Live and heat-treated probiotics differently modulate IL10 mRNA stabilization and microRNA expression

In inflammatory diseases and healthy animals, studies have shown a probiotic-induced IL-10 overproduction1 or an increase in regulatory FoxP3+ cell number.2 Interestingly, in vivo and in vitro studies have convincingly demonstrated differential activities of live and heat-treated organisms.3 Yet, little is known about the molecular mechanism involved in this modulation of IL10 mRNA expression. There are several AU-rich elements in the 3' untranslated region (UTR) of IL10 mRNA that have been shown to regulate IL10 gene expression level.4 PBMCs, transfected with a plasmid containing the IL10-3'UTR downstream of the luciferase (Luc) gene (Luc/IL10-3'UTR) and stimulated by heat-treated L paracasei NCC 2461 produced a significantly higher level of luciferase activity (3.6 ± 0.6 vs 0.6 ± 0.11; P < .05) than did transfected unstimulated cells (Fig 2, A), suggesting a role for IL10-3'UTR in heat-treated L paracasei NCC 2461-induced IL10 mRNA stabilization.