In this study, we put efforts on addressing the interactions between probiotics and intestinal epithelial cells, the mechanism different from the conventionally dichotomous Th1/Th2 Erismodegib in vitro cytokine paradigm. Probiotics have no pharmacological actions confirmed, but numerous benefits have been proposed, such as immunomodulation [6, 7], antioxidant capacities [8], hepatoprotective effects [9], maintenance of commensal microflora [10], pathogen antagonization [11], anti-allergic effects [12, 13] and decreased endotoxin level in plasma [14]. Lactobacillus plantarum, one of the most commonly used probiotics, is a member of the aerotolerant group of lactobacilli found in

several fermented foods [15]. It is also one of the dominant Lactobacillus species in the hosts’ intestinal tract. Recent studies have shown that some strains of Lactobacillus plantarum attenuate inflammation induced by Shigella flexneri peptidoglycan by inhibiting nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), inactivating mitogen-activated protein kinase (MAPK), and reducing NOD2 mRNA expression as well as protein levels, the actions which in turn lead to a decrease in pro-inflammatory cytokine secretion [16]. Moreover, van Baarlen et al. [17, 18] demonstrated that even dead L. plantarum can exert beneficial functions NSC23766 clinical trial protecting the host against the FAK inhibitor enormous array of commensal bacteria in the gut via epithelial

crosstalk of mucosal interface microbiota. Their research team further investigated in vivo transcriptome responses

to probiotics, the work shaping that different probiotic strains induced differential gene-regulatory networks and pathways in the Ribonucleotide reductase human mucosa [19]. This provides advanced concept that not only live probiotics can exert beneficial effects, but also dead probiotics are able to modulate GI homeostasis. Second, because of strain-dependent properties, the anti-inflammation mechanism of single strains could not be extrapolated from other specific consequences without empirical evidence. Systemic exposure to endotoxins accompanied with elevation of interleukin (IL)-6, IL-8 and IL-12 has been recognized as representative features of IBD progression [20, 21]. Endotoxins are a family of molecules that bind to many pattern recognition receptors. One of the most dominant endotoxins is lipopolysaccharide (LPS). Previous exposure to LPS leads to cells hyporesponsive to subsequent challenge with LPS. This phenomenon is regarded as LPS tolerance. LPS tolerance is typically associated with poor signal transduction in TLR4-NFκB pathway. TLR4 recognizes LPS from Gram-negative bacteria. Myeloid differentiation primary response gene 88 (Myd88) acts as a universal adapter protein used by TLRs (except for TLR3). Interleukin-1 receptor-associated kinase 1 (IRAK1) belongs to the serine/threonine protein kinase family.