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Therapeutic Evaluation of Fecal Microbiota Transplantation in an Interleukin 10-Deficient Mouse Model

With the development of microecology in recent years, the relationship between intestinal bacteria and inflammatory bowel disease (IBD) has attracted ...

University of texas Medical Branch at Galveston

University of Texas Medical Branch at Galveston

Early life adversity is considered a risk factor for the development of gastrointestinal diseases, including inflammatory bowel disease. We hypothesized that early life colonic inflammation causes susceptibility to aggravated overexpression of interleukin (IL)1β.

Neonatal Colonic Inflammation Epigenetically Aggravates Epithelial Inflammatory Responses to Injury in Adult Life.

Altered intestinal epithelial integrity is an important susceptibility trait in inflammatory bowel disease (IBD), and early life stressors are reported to contribute to this disease susceptibility in adulthood. To identify disease mechanisms associated with early-life trauma that exacerbate IBD in adulthood, we used a "double-hit" neonatal inflammation (NI) and adult inflammation (AI) model that exhibits more severe mucosal injury in the colon later in life. In this study, we explore the underlying mechanisms of this aggravated injury. In rats exposed to both NI and AI, we found sustained increases in colonic permeability accompanied by significantly attenuated expression of the epithelial junction protein E-cadherin. Quantitative RT-PCR revealed a decreased  (gene of E-cadherin) mRNA expression in NI + AI rats compared with NI or AI rats. Next, we performed microRNA microarrays to identify potential regulators of E-cadherin in NI + AI rats. We confirmed the overexpression of miR-155, a predicted regulator of E-cadherin, and selected it for further analysis based on reported significance in human IBD. Using ingenuity pathway analysis software, the targets and related canonical pathway of miR-155 were analyzed. Mechanistic studies identified histone hyperacetylation at the Mir155 promoter in NI + AI rats, concomitant with elevated RNA polymerase II binding. In vitro, E-cadherin knockdown markedly increased epithelial cell permeability, as did overexpression of miR-155 mimics, which significantly suppressed E-cadherin protein. In vivo, NI + AI colonic permeability was significantly reversed with administration of miR-155 inhibitor rectally. Our collective findings indicate that early-life inflammatory stressors trigger a significant and sustained epithelial injury by suppressing E-cadherin through epigenetic mechanisms.

Neonatal Injury Increases Gut Permeability by Epigenetically Suppressing E-Cadherin in Adulthood.

Ulcerative colitis and Crohn's disease are classified as chronic inflammatory bowel diseases (IBD) with known extraintestinal manifestations. The interplay between heart and gut in IBD has previously been noted, but the mechanisms remain elusive. Our objective was to identify microRNAs mediating molecular remodeling and resulting cardiac impairment in a rat model of colitis. To induce chronic colitis, dextran sodium sulfate (DSS) was given to adult rats for 5 days followed by 9 days with normal drinking water for 4 cycles over 8 weeks. Echocardiography was performed to evaluate heart function. DSS-induced colitis led to a significant decrease in ejection fraction, increased left ventricular mass and size, and elevated B-type natriuretic protein. MicroRNA profiling showed a total of 56 miRNAs significantly increased in the heart by colitis, 8 of which are predicted to target brain-derived neurotrophic factor (BDNF). RT-qPCR validated the increases of miR-1b, Let-7d, and miR-155. Transient transfection revealed that miR-155 significantly suppresses BDNF in H9c2 cells. Importantly, DSS colitis markedly decreased BDNF in both myocardium and serum. Levels of various proteins critical to cardiac homeostasis were also altered. Functional studies showed that BDNF increases cell viability and mitigates H2O2-induced oxidative damage in H9c2 cells, demonstrating its protective role in the adult heart. Mechanistically, cellular experiments identified IL-1β as the inflammatory mediator upregulating cardiac miR-155; this effect was confirmed in adult rats. Furthermore, IL-1β neutralizing antibody ameliorated the DSS-induced increase in miR-155 and concurrent decrease in BDNF in the adult heart, showing therapeutic potential. Our findings indicate that chronic colitis impairs heart function through an IL-1β→miR-155→BDNF signaling axis.

Chronic colitis upregulates microRNAs suppressing brain-derived neurotrophic factor in the adult heart.

 While the interplay between heart and gut in inflammatory bowel disease (IBD) has previously been noted, how the inflamed gut impairs heart function remain elusive. We hypothesized that exosomal miRNAs of gut origin induce cardiac remodeling in IBD. Our aim was to identify plasma exosomal miRNAs that not only are of diagnostic value but also contribute to cardiac remodeling in patients with ulcerative colitis (UC).  Plasma exosomes were isolated from UC patients and healthy control subjects and exosomal miRNAs were profiled by next-generation sequencing. Exosomal miR-29b levels in CCD841 CoN colon epithelial cells were detected by RT-qPCR. Exosomes packaged with miR-29b were incubated with H9c2 cells or administered to live mice.  The plasma exosomal miRNA profiles of the UC patients were significantly different from that of the controls and 20 miRNAs including miR-29b were differentially expressed. In CCD841 CoN cells, TNFα, IL-1β, and HO significantly elevated miR-29b in both the cells and their secreted exosomes ( < 0.01), suggesting that intestinal epithelium secrets exosomes rich in miR-29b in IBD. In H9c2 myoblast cells, miR-29b modulated multiple genes including brain-derived neurotrophic factor (BDNF). Epithelial cell-derived exosomes packaged with miR-29b also attenuated BDNF and increased cleaved caspase 3, suggestive of apoptosis. Furthermore, tail vein injection of engineered exosomes with high levels of miR-29b suppressed BDNF and augmented cleaved caspase 3 in the heart of adult mouse ( < 0.01).  Plasma exosomal miRNA profile could be a novel diagnostic approach for IBD. Excessive plasma exosomal miR-29b suppresses critical proteins like BDNF in IBD, leading to cardiac impairment.

Xiaoying S Zhong

Division of Gastroenterology,
Department of Internal Medicine,
Division of Gastroenterology, Department of Internal Medicine

University of texas Medical Branch at Galveston

Therapeutic Evaluation of Fecal Microbiota Transplantation in an Interleukin 10-Deficient Mouse Model

Xiaoying S Zhong

Division of Gastroenterology,Department of Internal Medicine,Division of Gastroenterology, Department of Internal Medicine

University of texas Medical Branch at Galveston

Therapeutic Evaluation of Fecal Microbiota Transplantation in an Interleukin 10-Deficient Mouse Model

Division of Gastroenterology,
Department of Internal Medicine,
Division of Gastroenterology, Department of Internal Medicine