Human Amniotic Membrane Mesenchymal Stem Cell-Synthesized PGE2 Exerts an Immunomodulatory Effect on Neutrophil Extracellular Trap in a PAD-4-Dependent Pathway through EP2 and EP4

Abstract

Human amniotic membrane mesenchymal stem cells (hAM-MSC) secrete a myriad of components with immunosuppressive activities. In the present research, we aimed to describe the effect of prostaglandin E2 (PGE2) secreted by hAM-MSCs on neutrophil extracellular trap (NET) release and to characterize the role of its receptors (EP2/EP4) in PAD-4 and NFkB activity in neutrophils. Human peripheral blood neutrophils were ionomycin-stimulated in the presence of hAM-MSC conditioned medium (CM) treated or not with the selective PGE2 inhibitor MF-63, PGE2, EP2/EP4 agonists, and the selective PAD-4 inhibitor GSK-484. NET release, PAD-4, and NFkB activation were analyzed. Ionomycin induced NET release, which was inhibited in the presence of hAM-MSC-CM, while CM from hAM-MSCs treated with MF-63 prevented NET release inhibition. PGE2 and EP2/EP4 agonists, and GSK-484 inhibited NET release. EP2/EP4 agonists and GSK-484 inhibited H3-citrullination but did not affect PAD-4 protein expression. Finally, PGE2 and EP2/EP4 agonists and GSK-484 increased NFkB phosphorylation. Taken together, these results suggest that hAM-MSC exert their immunomodulatory activities through PGE2, inhibiting NET release in a PAD-4-dependent pathway. This research proposes a new mechanism by which hAM-MSC exert their activities when modulating the innate immune response and inhibiting NET release.

Comparison of Cost and Potency of Human Mesenchymal Stromal Cell Conditioned Medium Derived from 2- and 3-Dimensional Cultures

“…This suggests that reducing volume is not enough to increase the potency of conditioned medium. PGE2 production was chosen since it has been described as a key molecule of the immune-modulatory effect of MSCs and MSC-CM, [ 50 , 51 ]. The concentration of PGE2 and production per cell were not significantly different among treatments, and 3D microcarrier-based spinner flask dynamic cultured cells produced higher amounts of total protein.…”

Immunomodulatory Mechanism and Potential Application of Dental Pulp-Derived Stem Cells in Immune-Mediated Diseases

“…PGE2 is one of the major effectors of MSC-mediated immunosuppression [70]. PGE2 is a catabolite of arachidonic acid, and during inflammation, PGE2 is thought to act as an antiinflammatory agent, modulating the inflammatory response and helping to restore tissue homeostasis [71]. PGE2 is an important regulatory molecule that normally synergizes with other immunomodulatory factors such as inducible nitric oxide synthase (iNOS) or IDO to inhibit the proliferation of immune cells and the production of inflammatory factors [72].…”