주 0 - 실험 하루 전에 살균 <ol><li> 플라스틱 욕조에 재료를 넣고 2 시간 동안 70 % 알코올로 소독 : <ul><li> 챔버스 </li><li> 뚜껑 </li><li> 프레임 (전체 3 개) </li><li> 나사 </li><li> 고무 가스켓 </li><li> 집게 </li><li> 가위 </li><li> 헥스 렌치 </li></ul></li><li> Aquet 비누와 증류수로 깨끗이 세포막. </li><li> 10 분 70 % 알콜에 세포막을 Sonicate. </li><li> 플라스틱 사각 접시에 깨끗한 세포막을 놓으십시오. 패턴 세포막을 사용하는 경우, 패턴 측면이 (막의 한쪽에 스프레이 알코올과 홈을 실행할 수있는 액체에 대한보고)까지 얼굴 있는지 확인합니다. </li><li> 2 시간 동안 70 %의 알코올로 덮여 세포막을 둡니다. </li><li> 내일 아침 autoclaving 위해 알루미늄 호일로 패키지 장갑. </li><li> 내일 autoclaving 위해 증류수 2 % (중량 / 부피) 젤라틴 솔루션 (2g/100mL)합니다. </li><li> 70 % 알콜에 2 시간 살균 후, 야간 자외선에 대한 후드로 모든 폴리머 재료와 세포막을 (비 autoclavable 소재) 장소 : <ul><li> 챔버스 </li><li> 뚜껑 </li><li> 프레임 (전체 3 개) </li><li> 세포막 </li></ul></li><li> autoclavable 가방에 나머지 재료를 패키지 : <ul><li> 나사 </li><li> 고무 가스켓 </li><li> 집게 </li><li> 가위 </li><li> 헥스 렌치 </li></ul></li></ol> 1 일 - 스트레치 챔버스 조립 <ol><li> 압력솥의 집게, 가위 20 분 총 240 ° F에서 작은 압력솥을 사용 헥스 렌치, 나사, 가스켓, 장갑, 그리고 젤라틴 </li><li> UV에서 세포막을 제거하고 ~ 1 분 O 2 플라즈마 (최대 패턴 사이드)로 처리합니다. </li><li> TC 후드에 젤라틴과 플라즈마 처리 세포막의 패턴 영역을 커버. 자외선을 쬐면 분 동안 코트 30. </li><li> PBS 2X 각 막 씻으십시오. 2 세척 후, 실에 쉽게 조립, 그들이 미끄러 유지하는 세포막의 일부 PBS 두십시오. (또한 쉽게 조립을위한 가스켓에 기름칠이 PBS를 사용한다). </li><li> (조립 중 autoclaved 장갑을 착용) 회의소로 세포막을 조립 <ol><li> 하나의 나사를 사용하여 프레임의 두 가지 주요 부분을 연결합니다. </li><li> 프레임을 뒤집어하고 프레임쪽으로 젤라틴 코팅 사이드 얼굴 (패턴 부분은 중앙에 있어야합니다) 그래서 위에 막 놓으십시오. </li><li> 양쪽에 가스켓을 사용하여 프레임에 멤브레인를 고정합니다. </li><li> 부드러운 사용에 가스켓을 누르면, 심지어 압력 때문에 같은 멤브레인 해낼 수 없습니다. </li></ol></li><li> T - 바에 조립 프레임을 연결합니다. </li><li> 거꾸로 챔버에 프레임과 장소를 뒤집기. 30 분 프레임과 막의 UV 백 사이드 </li><li> 다시 프레임을 플립, 그리고 회의소 (제어 챔버에 대한 변화하지만, 스트레치 챔버 들어, 챔버 하단 프레임의 끝 부분을 연결하는 두 개의 나사를 사용해야합니다, 그리고 단일 나사를 제거할 필요로 나사 ) 함께 프레임의 두 가지를 들고. 30 분 UV 프론트 사이드. 점막이 다음 단계로 진행하기 전에 완전히 말랐어요, 또는 다른 세포 솔루션 시딩 동안 벗어 버리는 수 있는지 확인하십시오. </li><li> 종자 세포. 3 세포막 1 판 = 지역의 지역은 너무 막 당 합류 접시의 1 / 3을 사용합니다. 멤브레인 당 세포 솔루션 1 ML을 사용합니다. 1.5mL보다 더 솔루션을 계속하기 어려운 것입니다. 전용 패턴 영역에 셀 솔루션을 넣어, 그리고 주변의 솔루션을 보급하기 위해 피펫 팁을 사용합니다. 실 커버하고 세포 후드 30 분만에 RT를 위해 첨부하자. </li><li> 인큐베이터에 방을 이동하며 세포는 1 개 시간 동안 부착하자. 셀 솔루션 벗어 버리는시키는 피하기 위해 회의소 이동 아주 조심해야! 솔루션은이 시점에서 굴러 떨어지면 챔버의 세포 생활이 엉망이 될 것입니다. </li><li> 후드로 챔버를 반환 20 ML 미디어를 추가합니다. </li><li> 알루미늄 호일 (또한 알코올과 물을 뿌리)으로 덮여있다 알코올 세척 욕조에 플레이스 실. 배양기를 (10 % CO 2) 운동 실 이동합니다. </li><li> 스트레치 머신에 보안 실. 세포가 더 이상 야간 첨부하고, 다음날에 스트레치를 시작하자. (참고 : 스트레치 머신에 실 퍼팅 때, 챔버 스를 배치하기 전에 &quot;제로&quot;위치에 컴퓨터를 잠금 다음 기어 주변의 고무 밴드를 조이는 데 기억 시스템을 시작하기 전에 기어 잠금을 해제하는 것을 잊지 마십시오.). </li></ol>

<ol>
	<li>Banes, A. J., Gilbert, J., Taylor, D., Monbureau, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+vacuum-operated+stress-providing+instrument+that+applies+static+or+variable+duration+cyclic+tension+or+compression+to+cells+in+vitro.">A new vacuum-operated stress-providing instrument that applies static or variable duration cyclic tension or compression to cells in vitro.</a> J Cell Sci. 75, 35-42 (1985).</li><li>Park, J. S., Chu, J. S., Cheng, C., Chen, F., Chen, D., Li, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+effects+of+equiaxial+and+uniaxial+strain+on+mesenchymal+stem+cells.">Differential effects of equiaxial and uniaxial strain on mesenchymal stem cells.</a> Biotechnol. Bioeng. 88, 359-368 (2004).</li><li>Kurpinski, K., Chu, J., Hashi, C., Li, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anisotropic+mechanosensing+by+mesenchymal+stem+cells.">Anisotropic mechanosensing by mesenchymal stem cells.</a> Proc. Natl. Acad. Sci. U S A. 103, 16095-16100 (2006).</li></ol>

베인스 외. 첫 번째 셀 1 기계적 힘을 전달하기 위해 유연하고 탄성 기판을 사용하여 체외에서 세포의 기계적 자극에 대한 시스템의 사용을보고했다. 이 시간 이후로,이 디자인에 많은 변화가 잉태하여 이용하고 있습니다. 일부 실험실 사용자 정의 - 기본 장치를 사용하는 동안 여러 기계 스트레치 시스템은 이름 &quot;Flexercell&quot;(Flexcell 국제 주식 회사)에서 상업적으로 사용할 수 있습니다. 이 비디오 프로토콜에서는 우리가 실험실에서 하나의 장치의 설치 및 사용을 설명합니다. 이 프로토콜에 묘사된 맞춤식 &quot;스트레치 머신은&quot;다른 세포 유형의 2,3에 uniaxial 순환 스트레인의 효과를 조사하기 위해 여러 연구에서 사용되고 있습니다. 이 기계는 기계적 스트레인 연구의 다양한 사용할 수 몇 가지 조정 매개 변수를 가진 다목적 기기입니다. 여기에 묘사된 설치 문화 자기편 세포 uniaxial 순환 변형을 제공하는 독특하고 강력한 방법을 나타냅니다.

미디어 참고 : 이러한 uniaxial 스트레치 실험은 생물 반응기 설정의 복잡으로 인해 오염하는 경향이 있습니다. 이것을 방지하기 위해, 우리는 항생제와 antifungal 대리인의 다양한 조합을 시도했습니다. 항생제의 조합과 함께 일반적으로 필요한 1 % fungizone. 어느 펜 / Strep 조합을 사용하거나 (하지만 내성 돌연변이 세균을 초래할 수 있으므로 함께 조합 / 칵테일 세이나 항생제를 사용하려고하지 않으며, 또한 세포에 해로운 수) Kanamycin과 Gentamicin의 조합을 사용 .

mechanical stimulation of stem cells using cyclic uniaxial strain

생물 학적 조직의 개발 및 유지 보수의 기계 군대의 역할은 물론 같은 뼈 리모델링, 근육 비대 및 평활근 세포 소성과 같은 몇 가지 기계 규제 현상을 포함하여 문서화되어있다. 그러나, 참여 세력은 종종 모니터링하고 생체내 제어하기가 매우 복잡하고 어렵습니다. 더 나은 세포에 기계적 세력의 영향을 조사하기 위해, 우리는 탄성 점막에 교양 자기편 세포 uniaxial 순환 인장 응력을 적용하기위한 체외 방식에을 개발했습니다. 이 방법은 원하는 힘을 적용하는 전동 캠 - 로터 시스템 맞춤 설계 생물 반응기를 활용합니다. 여기서 우리는 변형의 방향과 동양 세포 micropatterned의 지형을 가진 실리콘 막,이 경우를 포함하여 각 &quot;스트레치 챔버 &#39;의 다양한 구성 요소를 조립하는 방법을 보여주는 단계별 비디오 프로토콜을 제시한다. 우리는 또한, 챔버 스를 살균 막에 세포를 심는 생물 반응기에 챔버를 래치와 기계 매개 변수 (예 : 크기와 변형의 속도) 조정 절차를 설명합니다. 이 특정 프로토콜에 설명된 절차는 변형의 방향에 평행 방향으로 10 μm의 다양한 채널로 실리콘 점막에 인간 mesenchymal 줄기 세포을 심는 특정 있습니다. 그러나, 방법이 시스템의 제공 자료가이 주제에 대한 유사 콘텐츠 수를 수용할 수있을만큼 유연 : 변형 속도, 크기, 기간, 세포 유형, 멤브레인 지형, 막 코팅 등 모든 원하는 응용 프로그램 또는 맞출 수 결과. 이것은 체외에서 세포에 적용 uniaxial 인장 변형의 영향을 조사하는 강력한 방법입니다.

Watch this Scientific Journal Video about Mechanical Stimulation of Stem Cells Using Cyclic Uniaxial Strain at JoVE.com

Mechanical Stimulation of Stem Cells Using Cyclic Uniaxial Strain

그것은 널리 본문에 기계적 세력 세포 분화와 증식에 영향을 미칠 수 있음을 이해합니다. 여기 유연한 micropatterned 기판에 교양 세포를 막기 위해 uniaxial 순환 인장 응력을 제공하는 맞춤식 생물 반응기의 사용을 보여주는 비디오 프로토콜을 제시한다.

순환 Uniaxial 스트레인을 사용하여 줄기 세포의 기계적 자극

The role of mechanical forces in the development and maintenance of biological tissues is well documented, including several mechanically regulated ...

mechanical-stimulation-of-stem-cells-using-cyclic-uniaxial-strain

Nanyang Technological University

Research

JoVE Journal

Biology

12.7K 조회수.  University of California, Berkeley. 그것은 널리 본문에 기계적 세력 세포 분화와 증식에 영향을 미칠 수 있음을 이해합니다. 여기 유연한 micropatterned 기판에 교양 세포를 막기 위해 uniaxial 순환 인장 응력을 제공하는 맞춤식 생물 반응기의 사용을 보여주는 비디오 프로토콜을 제시한다.

비디오: Mechanical Stimulation of Stem Cells Using Cyclic Uniaxial Strain

Derivation of Hematopoietic Stem Cells from Murine Embryonic Stem Cells

A stem cell is defined as a cell with the capacity to both self-renew and generate multiple differentiated progeny.  Embryonic stem cells (ESC) are derived from the blastocyst of the early embryo and are pluripotent in differentiative ability.  Their vast differentiative potential has made them the focus of much research centered on deducing how to coax them to generate clinically useful cell types.  The successful derivation of hematopoietic stem cells (HSC) from mouse ESC has recently been accomplished and can be visualized in this video protocol.  HSC, arguably the most clinically exploited cell population, are used to treat a myriad of hematopoietic malignancies and disorders.  However, many patients that might benefit from HSC therapy lack access to suitable donors.  ESC could provide an alternative source of HSC for these patients.  The following protocol establishes a baseline from which ESC-HSC can be studied and inform efforts to isolate HSC from human ESC.  In this protocol, ESC are differentiated as embryoid bodies (EBs) for 6 days in commercially available serum pre-screened for optimal hematopoietic differentiation.  EBs are then dissociated and infected with retroviral HoxB4.  Infected EB-derived cells are plated on OP9 stroma, a bone marrow stromal cell line derived from the calvaria of  M-CSF-/- mice, and co-cultured in the presence of hematopoiesis promoting cytokines for ten days.  During this co-culture, the infected cells expand greatly, resulting in the generation a heterogeneous pool of 100s of millions of cells.  These cells can then be used to rescue and reconstitute lethally irradiated mice.

This protocol details the derivation of transplantable hematopoietic stem cells from mouse embryonic stem cells (ESC) and their subsequent injection into lethally irradiated recipient mice. Briefly, ESC are differentiated as embryoid bodies, which are then infected with retroviral HoxB4 and co-cultured with OP9 stromal cells and hematopoietic cytokines.

Murine 배아 줄기 세포로부터 조혈 줄기 세포의 유도

A stem cell is defined as a cell with the capacity to both self-renew and generate multiple differentiated progeny.  Embryonic stem cells (ESC) are ...

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생물학

Patterning of Embryonic Stem Cells Using the Bio Flip Chip

Cell-cell interactions consisting of diffusible signaling and cell-cell contact (juxtacrine signaling) are important in numerous biological processes such as tumor growth, stem cell differentiation, and stem cell self-renewal. A number of methods currently exist to modulate cell signaling in vitro. One method of modulating the total amount of diffusible signaling is to vary the cell seeding density during culture. Due to the random nature of cell seeding, this results in considerable variation in the actual cell-cell spacing and amount of cell-cell contact, and cannot prescribe the local environment. A more specific approach for modulating cell signaling is to use molecular inhibitors or genetic approaches to knock down specific signaling proteins, but both of these methods are best suited to manipulating small numbers of molecules. Here, we demonstrate a new approach to modulating cell-cell signaling that modulates the local environment of a cluster of cells by placing different numbers of cells at desired locations on a substrate. This method provides a complementary way to control the local diffusible and juxtacrine signaling between cells. Our method makes use of the Bio Flip Chip (BFC), a microfabricated silicone chip containing hundreds-to-thousands of microwells, each sized to hold either a single cell or small numbers of cells. We load the chip with cells simply by pipetting them onto the array of wells and washing unloaded cells off the array. The chip is then flipped onto a substrate, whereby the cells fall out of the wells and onto the substrate, maintaining their patterning. After the cells have attached, the chip can be removed (or left on). This approach to cell patterning is unique in that it: 1) doesn't alter the chemistry of the substrate, thus allowing cells to proliferate and migrate; 2) allows patterning onto any substrate, including tissue-culture polystyrene, glass, matrigel, and even feeder cell layers; and 3) is compatible with traditional microcontact printing, allowing the creation of extracellular matrix islands with cells placed inside those islands. In this video, we demonstrate the patterning of mouse embryonic stem cells onto tissue-culture polystyrene using the BFC.

We demonstrate a simple method for placing cells at desired locations on a substrate. This method patterns cells by flipping a silicone chip containing microwells filled with cells onto the substrate. This method provides a new way to modulate diffusible and juxtacrine signaling between cells.

바이오 플립 칩을 사용하여 배아 줄기 세포의 Patterning

Cell-cell interactions consisting of diffusible signaling and cell-cell contact (juxtacrine signaling) are important in numerous biological processes such ...

Isolation and Animal Serum Free Expansion of Human Umbilical Cord Derived Mesenchymal Stromal Cells (MSCs) and Endothelial Colony Forming Progenitor Cells (ECFCs)

The umbilical cord is a rich source for progenitor cells with high proliferative potential including mesenchymal stromal cells (also termed mesenchymal stem cells, MSCs) and endothelial colony forming progenitor cells (ECFCs). Both cell types are key players in maintaining the integrity of tissue and are probably also involved in regenerative processes and tumor formation.
To study their biology and function in a comparative manner it is important to have both cells types available from the same donor. It may also be beneficial for regenerative purposes to derive MSCs and ECFCs from the same tissue.
Because cellular therapeutics should eventually find their way from bench to bedside we established a new method to isolate and further expand progenitor cells without the use of animal protein. Pooled human platelet lysate (pHPL) replaced fetal bovine serum in all steps of our protocol to completely avoid contact of the cells to xenogeneic proteins.
This video demonstrates a methodology for the isolation and expansion of progenitor cells from one umbilical cord.
All materials and procedures will be described.

Isolation and Animal Serum Free Expansion of Human Umbilical Cord Derived Mesenchymal Stromal Cells MSCs and Endothelial Colony Forming Progenitor Cells ECFCs

This protocol describes the isolation and subsequent expansion of mesenchymal stromal cells and endothelial colony forming cells without the use of animal serum to generate autologous pairs for experimental transplantation purposes.

인간 탯줄의 분리 및 동물 혈청 무료 확장 Mesenchymal Stromal 세포 (MSCS)와 내피 콜로니 형성 전구 세포 (ECFCs)을 유래

The umbilical cord is a rich source for progenitor cells with high proliferative potential including mesenchymal stromal cells (also termed mesenchymal ...

Live Cell Response to Mechanical Stimulation Studied by Integrated Optical and Atomic Force Microscopy

To understand the mechanism by which living cells sense mechanical forces, and how they respond and adapt to their environment, a new technology able to investigate cells behavior at sub-cellular level with high spatial and temporal resolution was developed. Thus, an atomic force microscope (AFM) was integrated with total internal reflection fluorescence (TIRF) microscopy and fast-spinning disk (FSD) confocal microscopy. The integrated system is broadly applicable across a wide range of molecular dynamic studies in any adherent live cells, allowing direct optical imaging of cell responses to mechanical stimulation in real-time. Significant rearrangement of the actin filaments and focal adhesions was shown due to local mechanical stimulation at the apical cell surface that induced changes into the cellular structure throughout the cell body. These innovative techniques will provide new information for understanding live cell restructuring and dynamics in response to mechanical force. A detailed protocol and a representative data set that show live cell response to mechanical stimulation are presented.

This paper aims to instruct the reader in the operation of an integrated atomic force-optical imaging microscope for mechanical stimulation of live cells in culture. A step-by-step protocol is presented. A representative data set that shows live cell response to mechanical stimulation is presented.

기계 자극에 라이브 세포 응답 통합 광학과 원자 힘 현미경에 의해 연구

To understand the mechanism by which living cells sense mechanical forces, and how they respond and adapt to their environment, a new technology able to ...

Analysis of Pluripotent Stem Cells by using Cryosections of Embryoid Bodies

Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of blastocyst-stage early mammalian embryos 1. A crucial stage in the differentiation of ES cells is the formation of embryoid bodies (EBs) aggregates 2, 3. EB formation is based on spontaneous aggregation when ES cells are cultured in non adherent plates. Three-dimensional EB recapitulates many aspects of early mammalian embryogenesis and differentiate into the three germ layers: ectoderm, mesoderm and endoderm 4.
Immunofluorescence and in situ hybridization are widely used techniques for the detection of target proteins and mRNA present in cells of a tissue section 5, 6, 7. Here we present a simple technique to generate high quality cryosections of embryoid bodies. This approach relies on the spatial orientation of EB embedding in OCT followed by the cryosection technique. The resulting sections can be subjected to a wide variety of analytical procedures in order to characterize populations of cells containing certain proteins, RNA or DNA. In this sense, the preparation of EB cryosections (10&mu;m) are essential tools for histology staining analysis (e.g. Hematoxilin and Eosin, DAPI), immunofluorescence (e.g. Oct4, nestin) or in situ hybridization. This technique can also help to understand aspects of embryogenesis with regards to the maintenance of the tri-dimensional spherical structure of EBs.

Pluripotent stem cells growing in suspension differentiate into embryoid bodies (EBs). Here we demonstrate how to obtain high quality EB cryosections useful for studying cellular and molecular aspects of embryogenesis, while preserving their organization as aggregates.

Embryoid 기관의 Cryosections를 사용하여 Pluripotent 줄기 세포 분석

Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of blastocyst-stage early mammalian embryos 1. A crucial stage in the ...

Quantifying the Frequency of Tumor-propagating Cells Using Limiting Dilution Cell Transplantation in Syngeneic Zebrafish

Self-renewing cancer cells are the only cell types within a tumor that have an unlimited ability to promote tumor growth, and are thus known as tumor-propagating cells, or tumor-initiating cells. It is thought that targeting these self-renewing cells for destruction will block tumor progression and stop relapse, greatly improving patient prognosis1. The most common way to determine the frequency of self-renewing cells within a tumor is a limiting dilution cell transplantation assay, in which tumor cells are transplanted into recipient animals at increasing doses; the proportion of animals that develop tumors is used the calculate the number of self-renewing cells within the original tumor sample2, 3. Ideally, a large number of animals would be used in each limiting dilution experiment to accurately determine the frequency of tumor-propagating cells. However, large scale experiments involving mice are costly, and most limiting dilution assays use only 10-15 mice per experiment. 
Zebrafish have gained prominence as a cancer model, in large part due to their ease of genetic manipulation and the economy by which large scale experiments can be performed. Additionally, the cancer types modeled in zebrafish have been found to closely mimic their counterpart human disease4. While it is possible to transplant tumor cells from one fish to another by sub-lethal irradiation of recipient animals, the regeneration of the immune system after 21 days often causes tumor regression5. The recent creation of syngeneic zebrafish has greatly facilitated tumor transplantation studies 6-8. Because these animals are genetically identical, transplanted tumor cells engraft robustly into recipient fish, and tumor growth can be monitored over long periods of time. Syngeneic zebrafish are ideal for limiting dilution transplantation assays in that tumor cells do not have to adapt to growth in a foreign microenvironment, which may underestimate self-renewing cell frequency9, 10. Additionally, one-cell transplants have been successfully completed using syngeneic zebrafish8 and several hundred animals can be easily and economically transplanted at one time, both of which serve to provide a more accurate estimate of self-renewing cell frequency.
Here, a method is presented for creating primary, fluorescently-labeled T-cell acute lymphoblastic leukemia (T-ALL) in syngeneic zebrafish, and transplanting these tumors at limiting dilution into adult fish to determine self-renewing cell frequency. While leukemia is provided as an example, this protocol is suitable to determine the frequency of tumor-propagating cells using any cancer model in the zebrafish.

Limiting dilution cell transplantation assays are used to determine the frequency of tumor-propagating cells. This protocol describes a method for generating syngeneic zebrafish that develop fluorescently-labeled leukemia and details how to isolate and transplant these leukemia cells at limiting dilution into the peritoneal cavity of adult zebrafish.

Syngeneic Zebrafish의 제한 희석 세포 이식을 사용하여 종양 - 증식 세포의 주파수 Quantifying

Self-renewing cancer cells are the only cell types within a tumor that have an unlimited ability to promote tumor growth, and are thus known as ...

Micro-Mechanical Characterization of Lung Tissue Using Atomic Force Microscopy

Matrix stiffness strongly influences growth, differentiation and function of adherent cells1-3. On the macro scale the stiffness of tissues and organs within the human body span several orders of magnitude4. Much less is known about how stiffness varies spatially within tissues, and what the scope and spatial scale of stiffness changes are in disease processes that result in tissue remodeling. To better understand how changes in matrix stiffness contribute to cellular physiology in health and disease, measurements of tissue stiffness obtained at a spatial scale relevant to resident cells are needed. This is particularly true for the lung, a highly compliant and elastic tissue in which matrix remodeling is a prominent feature in diseases such as asthma, emphysema, hypertension and fibrosis. To characterize the local mechanical environment of lung parenchyma at a spatial scale relevant to resident cells, we have developed methods to directly measure the local elastic properties of fresh murine lung tissue using atomic force microscopy (AFM) microindentation. With appropriate choice of AFM indentor, cantilever, and indentation depth, these methods allow measurements of local tissue shear modulus in parallel with phase contrast and fluorescence imaging of the region of interest. Systematic sampling of tissue strips provides maps of tissue mechanical properties that reveal local spatial variations in shear modulus. Correlations between mechanical properties and underlying anatomical and pathological features illustrate how stiffness varies with matrix deposition in fibrosis. These methods can be extended to other soft tissues and disease processes to reveal how local tissue mechanical properties vary across space and disease progression.

The stiffness of the extracellular matrix strongly influences multiple behaviors of adherent cells. Matrix stiffness varies spatially throughout a tissue, and undergoes modification in various disease conditions. Here we develop methods to characterize spatial variations in stiffness in normal and fibrotic mouse lung tissue using atomic force microscopy microindentation.

원자 힘 현미경을 사용하여 폐 조직의 미세 기계적 특성

Matrix stiffness strongly influences growth, differentiation and function of adherent cells1-3.  On the macro scale the stiffness of tissues and organs ...

Biophysical Assays to Probe the Mechanical Properties of the Interphase Cell Nucleus: Substrate Strain Application and Microneedle Manipulation

In most eukaryotic cells, the nucleus is the largest organelle and is typically 2 to 10 times stiffer than the surrounding cytoskeleton; consequently, the physical properties of the nucleus contribute significantly to the overall biomechanical behavior of cells under physiological and pathological conditions. For example, in migrating neutrophils and invading cancer cells, nuclear stiffness can pose a major obstacle during extravasation or passage through narrow spaces within tissues.1 On the other hand, the nucleus of cells in mechanically active tissue such as muscle requires sufficient structural support to withstand repetitive mechanical stress. Importantly, the nucleus is tightly integrated into the cellular architecture; it is physically connected to the surrounding cytoskeleton, which is a critical requirement for the intracellular movement and positioning of the nucleus, for example, in polarized cells, synaptic nuclei at neuromuscular junctions, or in migrating cells.2 Not surprisingly, mutations in nuclear envelope proteins such as lamins and nesprins, which play a critical role in determining nuclear stiffness and nucleo-cytoskeletal coupling, have been shown recently to result in a number of human diseases, including Emery-Dreifuss muscular dystrophy, limb-girdle muscular dystrophy, and dilated cardiomyopathy.3 To investigate the biophysical function of diverse nuclear envelope proteins and the effect of specific mutations, we have developed experimental methods to study the physical properties of the nucleus in single, living cells subjected to global or localized mechanical perturbation. Measuring induced nuclear deformations in response to precisely applied substrate strain application yields important information on the deformability of the nucleus and allows quantitative comparison between different mutations or cell lines deficient for specific nuclear envelope proteins. Localized cytoskeletal strain application with a microneedle is used to complement this assay and can yield additional information on intracellular force transmission between the nucleus and the cytoskeleton. Studying nuclear mechanics in intact living cells preserves the normal intracellular architecture and avoids potential artifacts that can arise when working with isolated nuclei. Furthermore, substrate strain application presents a good model for the physiological stress experienced by cells in muscle or other tissues (e.g., vascular smooth muscle cells exposed to vessel strain). Lastly, while these tools have been developed primarily to study nuclear mechanics, they can also be applied to investigate the function of cytoskeletal proteins and mechanotransduction signaling.

We present two independent, microscope-based tools to measure the induced nuclear and cytoskeletal deformations in single, living adherent cells in response to global or localized strain application. These techniques are used to determine nuclear stiffness (i.e., deformability) and to probe intracellular force transmission between the nucleus and the cytoskeleton.

계면 세포 핵의 기계적 성질을 알아내기 위해 Biophysical Assays : 기판 스트레인 신청 및 Microneedle 조작

In most eukaryotic cells, the nucleus is the largest organelle and is typically 2 to 10 times stiffer than the surrounding cytoskeleton; consequently, the ...

Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells (iPSCs) Using Retroviral Vector with GFP

Human embryonic stem cells (hESCs) are pluripotent and an invaluable cellular sources for in vitro disease modeling and regenerative medicine1. It has been previously shown that human somatic cells can be reprogrammed to pluripotency by ectopic expression of four transcription factors (Oct4, Sox2, Klf4 and Myc) and become induced pluripotent stem cells (iPSCs)2-4 . Like hESCs, human iPSCs are pluripotent and a potential source for autologous cells. Here we describe the protocol to reprogram human fibroblast cells with the four reprogramming factors cloned into GFP-containing retroviral backbone4. Using the following protocol, we generate human iPSCs in 3-4 weeks under human ESC culture condition. Human iPSC colonies closely resemble hESCs in morphology and display the loss of GFP fluorescence as a result of retroviral transgene silencing. iPSC colonies isolated mechanically under a fluorescence microscope behave in a similar fashion as hESCs. In these cells, we detect the expression of multiple pluripotency genes and surface markers.

Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells iPSCs Using Retroviral Vector with GFP

A method to generate human induced pluripotent stem cells (iPSCs) via retrovirus-mediated ectopic expression of OCT4, SOX2, KLF4 and MYC is described. A practical way to identify human iPSC colonies based on GFP expression is also discussed.

GFP와 Retroviral 벡터를 사용하여 유도 Pluripotent 줄기 세포 (iPSCs)로 인간 체세포를 프로그래밍

Human embryonic stem cells (hESCs) are pluripotent and an invaluable cellular sources for in vitro disease modeling and regenerative medicine1. It has ...

Mechanical Stimulation of Chondrocyte-agarose Hydrogels

Articular cartilage suffers from a limited repair capacity when damaged by mechanical insult or degraded by disease, such as osteoarthritis. To remedy this deficiency, several medical interventions have been developed. One such method is to resurface the damaged area with tissue-engineered cartilage; however, the engineered tissue typically lacks the biochemical properties and durability of native cartilage, questioning its long-term survivability. This limits the application of cartilage tissue engineering to the repair of small focal defects, relying on the surrounding tissue to protect the implanted material. To improve the properties of the developed tissue, mechanical stimulation is a popular method utilized to enhance the synthesis of cartilaginous extracellular matrix as well as the resultant mechanical properties of the engineered tissue. Mechanical stimulation applies forces to the tissue constructs analogous to those experienced in vivo. This is based on the premise that the mechanical environment, in part, regulates the development and maintenance of native tissue1,2. The most commonly applied form of mechanical stimulation in cartilage tissue engineering is dynamic compression at physiologic strains of approximately 5-20% at a frequency of 1 Hz1,3. Several studies have investigated the effects of dynamic compression and have shown it to have a positive effect on chondrocyte metabolism and biosynthesis, ultimately affecting the functional properties of the developed tissue4-8. In this paper, we illustrate the method to mechanically stimulate chondrocyte-agarose hydrogel constructs under dynamic compression and analyze changes in biosynthesis through biochemical and radioisotope assays. This method can also be readily modified to assess any potentially induced changes in cellular response as a result of mechanical stimuli.

The biosynthesis of cartilaginous extracellular matrix by chondrocytes can be affected by application of mechanical stimuli. This method describes the technique of applying dynamic compressive strains to chondrocytes encapsulated in 3D constructs and the evaluation of induced changes in chondrocyte metabolism.

Chondrocyte - 아가로 오스 Hydrogels의 기계적 자극

Articular cartilage suffers from a limited repair capacity when damaged by mechanical insult or degraded by disease, such as osteoarthritis. To remedy ...