Adipose stromal cells mediated switching of the pro-inflammatory profile of M1-like macrophages is facilitated by PGE2: in vitro evaluation.
OBJECTIVE
To define if adipose mesenchymal stromal cell (ASC) treatment mediated switching of the pro-inflammatory profile of M1-like macrophages as a means to develop a tailored in vitro efficacy/potency test.


DESIGN
We firstly performed immunohistochemical analysis of CD68, CD80 (M1-like) and CD206 (M2-like) macrophages in osteoarthritic (OA) synovial tissue. ASC were co-cultured in contact and in transwell with activated (GM-CSF + IFNγ)-M1 macrophages. We analyzed IL1β, TNFα, IL6, MIP1α/CCL3, S100A8, S100A9, IL10, CD163 and CD206 by qRT-PCR or immunoassays. Prostaglandin E2 (PGE2) blocking experiments were performed using PGE2 receptor antagonist.


RESULTS
In moderate grade OA synovium we did not always find a higher percentage of CD80 with respect to CD206. M1-like-activated macrophage factors IL1β, TNFα, IL6, MIP1α/CCL3, S100A8 and S100A9 were down-modulated both in contact and in transwell by ASC. However, in both systems ASC induced the typical M2-like macrophage markers IL10, CD163 and CD206. Activated-M1-like macrophages pre-treated with PGE2 receptor antagonist failed to decrease secretion of TNFα, IL6 and to increase that of IL10, CD163 and CD206 when co-cultured with ASC confirming a PGE2 specific role.


CONCLUSIONS
We demonstrated that ASC are responsible for the switching of activated-M1-like inflammatory macrophages to a M2-like phenotype, mainly through PGE2. This evidenced that activated-M1-like macrophages may represent a relevant cell model to test the efficacy/potency of ASC and suggests a specific role of ASC as important determinants in therapeutic dampening of synovial inflammation in OA.
['Manferdini|C|C|', 'Paolella|F|F|', 'Gabusi|E|E|', 'Gambari|L|L|', 'Piacentini|A|A|', 'Filardo|G|G|', 'Fleury-Cappellesso|S|S|', 'Barbero|A|A|', 'Murphy|M|M|', 'Lisignoli|G|G|']
D017667:Adipocytes D000328:Adult D015703:Antigens, CD D016022:Case-Control Studies D002454:Cell Differentiation D002465:Cell Movement D002478:Cells, Cultured D015232:Dinoprostone D005260:Female D006801:Humans D007963:Leukocytes, Mononuclear D008264:Macrophages D008297:Male D059630:Mesenchymal Stem Cells D008875:Middle Aged D010003:Osteoarthritis D010120:Oxytocics D050507:Subcutaneous Fat, Abdominal D013583:Synovial Membrane
Adipose mesenchymal stromal cells Inflammation Monocytes/macrophages Osteoarthritis Synovitis