Summary
Abstract
Introduction
Protocol
Representative Results
Discussion
Acknowledgements
Materials
References
Bioengineering
Presentamos un protocolo para visualizar directamente las actividades metabólicas en células reguladas por aminoácidos utilizando microscopía de dispersión Raman estimulada con sonda de óxido de deuterio (agua pesada D2O) (DO-SRS), que se integra con microscopía de fluorescencia por excitación de dos fotones (2PEF).
Los aminoácidos aromáticos esenciales (AAA) son componentes básicos para sintetizar nuevas biomasas en las células y mantener las funciones biológicas normales. Por ejemplo, un suministro abundante de AAA es importante para que las células cancerosas mantengan su rápido crecimiento y división. Con esto, existe una creciente demanda de un enfoque de imagen altamente específico y no invasivo con una preparación mínima de la muestra para visualizar directamente cómo las células aprovechan los AAA para su metabolismo in situ. Aquí, desarrollamos una plataforma de imágenes ópticas que combina el sondeo de óxido de deuterio (D2O) con la dispersión Raman estimulada (DO-SRS) e integra DO-SRS con fluorescencia de excitación de dos fotones (2PEF) en un solo microscopio para visualizar directamente las actividades metabólicas de las células HeLa bajo regulación AAA. En conjunto, la plataforma DO-SRS proporciona una alta resolución espacial y especificidad de proteínas y lípidos recién sintetizados en unidades celulares HeLa individuales. Además, la modalidad 2PEF puede detectar señales de autofluorescencia de nicotinamida adenina dinucleótido (NADH) y flavina de forma libre de marcas. El sistema de imágenes descrito aquí es compatible con modelos in vitro e in vivo , lo que es flexible para varios experimentos. El flujo de trabajo general de este protocolo incluye el cultivo celular, la preparación de los medios de cultivo, la sincronización celular, la fijación celular y la obtención de imágenes de muestras con las modalidades DO-SRS y 2PEF.
Al ser aminoácidos aromáticos esenciales (AAA), la fenilalanina (Phe) y el triptófano (Tryp) pueden ser absorbidos por el cuerpo humano para sintetizar nuevas moléculas para mantener las funciones biológicas normales1. La Phe es necesaria para la síntesis de proteínas, melanina y tirosina, mientras que Tryp es necesaria para la síntesis de melatonina, serotonina y niacina 2,3. Sin embargo, el consumo excesivo de estos AAA puede aumentar la diana de la vía de la rapamicina (mTOR) en los mamíferos, inhibir la proteína quinasa activada por AMP e interferir con el metabolismo mitocondrial, ....
1. Preparación de los medios
La adición de un exceso de AAA a concentraciones de 15x a los medios de cultivo celular que contienen D2O al 50% produjo distintas bandas C-D Raman de lípidos y proteínas recién sintetizados en células HeLa (Figura 2B). Los experimentos anteriores se realizaron con diferentes niveles de concentración, como 2x y 5x, y aunque no se presentan los datos, la concentración de 15x produjo las bandas C-D Raman más distintivas de lípidos y proteínas recién sintetizados. Específ.......
Las imágenes DO-SRS y 2PEF se han aplicado para investigar la dinámica metabólica en varios modelos ex vivo, incluyendo Drosophila y tejidos humanos 21,22,23,24,26,27,33. La modalidad de imagen utilizada en este estudio integra DO-SRS y microscopía 2PEF, que puede superar a otro.......
Agradecemos al Dr. Yajuan Li y Anthony Fung por su apoyo técnico, y al laboratorio Fraley por la línea celular. Agradecemos los fondos iniciales de UCSD, NIH U54CA132378, NIH 5R01NS111039, NIH R21NS125395, NIHU54DK134301, NIHU54 HL165443 y Hellman Fellow Award.
....Name | Company | Catalog Number | Comments |
10 mL Serological Pipettes | Avantor (by VWR) | 75816-100 | https://us.vwr.com/store/product?keyword=75816-100 |
15 mL Conical Centrifuge Tube | VWR | 89039-664 | https://mms.mckesson.com/product/1001859/VWR-International-89039-664 |
16% Formaldehyde, Methanol-free | ThermoFisher Scientific | 28906 | https://www.thermofisher.com/order/catalog/product/28906 |
24-well plate | Fisherbrand | FB0112929 | https://www.fishersci.com/shop/products/24-well-tc-multidish-100-cs/FB012929#?keyword=FB012929 |
25 mm Syringe Filter, 2 μm PES | Foxx Life Sciences | 381-2216-OEM | https://www.foxxlifesciences.com/collections/pes-syringe-filters/products/381-2216-oem?variant=16274336003 |
460 nm Filter Cube | Olympus | OCT-ET460/50M32 | |
AC Adapters of the Power Supply for LD OBIS 6 Laser Remote | Olympus | Supply power to the laser | |
Band-pass Filter | KR Electronics | KR2724 | 8 MHz |
BNC 50 Ohm Terminator | Mini Circuits | STRM-50 | |
BNC Cable | Thorlabs | 2249-C | Coaxial Cable, BNC Male/Male |
Broadband Dielectric Mirror | Thorlabs | BB1-E03 | 750 - 1100 nm |
Centrifuge | |||
Condenser | Olympus | ||
Cover Glass | Corning | 2850-25 | https://ecatalog.corning.com/life-sciences/b2b/NL/en/Glassware/Cover-Glass/Corning%C2%AE-Square-%231%C2%BD-Cover-Glass/p/2850-25 |
DC power supply | TopWard | 6302D | |
Dichroic Mount | Thorlabs | KM100CL | |
Dimethyl Sulfoxide Cell Culture Reagent | mpbio | 196055 | https://www.mpbio.com/0219605525-dimethyl-sulfoxide-cf |
Dulbecco's Modified Eagle’s Medium without Methionine, Threonine, and Sodium Pyruvate | MilliporeSigma | 38210000 | https://www.usbio.net/media/D9800-22/dulbeccorsquos-mem-dmem-wsodium-bicarbonate-wo-methionine-threonine-sodium-pyruvate-powder With Sodium Bicarbonate and without Methionine, Threonine, and Sodium Pyruvate |
Dulbecco’s Modified Eagle’s Medium | Corning | MT10027CV | https://www.fishersci.com/shop/products/dmem-dulbecco-s-modified-eagle-s-medium-4/MT10027CV#:~:text=Dulbecco's%20Modified%20Eagle's%20Medium%20 |
FIJI ImageJ | ImageJ | Version 1.53t 24 August 2022 | https://imagej.net/software/fiji/downloads |
Heavy Water (Deuterium Oxide) | Cambridge Isotope Laboratories, Inc. | 7732-18-5 | https://shop.isotope.com/productdetails.aspx?itemno=DLM-4-1L |
Hela Cells | ATCC | CCL-2 | https://www.atcc.org/products/ccl-2 |
Hemocymeter | MilliporeSigma | Z359629-1EA | https://www.sigmaaldrich.com/US/en/product/sigma/z359629?gclid=Cj0KCQiA37KbBhDgARIsAI zce15A5FIy0WS7I6ec2KVk QPXVMEqlAnYis_bKB6P6lr SIZ-wAXOyAELIaAhhEEAL w_wcB&gclsrc=aw.ds |
High O.D. Bandpass Filter | Chroma Technology | ET890/220m | Filter the Stokes beam and transmit the pump beam |
HyClone Fetal Bovine Serum (FBS) | Cytiva | SH300880340 | https://www.fishersci.com/shop/products/hyclone-fetal-bovine-serum-u-s-standard-4/SH300880340 |
HyClone Trypsin 0.25% (1x) Solution | Cytiva | SH30042.02 | https://www.cytivalifesciences.com/en/us/shop/cell-culture-and-fermentation/reagents-and-supplements/cell-disassociation-reagents/hyclone-trypsin-protease-p-00445 |
Integrated SRS Laser System | Applied Physics & Electronics, Inc. | picoEMERALD | picoEMERALD provides an output pulse at 1031 nm with 6-ps pulse width and 80-MHz repetition rate, which serves as the Stokes beam. The frequency doubled beam at 532 nm is used to synchronously seed a picosecond optical parametric oscillator (OPO) to produce a mode-locked pulse train with five~6 ps pulse width (the idler beam of the OPO is blocked with an,interferometric filter). The output wavelength of the OPO is tunable from 720–950 nm, which serves as the pump beam. The intensity of the 1031 nm Stokes beam is modulated sinusoidally by a built-in EOM at 8 MHz with a modulation depth of more than 90%. The pump beam is spatially overlapped with the Stokes beam by using a dichroic mirror inside picoEMERALD. The temporal overlap between pump and Stokes pulses are achieved with a built-in delay stage and optimized by the SRS signal of pure D2O at the microscope. |
Inverted Laser-scanning Microscope | Olympus | FV1200MPE | |
IX3-CBH Control box | Olympus | Control the laser-scanning microscope | |
Kinematic Mirror Mount | Thorlabs | POLARIS-K1-2AH | 2 Low-Profile Hex Adjusters |
L-Phenalynine | Sigma | P5482-25G | https://www.sigmaaldrich.com/US/en/product/sigma/p5482 |
L-Tryptophan | Sigma | T8941-25G | https://www.sigmaaldrich.com/US/en/product/sigma/t8941 |
LabSpec 6 | Horiba XploRA | N/A | https://www.horiba.com/gbr/scientific/products/detail/action/show/Product/labspec-6-spectroscopy-suite-software-1843/ |
Lock-In Amplifier | Zurich Instruments | N/A | https://www.zhinst.com/americas/en/products/shfli-lock-in-amplifier |
Long-pass Dichroic Beam Splitter | Semrock | Di02-R980-25x36 | 980 nm laser BrightLine single-edge laser-flat dichroic beamsplitter |
MATLAB | MathWorks | Version: R2022b | https://www.mathworks.com/products/new_products/latest_features.html |
Microscope Slides | Fisherbrand | 12-550-003 | https://www.fishersci.com/shop/products/fisherbrand-selectfrost-microscope-slides-9/12550003#?keyword=12-550-003 |
Microscopy Imaging Software | Olympus | FluoView | |
MPLN 100x, Olympus | Olympus | MPLAPON | https://www.olympus-ims.com/en/microscope/mplapon/#!cms[focus]=cmsContent11364 |
MPLN 50x, Olympus | Olympus | MPLAPON | https://www.olympus-ims.com/en/microscope/mplapon/#!cms[focus]=cmsContent11363 |
NA Oil Condenser | Olympus | 6-U130 | https://www.hitechinstruments.com/Product-Details/olympus-achromatic-aplanatic-high-na-condneser |
Nail Polish | Wet n Wild | B01EO2G5O4 | https://www.amazon.com/dp/B01EO2G5O4/ref=cm_sw_r_api_i_E609VVDWW HHQP38FXXDC_0 |
Origin | OriginLab | Origin 2022b (9.95) | https://www.originlab.com/index.aspx?go=PRODUCTS/Origin |
Parafilm | Fisher Scientific | S37440 | https://www.fishersci.com/shop/products/parafilm-m-wrapping-film-3/p-2379782 |
PBS 1x (Dulbecco's Phosphate Buffered Saline) | Thermofischer - Gibco | 14040117 | https://www.thermofisher.com/order/catalog/product/14040117?SID=srch-hj-14040117 |
Penicillin/Streptomycin | Thermofischer - Gibco | 15140122 | https://www.thermofisher.com/order/catalog/product/15140122 |
Periscope Assembly | Thorlabs | RS99 | Includes the top and bottom units, Ø1" post, and clamping fork. |
picoEmerald System | A.P.E | N/A | https://www.ape-berlin.de/en/cars-srs/ |
Shielded Box with BNC Connectors | Pomona Electronics | 2902 | Aluminum Box with Cover, BNC Female/Female |
Si Photodiode Detector | Home Built | N/A | DYI series |
Silicon Wafer | |||
Spacers | Grace Bio-Labs | 654008 | https://gracebio.com/product/secureseal-imaging-spacers-654008/ |
Spontaneous Raman spectroscopy | Horiba XploRA | N/A | https://www.horiba.com/int/products/detail/action/show/Product/xploratm-plus-1528/ |
Stimulated Raman Scattering Microscopy | Home Built | N/A | |
Touch Panel Controller | Olympus | Control the X-Y direction of the laser-scanning microscope | |
Trypan Blue 0.4% (0.85% NaCl) | Lonza | 17-942E | https://bioscience.lonza.com/lonza_bs/US/en/Culture-Media-and-Reagents/p/000000000000181876/Trypan-Blue%2C-0-4%25-Solution" |
Tweezers | Kaverme - Amazon | B07RNVXXV1 | https://www.amazon.com/Precision-Anti-Static-Electronics-Laboratory-Jewelry-Making/dp/B07RNVXXV1" |
Two Photon Excitation Fluorescence Microscopy | Home Built | N/A | |
Weighing Paper | VWR | 12578-165 | https://us.vwr.com/store/product/4597617/vwr-weighing-paper |
Zurich LabOneQ Software | Zurich Instruments | Control the Zurich lock-in amplifier |
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