Fig. 2
Direct stimulation of canine ASCs and PMSCs leads to production of IDO and PGE2. Canine adipose-derived MSCs (ASCs) and placenta-derived MSCs (PMSCs) secrete increased levels of indoleamine 2,3 dioxygenase (IDO) activity and prostaglandin E2 (PGE2) in response to direct stimulation using recombinant interferon gamma (IFNγ) and tumor necrosis factor alpha (TNFα). a IDO activity is directly proportional to the conversion of tryptophan to N-formyl kynurenine. ASCs and PMSCs increase IDO activity in response to dual stimulation with IFNγ and TNFα. IFNγ is the main contributor to the production of IDO. IFNγ- and TNFα-stimulated ASCs promote significantly higher levels of IDO activity as compared to PMSCs. b Canine ASCs and PMSCs produce comparable levels of prostaglandin E2 (PGE2) in response to dual stimulation with IFNγ and TNFα. TNFα is the major contributor to MSC-mediated PGE2 production. Data presented as mean and standard error. *p < 0.05, **p < 0.01, ***p < 0.001. IDO, indoleamine 2,3 dioxygenase; IFNγ, interferon gamma; MSC, mesenchymal stem cell; PGE2, prostaglandin E2; TNFα, tumor necrosis factor alpha