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Published on: June 2, 2023
Alpha-Defensin 5 Expression is Regulated by microRNAs in the Caco-2 Intestinal Epithelial Cell Line
Donald R B Miles1, Jun Shen2, Alice Y Chuang2
1Johns Hopkins School of Medicine, USA.
Background:
In inflammatory bowel disease (IBD), an inappropriate immune response leads to chronic mucosal inflammation. This response may be partly due to dysregulation of defensins, which are endogenously produced antimicrobial peptides. This study determined whether microRNAs (miRNAs) regulate α-defensin 5 (DEFA5), which could further implicate both in IBD pathogenesis.
Methods:
Induction of DEFA5 mRNA and protein expression was determined in Caco-2 cells. An in silico analysis identified putative miRNA binding sites of DEFA5. Expression of these miRNAs was assessed in Caco-2 cells. Regulation of DEFA5 expression by these miRNAs was measured by luciferase assays. Caco-2 cells were transfected with miR-124 and miR-924 mimics, and DEFA5 mRNA and protein expression was measured.
Results:
DEFA5 mRNA and protein expression was inducible in Caco-2 cells. Fifteen putative miRNA binding sites were found in DEFA5. The expression of miR-124 and miR-924 decreased following induction. Transfection of a luciferase construct containing the DEFA5 miRNA binding sites resulted in a decrease in luciferase activity compared to transfection of the empty vector. Transfection of a reporter construct containing mismatched miRNA binding sites resulted in restoration of luciferase activities. Transfection of miRNA mimics decreased DEFA5 mRNA expression and protein expression.
Conclusions:
miR-124 and miR-924 negatively regulate DEFA5 mRNA and protein expression. These data implicate miRNAs in intestinal innate immune regulation and IBD pathogenesis.
Insights
MicroRNAs (miRNAs) like miR-124 and miR-924 regulate alpha-defensin 5 (DEFA5) expression. This finding suggests miRNAs play a role in inflammatory bowel disease (IBD) pathogenesis.
Area of Science:
- Molecular Biology
- Immunology
- Gastroenterology
Background:
- Inflammatory bowel disease (IBD) involves chronic mucosal inflammation due to inappropriate immune responses.
- Dysregulation of antimicrobial peptides like defensins may contribute to IBD.
- Alpha-defensin 5 (DEFA5) is an antimicrobial peptide implicated in IBD.
Purpose of the Study:
- To investigate the role of microRNAs (miRNAs) in regulating DEFA5 expression.
- To determine if miRNAs contribute to the pathogenesis of IBD.
Main Methods:
- DEFA5 mRNA and protein expression was induced and measured in Caco-2 cells.
- Bioinformatic analysis identified potential miRNA binding sites on DEFA5.
- Luciferase assays and miRNA mimic transfections were used to assess miRNA regulation of DEFA5.
Main Results:
- DEFA5 expression was inducible in Caco-2 cells.
- miR-124 and miR-924 were found to bind to DEFA5.
- Transfection with miR-124 and miR-924 mimics reduced DEFA5 mRNA and protein levels.
Conclusions:
- miR-124 and miR-924 negatively regulate DEFA5 expression.
- These miRNAs are implicated in the innate immune regulation of the intestine.
- The findings suggest a role for miRNAs in the pathogenesis of IBD.
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