gms | German Medical Science

German Congress of Orthopedic and Trauma Surgery (DKOU 2017)

24.10. - 27.10.2017, Berlin

NADPH-oxidase 4 might represent a pivotal molecular target in improving the osteogenic differentiation potential of regular as well as osteogenically dysfunctional human bone marrow mesenchymal stem cells

Meeting Abstract

  • presenting/speaker Dana-Chantal Strangmann - Unfall- und Handchirurgie, Düsseldorf, Germany
  • Christoph V. Suschek - Unfall- und Handchirurgie, Düsseldorf, Germany
  • Joachim Windolf - Universitätsklinikum Düsseldorf, Klinik für Unfall- und Handchirurgie, Düsseldorf, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2017). Berlin, 24.-27.10.2017. Düsseldorf: German Medical Science GMS Publishing House; 2017. DocGR18-1224

doi: 10.3205/17dkou528, urn:nbn:de:0183-17dkou5285

Published: October 23, 2017

© 2017 Strangmann 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 as a treatment for bone defects are becoming increasingly important in the regenerative medicine. Therefore, multipotent stem cells of the bone marrow are gaining increasing importance. The potential autologous retransplantation of these cells is advantageous due to reduced risk of rejection.

The reduced osteogenic differentiation potential of some donor cells is challenging. Regarding osteogenic differentiation, oxidative stress which is mediated by reactive oxygen species (ROS) might exert inhibiting effects at elevated concentrations and promoting effects at physiological concentrations. In this context, the ROS-generating NADPH-oxidase 4 (NOX4) plays an essential role. In the present work we have examined hBMSC cultures which have lost their osteogenic differentiation potential (non-responder cells; NR-hBMSCs) as well as responder cells which showed a regular differentiation potential (R-hBMSCs). We assessed the impact of pro- and anti-oxidative approaches on their osteogenic differentiation potential with particular regard to the NOX4, catalase, superoxide dismutase (SOD) as well as the transcription factor FOXO1.

Methods: We received human adult BMSCs from our cooperation partners of the medical school Hannover. Plastic adherence, antigen-phentotype-characterization, and the differentiation potential proved the mesenchymal stem cell identity. Dexamethasone (500nM), ascorbate (50µM), and beta-glycerophosphate (10 mM) were added to induce the osteogenic differentiation (OD). The hBMSCs were treated with H2O2-concentrations from 0 µM - 100 µM. The osteogenic differentiation (OD) was evaluated by the detection and quantification of calcified matrix, alkaline phosphatase-expression and the expression of osteoblast-specific proteins. We used catalase (125U and 250U) as antioxidant. The expression of redox-relevant proteins (catalase, SOD, NOX4, FOXO1) was quantified by Western blot analysis.

Results and Conclusion: Exogenous addition of catalase (125U and 250U) nearly completely restored the missing osteogenic differentiation potential of NR-BMSC cultures, as showed by significantly an enhanced formation of calcified matrix. This catalase-restored potential for osteogenic differentiation strongly correlated with the cellular decrease in NOX4, RUNX2, and catalase protein expression, as compared to untreated cultures. In contrast, catalase induced a strongly elevated expression of Mn-SOD as well as a strong increase in the Mn-SOD/NOX4 expression-ratio. Interestingly, the FOXO1/Mn-SOD-ratio also was highly increased which underlined the role of FOXO1 as a pivotal regulator of osteogenic differentiation.

In summary, our results give new important hints on the interaction of catalase, NOX4, Mn-SOD, and FOXO1 in a yet not fully understood osteogenesis-relevant redox-network which might represent a pivotal molecular target to bridge over impaired osteogenic potential of mesenchymal stem cells.