Yin-Ping Li 1,2 *, Sophie Paczesny 3,4 *, Evelyne Lauret 5, Sonia Poirault 5, Pierre Bordigoni 3, Jing-Ping Ou-Yang 2, Jean-Francois Stoltz 1, Assia Eljaafari 1
- These 2 authors contributed equally to this work
1 Laboratory of Mechanobiology and Engineering of Cells and Tissues, CNRS UMR 7563, Faculty of Medicine, Nancy and Unit of Cellular and Tissue Therapy CHU Nancy, 54511 Nancy, France
2 Department of pathology and pathophysiology, Wuhan University, China
3 Hematology Department, Children Hospital, CHU Nancy, 54511 Nancy, France
4 Department of Internal Medicine, University of Michigan Cancer Center, Ann Arbor, MI,48105, USA.
5 INSERM U362 - Institute Gustave Roussy, 94805 Villejuif, France
The influence of bone marrow stroma on dendritic cells (DC) is mostly unknown. Mesenchymal stem cells (MSC), which are part of the bone marrow stroma, have been shown to inhibit interstitial DC differentiation from monocytes and umbilical CD34+ hematopoietic stem cells (HSC), without affecting Langerhans cells. Here, we show that MSC halt both interstitial DC and Langerhans cell differentiation from adult CD34+HSC, as assessed by the decreased expression of CD1a, CD14, CD86, CD80 and CD83 antigens on their cell surface. Accordingly, the functional capacity of these adult CD34-DC to stimulate alloreactive T cells was impaired, as well as IFN-gamma secretion and expression of activation markers in alloreactive T cells. Furthermore, we showed that (i) MSC inhibited commitment of CD34+HSC into immature DC, but not maturation of CD34-DC (ii) this inhibitory effect was reversible and (iii) T cell unresponsiveness mediated by MSC-DC was related to T cell anergy and generation of IL-10-producing T cells. This inhibition was mediated by cell-to-cell contact and secretion of soluble factors. Finally, IL-10, but not IL-12 mRNA levels were markedly upregulated in MSC-DC. In conclusion, our data suggest that MSC may drive both adult interstitial DC and Langerhans cell precursors to differentiate into regulatory IL-10+DC.