein (EGFP)-labelled neurons and fibroblasts yielding profiles similar to those obtained with DRAQ5. Contrary to DRAQ5, MA-stained cells survived in culture, and the sorted cells lost the MA signal suggesting reversible binding of the dye to the DNA. CONCLUSION: The results proved that MA may readily be used for chromosomes depicting and mitosis monitoring by time-lapse microscopy. In addition, MA has shown to be a suitable probe for sorting of EGFP-labelled cells, including neurons, that survived the labelling process. SIGNIFICANCE: In consideration of the results, we highly anticipate an onward use of MA in a broad range of applications based on live cell sorting and imaging, for example, cell synchronisation and monitoring of proliferation as an important experimental and/or diagnostic utility.
- MeSH
- benzofenantridiny analýza MeSH
- buněčné kultury MeSH
- buněčný cyklus fyziologie MeSH
- DNA analýza MeSH
- fluorescenční barviva analýza MeSH
- fluorescenční mikroskopie metody MeSH
- lidé MeSH
- průtoková cytometrie * metody MeSH
- separace buněk metody MeSH
- viabilita buněk MeSH
- zelené fluorescenční proteiny metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Quaternary benzo[c]phenanthridine alkaloids (QBAs) are naturally occurring compounds isolated from plants in the Fumariaceae, Papaveraceae, Ranunculaceae, and Rutaceae families. In addition to having a wide range of biological activities, they are also attractive for their fluorescent properties. We observed interesting fluorescent characteristics in the QBAs-macarpine (MA), sanguirubine (SR), chelirubine (CHR), sanguilutine (SL), chelilutine (CHL), sanguinarine (SA) and chelerythrine (CHE) after interaction with living cells. METHODS: Water stock solutions of the alkaloids (10-100 microg/ml) were added to intact cells, and after a brief incubation the cells were observed. Human cell lines HL60 (human promyelocytic leukemia), HeLa (human cervix adenocarcinoma), and LEP (human lung fibroblasts), and piglet blood were used in the experiments. Blood cells were stained with MA in combination with FITC-conjugated anti-CD45 surface marker antibody. Cells were analyzed by fluorescence microscopy and by flow cytometry. RESULTS: All tested alkaloids immediately entered living cells with MA, CHR, and SA binding to DNA. MA showed the best DNA staining properties. Fluorescence microscopy of MA, CHR, and SA stained cells described the nuclear architecture and clearly described chromosomes and apoptotic fragments in living cells. Moreover MA can rapidly represent the cellular DNA content of living cells at a resolution adequate for cell cycle analysis. QBAs were excitable using common argon lasers (488 nm) emitting at a range of 575-755 nm (i.e. fluorescence detectors FL2-5). Spectral characteristics of MA allow simultaneous surface immunophenotyping. CONCLUSIONS: It was shown that MA, CHR, and SA stain nucleic acids in living cells. They can be used as supravital fluorescent DNA probes, both in fluorescence microscopy and flow cytometry, including multiparameter analysis of peripheral blood and bone marrow. MA binds DNA stochiometrically and can provide information on DNA content. Copyright (c) 2007 International Society for Analytical Cytology.
A critical component of the EuroFlow standardization of leukemia/lymphoma immunophenotyping is instrument setup. Initially, the EuroFlow consortium developed a step-by-step standard operating protocol for instrument setup of ≥8-color flow cytometers that were available in 2006, when the EuroFlow activities started. Currently, there are 14 instruments from 9 manufacturers capable of 3-laser excitation and ≥8 color measurements. The specific adaptations required in the instrument set-up to enable them to acquire the standardized 8-color EuroFlow protocols are described here. Overall, all 14 instruments can be fitted with similar violet, blue and red lasers for simultaneous measurements of ≥8 fluorescent dyes. Since individual instruments differ both on their dynamic range (scale) and emission filters, it is not accurate to simply recalculate the target values to different scale, but adjustment of PMT voltages to a given emission filter and fluorochrome, is essential. For this purpose, EuroFlow has developed an approach using Type IIB (spectrally matching) particles to set-up standardized and fully comparable fluorescence measurements, in instruments from different manufacturers, as demonstrated here for the FACSCanto II, and Navios and MACSQuant flow cytometers. Data acquired after such adjustment on any of the tested cytometry platforms could be fully superimposed and therefore analyzed together. The proposed approach can be used to derive target values for any combination of spectrally distinct fluorochromes and any distinct emission filter of any new flow cytometry platform, which enables the measurement of the 8-color EuroFlow panels in a standardized way, by creating superimposable datafiles.
- MeSH
- hematologické nádory diagnóza MeSH
- imunofenotypizace přístrojové vybavení normy MeSH
- lidé MeSH
- průtoková cytometrie přístrojové vybavení normy MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Úvod: Biklonální gamapatie nejistého významu (BGUS) je méně obvyklé onemocnění charakterizované přítomností dvou monoklonálních gradientů a relativně příznivým biologickým chováním. Cíl: Cílem práce bylo posouzení možného přínosu či naopak limitací obvyklých parametrů používaných u monoklonální gamapatie nejistého významu (MGUS) ve skupině jedinců s BGUS. Metody: Analyzovaná sestava čítala 18 vzorků sér od jedinců s BGUS (9x IgG–IgA, 7x IgG–IgM a 2x IgG–IgG typ). Pro analýzu byl použit turbidimetr SPA Plus a stanovované parametry zahrnovaly sérové hladiny volných lehkých řetězců imunoglobulinu (FreeLite™), hladiny polyklonálních imunoglobulinů a hladiny párů těžkých/lehkých řetězců imunoglobulinu (HevyLite ™). Výsledky a závěr: Pilotní analýza a zjištěné výsledky potvrzují skutečnost, že u velké části BGUS dochází k ovlivnění některých parametrů užívaných ve stratifikaci a sledování jedinců s MGUS, zejména v případě odlišnosti lehkých řetězců v obou molekulách monoklonálních imunoglobulinů. Jako velmi perspektivní se jeví analýza párů těžkých/lehkých řetězců imunoglobulinu (HLC), zohledňující možnost izotypové suprese alternativního páru s ovlivněním HLC indexu. Avšak v podmínkách běžné klinické praxe je zřejmé, že zásadní pro určení prognózy BGUS bude nutná izolace a analýza klonálních populací buněk na molekulárně-cytogenetické úrovni.
Introduction: Biclonal gammopathy of undetermined significance (BGUS) is a less frequent disease characterized by the presence of two monoclonal gradients and a relatively favourable biological development. Objective: The objective was to assess potential benefits and/or limitations of laboratory parameters typically used with monoclonal gammopathy of undetermined significance (MGUS) when applied to a group of BGUS patients. Methods: The analysed batch comprised 18 serum samples from BGUS patients (9x IgG–IgA, 7x IgG–IgM a 2x IgG–IgG type). The assays were performed with a SPA Plus turbidimeter. Serum levels of polyclonal immunoglobulins, free light immunoglobulin chains (FreeLite™), and pairs of heavy/light immunoglobulin chains (HevyLite™) were assayed. Results and conclusion: The results of the pilot analyses confirm that a significant portion of BGUS patients exhibits changes of certain parameters typically applied to the stratification and monitoring of MGUS patients, particularly when the light chains in both molecules of monoclonal immunoglobulins differ. The analysis of heavy/light immunoglobulin chain pairs (HLC) appears very promising, indicating the possibility of an isotype suppression of the alternative pair affecting the HLC index. It is apparent, however, that the isolation and analysis of cell clones on a molecular and cytogenetic level will be essential for BGUS prognosis in clinical practice.
- MeSH
- 2D gelová elektroforéza MeSH
- cytogenetické vyšetření MeSH
- imunoglobuliny - kappa-řetězce analýza diagnostické užití krev MeSH
- imunoglobuliny - lambda-řetězce analýza diagnostické užití krev MeSH
- lehké řetězce imunoglobulinů analýza diagnostické užití krev MeSH
- lidé MeSH
- nádorová transformace buněk MeSH
- paraproteinemie diagnóza MeSH
- prognóza MeSH
- průtoková cytometrie MeSH
- spektrální karyotypizace MeSH
- těžké řetězce imunoglobulinů analýza diagnostické užití krev MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
... intenzity 26 -- 1.2.3.3 Kvantifikace fluorescence 28 -- 1.2.4 Kompenzace fluorescenčního přísvitu (spectral-overlap ...
2., přeprac. a rozš. vyd. 148 s. : il., tab. ; 24 cm
Vývoj aplikací průtokové cytometrie v medicíně představuje unikátní příklad prolínání nejmodernějších metod techniky a biologie v čase. Významný pokrok v počítačových a laserových technologiích a implementace nových fluorochromů umožnily vývoj moderních kompaktních a cenově dostupných průtokových cytometrů, jejichž využití se postupně soustředilo na obory klinické hematologie: imunologická diagnostika, diferenciální diagnostika, klasifikace, prognostická stratifikace hematoonkologických chorob (leukemie, myeloproliferace, lymfoproliferace, myelodysplastické syndromy) a posléze i na detekci a sledování minimální reziduální choroby. Předkládaná monografie pojednává o této složité problematice, která takto přehledně v českém písemnictví doposud nebyla zpracována. Systematicky vysvětluje principy fungování cytometru, zacházení s ním, přípravu vzorků, typy analýzy i interpretaci dat od zkumavky k diagnóze. Nepochybně není určena pouze specialistům ve flow cytometrii a hematoonkologii, ale široké odborné lékařské veřejnosti. Každý se zde může seznámit s problematikou zasahující do jeho oboru a i když sám flow cytometrii neprovádí, dozví se, jak správně indikovat vyšetření a jak jejich výsledky interpretovat.
Quaternary benzo[c]phenanthridine alkaloids (QBAs) are natural products isolated from plants of Fumariaceae, Papaveraceae, Ranunculaceae and Rutaceae families. They are intensively studied for their biological activities, but they have also attractive fluorescence properties. Chromophores responsible for fluorescence are fused aromatic ring systems with electron-donor groups containing oxygen (OH, OCH3, OCH2O). Recently we have described fluorescent characteristics of QBAs - macarpine (MA), sanguirubine (SR), chelirubine (CHR), sanguilutine (SL), chelilutine (CHL), sanguinarine (SA) and chelerythrine (CHE) - on interaction with living cells. All these alkaloids immediately enter the living cells and MA-, CHRand SA-bound DNA; they showed a nucleus architecture similar to common DNA dyes. Moreover, MA binds to DNA stoichiometrically and can rapidly report the cellular DNA content in living cells at a resolution adequate for cell cycle analysis. QBAs could be excited by common argon lasers (488 nm) emitting light in the 575-755 nm range. Spectral characteristics of MA allow simultaneous surface immunophenotyping. These characteristics allow multiple applications of the above-mentioned QBAs with significant diagnostic utility. They can be used as supravital fluorescent DNA probes both in fluorescence microscopy and flow cytometry including multiparameter analysis.
The genus Acaryochloris is unique among phototrophic organisms due to the dominance of chlorophyll d in its photosynthetic reaction centres and light-harvesting proteins. This allows Acaryochloris to capture light energy for photosynthesis over an extended spectrum of up to ~760 nm in the near infra-red (NIR) spectrum. Acaryochloris sp. has been reported in a variety of ecological niches, ranging from polar to tropical shallow aquatic sites. Here, we report a new Acarychloris strain isolated from an NIR-enriched stratified microbial layer 4-6 mm under the surface of stromatolite mats located in the Hamelin Pool of Shark Bay, Western Australia. Pigment analysis by spectrometry/fluorometry, flow cytometry and spectral confocal microscopy identifies unique patterns in pigment content that likely reflect niche adaption. For example, unlike the original A. marina species (type strain MBIC11017), this new strain, Acarychloris LARK001, shows little change in the chlorophyll d/a ratio in response to changes in light wavelength, displays a different Fv/Fm response and lacks detectable levels of phycocyanin. Indeed, 16S rRNA analysis supports the identity of the A. marina LARK001 strain as close to but distinct from from the A. marina HICR111A strain first isolated from Heron Island and previously found on the Great Barrier Reef under coral rubble on the reef flat. Taken together, A. marina LARK001 is a new cyanobacterial strain adapted to the stromatolite mats in Shark Bay.
- Publikační typ
- časopisecké články MeSH
