Quantum dot labeling of mesenchymal stem cells

Muller-Borer, Collins, Gunst, Cascio, Kypson

Description

Mesenchymal stem cells (MSCs) are multipotent cells with the potential to differentiate into bone, cartilage, fat and muscle cells and are being investigated for their utility in cell-based transplantation therapy. Yet, adequate methods to track transplanted MSCs in vivo are limited, precluding functional studies. Quantum Dots (QDs) offer an alternative to organic dyes and fluorescent proteins to label and track cells in vitro and in vivo . These nanoparticles are resistant to chemical and metabolic degradation, demonstrating long term photostability. Here, we investigate the cytotoxic effects of in vitro QD labeling on MSC proliferation and differentiation and use as a cell label in a cardiomyocyte co-culture. Results A dose-response to QDs in rat bone marrow MSCs was assessed in Control (no-QDs), Low concentration (LC, 5 nmol/L) and High concentration (HC, 20 nmol/L) groups. QD yield and retention, MSC survival, proinflammatory cytokines, proliferation and DNA damage were evaluated in MSCs, 24 -120 hrs post QD labeling. In addition, functional integration of QD labeled MSCs in an in vitro cardiomyocyte co-culture was assessed. A dose-dependent effect was measured with increased yield in HC vs. LC labeled MSCs (93 ± 3% vs. 50% ± 15%, p < 0.05), with a larger number of QD aggregates per cell in HC vs. LC MSCs at each time point (p < 0.05). At 24 hrs >90% of QD labeled cells were viable in all groups, however, at 120 hrs increased apoptosis was measured in HC vs. Control MSCs (7.2% ± 2.7% vs. 0.5% ± 0.4%, p < 0.05). MCP-1 and IL-6 levels doubled in HC MSCs when measured 24 hrs after QD labeling. No change in MSC proliferation or DNA damage was observed in QD labeled MSCs at 24, 72 and 120 hrs post labeling. Finally, in a cardiomyocyte co-culture QD labeled MSCs were easy to locate and formed functional cell-to-cell couplings, assessed by dye diffusion. Conclusion Fluorescent QDs label MSC effectively in an in vitro co-culture model. QDs are easy to use, show a high yield and survival rate with minimal cytotoxic effects. Dose-dependent effects suggest limiting MSC QD exposure.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2007
• Nombre de lectures: 12
• Langue: English
• Poids de l'ouvrage: 2 Mo

Extrait

Journal of Nanobiotechnology

BioMedCentral

Open Access Research Quantum dot labeling of mesenchymal stem cells 1 1 1 1 Barbara J MullerBorer* , Maria C Collins , Philip R Gunst , Wayne E Cascio 2 and Alan P Kypson

1 Address: Department of Internal Medicine, The Brody School of Medicine at East Carolina University, Greenville, NC27834, USA and 2 Department of Surgery, The Brody School of Medicine at East Carolina University, Greenville, NC27834, USA Email: Barbara J MullerBorer*  [e-mail]; Maria C Collins  [e-mail]; Philip R Gunst  [e-mail]; Wayne E Cascio  [e-mail]; Alan P Kypson  [e-mail] * Corresponding author

Published: 7 November 2007 Received: 21 May 2007 Accepted: 7 November 2007 Journal of Nanobiotechnology2007,5:9 doi:10.1186/1477315559 This article is available from: http://www.jnanobiotechnology.com/content/5/1/9 © 2007 MullerBorer et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:Mesenchymal stem cells (MSCs) are multipotent cells with the potential to differentiate into bone, cartilage, fat and muscle cells and are being investigated for their utility in cellbased transplantation therapy. Yet, adequate methods to track transplanted MSCsin vivoare limited, precluding functional studies. Quantum Dots (QDs) offer an alternative to organic dyes and fluorescent proteins to label and track cellsin vitroandin vivo. These nanoparticles are resistant to chemical and metabolic degradation, demonstrating long term photostability. Here, we investigate the cytotoxic effects ofin vitroQD labeling on MSC proliferation and differentiation and use as a cell label in a cardiomyocyte coculture.

Results:A doseresponse to QDs in rat bone marrow MSCs was assessed in Control (noQDs), Low concentration (LC, 5 nmol/L) and High concentration (HC, 20 nmol/L) groups. QD yield and retention, MSC survival, proinflammatory cytokines, proliferation and DNA damage were evaluated in MSCs, 24 120 hrs post QD labeling. In addition, functional integration of QD labeled MSCs in anin vitrocardiomyocyte coculture was assessed. A dosedependent effect was measured with increased yield in HC vs. LC labeled MSCs (93 ± 3% vs. 50% ± 15%, p < 0.05), with a larger number of QD aggregates per cell in HC vs. LC MSCs at each time point (p < 0.05). At 24 hrs >90% of QD labeled cells were viable in all groups, however, at 120 hrs increased apoptosis was measured in HC vs. Control MSCs (7.2% ± 2.7% vs. 0.5% ± 0.4%, p < 0.05). MCP1 and IL6 levels doubled in HC MSCs when measured 24 hrs after QD labeling. No change in MSC proliferation or DNA damage was observed in QD labeled MSCs at 24, 72 and 120 hrs post labeling. Finally, in a cardiomyocyte coculture QD labeled MSCs were easy to locate and formed functional celltocell couplings, assessed by dye diffusion.

Conclusion:Fluorescent QDs label MSC effectively in anin vitrococulture model. QDs are easy to use, show a high yield and survival rate with minimal cytotoxic effects. Dosedependent effects suggest limiting MSC QD exposure.

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