저자는 H188 cAMP FRET 바이오 센서와 케니 트린 (사우스 앨라배마 대학)을 제공하는 데 도움이 우리의 사용자 정의 개발 프로그래밍 스크립트를 실행하는 데 걸린 시간을 줄이기 위해 우리에게 제공하는 박사 Kees Jalink (네덜란드 암 연구소 및 고급 현미경 검사법을위한 반 Leeuwenhoek 센터) 인정하고 싶습니다.
저자는 자금 출처를 인정하고 싶습니다: 미국 심장 협회 (16PRE2713004), 국립 과학 재단; (1725937) NIH, S100D020149, S10RR027535, R01HL058506, P01HL0666299).

<ol>
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리프슬리 박사와 리치 박사는 스펙트럼 이미징 기술을 상용화하기 위해 설립된 스타트업 회사인 SpectraCyte, LLC에 대한 재정적 관심을 공개합니다. 그러나 이 프로토콜에 설명된 모든 절차는 SPECtraCyte, LLC와 관련이 없는 상업적으로 이용 가능한 제품을 사용하여 수행되었습니다.

FRET 바이오센서의 개발은 단일 세포에서 순환 뉴클레오티드 신호의 측정 및 시각화를 허용하고, 세포 외 신호 이벤트13,22,37,38을시각화하기위한 큰 약속이있다. 그러나 FRET 바이오 센서의 사용은 많은 형광 단백질 계 FRET 리포터의 낮은 신호-잡음 특성 및 FRET 기자의 약한 트랜스퍼션 또는 발현 효율을 ...

순환 아데노신 모노인산염(cAMP)은 세포 분열, 칼슘 유입, 유전자 전사 및 신호 변환을 포함한 주요 세포 및 생리적 과정에 관여하는 두 번째 메신저입니다. 증거의 성장 몸은 신호 특이성을 달성하는 세포를 통해 cAMP 구획의 존재를 제안1,2,3,4,5,6,7. 최근까지, cAMP 구획화는 다른 G-결합 수용체작용제에의해 유도된 뚜렷한 생리적 또는 세포 효과에 기초하여 유추되었다8,9,10,11. 최근에는 FRET 기반 형광 이미징 프로브가 세포12,13,14에서cAMP 신호를 직접 측정 및 관찰하기 위한 새로운접근법을제공하고 있다.
Förster 공명 에너지 전달(FRET)은 분자가15,16에근접할 때 비방사적 방식으로 기증자와 수용자 분자 간에 에너지 전달이 발생하는 물리적 현상이다. FRET 기반 형광 지표의 발달과 함께, 이러한 물리적 현상은 단백질-단백질 상호 작용17,단백질 공동 국소화18,Ca+2 신호19,유전자 발현20,세포 부문21 및 순환 뉴클레오티드 신호화를 연구하기 위해 생물학적 응용 분야에서 사용되었습니다. FRET 기반 cAMP 지표는 일반적으로 cAMP 결합 도메인, 기증자 불소 호및 수용자불소호레(22)로구성됩니다. 예를 들어, 이 방법론에 사용되는 H188 cAMP센서(12)22는 에팍으로부터 얻은 cAMP 결합 도메인으로 구성되며, 청록색(기증자)과 금성(수용자) 형광 사이에 끼어 있다. 기저 조건(언바운드)에서 청록색과 금성은 형광류 사이에 FRET가 발생하는 방향으로 있습니다. 바인딩 도메인에 대한 cAMP의 바인딩시, 청록색과 금성이 떨어져 이동하도록 형성 변화가 발생하여 FRET가 감소합니다.
FRET 기반 이미징 접근 방식은 셀 내에서 cAMP 신호를 조사하고 시각화하기 위한 유망한 도구를 제공합니다. 그러나, 현재 FRET 기반 현미경 이미징 기술은 종종 세포 전 세포 공간 선명도로 FRET를 측정하기에 충분한 신호 강도를 달성하는 데 부분적으로만 성공적입니다. 이는 많은 FRET 기자의 제한된 신호 강도, FRET 효율의 변화를 정확하게 정량화하는 데 필요한 높은 수준의 정밀도, 세포 자동불화(23)및24와같은 혼란스러운 요인의 존재를 포함한 여러 가지 요인에 기인한다. 결과는 종종 약한 SNR에 의해 괴롭히는 FRET 이미지, FRET에 있는 세포 극변경의 시각화를 아주 어렵게 만듭니다. 또한, 공간적으로 국소화된 cAMP 신호에 대한 조사는 거의 2개의 공간 차원에서만 거의 독점적으로 수행되었으며 축 cAMP 분포는거의 25로간주되지 않습니다. 이는 SNR이 cAMP 그라데이션을 세 가지 공간 차원으로 측정하고 시각화하는 기능을 방해했기 때문일 수 있습니다. 낮은 SNR을 가진 FRET 센서를 사용하는 한계를 극복하기 위하여는, 우리는 단하나세포25,26,27에서FRET를 측정하기 위하여 하이퍼 스펙트럼 화상 진찰 및 분석 접근법을 구현했습니다.
하이퍼스펙트럼 이미징 접근법은 NASA가 위성 이미지28,29에존재하는 지상파 물체를 차별화하기 위해 개발되었다. 이러한 기술은 이후 형광 현미경 필드(30)로번역되었으며, 스펙트럼 검출기를 제공하는 여러 상용 공초점 현미경 시스템이 있습니다. 기존의 (비 스펙트럼) 형광 이미징에서, 샘플은 밴드 패스 필터 또는 레이저 라인을 사용하여 흥분하고, 방출은 종종 형광의 피크 방출 파장에 맞게 선택된 제2 밴드 패스 필터를 사용하여 수집된다. 대조적으로, hyperspectral 화상 진찰 접근은 특정 파장 간격에 형광 방출26,31,32 또는 여기33,34의 완전한 스펙트럼 단면도를 샘플링하는 것을 추구합니다. 우리의 이전 연구에서, 우리는 Hyperspectral 화상 진찰 및 분석 접근이 전통적인 필터 기지를 둔 FRET 화상 진찰 기술(26)에비교될 때 세포에 있는 FRET 신호의 향상한 정량화를 제공할 수 있다는 것을 보여주었습니다. 여기서는 4차원(x, y, z 및 λ) 하이퍼스펙트럼 FRET 이미징 및 분석을 수행하여 3개의 공간 차원에서 cAMP 분포를 측정하고 시각화하는 방법론을 제시합니다. 이러한 접근법은 단일세포(25)에서작용제 유도 된 cAMP 공간 그라데이션의 시각화를 허용하였다. 흥미롭게도, 고뇌에 따라, cAMP 그라데이션은 세포에서 명백할 수 있습니다. 여기에 제시된 방법론은 FRET 측정의 정확도를 향상시키기 위해 비 균일한 배경 및 세포 자동 형광의 스펙트럼 미혼을 사용합니다. 이 방법론은 cAMP FRET 바이오 센서를 사용하여 폐 미세 혈관 내피 세포 (PMVEC)에서 입증되지만, 방법론은 대체 FRET 기자 또는 대체 세포주와 함께 사용하기 위해 쉽게 수정 될 수 있습니다.

<table>
	<tbody>
		<tr>
			<td>Attofluor Cell Chamber</td>
			<td>Invitrogen</td>
			<td>A7816</td>
			<td>Attofluor contains steel cell chambers and a rubber O-ring. Cell chamber holds the coverslip and O-ring provides a lock in mechanism to hold the buffer in cell chamber with out leakage</td>
		</tr>
		<tr>
			<td>Dimethyl Sulfoxide (DMSO)</td>
			<td>Fisher Scientific</td>
			<td>BP231-100</td>
			<td>Solvent used to prepare stock solution forskolin.</td>
		</tr>
		<tr>
			<td>DRAQ5 Fluoroscent Probe Solution</td>
			<td>Thermo Scientific</td>
			<td>62252</td>
			<td>Nuclear label</td>
		</tr>
		<tr>
			<td>Dulbecco Modified Eagle Medium (DMEM)</td>
			<td>Gibco</td>
			<td>11965-092</td>
			<td>Contains nutrients and growth factors for the cells to grow and divide in the culture dishes.</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>Sigma</td>
			<td>F6178</td>
			<td>Growth factor suppliment that is added to culture medium, DMEM</td>
		</tr>
		<tr>
			<td>Forskolin</td>
			<td>Sigma</td>
			<td>F3917</td>
			<td>Adenyly cyclase activator.</td>
		</tr>
		<tr>
			<td>H188 Cyclic AMP FRET biosensor</td>
			<td>Netherland Cancer Institute, Dr. K. Jalink</td>
			<td>Gift</td>
			<td>Plasmid encoding Turquoise (donor fluorophore), Venus (acceptor fluorophore), and binding domain obtained from Epac.</td>
		</tr>
		<tr>
			<td>Image J</td>
			<td>image.net</td>
			<td>Free download</td>
			<td>Another image processing platform used to extact spectral information and image processing.</td>
		</tr>
		<tr>
			<td>Integrating Sphere</td>
			<td>Ocean Optics</td>
			<td>FOIS-1</td>
			<td>Used to measure illumination intensity of the laser line at different laser intensities (?).</td>
		</tr>
		<tr>
			<td>Laminin Mouse Protein, Natural</td>
			<td>Invitrogen</td>
			<td>23017-015</td>
			<td>Coverslips are coated with laminin and this helps in cell attachment, growth and motility of the cell.</td>
		</tr>
		<tr>
			<td>Lipofectamine 3000 Transfection Kit</td>
			<td>Invitrogen</td>
			<td>L3000-015</td>
			<td>Transfection reagent used to transfect cells with H188 FRET biosensor</td>
		</tr>
		<tr>
			<td>MATLAB</td>
			<td>Mathworks</td>
			<td>R2019a</td>
			<td>Image processing operations (linear unmixing and FRET efficiency calculations) are performed by writing custom programs in MATLAB programming environment</td>
		</tr>
		<tr>
			<td>Nikon A1R confocal microscope</td>
			<td>Nikon Instruments</td>
			<td>Nikon A1R</td>
			<td>Spectral image acquisition is performed using confocal microscope.</td>
		</tr>
		<tr>
			<td>Nikon Elements Software</td>
			<td>Nikon Instruments</td>
			<td>Software dongle</td>
			<td>used to export and handle nd2 image files (multidimensional image files) that are aquired using Nikon A1R</td>
		</tr>
		<tr>
			<td>NIST-Traceable Calibration Lamp</td>
			<td>Ocean Optics</td>
			<td>LS-1-CAL-INT</td>
			<td>A lamp with a known spectrum for use as a standard</td>
		</tr>
		<tr>
			<td>PBS pH 7.4 (1X)</td>
			<td>Gibco</td>
			<td>10010-023</td>
			<td>coomonly used buffer suring cell culture</td>
		</tr>
		<tr>
			<td>Pulmonary Microvascular Endothelial Cells (PMVECs)</td>
			<td>In house - Cell culture core, Univeristy of South Alabama</td>
			<td>Isolated from Rat pulmonary microvasculature</td>
			<td>PMVECs form inner lining of a blood vessel.</td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin (10,000 U/ml)</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td>antibiotics are added to culture medum to prevent contamination of the cells.</td>
		</tr>
		<tr>
			<td>Pre-Cleaned Gold Seal Micro Slides</td>
			<td>Clay Adams</td>
			<td>3010</td>
			<td>Microscope slides used for cell fixation</td>
		</tr>
		<tr>
			<td>ProLong Diamond Antifade Mounting Media</td>
			<td>Invitrogen</td>
			<td>P36961</td>
			<td>If samples are fixed using antifade mountant, then the later protects fluoroscent dyes and chromophores from fading.</td>
		</tr>
		<tr>
			<td>Spectrometer</td>
			<td>Ocean Optics</td>
			<td>QE65000</td>
			<td>Used to measure spectral response of the light source (?)</td>
		</tr>
		<tr>
			<td>Trypsin-EDTA (0.25%)</td>
			<td>Gibco</td>
			<td>25200-056</td>
			<td>Digests the protein-protein bond between the cell and cell matrix and helps to disscociate and lift the cells during cell plating.</td>
		</tr>
		<tr>
			<td>Tyrodes Buffer</td>
			<td>Made in-house</td>
			<td>Made in-house</td>
			<td>Tyrodes buffer is used to make working solutions and to maintain cells in aqueous solution during image acquisition.</td>
		</tr>
		<tr>
			<td>6 Well Cell Culture Plate</td>
			<td>Corning</td>
			<td>3506</td>
			<td>Laminin coated coverslips are placed in 6-well culture dish (one coverlisps/well). Cells along with medium is added into each well.</td>
		</tr>
		<tr>
			<td>25 mm Round Microscope Cover Slips</td>
			<td>Fisher Scientific</td>
			<td>12545102</td>
			<td>Cells were grown on round glass coverslips</td>
		</tr>
		<tr>
			<td>60X Ojective</td>
			<td>Nikon Instruments</td>
			<td>Plan Apo VC 60X/1.2 WI &#8734;/0.15-0.18 WD 0.27</td>
			<td>water immersion and commonly used objective for cells</td>
		</tr>
	</tbody>
</table>

measurement of 3-dimensional camp distributions in living cells using 4-dimensional (x, y, z, and &lambda;) hyperspectral fret imaging and analysis

순환 AMP는 세포 및 생리 활동의 넓은 범위에 관여하는 두 번째 메신저입니다. 몇몇 연구 결과는 cAMP 신호가 구획화되고, 그 구획화가 cAMP 신호 통로 내의 신호 특이성에 기여한다는 것을 건의합니다. F렌스터 공명 에너지 전달(FRET) 기반 바이오 센서의 개발은 세포내 cAMP 신호를 측정하고 시각화하는 능력을 발전시켰습니다. 그러나 이러한 측정은 종종 두 개의 공간 차원으로 제한되어 데이터를 잘못 해석할 수 있습니다. 현재까지, 본질적으로 낮은 신호 대 잡음 비(SNR)를 나타내는 FRET 센서를 사용하는 기술적 한계로 인해 3개의 공간 차원(x, y 및 z)으로 cAMP 신호의 측정이 매우 제한적이었습니다. 또한, 전통적인 필터 기반 이미징 접근법은 스펙트럼 크로스토크, 제한된 신호 강도 및 자동 형광을 포함한 다양한 요인으로 인해 국소화 된 세포 이형 지역에서 cAMP 신호를 정확하게 측정하는 데 효과가 없습니다. 이러한 한계를 극복하고 FRET 기반 바이오 센서를 여러 형광과 함께 사용할 수 있도록 FRET 기반 의 바이오 센서를 여러 형광과 함께 사용할 수 있도록 FRET 효율을 계산하기 위한 스펙트럼 특이성 및 추가 형광 라벨에서 접건 성 자동 형광 및/또는 신호를 반사적으로 분리하는 기능을 제공하는 하이퍼 스펙트럼 FRET 이미징 및 분석 접근 방식을 개발했습니다. 여기서는 하이퍼스펙트럼 FRET 이미징을 구현하기 위한 방법론과 스펙트럼 미혼을 수행하기 위해 샘플링되거나 과샘플링되지 않은 적절한 스펙트럼 라이브러리를 구성할 필요성을 제시합니다. 우리는 폐 미세 혈관 내피 세포 (PMVEC)에서 3 차원 cAMP 분포의 측정을위한이 방법론을 제시하는 동안,이 방법론은 세포 유형의 범위에서 cAMP의 공간 분포를 연구하는 데 사용할 수 있습니다.

이 프로토콜은 살아있는 세포에 있는 3개의 공간 차원에서 cAMP 그라데이션을 측정하기 위하여 hyperspectral FRET 화상 진찰 및 분석 접근의 사용을 기술합니다. 이러한 결과를 생성하는 데 관련된 몇 가지 주요 단계가 있으며, 데이터를 분석하고 정량화하는 동안 주의 깊게 주의를 기울여야 합니다. 이러한 주요 단계에는 적절한 스펙트럼 라이브러리 구성, 백그라운드 스펙트럼 해제, 셀 테두리 식별을...

Watch this Scientific Journal Video about Measurement of 3-Dimensional cAMP Distributions in Living Cells using 4-Dimensional x, y, z, and ÃŽÂ» Hyperspectral FRET Imaging and Analysis at JoVE.com

Measurement of 3-Dimensional cAMP Distributions in Living Cells using 4-Dimensional x, y, z, and &lambda; Hyperspectral FRET Imaging and Analysis

Fónster 공명 에너지 전송 (FRET) 기반 센서의 내재 된 낮은 신호 대 잡음 비율 (SNR)으로 인해, 특히 세 공간 차원에서 cAMP 신호의 측정이 도전하고있다. 여기서는 3개의 공간 차원에서 cAMP 분포를 측정할 수 있는 하이퍼스펙트럼 FRET 이미징 및 분석 방법론을 설명합니다.

4차원(x, y, z 및 λ) 하이퍼스펙트럼 FRET 이미징 및 분석을 사용하여 살아있는 세포에서 3차원 cAMP 분포 측정

Cyclic AMP is a second messenger that is involved in a wide range of cellular and physiological activities. Several studies suggest that cAMP signals are ...

measurement-3-dimensional-camp-distributions-living-cells-using-4

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Measurement of 3-Dimensional cAMP Distributions in Living Cells using 4-Dimensional (x, y, z, and &lambda;) Hyperspectral FRET Imaging and Analysis

3.8K 조회수.  University of South Alabama. Fónster 공명 에너지 전송 (FRET) 기반 센서의 내재 된 낮은 신호 대 잡음 비율 (SNR)으로 인해, 특히 세 공간 차원에서 cAMP 신호의 측정이 도전하고있다. 여기서는 3개의 공간 차원에서 cAMP 분포를 측정할 수 있는 하이퍼스펙트럼 FRET 이미징 및 분석 방법론을 설명합니다.

비디오: Measurement of 3-Dimensional cAMP Distributions in Living Cells using 4-Dimensional x, y, z, and λ Hyperspectral FRET Imaging and Analysis

Pulse-chase Analysis of N-linked Sugar Chains from Glycoproteins in Mammalian Cells

Attachment of the Glc3Man9GlcNAc2 precursor oligosaccharide to nascent polypeptides in the ER is a common modification for secretory proteins. Although this modification was implicated in several biological processes, additional aspects of its function are emerging, with recent evidence of its role in the production of signals for glycoprotein quality control and trafficking. Thus, phenomena related to N-linked glycans and their processing are being intensively investigated. Methods that have been recently developed for proteomic analysis have greatly improved the characterization of glycoprotein N-linked glycans. Nevertheless, they do not provide insight into the dynamics of the sugar chain processing involved. For this, labeling and pulse-chase analysis protocols are used that are usually complex and give very low yields. We describe here a simple method for the isolation and analysis of metabolically labeled N-linked oligosaccharides. The protocol is based on labeling of cells with [2-3H] mannose, denaturing lysis and enzymatic release of the oligosaccharides from either a specifically immunoprecipitated protein of interest or from the general glycoprotein pool by sequential treatments with endo H and N-glycosidase F, followed by molecular filtration (Amicon). In this method the isolated oligosaccharides serve as an input for HPLC analysis, which allows discrimination between various glycan structures according to the number of monosaccharide units comprising them, with a resolution of a single monosaccharide. Using this method we were able to study high mannose N-linked oligosaccharide profiles of total cell glycoproteins after pulse-chase in normal conditions and under proteasome inhibition. These profiles were compared to those obtained from an immunoprecipitated ER-associated degradation (ERAD) substrate. Our results suggest that most NIH 3T3 cellular glycoproteins are relatively stable and that most of their oligosaccharides are trimmed to Man9-8GlcNAc2. In contrast, unstable ERAD substrates are trimmed to Man6-5GlcNAc2 and glycoproteins bearing these species accumulate upon inhibition of proteasomal degradation.

We describe a method for analysis of the alteration of N-linked glycans through the early life of glycoproteins after their biosynthesis in mammalian cells. This is achieved by pulse-chase analysis of metabolically labeled glycans, enzymatic release from glycoproteins and examination by HPLC.

포유 동물 세포에 Glycoproteins의 N - 연결 설탕 체인 펄스 체이스 분석

Attachment of the Glc3Man9GlcNAc2 precursor oligosaccharide to nascent polypeptides in the ER is a common modification for secretory proteins. Although ...

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Immunocytochemical Analysis of Human Pluripotent Stem Cells using a Self-Made Cytospin Apparatus

Human pluripotent stem cells (hPSCs) that include human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) are exciting cell sources due to their limitless self-renewal capabilities and their potential to differentiate into multiple cell types. The pluripotent state of hPSCs is typically assessed by techniques such as qPCR, immunocytochemistry, and by other in vitro and in vivo differentiation strategies into multiple cell types. Among these, immunocytochemical techniques have been developed for routine characterization of the undifferentiated state of hPSCs based on analysis of candidate intracellular and cell-surface biomarkers. Given the fact that hPSCs grow as colonies, problems arise in quantifying the expression of these markers at the individual cell level on a routine basis. Flow cytometry analyses serve to address this issue but require cell numbers and use of reagents that are not normally conducive for routine quality control assessment of hPSC cultures. Thus, the development of practical and reproducible means of creating monolayer cell samples with preserved integrity for marker evaluation has many advantages in stem cell research. This greatly benefits immunocytochemical analysis because individual cells from the monolayer can be easily observed and quantified for the expression of specific markers. Towards this goal, a self-made cytospin apparatus was constructed and optimized for use with immunocytochemical staining. Two cell-surface markers (SSEA3/SSEA4) expression were analyzed in a variant BG01 stem cell line for the purpose of this protocol.

Suspension immunocytochemical staining of human pluripotent stem cells (hPSCs) for cell-surface markers (SSEA-3/SSEA-4) was achieved based on use of a self-made cytospin apparatus to create a monolayer of cells for observation and quantification.

자수 성 가한 Cytospin 장치를 사용하여 인간 Pluripotent 줄기 세포의 Immunocytochemical 분석

Human pluripotent stem cells (hPSCs) that include human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) are exciting cell ...

Imaging Cell Shape Change in Living Drosophila Embryos

The developing Drosophila melanogaster embryo undergoes a number of cell shape changes that are highly amenable to live confocal imaging. Cell shape changes in the fly are analogous to those in higher organisms, and they drive tissue morphogenesis. So, in many cases, their study has direct implications for understanding human disease (Table 1)1-5. On the sub-cellular scale, these cell shape changes are the product of activities ranging from gene expression to signal transduction, cell polarity, cytoskeletal remodeling and membrane trafficking. Thus, the Drosophila embryo provides not only the context to evaluate cell shape changes as they relate to tissue morphogenesis, but also offers a completely physiological environment to study the sub-cellular activities that shape cells.
The protocol described here is designed to image a specific cell shape change called cellularization. Cellularization is a process of dramatic plasma membrane growth, and it ultimately converts the syncytial embryo into the cellular blastoderm. That is, at interphase of mitotic cycle 14, the plasma membrane simultaneously invaginates around each of ~6000 cortically anchored nuclei to generate a sheet of primary epithelial cells. Counter to previous suggestions, cellularization is not driven by Myosin-2 contractility6, but is instead fueled largely by exocytosis of membrane from internal stores7. Thus, cellularization is an excellent system for studying membrane trafficking during cell shape changes that require plasma membrane invagination or expansion, such as cytokinesis or transverse-tubule (T-tubule) morphogenesis in muscle.
Note that this protocol is easily applied to the imaging of other cell shape changes in the fly embryo, and only requires slight adaptations such as changing the stage of embryo collection, or using "embryo glue" to mount the embryo in a specific orientation (Table 1)8-19. In all cases, the workflow is basically the same (Figure 1). Standard methods for cloning and Drosophila transgenesis are used to prepare stable fly stocks that express a protein of interest, fused to Green Fluorescent Protein (GFP) or its variants, and these flies provide a renewable source of embryos. Alternatively, fluorescent proteins/probes are directly introduced into fly embryos via straightforward micro-injection techniques9-10. Then, depending on the developmental event and cell shape change to be imaged, embryos are collected and staged by morphology on a dissecting microscope, and finally positioned and mounted for time-lapse imaging on a confocal microscope.

Imaging Cell Shape Change in Living Drosophila Embryos

Early development of the fruit fly, Drosophila melanogaster, is characterized by a number of cell shape changes that are well suited for imaging approaches. This article will describe basic tools and methods required for live confocal imaging of Drosophila embryos, and will focus on a cell shape change called cellularization.

생활의 이미징 셀 모양 변경 Drosophila 태아

The developing Drosophila melanogaster embryo undergoes a number of cell shape changes that are highly amenable to live confocal imaging.  Cell shape ...

Rapid Genetic Analysis of Epithelial-Mesenchymal Signaling During Hair Regeneration

Hair follicle morphogenesis, a complex process requiring interaction between epithelia-derived keratinocytes and the underlying mesenchyme, is an attractive model system to study organ development and tissue-specific signaling. Although hair follicle development is genetically tractable, fast and reproducible analysis of factors essential for this process remains a challenge. Here we describe a procedure to generate targeted overexpression or shRNA-mediated knockdown of factors using lentivirus in a tissue-specific manner. Using a modified version of a hair regeneration model 5, 6, 11, we can achieve robust gain- or loss-of-function analysis in primary mouse keratinocytes or dermal cells to facilitate study of epithelial-mesenchymal signaling pathways that lead to hair follicle morphogenesis. We describe how to isolate fresh primary mouse keratinocytes and dermal cells, which contain dermal papilla cells and their precursors, deliver lentivirus containing either shRNA or cDNA to one of the cell populations, and combine the cells to generate fully formed hair follicles on the backs of nude mice. This approach allows analysis of tissue-specific factors required to generate hair follicles within three weeks and provides a fast and convenient companion to existing genetic models.

Tissue-specific analysis of a hair follicle regeneration model using lentivirus to mediate gain- or loss-of-function.

헤어 재생시 상피 - 중간 엽 시그널링의 빠른 유전 분석

Hair follicle morphogenesis, a complex process requiring interaction between epithelia-derived keratinocytes and the underlying mesenchyme, is an ...

Simultaneous pH Measurement in Endocytic and Cytosolic Compartments in Living Cells using Confocal Microscopy

Intracellular pH is tightly regulated and differences in pH between the cytoplasm and organelles have been reported1. Regulation of cellular pH is crucial for homeostatic control of physiological processes that include: protein, DNA and RNA synthesis, vesicular trafficking, cell growth and cell division. Alterations in cellular pH homeostasis can lead to detrimental functional changes and promote progression of various diseases2. Various methods are available for measuring intracellular pH but very few of these allow simultaneous measurement of pH in the cytoplasm and in organelles. Here, we describe in detail a rapid and accurate method for the simultaneous measurement of cytoplasmic and organellar pH by using confocal microscopy on living cells3. This goal is achieved with the use of two pH-sensing ratiometric dyes that possess selective cellular compartment partitioning. For instance, SNARF-1 is compartmentalized inside the cytoplasm whereas HPTS is compartmentalized inside endosomal/lysosomal organelles. Although HPTS is commonly used as a cytoplasmic pH indicator, this dye can specifically label vesicles along the endosomal-lysosomal pathway after being taken up by pinocytosis3,4. Using these pH-sensing probes, it is possible to simultaneously measure pH within the endocytic and cytoplasmic compartments. The optimal excitation wavelength of HPTS varies depending on the pH while for SNARF-1, it is the optimal emission wavelength that varies. Following loading with SNARF-1 and HPTS, cells are cultured in different pH-calibrated solutions to construct a pH standard curve for each probe. Cell imaging by confocal microscopy allows elimination of artifacts and background noise. Because of the spectral properties of HPTS, this probe is better suited for measurement of the mildly acidic endosomal compartment or to demonstrate alkalinization of the endosomal/lysosomal organelles. This method simplifies data analysis, improves accuracy of pH measurements and can be used to address fundamental questions related to pH modulation during cell responses to external challenges.

Several methods are available for measuring intracellular pH but very few of these allow simultaneous measurement of cytoplasmic and organellar pH. Here, we describe in detail a rapid and accurate methodology to simultaneously measure cytoplasmic and vesicular pH by ratiometric imaging of living cells.

공 초점 현미경을 사용하여 살아있는 세포에서 세포 내 이입과 세포질 구획 동시 pH 측정

Intracellular pH is tightly regulated and differences in pH between the cytoplasm and organelles have been reported1. Regulation of cellular pH is crucial ...

Real-time Imaging of Single Engineered RNA Transcripts in Living Cells Using Ratiometric Bimolecular Beacons

The growing realization that both the temporal and spatial regulation of gene expression can have important consequences on cell function has led to the development of diverse techniques to visualize individual RNA transcripts in single living cells. One promising technique that has recently been described utilizes an oligonucleotide-based optical probe, ratiometric bimolecular beacon (RBMB), to detect RNA transcripts that were engineered to contain at least four tandem repeats of the RBMB target sequence in the 3&#8217;-untranslated region. RBMBs are specifically designed to emit a bright fluorescent signal upon hybridization to complementary RNA, but otherwise remain quenched. The use of a synthetic probe in this approach allows photostable, red-shifted, and highly emissive organic dyes to be used for imaging. Binding of multiple RBMBs to the engineered RNA transcripts results in discrete fluorescence spots when viewed under a wide-field fluorescent microscope. Consequently, the movement of individual RNA transcripts can be readily visualized in real-time by taking a time series of fluorescent images. Here we describe the preparation and purification of RBMBs, delivery into cells by microporation and live-cell imaging of single RNA transcripts.

Ratiometric bimolecular beacons (RBMBs) can be used to image single engineered RNA transcripts in living cells. Here, we describe the preparation and purification of RBMBs, delivery of RBMBs into cells by microporation and fluorescent imaging of single RNA transcripts in real-time.

비례 생체 분자 비콘을 사용하여 살아있는 세포의 단일 엔지니어링 RNA 성적 증명서의 실시간 영상

The growing realization that both the temporal and spatial regulation of gene expression can have important consequences on cell function has led to the ...

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) maintain the turnover of all mature blood cell lineages. The coordination of the complex signals leading to specific HSC fates relies upon the interaction between HSCs and the intricate bone marrow microenvironment, which is still poorly understood[1-2].
We describe how by combining a newly developed specimen holder for stable animal positioning with multi-step confocal and two-photon in vivo imaging techniques, it is possible to obtain high-resolution 3D stacks containing HSPCs and their surrounding niches and to monitor them over time through multi-point time-lapse imaging. High definition imaging allows detecting ex vivo labeled hematopoietic stem and progenitor cells (HSPCs) residing within the bone marrow. Moreover, multi-point time-lapse 3D imaging, obtained with faster acquisition settings, provides accurate information about HSPC movement and the reciprocal interactions between HSPCs and stroma cells.
Tracking of HSPCs in relation to GFP positive osteoblastic cells is shown as an exemplary application of this method. This technique can be utilized to track any appropriately labeled hematopoietic or stromal cell of interest within the mouse calvarium bone marrow space.

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

The nature of the interactions between hematopoietic stem and progenitor cells (HSPCs) and bone marrow niches is poorly understood. Custom hardware modifications and a multi-step acquisition protocol allow the use of two-photon and confocal microscopy to image ex vivo labeled HSPCs homed within bone marrow areas, tracking interactions and movement.

성인 마우스 두개골 골수에서 조혈 줄기 및 전구 세포의 생체 내 4 차원 추적에서

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) ...

Fluorescence Imaging with One-nanometer Accuracy (FIONA)

Fluorescence imaging with one-nanometer accuracy (FIONA) is a simple but useful technique for localizing single fluorophores with nanometer precision in the x-y plane. Here a summary of the FIONA technique is reported and examples of research that have been performed using FIONA are briefly described. First, how to set up the required equipment for FIONA experiments, i.e., a total internal reflection fluorescence microscopy (TIRFM), with details on aligning the optics, is described. Then how to carry out a simple FIONA experiment on localizing immobilized Cy3-DNA single molecules using appropriate protocols, followed by the use of FIONA to measure the 36 nm step size of a single truncated myosin Va motor labeled with a quantum dot, is illustrated. Lastly, recent effort to extend the application of FIONA to thick samples is reported. It is shown that, using a water immersion objective and quantum dots soaked deep in sol-gels and rabbit eye corneas (&#62;200 &#181;m), localization precision of 2-3 nm can be achieved.

Fluorescence Imaging with One-nanometer Accuracy FIONA

Single fluorophores can be localized with nanometer precision using FIONA. Here a summary of the FIONA technique is reported, and how to carry out FIONA experiments is described.

하나 나노 미터의 정확도와 형광 이미징 (피오나)

Fluorescence imaging with one-nanometer accuracy (FIONA) is a simple but useful technique for localizing single fluorophores with nanometer precision in ...

Measurement of Calcium Fluctuations Within the Sarcoplasmic Reticulum of Cultured Smooth Muscle Cells Using FRET-based Confocal Imaging

Maintenance of steady-state calcium (Ca2+) levels in the sarcoplasmic reticulum (SR) of vascular smooth muscle cells (VSMCs) is vital to their overall health. A significant portion of intracellular Ca2+ content is found within the SR stores in VSMCs. As the only intracellular organelle with a close association to the surrounding extracellular space through plasma membrane-SR junctions, the SR can be considered to constitute the first line of response to any irregularity in Ca2+ transients, or stress experienced by the cell. Among its many functions, one of the most important is its role in the transmission of Ca2+-regulated signals throughout the cell to induce further cell-wide reactions downstream. The more common use of cytoplasmic Ca2+ indicators in this regard is overall insufficient for research into the highly dynamic changes to the intraluminal SR Ca2+ store that have yet to be fully characterized. Here, we provide a detailed protocol for the direct and clear measurement of luminal SR Ca2+. This tool is useful for investigation into the nuanced changes in SR Ca2+ that have significant subsequent effects on the normal function and health of the cell. Fluctuations in SR Ca2+ content specifically can provide us with a significant amount of information pertaining to cellular responses to disease or stress conditions experienced by the cell. In this method, a modified version of a SR-targeted Ca2+ indicator, D1SR, is used to detect Ca2+ fluctuations in response to the introduction of agents to cultured rat aortic smooth muscle cells (SMCs). Following incubation with the D1SR indicator, confocal fluorescence microscopy and fluorescence resonance energy transfer (FRET)-based imaging are used to directly observe changes to intraluminal SR Ca2+ levels under control conditions and with the addition of agonist agents that function to induce intracellular Ca2+ movement.

Currently, most available calcium indicators are used to quantify cytoplasmic calcium transients as indirect measures of calcium released from the sarcoplasmic reticulum in cultured smooth muscle cells. This protocol describes the use of a specific FRET-based indicator that allows direct measurement of calcium signals within the sarcoplasmic reticulum lumen.

배양 된 평활근 세포의 근질 그물 자리 내 칼슘 변동 FRET 측정을 기반으로 공 촛점 이미지

Maintenance of steady-state calcium (Ca2+) levels in the sarcoplasmic reticulum (SR) of vascular smooth muscle cells (VSMCs) is vital to their overall ...

FRET Imaging in Three-dimensional Hydrogels

Imaging of F&#246;rster resonance energy transfer (FRET)&#160;is a powerful tool for examining cell biology in real-time. Studies utilizing FRET commonly employ two-dimensional (2D) culture, which does not mimic the three-dimensional (3D) cellular microenvironment. A method to perform quenched emission FRET imaging using conventional widefield epifluorescence microscopy of cells within a 3D hydrogel environment is presented. Here an analysis method for ratiometric FRET probes that yields linear ratios over the probe activation range is described. Measurement of intracellular cyclic adenosine monophosphate (cAMP) levels is demonstrated in chondrocytes under forskolin stimulation using a probe for EPAC1 activation (ICUE1) and the ability to detect differences in cAMP signaling dependent on hydrogel material type, herein a photocrosslinking hydrogel (PC-gel, polyethylene glycol dimethacrylate) and a thermoresponsive hydrogel (TR-gel). Compared with 2D FRET methods, this method requires little additional work. Laboratories already utilizing FRET imaging in 2D can easily adopt this method to perform cellular studies in a 3D microenvironment. It can further be applied to high throughput drug screening in engineered 3D microtissues. Additionally, it is compatible with other forms of FRET imaging, such as anisotropy measurement and fluorescence lifetime imaging (FLIM), and with advanced microscopy platforms using confocal, pulsed, or modulated illumination.

F&#246;rster resonance energy transfer (FRET) imaging is a powerful tool for real-time cell biology studies. Here a method for FRET imaging cells in physiologic three-dimensional (3D) hydrogel microenvironments using conventional epifluorescence microscopy is presented. An analysis for ratiometric FRET probes that yields linear ratios over the activation range is described.

3 차원 히드로 겔의 이미지를 FRET

Imaging of F&#246;rster resonance energy transfer (FRET)&#160;is a powerful tool for examining cell biology in real-time. Studies utilizing FRET commonly ...