Browsing by Subject "Fatty Acids, Unsaturated"
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Item Administration of Fatty Acid Emulsions to Reduce Secondary Brain Injury in Mice(2018-01-23) Rodgers, Clifford; Chowdary, Ashish; Liu, Ming-Mei; Carlson, Deborah; Wolf, Steven E.; Minei, Joseph P.; Gatson, JoshuaBACKGROUND: Mild traumatic brain injuries are the most common type of injury to the head. Seventy-five to eighty percent of all traumatic brain injuries (TBI) are considered a mild TBI, or concussions, and involve only a short interruption of mental state and consciousness. Although the FDA reports no nutrition supplements for TBI therapy and/or symptom prevention, preclinical data has suggested that omega-3 poly unsaturated fatty acid (PUFAs) treatment decreases apoptosis, inflammation, and neurodegeneration following brain trauma. In this study, we hypothesized that Smoflipid® reduces inflammation in the brain of adult mice that have suffered a mild-to-moderate brain injury. Smoflipid® is an injectable liquid emulsion solution that contains omega-3, omega-6, omega-9, and medium chain triglycerides. METHODS: In this study, mice were subjected to a moderate brain injury using the controlled skull impact device (Leica microsystems) and we administered Smoflipid® intraperitoneally at day 1 and 3 after injury. At Day 14 after injury and treatment the mouse brains were harvested, processed, and stained using immunohistochemistry for the inflammatory markers, glial fibrillary acidic protein (GFAP) and Iba1. RESULTS: In this study after TBI, within the corpus callosum (C.C.) and cerebral cortex there was a significant increase in the levels of activated microglia (Day 14 p=0.05) compared to the control animals. Treatment with Smoflipid® shortly after injury, resulted in a significant decrease in the number of active microglia within these brain regions. CONCLUSIONS: Chronic activation of microglia and heightened inflammation in the cerebral cortex/C.C. after TBI, results in cognitive decline and long-term memory deficits. As a therapeutic strategy, by targeting these pro-inflammatory cells with Smoflipid®, we hypothesize that a reduction in the activity of microglia will improve results in better neurological outcomes. More definitive studies will be conducted to test the efficacy of Smoflipid® at reducing secondary brain injury after TBI.Item Identification of Cellular Sensors for Unsaturated Fatty Acids(2013-03-04) Kim, Hyeonwoo; DeBose-Boyd, Russell A.; Scherer, Philipp; Goodman, Joel M.In mammalian cells fatty acids (FAs) are required for the synthesis of membrane phospholipid components and energy generation. However, overaccumulation of FA is toxic. Accumulation of FAs prevents their further synthesis by stabilization of Insulin-induced gene 1(Insig-1), an ER membrane protein that inhibits proteolytic activation of sterol regulatory element binding protein-1 (SREBP-1), a transcription factor that activates all genes required for FA synthesis. This regulatory reaction is stimulated by unsaturated but not saturated FAs. Unsaturated FAs stabilize Insig-1 through disrupting the interaction between Insig-1 and UBX domain-containing protein 8 (Ubxd8), which recruits p97, a protein required for degradation of endoplasmic-reticulum (ER) membrane proteins, to Insig-1. Here, we identified Ubxd8, a protein that does not contain any previously recognized domains that bind FAs, as a sensor for unsaturated FAs. In cultured cells, we demonstrated that unsaturated FAs but not saturated FAs stimulated polymerization of Ubxd8 through bimolecular fluorescence complementation (BiFC) assays. In vitro, unsaturated but not saturated FAs also stimulated polymerization of purified recombinant Ubxd8. The effect of different FAs and their derivatives on polymerization of Ubxd8 in vitro correlated with their effect on stabilization of Insig-1 in cultured cells. Ubxd8 contains 3 domains, namely ubiquitin X (UBX), ubiquitin associated (UBA) and ubiquitin associating (UAS) domain. Deletion analysis showed that UAS domain was necessary and sufficient for polymerization of the protein in response to unsaturated FAs. Point mutations in UAS domain that disrupted its interaction with unsaturated FAs in vitro also impaired the ability of full length Ubxd8 to stabilize Insig-1 in response to unsaturated FAs in cultured cells. In addition to Ubxd8, the only other protein expressed in mammalian cells that contains a UAS domain similar to that of Ubxd8 is Fas-associated factor 1 (FAF1). We showed that unsaturated FAs also specifically induced polymerization of FAF1, and this polymerization was mediated by the UAS domain. The identification of UAS domain as a motif polymerizing upon interaction with unsaturated FAs should provide more insights into cellular responses to FAs.Item Natural Products as Selective Chemotherapeutic Agents and as Chemical Probes to Understand Biological Processes(2013-09-26) Carrasco, Yazmin Paulina; Tambar, Uttam; MacMillan, John; Roth, Michael G.; Ready, Joseph M.Aware of the important role that terrestrial microbial natural products play in the discovery of therapeutics and the decrease in rate of discovery of new natural products in the pharmaceutical industry, there is an immediate need to explore novel sources of microbial natural products with biological relevance. Marine bacteria are an excellent source of bioactive metabolites. With this idea in mind our laboratory has developed new techniques to isolate >600 species of marine actinomycetes and has created a natural product fraction library from these bacterial strains. My research efforts have focused on the isolation of natural products that exhibit selective activity against a panel of tumor derived cell lines that include lung, colon, melanoma, pancreatic cancer and glioblastoma. In parallel to structure elucidation efforts of our active metabolite, the determination of its mode of action was ongoing in the laboratory of Dr. White. Through the use of a new screening tool, called FUSION (Functional Signature Ontology) we were able to determine that our active compound had similar activity to inhibitors of the TBK1 signaling pathway. Additionally, a novel polyketide was isolated from the marine-derived bacteria Salinispora arenicola, believed to be a key intermediate in the biosynthetic pathway of saliniketal, an inhibitor of ornithine decarboxylase induction. In addition, we have utilized the natural product leptomycin B (LMB), as a chemical tool to understand its inhibition of CRM1, a protein involved in export of cargo from the nucleus to the cytoplasm and a possible chemotherapeutic target. This work was done in collaboration with Dr. Chook. We observed that LMB irreversibly binds to CRM1 due to the hydrolysis of its lactone moiety causing stabilization of the protein-LMB complex. In contrast, compounds that lack the capability of being hydrolyzed by CRM1 are reversible inhibitors of CRM1. These research findings probe the question of designing molecules capable of reversibly inhibiting CRM1 and this perhaps will lead to reduced toxicity. This work illustrates the importance that natural products have not only as therapeutic agents for the treatment of diseases such as cancer but also as important chemical tools to understand complex biological processes.