DNA Damage-Regulated Autophagy Modulator 1 (DRAM1) Mediates Autophagy and Apoptosis of Intestinal Epithelial Cells in Inflammatory Bowel Disease.

BACKGROUND AND AIMS

DNA damage-regulated autophagy modulator 1 (DRAM1) is required for induction of autophagy and apoptosis. However, the influence of DRAM1 on the pathogenesis of inflammatory bowel disease (IBD) has not been explored.

METHODS

DRAM1 expression was examined in the intestinal mucosa of patients with IBD and colons of colitis mice. We used a recombinant adeno-associated virus carrying small hairpain DRAM1 to knock down the DRAM1 gene to treat colitis in the mice. The effect of DRAM1 on autophagy and apoptosis of intestinal epithelial cells was explored. DRAM1-mediated interaction with the c-Jun N-terminal kinase (JNK) pathway was also examined.

RESULTS

DRAM1 expression in the intestinal mucosa of the IBD patients was higher than that in the control participates. DRAM1 expression in the inflammatory cells in patients with Crohn's disease (CD) was lower than that in patients with ulcerative colitis (UC). Additionally, DRAM1 expression was correlated with the Simple Endoscopic Score for CD and the Mayo endoscopic score for UC. Serum levels of DRAM1 in the IBD group were substantially higher than those in the normal group. The knockdown of DRAM1 could alleviate colitis symptoms in mice. In in vitro experiments, knocking down DRAM1 could reduce autophagy and apoptosis levels. Mechanistically, DRAM1 may participate in the regulation of these two processes by positively regulating JNK activation.

CONCLUSIONS

During intestinal inflammation, the upregulation of DRAM1 may promote the activation of JNK and further aggravate intestinal epithelium damage.