NOS2 and inflammatory bowel disease: Additionally, doxycycline has been shown to modulate multiple molecular targets relevant to IBD pathogenesis, including Th1/Th17 cytokines (IL-12, IL-1β, IL-17, TNF-α), cell adhesion molecules (ICAM-1), barrier integrity proteins (MUC-1, MUC-3), and enzymes such as MMPs and iNOS [21].