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42. Kongress der Deutschen Gesellschaft für Rheumatologie, 28. Jahrestagung der Deutschen Gesellschaft für Orthopädische Rheumatologie, 24. Wissenschaftliche Jahrestagung der Gesellschaft für Kinder- und Jugendrheumatologie

17.-20. September 2014, Düsseldorf

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Do Human Mesenchymal Stromal Cells express Cytotoxic T-Lymphocyte Antigen-4?

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  • Kerstin Schönbeck - Deutsches Rheuma-Forschungszentrum (DRFZ), AG Buttgereit, Berlin
  • Cindy Strehl - Charité - Universitätsmedizin Berlin, Medizinische Klinik mit Schwerpunkt Rheumatologie und klinische Immunologie, Berlin
  • Timo Gaber - Charité - Universitätsmedizin Berlin, Medizinische Klinik mit Schwerpunkt Rheumatologie und klinische Immunologie, Berlin
  • Cam Loan Tran - Charité - Universitätsmedizin Berlin, Medizinische Klinik mit Schwerpunkt Rheumatologie und klinische Immunologie, Berlin
  • Manuela Jakstadt - Charité - Universitätsmedizin Berlin, Medizinische Klinik mit Schwerpunkt Rheumatologie und klinische Immunologie, Berlin
  • Eric Röhner - Charité - Universitätsmedizin Berlin, Centrum für Muskuloskeletale Chirurgie, Berlin
  • Frank Buttgereit - Charité - Universitätsmedizin Berlin, Medizinische Klinik mit Schwerpunkt Rheumatologie und klinische Immunologie, Berlin
  • Gerd-Rüdiger Burmester - Charité - Universitätsmedizin Berlin, Medizinische Klinik mit Schwerpunkt Rheumatologie und klinische Immunologie, Berlin
  • Paula Hoff - Charité - Universitätsmedizin Berlin, Medizinische Klinik mit Schwerpunkt Rheumatologie und klinische Immunologie, Berlin

Deutsche Gesellschaft für Rheumatologie. Deutsche Gesellschaft für Orthopädische Rheumatologie. Gesellschaft für Kinder- und Jugendrheumatologie. 42. Kongress der Deutschen Gesellschaft für Rheumatologie (DGRh); 28. Jahrestagung der Deutschen Gesellschaft für Orthopädische Rheumatologie (DGORh); 24. wissenschaftliche Jahrestagung der Gesellschaft für Kinder- und Jugendrheumatologie (GKJR). Düsseldorf, 17.-20.09.2014. Düsseldorf: German Medical Science GMS Publishing House; 2014. DocOS.01

doi: 10.3205/14dgrh119, urn:nbn:de:0183-14dgrh1196

Published: September 12, 2014

© 2014 Schönbeck et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Background: Human mesenchymal stromal cells (hMSC) are capable of multi-lineage differentiation, thereby facilitating tissue regeneration. This often needs to happen under pathophysiological hypoxia. hMSC also possess immunomodulatory characteristics, but their interaction with immune cells is largely unknown.

The Cytotoxic T-Lymphocyte Antigen-4 (CTLA-4) is an inhibitory costimulatory molecule which plays a crucial role in conveying immune tolerance by adjusting the threshold of T cell activation. Abnormal CTLA-4 expression and/or function is thought to be involved in the pathophysiology of autoimmune disorders such as type 1 diabetes, SLE and rheumatoid arthritis.

Aim of this work was to analyze hMSC with regard to their expression and potential function of CTLA-4 under normoxic versus hypoxic conditions.

Methods: hMSC were isolated from femoral bone marrow. Isolation of human peripheral blood mononuclear cells (PBMC) from venous blood was followed by stimulation with PHA (5µg/ml) for 48h. Human MSC were characterized via flow cytometry and differentiation potential. After culturing the hMSC under normoxic (~18% O2) and hypoxic (<1.5% O2) conditions, respectively, the protein expression of CTLA-4 was analyzed by immunoblotting, immunoassay and flow cytometry whereas mRNA expression level was detected by qRT-PCR.

Results: Human MSC were characterized via (i) plastic adherence, (ii) surface marker expression (positive markers: CD13, CD44, CD90, CD105; negative markers: CD14, CD19, CD34, CD45) and (iii) assessing their osteogenic and adipogenic differentiation potential. The extra- and intracellular analysis of CTLA-4 expression in mitogen stimulated human PBMC demonstrated a CTLA-4 positive population of about 10%. CTLA-4 staining of hMSC revealed a significantly positive shift (p=0.027), confirmed by western blot analyses. Human MSC showed a significantly higher mRNA level of CTLA-4 when cultured under normoxia as compared to hypoxia. However, CTLA-4 protein expression did not alter under different oxygen availabilities.

Altogether, hMSC indeed express CTLA 4. Hypoxia has no measurable effect on CTLA-4 expression of hMSC, merely the mRNA level decreased.

Conclusion: We clearly demonstrated for the first time the existence of CTLA-4 on hMSC. We assume the expression of CTLA-4 to contribute to the immunomodulatory capacity of hMSC. These hypotheses will be proven in further studies.