TNF and inflammatory bowel disease: Microbial immunomodulators such as peptidoglycan fragments (GlcNAc-MurNAc) activate NF-κB signaling through TLR2/NOD pathways (92), thereby inducing the production of key pro-inflammatory cytokines including IL-1β and TNF-α—a mechanism well-characterized in inflammatory bowel disease (IBD) and type 2 diabetes (93).