Osteogenic Differentiation and Analysis of MSC

Transcription

1 Osteogenic Differentiation and Analysis of MSC Application Note Background Mesenchymal Stem Cells (MSC) are fibroblastoid multipotent adult stem cells with a high capacity for self-renewal. So far, these cells have been isolated from several human tissues, e.g. bone marrow, adipose tissue, umbilical cord matrix, tendon, lung, and the periosteum [1]. Recently it was shown that MSC recruit from the perivascular niche which represents a tight network throughout the vasculature of the whole body. These perivascular cells lack endothelial/hematopoietic markers (CD31, CD34) but express CD146, PDGF-R beta, and alkaline Phosphatase [2]. Characterization MSC show a CD10 +, CD13 +, CD44 +, CD73 +, CD105 + phenotype, but do not express CD31 or CD45 [1]. In addition to surface marker analysis, the most common and reliable way to identify a population of MSC is to verify their multipotency. MSC can be differentiated in adipocytes, osteoblasts, myocytes, and chondrocytes in vivo and in vitro [1,3]. In addition, trans-differentiation of MSC into cells of non-mesenchymal origin, e.g. hepatocytes, neurons and pancreatic islet cells, has been observed in vitro when specific culture conditions and stimuli apply [1]. The directed differentiation of MSC is carried out in vitro using the appropriate differentiation media, e.g. the ready to use PromoCell MSC Differentiation Media (see below for differentiation protocols). These terminally differentiated cells are histochemically stained to determine their specific marker profile (see below for staining protocol).

2 2 Application Note - Osteogenic Differentiation and Analysis of MSC Use aseptic techniques and a laminar flow bench. Osteogenic Differentiation 1. Seed Mesenchymal Stem Cells Plate 6 x 10 4 MSC per well of a 24-well tissue culture plate (3.15 x 10 4 cells/cm 2 ) using MSC Growth Medium. Work in duplicate. Osteogenic Differentiation 2. Grow Mesenchymal Stem Cells Important: Let the cells reach 100% confluency (24-72 hours). 3. Induce Mesenchymal Stem Cells Induce one of the duplicate samples with MSC Osteogenic Differentiation Medium. Use MSC Growth Medium for the remaining well as a negative control. 4. Differentiation culture of induced Mesenchymal Stem Cells Incubate for 21 days. Change Medium every third day. Be careful not to disturb the cell monolayer.

3 Application Note - Osteogenic Differentiation and Analysis of MSC 3 Important: Do not let the cells dry for longer than 30 sec. throughout the entire staining procedure! Osteoblast Detection (Calcium Deposits) Undifferentiated Mesenchymal Stem Cells have no extracellular calcium deposits, whereas differentiated osteoblasts feature vast extracellular calcium deposits in vivo and in vitro. Calcium deposits are therefore an indication of successful differentiation of MSC into osteoblasts and in vitro bone-formation. Calcium deposits can specifically be stained bright orange-red using Alizarin Red S. Osteoblast Detection 1. Prepare solutions and buffers Dissolve 2 g Alizarin Red S (C. I ) in 100 ml distilled water, mix, and adjust ph to with 0.1% NH 4 OH to prepare the Alizarin Red S staining solution. Filter the dark-brown solution and store it in the dark. Note: The correct ph of the solution is critical. Check ph, if the solution is older than 1 month. 2. Wash the cells Take the cells from the incubator and carefully aspirate the medium. Carefully wash the cells with Dulbecco s PBS, w/o Ca ++ / Mg ++ (Cat. No. C-40232). Note: Do not disrupt the cell monolayer! 3. Fixation of the cells Carefully aspirate the PBS and transfer the flask to a fume hood. Add enough neutral buffered formalin (10%) to cover the cellular monolayer. After at least 30 min. carefully aspirate the formalin and wash the cells with destilled water. 4. Stain the cells Carefully aspirate the destilled water and add enough Alizarin Red S staining solution to cover the cellular monolayer. Incubate at room temperature in the dark for 45 min. 5. Wash the cells Carefully aspirate the Alizarin Red S staining solution and wash the cell monolayer four times with 1 ml destilled water. Carefully aspirate the Washing Buffer and add PBS. 6. Analyze the cells Undifferentiated MSC (without extracellular calcium deposits) are slightly reddish, whereas MSC-derived osteoblasts (with extracellular calcium deposits) are bright orange-red. Fig. 1: hmsc-bm after osteogenic differentiation in vitro. Control (upper row) is slightly reddish, whereas the differentiated MSCderived osteoblasts show vast extracellular calcium deposits, stained in bright orange-red (lower row) Please follow the recommended safety precautions for the chemicals used in this procedure!

4 4 Application Note - Osteogenic Differentiation and Analysis of MSC Important: Do not let the cells dry for longer than 30 sec. throughout the entire staining procedure! Osteoblast Detection (Alkaline Phosphatase) Undifferentiated Mesenchymal Stem Cells show weak alkaline phosphatase (AP) activity, whereas differentiated osteoblasts feature very high phosphatase activity. AP activity is therefore an indication of successful differentiation of MSC into osteoblasts*. AP can easily be detected using BCIP/NBT as a substrate, which stains cells blue-violet when AP is present. Osteoblast Detection 1. Prepare solutions and buffers Dissolve one BCIP/NBT tablet (SigmaFast TM BCIP-NBT; Sigma Aldrich) in 10 ml distilled water to prepare the substrate solution. Store in the dark and use within 2 hours. Add 0.05% Tween 20 to Dulbecco s PBS, w/o Ca++/ Mg++ (Cat. No. C-40232) to prepare the Washing Buffer. 2. Wash the cells Take the cells from the incubator and carefully aspirate the medium. Carefully wash the cells with PBS. Note: Do not disrupt the cell monolayer! 3. Fixation of the cells Carefully aspirate the PBS and transfer the tissue culture dish to a fume hood. Add enough neutral buffered formalin (10%) to cover the cellular monolayer. After 60 sec. carefully aspirate the formalin and wash the cells with Washing Buffer. Note: Longer fixation will lead to irreversible inactivation of AP. 4. Stain the cells Carefully aspirate the Washing Buffer and add enough BCIP/NBT substrate solution to cover the cellular monolayer. Incubate at room temperature in the dark for 5-10 min. Check staining progress every 2-3 min. 5. Wash the cells Carefully aspirate the substrate solution and wash the cell monolayer with Washing Buffer. Carefully aspirate the Washing Buffer and add PBS. 6. Analyze the cells Evaluate staining results. Fig. 2: Undifferentiated MSC (AP negative, upper row) are colorless or faintly bluish, whereas MSC-derived osteoblasts (AP positive, lower row) are dark blue-violet. The higher the AP activity, the more intense the color. Please follow the recommended safety precautions for the chemicals used in this procedure! * AP activity is not limited to osteoblasts. Therefore a second confirmation, e.g. direct staining of extracellular calcium deposits (mineralization), may be necessary to confirm the differentiation of MSC into osteoblasts.

5 References [1] da Silva Meirelles L, Caplan AI, Nardi NB., Stem Cells 2008; 26(9): [2] Crisan M, Yap S, Casteilla L, et al., Cell Stem Cell 2008; 3(3): [3] Caplan AI. Cell Stem Cell 2008, 3(3): Related Products Product Size Catalog Number from Bone Marrow (hmsc-bm) from Umbilical Cord Matrix (hmsc-uc) from Adipose Tissue (hmsc-at) Mesenchymal Stem Cell Growth Medium (Ready-to-use) Mesenchymal Stem Cell Adipogenic Mesenchymal Stem Cell Chondrogenic Mesenchymal Stem Cell Chondrogenic Differentiation Medium w/o Inducers (Ready-to-use) Mesenchymal Stem Cell Osteogenic Mesenchymal Stem Cell Neurogenic MSC-Qualified Fetal Calf Serum DetachKit Cryo-SFM C C C C C C ml C ml C ml C ml C ml C ml C ml 500 ml 30 ml 125 ml 250 ml 30 ml 125 ml C C C C C C C Dulbecco s PBS, w/o Ca ++ / Mg ml C hmsc-bm Pellet > 1 million cells per pellet C hmsc-uc Pellet > 1 million cells per pellet C hmsc-at Pellet > 1 million cells per pellet C PromoCell GmbH Sickingenstr. 63/ Heidelberg Germany info@promocell.com North America Phone: (toll free) Fax: (toll free) Deutschland Telefon: (gebührenfrei) Fax: (gebührenfrei) France Téléphone: (ligne verte) Téléfax: (ligne verte) United Kingdom Phone: (toll free) Fax: (toll free) Other Countries Phone: Fax: