NOD2 and inflammatory bowel disease: Of importance in IBD, VDR mediates enhanced production of antimicrobial peptides, such as β-defensin 2 (DEFB4/HBD2) and cathelicidin (CAMP) that are traditionally boosted by the activation of nucleotide-binding oligomerization domain-containing protein 2 (NOD2) after stimulation by microbial muramyl dipeptides [73].