The inflammatory response protects the body against infection and injury but can itself become dysregulated with deleterious consequences to the host. In recent years the inflammatory cytokine TNF-? has been clinically validated as a primary driver of several inflammatory diseases, and biopharmaceutical drugs have been marketed that block TNF-? action. These drugs, however, are effective in only a subset of patients, and can cause severe and even fatal side effects. Moreover, because they are recombinant proteins these drugs must be administered perenterally, thus requiring repeated injections. There is a continued critical need for novel anti-inflammatory drugs that possess improved efficacy/toxicity profiles, and in particular for small molecule drugs that can be taken orally. We have recently screened a small molecule compound library in an attempt to identify compounds capable of interfering with a TNF-? transcription factor that we cloned in our laboratory 12 years ago named LITAF. The screening library, comprising in part dietary supplements and established nutraceuticals, contained at least one class of natural products that displayed TNF-? suppression activity. In particular, several compounds isolated from kava root extract were found to mediate substantial reduction of TNF-? secretion in a cellular assay. Moreover, specific kava-derived compounds were found to protect mice against lethal doses of LPS or experimental periodontitis, compared to control animals. Importantly, a representative compound from this series was shown to possess promising pharmaceutical properties including oral bioavailability in rats, and a preliminary medicinal chemistry effort has identified regions on the molecule that can be modified to optimize the compound's properties. A key objective of our over-arching research program is to identify the molecular target(s) by which kava compounds elicit their biological effect, and to elucidate their mechanism of action. However the potency of the compounds must be improved to enable these goals. The present application outlines 3 Aims: First, a comprehensive medicinal chemistry approach will be taken to design, synthesize and test compounds with the goal of delivering 2-3 biochemically well- characterized and validated tool compounds optimized for potency and for in vivo exposure. Second, these optimized, kava-derived compounds will be tested in animal models of inflammation to validate them in vivo for target identification and mechanism of action studies, and to establish their potential as a new class of anti-inflammatory drugs. Third to determine the molecular target(s) in the signal transduction pathway by which kava compounds mediate LITAF inhibition of LPS-induced cytokine secretion. Our goal is the elucidation of the mechanism of action of optimized kava compounds, a step towards identifying novel anti-inflammatory compounds suitable for clinical development.
The ultimate goal of this project is to optimize the structures of a class of natural product compounds that have been implicated in the regulation of inflammatory response to find new and effective drugs. As a first step toward that goal, highly potent tool compounds developed in this project will be tested in different animal models of inflammation (including periodontal disease and rheumatoid arthritis). The results will provide a basis for the development of new compounds for treating inflammatory diseases that can be advanced into pre-clinical evaluation and ultimately in clinical trials.
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|Cai, Bin; Panek, James S; Amar, Salomon (2018) Kava analogues as agents for treatment of periodontal diseases: Synthesis and initial biological evaluation. Bioorg Med Chem Lett 28:2667-2669|
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|Tang, Xiaoren; Amar, Salomon (2016) Kavain Involvement in LPS-Induced Signaling Pathways. J Cell Biochem 117:2272-80|
|Tang, Xiaoren; Amar, Salomon (2015) p53 suppresses CCL2-induced subcutaneous tumor xenograft. Tumour Biol 36:2801-8|
|Tang, Xiaoren; Yang, Yu; Yuan, Huaiping et al. (2013) Novel transcriptional regulation of VEGF in inflammatory processes. J Cell Mol Med 17:386-97|
|Bertolo, Cristina; Roa, Sergio; Sagardoy, Ainara et al. (2013) LITAF, a BCL6 target gene, regulates autophagy in mature B-cell lymphomas. Br J Haematol 162:621-30|
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