Circular RNA Cdr1as inhibits proliferation and delays injury-induced regeneration of the intestinal epithelium
Hee Kyoung Chung, Lan Xiao, Naomi Han, Jason Chen, Vivian Yao, Cassandra M. Cairns, Benjamin Raufman, Jaladanki N. Rao, Douglas J. Turner, Rosemary Kozar, Myriam Gorospe, Jian-Ying Wang
Hee Kyoung Chung, Lan Xiao, Naomi Han, Jason Chen, Vivian Yao, Cassandra M. Cairns, Benjamin Raufman, Jaladanki N. Rao, Douglas J. Turner, Rosemary Kozar, Myriam Gorospe, Jian-Ying Wang
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Research Article Gastroenterology

Circular RNA Cdr1as inhibits proliferation and delays injury-induced regeneration of the intestinal epithelium

Abstract

Circular RNAs (circRNAs) are highly expressed in the mammalian intestinal epithelium, but their functions remain largely unknown. Here, we identified the circRNA Cdr1as as a repressor of intestinal epithelial regeneration and defense. Cdr1as levels increased in mouse intestinal mucosa after colitis and septic stress, as well as in human intestinal mucosa from patients with inflammatory bowel disease and sepsis. Ablation of the Cdr1as locus from the mouse genome enhanced renewal of the intestinal mucosa, promoted injury-induced epithelial regeneration, and protected the mucosa against colitis. We found approximately 40 microRNAs, including miR-195, differentially expressed between intestinal mucosa of Cdr1as-knockout (Cdr1as–/–) versus littermate mice. Increasing the levels of Cdr1as inhibited intestinal epithelial repair after wounding in cultured cells and repressed growth of intestinal organoids cultured ex vivo, but this inhibition was abolished by miR-195 silencing. The reduction in miR-195 levels in the Cdr1as–/– intestinal epithelium was the result of reduced stability and processing of the precursor miR-195. These findings indicate that Cdr1as reduces proliferation and repair of the intestinal epithelium at least in part via interaction with miR-195 and highlight a role for induced Cdr1as in the pathogenesis of unhealed wounds and disrupted renewal of the intestinal mucosa.

Authors

Hee Kyoung Chung, Lan Xiao, Naomi Han, Jason Chen, Vivian Yao, Cassandra M. Cairns, Benjamin Raufman, Jaladanki N. Rao, Douglas J. Turner, Rosemary Kozar, Myriam Gorospe, Jian-Ying Wang

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Figure 8

Cdr1as regulates miRNA biogenesis and stabilizes pre-miR-195 transcripts.

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Cdr1as regulates miRNA biogenesis and stabilizes pre-miR-195 transcript...
(A) Levels of mucosal primary (pri-) miR-195 in the small intestine of littermate and Cdr1as–/– mice. Values are the mean ± SEM (n = 5). *P < 0.05 compared with littermates. (B) Levels of mucosal precursor (pre-) miR-195, pre-miR-7, and pre-miR-29b in the small intestine. *P <0.05 compared with littermates (n = 5). (C) Immunoblots of Drosha and Dicer complex proteins in the small intestinal mucosa of littermate and Cdr1as–/– mice. Equal loading was monitored by HSC70. (D) Stability of pre-miR-195 and pre-miR-29b after Cdr1as overexpression. Caco-2 cells were infected with Lenti-Cdr1as or Lenti-Con, and actinomycin D was added to the medium 72 hours after the infection. Levels of pre-miR-195 and pre-miR-29b were examined at different times thereafter. Three separate experiments were performed and showed similar results. In A and B, statistical significance was analyzed using unpaired, 2-tailed Student’s t tests. In D, statistical comparison between time-course curves was by 2-way ANOVA with Bonferroni’s post hoc test.