1. Epithelial OPA1 links mitochondrial fusion to inflammatory bowel disease.
- Author
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Bao, Li-Li, Yu, Yu-Qiang, González-Acera, Miguel, Patankar, Jay V., Giessl, Andreas, Sturm, Gregor, Kühl, Anja A., Atreya, Raja, Erkert, Lena, Gámez-Belmonte, Reyes, Krug, Susanne M., Schmid, Benjamin, Tripal, Philipp, Chiriac, Mircea T., Hildner, Kai, Siegmund, Britta, Wirtz, Stefan, Stürzl, Michael, Mohamed Abdou, Mariam, and Trajanoski, Zlatko
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INFLAMMATORY bowel diseases ,MITOCHONDRIAL dynamics ,PATHOLOGICAL physiology ,GUANOSINE triphosphatase ,EPITHELIAL cells - Abstract
Dysregulation at the intestinal epithelial barrier is a driver of inflammatory bowel disease (IBD). However, the molecular mechanisms of barrier failure are not well understood. Here, we demonstrate dysregulated mitochondrial fusion in intestinal epithelial cells (IECs) of patients with IBD and show that impaired fusion is sufficient to drive chronic intestinal inflammation. We found reduced expression of mitochondrial fusion–related genes, such as the dynamin-related guanosine triphosphatase (GTPase) optic atrophy 1 (OPA1), and fragmented mitochondrial networks in crypt IECs of patients with IBD. Mice with Opa1 deficiency in the gut epithelium (Opa1
i∆IEC ) spontaneously developed chronic intestinal inflammation with mucosal ulcerations and immune cell infiltration. Intestinal inflammation in Opa1i∆IEC mice was driven by microbial translocation and associated with epithelial progenitor cell death and gut barrier dysfunction. Opa1-deficient epithelial cells and human organoids exposed to a pharmacological OPA1 inhibitor showed disruption of the mitochondrial network with mitochondrial fragmentation and changes in mitochondrial size, ultrastructure, and function, resembling changes observed in patient samples. Pharmacological inhibition of the GTPase dynamin-1–like protein in organoids derived from Opa1i∆IEC mice partially reverted this phenotype. Together, our data demonstrate a role for epithelial OPA1 in regulating intestinal immune homeostasis and epithelial barrier function. Our data provide a mechanistic explanation for the observed mitochondrial dysfunction in IBD and identify mitochondrial fusion as a potential therapeutic target in this disease. Editor's summary: Inflammatory bowel disease (IBD) is characterized by intestinal barrier dysfunction. How cellular energetics and mitochondria may influence barrier function is not fully understood. Bao et al. showed that intestinal epithelial cells from patients with IBD had decreased optic atrophy 1 (OPA1), a gene that promotes mitochondrial fusion. Opa1 was also decreased in a mouse model of IBD. Deletion of Opa1 in the mouse gut epithelium was sufficient to cause mitochondrial fragmentation and disease phenotypes. Human and mouse intestinal organoids confirmed that OPA1 was required for epithelial barrier functions. In OPA1-depleted organoids, inhibiting dynamin-related protein 1, an enzyme that promotes mitochondrial fission, reversed some pathological changes. Together, these results show that mitochondrial fission is a driver of IBD pathology and that targeting mitochondrial dynamics could be a strategy for therapeutic development. —Brandon Berry [ABSTRACT FROM AUTHOR]- Published
- 2025
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