IL1B and renal fibrosis: To address the mechanisms by which Chop deficiency attenuates UUO-induced renal fibrosis, we next assessed IL-1β expression, a cytokine transcribed by NFκB, which is essential for the initiation of renal fibrosis.7 In consistent with the attenuated NFκB transcriptional activity, Chop−/− mice were featured by a 2.6-fold reduction of pro-IL1β expression in the kidneys following UUO induction (Figure 8a).