P087 Increased wnt ligands expression in M2c macrophages is associated with fibrosis in Stat6 knockout mice
Ortiz-Masia D.*1,2, Salvador P.3, Macias-Ceja D.C.4, Gisbert-Ferrándiz L.3, Hernandez C.4, Calatayud S.3, Esplugues J.V.3,4, Barrachina D.3
1Universidad de Valencia-CIBERehd, Pharmacology, Valencia, Spain 2Universidad de Valencia, Medicine, Valencia, Spain 3Universidad de Valencia, Pharmacology, Valencia, Spain 4FISABIO Hospital Peset, Pharmacology, Valencia, Spain
STAT6 plays a crucial role in M2a macrophage polarization
WT or STAT6(−/−) mice were given TNBs (0.5, 0.5, 0.75, 0.75, 1, and 1 mg, intrarectally) or saline weekly and they were sacrificed 3, 5 or 7 weeks after the first TNBs administration. The percentage of CD206, CD16, and CD86 positive cells was analyzed by flow cytometry in F4/80+ macrophages isolated from the intestinal mucosa. The mRNA expression of Wnt ligands was evaluated in F4/80+ CD16+ macrophages isolated from the mucosa, 7 weeks after the first TNBs administration and results are expressed as fold induction vs vehicle-treated mice. Data are expressed as mean ± SEM with n≥8 in all groups (*p<0.05).
TNBs increased the percentage of CD206 positive macrophages in the mucosa of TNBS-WT animals while it failed to do that in TNBS-STAT6(−/−) mice. The percentage of CD16 positive macrophages increased in a time-dependent manner only in the mucosa of STAT6(−/−)-TNBS-treated mice. The number of CD86+ cells was similar in TNBS-WT and TNBS-STAT6(−/−) mice.
In CD16+ macrophages isolated from TNBS-STAT6(−/−) mice the mRNA expression of canonical and non-canonical Wnt ligands was significantly increased compared with cells isolated from TNBS-WT mice.
Wnt ligand 2B 5A 6 7B 10A 10B 7-week WT 1.6±0.2 2.1± 0.5 1.2±0.1 2.7±0.6 3.3± 0.8 1.9±0.2 7-week STAT6(−/−) 1.9±0.4 6.4±0.6* 2.7±0.4* 15.3±2.2* 2.9±1.0 15.3±2.5*
An increased percentage of M2c macrophages which exhibited an increased expression of Wnt ligands is detected in the mucosa of TNBS-STAT6 knockout mice and it could mediate the increased fibrosis detected in these animals.
 Cosín-Roger J, Ortiz-Masiá D, Calatayud S, Hernández C, Esplugues JV, Barrachina MD., (2016), The activation of Wnt signaling by a STAT6-dependent macrophage phenotype promotes mucosal repair in murine IBD., Mucosal Immunol. 2016 Jul;9(4):986–98. doi: 10.1038/mi.2015.123.
 P. Salvador, (2016), STAT6 deficiency alters macrophage polarization and promotes fibrosis in a murine model of chronic inflammation. ECCO2016