Long noncoding RNA H19 disrupts the intestinal barrier by inhibiting Goblet cell function

다국어 초록 (Multilingual Abstract)

The intestinal mucosal barrier consists of multiple elements including mucus, epithelial layer, and immune defense; nonetheless, barrier dysfunction occurs commonly in various disorders. Goblet cells secrete mucin proteins that form surface mucus layer to act as the first physical defense in the barrier, but the exact mechanism underlying the control of Goblet cell function remains largely unknown. Long noncoding RNAs (lncRNAs) modulate a variety of biological functions by controlling gene expression at different levels. The lncRNA H19 is transcribed from the conserved imprinted H19/igf2 gene cluster and implicated in many aspects of gut mucosal pathophysiology. In this study, we examined if H19 regulates Goblet cell function and further investigated its impact in intestinal barrier function.
Intestinal mucosal tissues were collected from H19‐deficient (H19−/−) and control littermate mice. The function of Goblet cells was examined by alcian blue staining and mucin 2 immunohistochemical staining assays. Septic stress was induced by cecal ligation and puncture (CLP), and gut permeability was detected by tracer FITC‐dextran assays. Intestinal organoids were isolated from H19−/− and littermate mice and treated with lipopolysaccharide (LPS).
H19 deletion in mice promoted Goblet cell function in vivo and ex vivo, as evidenced by increases in the numbers of alcian blue‐positive cells in the intestinal mucosa of H19−/− mice and mucin 2‐positive cells in the H19‐deficient intestinal organoids isolated from H19−/− mice, compared with those in control littermate mice. In contrast, ectopically expressed H19 prevented the increased numbers of Goblet cells in the H19‐deficient organoids from H19−/− mice, although it had only a minor inhibition on Goblet cells in the organoids from littermate mice. H19 knockout also elevated the levels of autophagy proteins LC3‐II, lysozyme and beclin in the intestinal epithelium. H19 deletion in mice protected the intestinal barrier function in response to septic stress by protecting Goblet cells. Exposure to CLP reduced the numbers of Goblet cells in littermate mice, but H19 deletion significantly prevented the CLP‐elicited loss of Goblet cells. H19−/− mice also displayed much minor increase in gut permeability than that observed in control littermates after CLP. In the ex vivo model, treatment with LPS suppressed the formation of Goblet cells as shown by a dramatic decrease in the number of mucin 2‐positive cells in intestinal organoids generated from control littermate mice, but this inhibition was alleviated in the organoids from H19−/− mice.
These results indicate that 1) H19 deletion in mice enhances Goblet cell function in the intestinal mucosa; and 2) preventing the rise in H19 protects Goblet cells from septic stress. These results suggest that induced H19 disrupts intestinal mucosal barrier by inhibiting Goblet cell function.
US Department of Veterans Affairs (JNR, J‐Y.W) and NIH (J‐Y.W)