Long noncoding RNA<i>uc.173</i>regulates mitochondrial metabolism essential for Paneth cell function and intestinal mucosal renewal

The intestinal epithelium self-renews rapidly and functions as a physical barrier between luminal microbiota and body. We have reported that long noncoding RNA uc.173 promotes intestinal mucosal growth, but the underlying mechanism remains unknown. Mitochondria are bioenergetic factories and also coordinate signaling networks, and mitochondrial integrity is essential for maintaining the intestinal epithelium homeostasis. In this study, we examined the role of uc.173 in the regulation of mitochondrial metabolism and further determined if altered mitochondrial activity by uc.173 affects function of Paneth cell (PC)/stem cell niche. Methods: Tissue-specificCRISPR-Cas9 knock-in (IE-Cas9) mice were used to delete uc.173 in the intestinal epithelium by overexpressing small guide RNA targeting uc.173 (sgRNA-uc173). Intestinal organoids derived from the intestinal crypt were used as an ex vivo model, while Caco-2 cells were used for in vitro study. Mitochondrial metabolism was measured by seahorse analysis. PCs were examined by immunostaining assay using lysozyme. Results: IE-Cas9 mice infected with lentiviral vector carrying sgRNA-uc173 for two weeks exhibited decreased uc.173 specifically in the small intestinal mucosa without effect on its content in other tissues. This transient deletion of uc.173 decreased the levels of mucosal mitochondrial proteins including prohibitin 1 (PHB1), PHB2, VDAC, cyto-C, and PDHG. uc.173-deficient mice also displayed reduced PCs, along with an inhibition of small intestinal mucosal growth. In primarily cultured organoids, decreasing the levels of uc.173 by transfection with anti-uc.173 antimeres also caused PC defects, which was associated with decreased levels of PC-derived niche signals Wnt3 and Notch2, inactivation of stem cells (marked by LGR5), and subsequent inhibition of DNA synthesis and organoid growth. In cultured Caco-2 cells, uc.173 silencing not only decreased mitochondrial proteins but also impaired mitochondrial function, as shown by decreases in both mitochondrial respiration and MitoTracker green and an increase in superoxide production. Conclusions: These results indicate that uc.173 is required for activating the mitochondrial metabolism, in turn inducing intestinal mucosal renewal. R01DK68491; R01DK 61972; R01Dk057819;R01AG084613 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.