IL1B and colitis: In addition, Shi et al. found that defensin-deficient (Mmp7−/−) mice produce more IL-1β in the colon and cecum and are more susceptible to DSS-induced colitis.171 Exogenous supplementation with mature α-defensins, rather than precursor α-defensins or β-defensins, inhibit IL-1β secretion following activation of inflammatory NLRP3 inflammasomes in human and mouse macrophages171,172 (Fig. 4b).