gms | German Medical Science

German Congress of Orthopaedics and Traumatology (DKOU 2016)

25.10. - 28.10.2016, Berlin

Rescued Chondrogenesis of Primary Mesenchymal Stem Cells Under Interleukin 1 Challenge by Foamyviral Interleukin 1 Receptor Antagonist Gene Transfer

Meeting Abstract

  • presenting/speaker Nicole Armbruster - University of Würzburg, Department of Virology, Würzburg, Germany
  • Jenny Krieg - University of Würzburg, Department of Virology, Würzburg, Germany
  • Carsten Scheller - University of Würzburg, Department of Virology, Würzburg, Germany
  • Andre Steinert - Orthopädische Klinik, König-Ludwig-Haus, Lehrstuhl für Orthopädie der Universität Würzburg, Würzburg, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2016). Berlin, 25.-28.10.2016. Düsseldorf: German Medical Science GMS Publishing House; 2016. DocGR16-1276

doi: 10.3205/16dkou443, urn:nbn:de:0183-16dkou4436

Published: October 10, 2016

© 2016 Armbruster et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.


Outline

Text

Objectives: Mesenchymal stem cells (MSCs) and their chondrogenic differentiation have been extensively investigated in vitro as MSCs provide an attractive source besides chondrocytes for cartilage repair therapies. Here we established prototype foamyviral vectors (FVV) that are derived from apathogenic parent viruses and are characterized by a broad host range and a favourable integration pattern into the cellular genome. The protective effects of FVV expressing the human interleukin 1 receptor antagonist protein (IL1RA) were studied in an established in vitro model (aggregate culture system) of chondrogenesis in the presence of interleukin 1beta (IL1beta).

Methods: We generated different recombinant foamyviral vectors (FVVs) encoding enhanced green fluorescent protein (EGFP) or IL1RA and examined their transduction efficiencies and transgene expression profiles using different cell lines and human primary mesenchymal stem cells (MSCs) derived from bone marrow-aspirates. Transgene expression was evaluated by fluorescence microscopy (EGFP), flow cytometry (EGFP) and ELISA (IL1RA). For evaluation of the functionality of the IL1RA transgene to block the inhibitory effects of IL1beta on chondrogenesis of primary MSCs and an immortalized MSC cell line (TERT4 cells), the cells were maintained following transduction as aggregate cultures in standard chondrogenic media in the presence or absence of IL1beta. After three weeks of culture, pellets were harvested and analyzed by histology and immunohistochemistry for chondrogenic phenotypes.

Results and Conclusion: The different FVV efficiently transduced cell lines as well as primary MSCs, thereby reaching high transgene expression levels of around 100 ng/ml IL1RA. MSC aggregate cultures which were maintained in chondrogenic media without IL1beta supplementation revealed a chondrogenic phenotype by means of strong positive staining for collagen type II and matrix proteoglycan (Alcian blue). Addition of IL1beta was inhibitory to chondrogenesis in untreated control pellets. In contrast, foamyviral mediated IL1RA expression rescued the chondrogenesis in pellets cultured in the presence of IL1beta in a dose dependent fashion. Transduced MSC pellets reached thereby very high IL1RA transgene expression levels with a peak of 1087 ng/ml after day 7, followed by a decrease to 194 ng/ml after day 21, while IL1RA concentrations of controls were permanently below 200 pg/ml.

We conclude that our results indicate that FVV are capable of efficient gene transfer to MSCs, while reaching IL1RA transgene expression levels, that were able to efficiently block the impacts of IL1beta in vitro. FVV merit further investigation as a means to study the potential as a gene transfer tool for MSC based therapies for cartilage regeneration and protection.