Inflammatory bowel disease (IBD) is a significant risk factor in the development of colorectal cancer (CRC), a leading contributor to cancer-related deaths in the United States. Both IBD and CRC are commonly associated with the exaggerated production of inflammatory cytokines which are regulated by the activation of various cell signaling pathways including the NF-kB family of transcription factors, IL-1, COX2 and IL6. The NLR (nucleotide binding domain and leucine-rich-repeat-containing or NOD-like receptor) family of proteins has received much attention in IBD research due to their role in regulating inflammation and the genetic association of certain NLR proteins with Crohns'disease. NLR is a multi-member gene family that encodes a group of cytosolic proteins that are involved in the intracellular sensing of microbial products as well as damage-associated molecular patterns. Thus NLR family members are crucial regulators of innate immune response which is an important link to IBD and CRC. We and others have begun to show the association of the inflammasome-associated NLRs in models of experimental colitis (EC) and colitis-associated colon cancer (CAC). This group of proteins respond to pathogen derived products and can assemble into inflammasomes in conjunction with the key NLR adaptor protein, ASC (apoptotic speck containing protein with a CARD) to activate the IL-12-processing enzyme caspase-1. Caspase-1 activation then leads to the cleavage and maturation of pro- IL-12 and IL-18. In addition to the analyses of these well- studied inflammasome components in models of EC and CAC, we have data to indicate a strong role for other NLRs which have anti-inflammatory functions, and can attenuate the clinical outcome in these models. This proposal plans to examine the roles of ASC and these other NLRs in these disease models. We will further delineate the molecular mechanisms by which these proteins affect disease outcome.
Innate immune sensors or receptors are crucial for immune response during inflammatory disorders and during microbial infections. We have been studying a new family of immune sensors called NLRs, and have found that several of these play crucial roles in the control of colitis and inflammation-induced colon cancer. This proposal will explore the mechanism by which these NLRs regulate gastro-intestinal inflammation and tumorgenesis.
|Huang, Juin-Hua; Liu, Chu-Yu; Wu, Sheng-Yang et al. (2018) NLRX1 Facilitates Histoplasma capsulatum-Induced LC3-Associated Phagocytosis for Cytokine Production in Macrophages. Front Immunol 9:2761|
|Truax, Agnieszka D; Chen, Liang; Tam, Jason W et al. (2018) The Inhibitory Innate Immune Sensor NLRP12 Maintains a Threshold against Obesity by Regulating Gut Microbiota Homeostasis. Cell Host Microbe 24:364-378.e6|
|Chen, Liang; Wilson, Justin E; Koenigsknecht, Mark J et al. (2017) NLRP12 attenuates colon inflammation by maintaining colonic microbial diversity and promoting protective commensal bacterial growth. Nat Immunol 18:541-551|
|Koblansky, A Alicia; Truax, Agnieszka D; Liu, Rongrong et al. (2016) The Innate Immune Receptor NLRX1 Functions as a Tumor Suppressor by Reducing Colon Tumorigenesis and Key Tumor-Promoting Signals. Cell Rep 14:2562-75|
|Liu, Rongrong; Truax, Agnieszka D; Chen, Liang et al. (2015) Expression profile of innate immune receptors, NLRs and AIM2, in human colorectal cancer: correlation with cancer stages and inflammasome components. Oncotarget 6:33456-69|
|Koehn, Brent H; Apostolova, Petya; Haverkamp, Jessica M et al. (2015) GVHD-associated, inflammasome-mediated loss of function in adoptively transferred myeloid-derived suppressor cells. Blood 126:1621-8|
|Wilson, Justin E; Petrucelli, Alex S; Chen, Liang et al. (2015) Inflammasome-independent role of AIM2 in suppressing colon tumorigenesis via DNA-PK and Akt. Nat Med 21:906-13|
|Krauss, Jennifer L; Zeng, Rong; Hickman-Brecks, Cynthia L et al. (2015) NLRP12 provides a critical checkpoint for osteoclast differentiation. Proc Natl Acad Sci U S A 112:10455-60|
|Guo, Haitao; Callaway, Justin B; Ting, Jenny P-Y (2015) Inflammasomes: mechanism of action, role in disease, and therapeutics. Nat Med 21:677-87|
|Fang, Liang; Gong, Jiuyu; Wang, Ying et al. (2014) MICA/B expression is inhibited by unfolded protein response and associated with poor prognosis in human hepatocellular carcinoma. J Exp Clin Cancer Res 33:76|
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