Open Access

ARTICLE

Low O₂ concentrations enhance the positive effect of IL-17 on the maintenance of erythroid progenitors during co-culture of CD34+ and mesenchymal stem cells

Aleksandra Krstić¹, Marija Vlaski^2,3, Mohammad Hammoud², Jean Chevaleyre², Pascale Duchez², Gordana Jovčić¹, Diana Bugarski¹, Pavle Milenković¹, Philippe Bourin⁴, Jean-Michel Boiron^2,3, Vincent Praloran^3,5, Zoran Ivanović²

1 Institute for Medical Research, Belgrade University, Belgrade, Serbia
2 French Blood Institute, Aquitaine-Limousin Branch, 5, place Amélie Raba Léon, BP 24, 33035 Bordeaux Cedex, France
3 Victor-Ségalen University (Bordeaux 2), Bordeaux, France
4 French Blood Institute, Pyrénées-Méditerranée Branch, Toulouse, France
5 CNRS UMR 5164

* Corresponding Author: Z. Ivanovic,

European Cytokine Network 2009, 20(1), 10-16. https://doi.org/10.1684/ecn.2009.0145

Accepted 16 January 2009;

Abstract

Co-culture of haematopoietic cells with a stromal cell layer does not mimic the physiological, micro-environmental niche, whose major feature is a low oxygen (O₂) concentration. Thus, in order to study the effects of IL-17 in a context which better approximates the physiological state, we investigated its effects on cell expansion, colony-forming ability, and the phenotypical profile of normal, human blood CD34⁺ cells co-cultured for five days with MSC layers at various O₂ concentrations (20%, 12.5% and 3% O₂). We demon-strated that IL-17 enhances CD34⁺ and total CFC production during the five days of MSC/CD34⁺ co-culture. This effect depends upon the O₂ concentration, reaching its maximum at 3% O₂, and is more pronounced on erythroid progenitors (BFU-E). In addition, the stimulation of IL-6 production by IL-17 in MSC cultures and co-cultures is enhanced by low O₂ concentration. The expression of some differentiation markers (CD34, CD13 and CD41) on haematopoietic cells in co-cultures also depends upon the oxygen concentration. Our results strengthen the concept that physiological levels of O₂ (mistakenly called hypoxia), should be considered as an important environmental factor that significantly influences cytokine activity.

---

Keywords

---