Department Of Biochemistry And Microbial Sciences
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Item Naphthylisoindolinone alkaloids: the first ring-contracted naphthylisoquinolines, from the tropical liana Ancistrocladus abbreviatus, with cytotoxic activity(Royal Society of Chemistry, 2022-10-12T00:00:00) Fayez, Shaimaa; Bruhn, Torsten; Feineis, Doris; Assi, Laurent Ak�; Kushwaha, Prem Prakash; Kumar, Shashank; Bringmann, GerhardThe West African liana Ancistrocladus abbreviatus is a rich source of structurally most diverse naphthylisoquinoline alkaloids. From its roots, a series of four novel representatives, named ancistrobrevolines A-D (14-17) have now been isolated, displaying an unprecedented heterocyclic ring system, where the usual isoquinoline entity is replaced by a ring-contracted isoindolinone part. Their constitutions were elucidated by 1D and 2D NMR and HR-ESI-MS. The absolute configurations at the chiral axis and at the stereogenic center were assigned by using experimental and computational electronic circular dichroism (ECD) investigations and a ruthenium-mediated oxidative degradation, respectively. For the biosynthetic origin of the isoindolinones from �normal� naphthyltetrahydroisoquinolines, a hypothetic pathway is presented. It involves oxidative decarboxylation steps leading to a ring contraction by a benzilic acid rearrangement. Ancistrobrevolines A (14) and B (15) were found to display moderate cytotoxic effects (up to 72%) against MCF-7 breast and A549 lung cancer cells and to reduce the formation of spheroids (mammospheres) in the breast cancer cell line. � 2022 The Royal Society of Chemistry.Item Nischarin inhibition alters energy metabolism by activating AMP-activated protein kinase(American Society for Biochemistry and Molecular Biology Inc., 2017) Dong, Shengli; Baranwal, Somesh; Garcia, Anapatricia; Serrano-Gomez, Silvia; Eastlack, Steven; Iwakuma, Tomoo; Mercante, Donald; Mauvais-Jarvis, Franck; Alahari, Suresh K.; Dong, S.; Baranwal, S.; Garcia, A.; Serrano-Gomez, S.J.; Eastlack, S.; Iwakuma, T.; Mercante, D.; Mauvais-Jarvis, F.; Alahari, S.K.Nischarin (Nisch) is a key protein functioning as a molecular scaffold and thereby hosting interactions with several protein partners. To explore the physiological importance of Nisch, here we generated Nisch loss-of-function mutant mice and analyzed their metabolic phenotype. Nisch-mutant embryos exhibited delayed development, characterized by small size and attenuated weight gain. We uncovered the reason for this phenotype by showing that Nisch binds to and inhibits the activity of AMP-activated protein kinase (AMPK), which regulates energy homeostasis by suppressing anabolic and activating catabolic processes. The Nisch mutations enhanced AMPK activation and inhibited mechanistic target of rapamycin signaling in mouse embryonic fibroblasts as well as in muscle and liver tissues of mutant mice. Nisch-mutant mice also exhibited increased rates of glucose oxidation with increased energy expenditure, despite reduced overall food intake. Moreover, the Nisch-mutant mice had reduced expression of liver markers of gluconeogenesis associated with increased glucose tolerance. As a result, these mice displayed decreased growth and body weight. Taken together, our results indicate that Nisch is an important AMPK inhibitor and a critical regulator of energy homeostasis, including lipid and glucose metabolism. ? 2017 by The American Society for Biochemistry and Molecular Biology, Inc.