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The generation of a tissue-specific intestinal hydrogel derived from the native intestine has the potential to support and promote the growth of intestinal organoids. In this study, we aimed to develop hydrogels derived exclusively from intestinal extracellular matrix (ECM) or composites comprised of intestinal ECM combined with alginate that allow for greater tuning of the hydrogel properties. A novel mouse intestinal decellularization protocol was developed and the ECM characterized. Our analyses demonstrate that our protocol effectively removed cellular and nuclear content while preserving key ECM components including collagens, glycosaminoglycans, fibronectin and laminin. When the decellularized small intestine (DSI) was used to generate hydrogels, the resulting ECM showed bioactivity as demonstrated by metabolic and pro-proliferative effects on NIH 3T3 murine fibroblasts. Importantly, our novel DSI hydrogels also supported murine intestinal and colonic organoid growth similar to Matrigel® controls. These studies demonstrate that murine tissue-specific DSI hydrogels can provide a supportive environment for the culture of intestinal and colonic organoids in vitro .

Esophageal adenocarcinoma has few known recurrent mutations and therefore robust, reliable and reproducible patient-specific models are needed for personalized treatment. Patient-derived organoid culture is a strategy that may allow for the personalized study of esophageal adenocarcinoma and the development of personalized induction therapy. We therefore developed a protocol to establish EAC organoids from endoscopic biopsies of naïve esophageal adenocarcinomas. Histologic characterization and molecular characterization of organoids by whole exome sequencing demonstrated recapitulation of the tumors’ histology and genomic (~ 60% SNV overlap) characteristics. Drug testing using clinically appropriate chemotherapeutics and targeted therapeutics showed an overlap between the patient’s tumor response and the corresponding organoids’ response. Furthermore, we identified Barrett’s esophagus epithelium as a potential source of organoid culture contamination. In conclusion, organoids can be robustly cultured from endoscopic biopsies of esophageal adenocarcinoma and recapitulate the originating tumor. This model demonstrates promise as a tool to better personalize therapy for esophageal adenocarcinoma patients.

Transposable elements (TEs) comprising nearly 50% of the genome are generally silenced by epigenetic mechanisms. Epigenetic anti-cancer drugs can lead to their re-expression, however, the role of TEs in tumorigenesis is unknown. Here, we demonstrate that TEs and their activation of a viral mimicry response plays an important tumor suppressive role in inflammation. We discovered that both patients and mice with colitis express TEs that lead to a viral mimicry response. Interestingly, this response inhibits stemness of cancer-initiating cells. Further activation of viral mimicry by DNA hypomethylation inhibits tumorigenesis. Conversely, knockout of the anti-viral signaling protein MAVS promotes tumorigenesis and reverses the anti-tumor effect of DNA hypomethylation, confirming a tumor suppressive role of viral mimicry. Consistent with this finding, patients with colitis-associated dysplasia show decreased expression of TEs and interferon-related genes. These findings suggest that activation of viral mimicry inhibits stemness and plays a key tumor suppressive role in inflammation. The role of normally silenced transposable elements (TEs) in tumorigenesis remains unclear. Here, the authors show that increased expression of TEs in both patients and mice with colitis or by DNA hypomethylating drugs elicits a viral mimicry response that suppresses tumorigenesis. This viral mimicry response inhibits the stemness of cancer initiating cells in a cell autonomous manner.

Cystic fibrosis (CF) is a fatal recessive genetic disorder caused by a mutation in the gene encoding CF transmembrane conductance regulator (CFTR) protein. Alteration in CFTR leads to thick airway mucus and bacterial infection. Cell therapy has been proposed for CFTR restoration, but efficacy has been limited by low engraftment levels. In our previous studies, we have shown that using a pre-conditioning regimen in combination with optimization of cell number and time of delivery, we could obtain greater bone marrow cell (BMC) retention in the lung. Here, we found that optimized delivery of wild-type (WT) BMC contributed to apical CFTR expression in airway epithelium and restoration of select ceramide species and fatty acids in CFTR−/− mice. Importantly, WT BMC delivery delayed Pseudomonas aeruginosa lung infection and increased survival of CFTR−/− recipients. Only WT BMCs had a beneficial effect beyond 6 months, suggesting a dual mechanism of BMC benefit: a non-specific effect early after cell delivery, possibly due to the recruitment of macrophages and neutrophils, and a late beneficial effect dependent on long-term CFTR expression. Taken together, our results suggest that BMC can improve overall lung function and may have potential therapeutic benefit for the treatment of CF. Cell and gene therapies are commonly used to treat various conditions and improve a patient’s daily life. In this issue of Molecular Therapy, Duchesneau et al. propose a method for lung epithelial replacement leading to wild-type CFTR expression and improved overall lung function.

The generation of a tissue-specific intestinal hydrogel derived from the native intestine has the potential to support and promote the growth of intestinal organoids. In this study, we aimed to develop hydrogels derived exclusively from intestinal extracellular matrix (ECM) or composites comprised of intestinal ECM combined with alginate that allow for greater tuning of the hydrogel properties. A novel mouse intestinal decellularization protocol was developed and the ECM characterized. Our analyses demonstrate that our protocol effectively removed cellular and nuclear content while preserving key ECM components including collagens, glycosaminoglycans, fibronectin and laminin. When the decellularized small intestine (DSI) was used to generate hydrogels, the resulting ECM showed bioactivity as demonstrated by metabolic and pro-proliferative effects on NIH 3T3 murine fibroblasts. Importantly, our novel DSI hydrogels also supported murine intestinal and colonic organoid growth similar to Matrigel® controls. These studies demonstrate that murine tissue-specific DSI hydrogels can provide a supportive environment for the culture of intestinal and colonic organoids in vitro.