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Browsing by Author "Rothschild, Daniel E."

Now showing 1 - 5 of 5
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    Enhanced Mucosal Defense and Reduced Tumor Burden in Mice with the Compromised Negative Regulator IRAK-M.
    Rothschild, Daniel E.; Zhang, Yao; Diao, Na; Lee, Christina K.; Chen, Keqiang; Caswell, Clayton C.; Slade, Daniel J.; Helm, Richard F.; LeRoith, Tanya; Li, Liwu; Allen, Irving C. (2016-12-03)
    Aberrant inflammation is a hallmark of inflammatory bowel disease (IBD) and colorectal cancer. IRAK-M is a critical negative regulator of TLR signaling and overzealous inflammation. Here we utilize data from human studies and Irak-m(-/-) mice to elucidate the role of IRAK-M in the modulation of gastrointestinal immune system homeostasis. In human patients, IRAK-M expression is up-regulated during IBD and colorectal cancer. Further functional studies in mice revealed that Irak-m(-/-) animals are protected against colitis and colitis associated tumorigenesis. Mechanistically, our data revealed that the gastrointestinal immune system of Irak-m(-/-) mice is highly efficient at eliminating microbial translocation following epithelial barrier damage. This attenuation of pathogenesis is associated with expanded areas of gastrointestinal associated lymphoid tissue (GALT), increased neutrophil migration, and enhanced T-cell recruitment. Further evaluation of Irak-m(-/-) mice revealed a splice variant that robustly activates NF-κB signaling. Together, these data identify IRAK-M as a potential target for future therapeutic intervention.
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    Negative Regulation of Inflammation: Implications for Inflammatory Bowel Disease and Colitis Associated Cancer
    Rothschild, Daniel E. (Virginia Tech, 2018)
    The ability to sense and respond to external environmental signals is closely regulated by a plurality of cell signaling pathways, thereby maintaining homeostasis. In particular, the inflammatory signaling cascade contributes to cellular homeostasis and regulates responses prompted by external stimuli. Such responses are diverse and range from a variety of processes, including tissue repair, cell fate decisions, and even immune-cell signaling. As with any signaling cascade, strict regulation is required for proper functioning, as abnormalities within the pathway are often associated with pathologic outcomes. A hyperactive inflammatory response within the gastrointestinal tract, for example, contributes to inflammatory bowel disease (IBD), presenting as Crohn’s disease or ulcerative colitis. Furthermore, as a chronic condition, IBD is associated with an increased risk for the development of colitis-associated cancer. In order to resolve inflammation and thus restore homeostasis, negative regulation may be utilized to mediate the activity of inflammatory molecules. The mechanistic action of a specific negative regulator of interest, interleukin receptor associated kinase M (IRAK- M), is explored in detail within the present dissertation. Investigation of IRAK-M in mouse models of colitis, which mimics human IBD, and in mouse models of inflammation-driven tumorigenesis, which models colitis associated cancer, demonstrated that loss of this molecule contributes to host protection. Therefore, IRAK- M may be a suitable target for inhibition in order to advance therapeutic options for human patients afflicted with a GI-related inflammatory disease, such as IBD and colitis associated cancer. Furthermore, an ex vivo method that models the interaction of intestinal epithelial cells with microbes present in the GI tract was optimized and is described in the present dissertation. This method takes advantage of primary intestinal derived organoids, also termed “mini-guts”, which display similar features corresponding to intestinal tissue in vivo. For this reason, the use of “mini-guts” has several advantages, particularly for the enhancement of personalized medicine. The method discussed herein aims to normalize experimental conditions in order to enhance reproducibility, which can further be used to uncover microbial-epithelial interactions that contribute to a pathological state, such as IBD. Finally, this method of intestinal epithelial cell culture was utilized to evaluate the role of a protein, termed NF-κB inducing kinase (NIK), in intestinal epithelial cell growth and proliferation. Ultimately, ex vivo organoid culture can serve as an important model system to study the contribution of NIK in intestinal stem cell renewal, cancer progression, as well as in maintenance of the integrity of the gastrointestinal barrier.
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    NF-κB Inducing Kinase Attenuates Colorectal Cancer by Regulating Noncanonical NF-κB Mediated Colonic Epithelial Cell Q1 Regeneration
    Morrison, Holly A.; Eden, Kristin; Trusiano, Brie; Rothschild, Daniel E.; Qin, Yufeng; Wade, Paul A.; Rowe, Audrey J.; Mounzer, Christina; Stephens, Morgan C.; Hanson, Katherine M.; Brown, Stephan L.; Holl, Eda K.; Allen, Irving C. (Elsevier, 2024-06)
    BACKGROUND & AIMS: Dysregulated colonic epithelial cell (CEC) proliferation is a critical feature in the development of colorectal cancer. We show that NF-𝜅B-inducing kinase (NIK) attenuates colorectal cancer through coordinating CEC regeneration/ differentiation via noncanonical NF-𝜅B signaling that is unique from canonical NF-𝜅B signaling. METHODS: Initial studies evaluated crypt morphology/functionality, organoid generation, transcriptome profiles, and the microbiome. Inflammation and inflammation-induced tumorigenesis were initiated in whole-body NIK knockout mice (Nik⁻/⁻) and conditional-knockout mice following administration of azoxymethane and dextran sulfate sodium. RESULTS: Human transcriptomic data revealed dysregulated noncanonical NF-𝜅B signaling. In vitro studies evaluating Nik⁻/⁻ crypts and organoids derived from mature, nondividing CECs, and colonic stem cells exhibited increased accumulation and stunted growth, respectively. Transcriptomic analysis of Nik⁻/⁻ cells revealed gene expression signatures associated with altered differentiation-regeneration. When assessed in vivo, Nik⁻/⁻ mice exhibited more severe colitis with dextran sulfate sodium administration and an altered microbiome characterized by increased colitogenic microbiota. In the inflammationinduced tumorigenesis model, we observed both increased tumor burdens and inflammation in mice where NIK is knocked out in CECs (NikΔCEC). Interestingly, this was not recapitulated when NIK was conditionally knocked out in myeloid cells (NikΔMYE). Surprisingly, conditional knockout of the canonical pathway in myeloid cells (RelAΔMYE) revealed decreased tumor burden and inflammation and no significant changes when conditionally knocked out in CECs (RelAΔCEC) CONCLUSIONS: Dysregulated noncanonical NF-𝜅B signaling is associated with the development of colorectal cancer in a tissue-dependent manner and defines a critical role for NIK in regulating gastrointestinal inflammation and regeneration associated with colorectal cancer.
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    Noncanonical NF-κB signaling and the essential kinase NIK modulate crucial features associated with eosinophilic esophagitis pathogenesis
    Eden, Kristin; Rothschild, Daniel E.; McDaniel, Dylan K.; Heid, Bettina; Allen, Irving C. (The Company of Biologists, 2017)
    Eosinophilic esophagitis (EoE) is an allergic disease of the esophagus driven by T cell and eosinophil responses to dietary allergens, resulting in chronic mucosal inflammation. Few spontaneous animal models of esophageal eosinophilia exist, with most studies relying on artificial sensitization procedures. NF-κBinducing kinase (NIK; MAP3K14) is a key signaling molecule of the noncanonical NF-κB (NFKB1) pathway, an alternative signaling cascade producing chemokines involved in lymphoid stroma development and leukocyte trafficking. Nik−/− mice have been shown to develop a hypereosinophilic syndrome in peripheral blood and major filtering organs; however, the gastrointestinal mucosa of these mice has not been well characterized. We show that Nik−/− mice develop significant, localized eosinophilic esophagitis that mimics human EoE, including features such as severe eosinophil accumulation, degranulation, mucosal thickening, fibrosis and basal cell hyperplasia. The remainder of the GI tract, including the caudal stomach, small intestine and colon, in mice with active EoE are unaffected, also similar to human patients. Gene expression patterns in esophageal tissue of Nik−/− mice mimics human EoE, with thymic stromal lymphopoetin (TSLP) in particular also elevated at the protein level. In gene expression data sets from human biopsy specimens, we further show that many genes associated with noncanonical NF- κB signaling are significantly dysregulated in EoE patients, most notably a paradoxical upregulation of NIK itself with concurrent upregulation of powerful protein-level destabilizers of NIK. These findings suggest that Nik−/− mice could be useful as a spontaneous model of specific features of EoE and highlight a novel role for noncanonical NF-κB signaling in human patients.
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    Nonessential Role for the NLRP1 Inflammasome Complex in a Murine Model of Traumatic Brain Injury
    Brickler, Thomas; Gresham, Kisha; Meza, Armand; Coutermarsh-Ott, Sheryl; Williams, Tere M.; Rothschild, Daniel E.; Allen, Irving C.; Theus, Michelle H. (Hindawi, 2016-01-01)
    Traumatic brain injury (TBI) elicits the immediate production of proinflammatory cytokines which participate in regulating the immune response. While the mechanisms of adaptive immunity in secondary injury are well characterized, the role of the innate response is unclear. Recently, the NLR inflammasome has been shown to become activated following TBI, causing processing and release of interleukin-1β (IL-1β). The inflammasome is a multiprotein complex consisting of nucleotide-binding domain and leucine-rich repeat containing proteins (NLR), caspase-1, and apoptosis-associated speck-like protein (ASC). ASC is upregulated after TBI and is critical in coupling the proteins during complex formation resulting in IL-1β cleavage. To directly test whether inflammasome activation contributes to acute TBI-induced damage, we assessed IL-1β, IL-18, and IL-6 expression, contusion volume, hippocampal cell death, and motor behavior recovery in Nlrp1−/−, Asc−/−, and wild type mice after moderate controlled cortical impact (CCI) injury. Although IL-1β expression is significantly attenuated in the cortex of Nlrp1−/− and Asc−/− mice following CCI injury, no difference in motor recovery, cell death, or contusion volume is observed compared to wild type. These findings indicate that inflammasome activation does not significantly contribute to acute neural injury in the murine model of moderate CCI injury.