Analysis of Pluripotent Stem Cells by using Cryosections of Embryoid Bodies

* These authors contributed equally
Published 12/08/2010
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Summary

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.

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Gomes, I. C., Acquarone, M., Maciel, R. d., Erlich, R. B., Rehen, S. K. Analysis of Pluripotent Stem Cells by using Cryosections of Embryoid Bodies. J. Vis. Exp. (46), e2344, doi:10.3791/2344 (2010).

Abstract

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 (10μm) 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.

Protocol

1. Fixation and Cryopreservation

Pluripotent stem cells were cultured onto mouse embryonic fibroblasts (MEF) inactivated with mitomycin C and maintained in DMEM/F12 supplemented with 20% knockout serum replacement (KSR) and 8ng/ mL of fibroblast growth factor (FGF-2). In order to induce EB formation H9 cells were transferred to non-adherent dishes and cultured for 7 days, maintained in DMEM/F12 supplemented with 15% KSR 8.

Note (!): This technique can be used for EBs derived from any embryonic and induced pluripotent stem cell.

  1. Collect the EBs from the culture dish with a pipette.
  2. Transfer EBs to a 15 mL conical tube and wait until the material sinks to the bottom of the tube.
  3. Remove medium and fix EBs with a 4% paraformaldehyde (PFA) solution in PBS for 30 minutes in room temperature.
    Note (!): For in situ hybridization antigen recovery should be done in order to avoid cross link reaction with antibodies due to the use of PFA6,7.
  4. Remove PFA solution and wash with PBS for 5 min.
  5. EBs should be placed in serial dilution of PBS-buffered sucrose solutions (10, 20 and 30%, in sequence) at 25-28°C, each solution must be replaced every 30 min. The material can then be stocked in the 30% sucrose solution at 4°C until the embedding step with OCT.

2. Tissue Embedding, Guidance and Freezing

  1. Carefully collect the EBs from the tube. Discharge as much sucrose solution as possible.

    Note (!): It is important to wet the internal wall of the tip with sucrose solution before collecting the EBs. This procedure can avoid EB to be attached to the tip.
  2. Place EBs in the mold and remove remaining sucrose solution with filter paper.

    Note (!): It is important not to fill the mold with EBs to avoid overlapping.
  3. Fill mold with OCT slowly, taking care not to re-suspend EBs. After that, place all EB at the center of the mold and remove bubbles with the pipette.
  4. Mildly agitate for 15 minutes.
  5. Surround the mold with crushed dry ice to freeze the sample. OCT should be completely frozen. At this point blocks can be stored at -70°C, for at least one year.

3. Cryosectioning Technique

  1. Remove the frozen block from -70°C and place on cryostat previously cooled at a temperature between -18 and -21 °C.

    Note (!): Temperatures outside this range may cause troubles like sections curling, melting or cracking.
  2. Detach the OCT block from the mold and place it into the cryostat support by adding more OCT.
  3. It is important to orient the block properly and align it parallel to the edge of the blade.

    Note(!): As EBs are smaller than other tissue samples, this step is extremely important to minimize loss of material.
  4. OCT blocks should be sectioned superficially until the surface plane is obtained. Thin sections (10μm) of the tissue specimen must be taken and mounted onto glass slides previously coated with 200 mg/mL poly L lysine (10 μL per slide) 9,10.

    Note(!): To avoid torned sections pay attention to any damages at the blade.
  5. All sections should be air-dried for 1 hour at room temperature and then be used or stored at -70°C until use.

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Discussion

The method described here provides an easy-to-follow protocol to obtain PFA fixed thin cryostat sections of embryoid bodies useful for immunofluorescence and in situ hybridization assays. The resulting cryosections permit the study of cellular and molecular aspects of human embryonic stem cells differentiation, while preserving their structure and organization as aggregates.

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Disclosures

No conflicts of interest declared.

Acknowledgements

This work was supported by Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Instituto Nacional de Ciência e Tecnologia (INCTC). We are grateful to Bruna S. Paulsen and Aline M. Fernandes for the EB images.

Materials

Name Type Company Catalog Number Comments
D (+) Sucrose Reagent Vetec 228
Paraformaldehyde Reagent Rieden-de Haën 16005
PBS solution Reagent LGC Biotecnology 13-30259.05
Poly-L-lysine hydrobromide Reagent Sigma-Aldrich P2636 200mg/mL in water
Tissue-Tek O.C.T. Compound Reagent Sakura Finetek P2636
Sucrose Solution Reagent 10% Sucrose Solution in PBS w/v
Sucrose Solution Reagent 20% Sucrose Solution in PBS w/v
Sucrose Solution Reagent 30% Sucrose Solution in PBS w/v
Conic Tube Tool Techno Plastic Products 91015 15mL conic tube
Plate shaker Tool Biomixer
Cryostat Tool Leica Microsystems CM 1850
Mold for OCT platform Tool Plastic mold plataform

DOWNLOAD MATERIALS LIST

References

  1. Thomson, J. A., Itskovitz-Eldor, J., Shapiro, S. S., Waknitz, M. A., Swiergiel, J. J., Marshall, V. S., Jones, J. M. Embryonic stem cell lines derived from human blastocysts. Science. 282, 1145-117 (1998).
  2. Itskovitz-Eldor, J., Schuldiner, M., Karsenti, D., Eden, A., Yanuka, O., Amit, M., Soreq, H., Benvenisty, N. Differentiation of human embryonic stem cells into embryoid bodies compromising the three embryonic germ layers. Mol Med. 6, 88-95 (2000).
  3. Kurosawa, H. Methods for inducing embryoid body formation: in vitro differentiation system of embryonic stem cells. J Biosci Bioeng. 103, 389-398 (2007).
  4. Conley, B. J., Young, J. C., Trounson, A. O., Mollard, R. Derivation propagation and differentiation of human embryonic stem cells. Int J Biochem Cell Biol. 36, 555-567 (2004).
  5. Moon, I. S., Cho, S. J., Jin, I., Walikonis, R. A simple method for combined fluorescence in situ hybridization and immunocytochemistry. Mol Cells. 24, 76-82 (2007).
  6. Daneshtalab, N., Doré, J. J., Smeda, J. S. Troubleshooting tissue specificity and antibody selection: Procedures in immunohistochemical studies. J Pharmacol Toxicol Methods. 61, 127-135 (2009).
  7. Krenacs, L., Krenacs, T., Stelkovics, E., Raffeld, M. Heat-induced antigen retrieval for immunohistochemical reactions in routinely processed paraffin sections. Methods Mol Biol. 588-5103 (2010).
  8. Nones, J., Spohr, T. C., Furtado, D. R., Sartore, R. C., Paulsen, B. S., Guimarães, M. Z., Rehen, S. K. Cannabinoids modulate cell survival in embryoid bodies. Cell Biol Int. 12, 399-408 (2010).
  9. Huang, W. M., Gibson, S. J., Facer, P., Gu, J., Polak, J. M. Improved section adhesion for immunocytochemistry using high molecular weight polymers of L-lysine as a slide coating. Histochemistry. 77, 275-279 (1983).
  10. Kuenzi, M. J., Sherwood, O. D. Immunohistochemical localization of specific relaxin-binding cells in thecervix, mammary glands, and nipples of pregnant rats. Endocrinology. 136, 1367-1373 (1995).

Comments

10 Comments

  1. Dear sir,

    I read the abstract of the paper, it's very interesting and I would like to read the full paper. could you please able to send this paper.
    Thanks a lot,
    Regards,
    Ranga

    Reply
    Posted by: Anonymous
    May 18, 2011 - 10:22 AM
  2. Dear Ranga,

    I would be glad to send you a pdf version of the article if you could give me your email.

    Best regards,

    Renata

    Reply
    Posted by: Anonymous
    May 31, 2011 - 3:27 PM
  3. Dear Renata,

    Thanks for your reply.

    here, I am giving my email ID details:
    rangarajan.sambathkumar@student.kuleuven.be
    or
    ranga.1987@hotmail.com

    Thank you so much.

    Kind Regards,
    Ranga.

    Reply
    Posted by: Anonymous
    May 31, 2011 - 5:27 PM
  4. Dear Dr,

    I read the abstract of this paper, it's very interesting. I'm working on embryonic stem cell differentiation into cardiomyocytes using formation of embryoid bodies. I would like to do cryosection of embryoid bodies in few weeks using OCT and I would like to read the full paper if it's possible and maybe see the video. could you please able to send this paper and video.
    Thanks you very much,

    Sincerely,

    Christophe.

    ps: could you please contact me using these email : christophe.fadainia@umontreal.ca

    aiolia²0@hotmail.com thank you very much

    Reply
    Posted by: Anonymous
    June 9, 2011 - 12:29 PM
  5. Dear Dr,

    I read the abstract of this paper, it's very interesting.
    I'm working on embryonic stem cell differentiation into hematopoietic stem cells using formation of embryoid bodies. I would like to do cryosection of embryoid bodies, so I want to read the full paper.
    Could you please able to send this paper? (pdf version)
    Thanks you very much.

    Sincerely,

    ji-hye jung

    (could you please contact me using this email : jhtree08@hanmail.net , jhtree08@korea.ac.kr)




    Reply
    Posted by: Anonymous
    August 25, 2011 - 4:14 AM
  6. Dear Dr:

    I am working on ES cells differentiating into viseral yolk sac stracture embryo bodies. I have read the abstract of your video, it is very interesting. At the moment I am very stucked by the cryosection of EBs. Although I have tried several times, I still could not get any result from it. Could you please send this video or paper or both to me? My Email address is jamie5188@live.cn.

    Thank you very much.

    Congshan Sun

    Reply
    Posted by: Anonymous
    October 10, 2011 - 5:53 AM
  7. Dr. Renata de Moraes Maciel

    Could you please send me a copy of this artile?
    I am also working on mouse ES cell differentiation to mesederm-type cells. I hope I can use this tech. in my research.

    Piyan

    Reply
    Posted by: Anonymous
    October 25, 2011 - 5:26 PM
  8. Dr. Renata de Moraes Maciel


    Could you please send me a copy of this artile?

    I am also working on mouse ES cell differentiation to mesederm-type cells. I hope I can use this tech. in my research.


    Piyan

    My Email: zhang.piyan@mayo.edu

    Reply
    Posted by: Anonymous
    October 25, 2011 - 5:27 PM
  9. Dear Dr,

    I am having major difficulties in fixing my EB's for cryosections. It would be most helpful to be assisted by your paper. Would it be possible for you to send it to my email account? it is meital_gabay@urmc.rochester.edu

    Also, I can't gain access to this movie through our library, is it possible to send that as well?

    Thank you,

    Meital

    Reply
    Posted by: Anonymous
    November 1, 2011 - 12:41 PM
  10. Dear Dr,
    I'm actually working on induced pluripotent stem cells and more specifically, the differentiation into mesoderm-derived cells using formation of embryoid bodies. That's why I am very interested in reading your article. Is it possible that you send me a pdf version ? My Email address is : jbrault@chu-grenoble.fr.
    Thank you in advance.
    Sincerely,
    Julie Brault

    Reply
    Posted by: Anonymous
    November 22, 2011 - 11:33 AM

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