Generation of myeloid-derived suppressor cells using prostaglandin E2.
Myeloid-derived suppressor cells (MDSCs) are natural immunosuppressive cells and endogenous inhibitors of the immune system. We describe a simple and clinically compatible method of generating large numbers of MDSCs using the cultures of peripheral blood-isolated monocytes supplemented with prostaglandin E2 (PGE2). We observed that PGE2 induces endogenous cyclooxygenase (COX)2 expression in cultured monocytes, blocking their differentiation into CD1a+ dendritic cells (DCs) and inducing the expression of indoleamine 2,3-dioxygenase 1, IL-4Rα, nitric oxide synthase 2 and IL-10 - typical MDSC-associated suppressive factors. The establishment of a positive feedback loop between PGE2 and COX2, the key regulator of PGE2 synthesis, is both necessary and sufficient to promote the development of CD1a+ DCs to CD14+CD33+CD34+ monocytic MDSCs in granulocyte macrophage colony stimulating factor/IL-4-supplemented monocyte cultures, their stability, production of multiple immunosuppressive mediators and cytotoxic T lymphocyte-suppressive function. In addition to PGE2, selective E-prostanoid receptor (EP)2- and EP4-agonists, but not EP3/1 agonists, also induce the MDSCs development, suggesting that other activators of the EP2/4- and EP2/4-driven signaling pathway (adenylate cyclase/cAMP/PKA/CREB) may be used to promote the development of suppressive cells. Our observations provide a simple method for generating large numbers of MDSCs for the immunotherapy of autoimmune diseases, chronic inflammatory disorders and transplant rejection.
Departments of Surgery, University of Pittsburgh, Hillman Cancer Center, Pittsburgh, PA, 15213, USA. kalinskip@upmc.edu.
Nataša
N
Obermajer
Pawel
P
Kalinski